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Thread: Shorted wire help (alternator or ecu issue)

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    Shorted wire help (alternator or ecu issue)

    During my hookup of the electrical system I managed to supply direct power right into my main ground terminal box for about 10 seconds just enough to completely fry the ground wire of the switch that I was connecting to power.

    I checked all the fuses and nothing looked blown (I will check again by pulling each out as I had only done a visual check from the top of each to see if there was a gap in the fuse). So I was able to turn the car over and it ran so I thought I was in the clear without any damage, however, when I tried to turn it over the next day both the emergency brake like and battery light stayed lit once the car was running and a code of P0230 (fuel pump controller) was appearing. As well the dash lights had dimmed once the car had started, which is odd because they were brighter before starting the car.

    The P0230 code says that the fuel pump controller experienced a voltage drop or insufficient voltage and I have cleared that code without it returning.

    The battery light and emergency brake light google tells me is a result of alternator issues and I may have fried the diodes or voltage regulator in the alternator. To determine if the diodes were fried I used a voltmeter turned to a low AC voltage and I checked the battery while the car while it was off for a baseline and it indicated an AC voltage across the battery of 0.1V and then again with the car running it came back as 0.22V... so I assumed my diodes were shot as I was seeing an AC voltage difference when really there shouldnít have been any change.

    I also noticed that while trialing my car it would randomly stall out and take a while for it to turn back on (cranking pumping the gas etc) I did have some stalling issues before from not having a proper tune yet but the car would fire right up again after it would stall. Now when it stalls I am fighting with the gas pedal and cranking it for a while before it fires. Not sure if this makes a difference but

    So now I have replaced my alternator and the good news is the emergency brake light on the dash has now gone out but the battery light is still lit and the dash lights are still dim.

    I am wondering if I have somehow fried the voltage regulator within the ECU itself... is there even a voltage regulator in the ecu? Or what else would cause some of these symptoms? I am pretty certain the fuel controller isnít fried because it still primes the pump and the car does run, that goes for the ecu as well as the car does idle and run but I am not sure if the voltage controller is a separate component within the ECU?

    I am at a loss of what the next step would be as I donít know if I should just be replacing the components that may be fried (ecu or fuel pump controller) without know what the real problem is as it might just fry another ecu or controller.

    Any help or suggestions are greatly appreciated as I am not the most electrical savvy person.

    Thanks
    Ian

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    Senior Member STiPWRD's Avatar
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    So the issues you're having are:
    1. Car is tough to start
    2. Battery light is on
    3. Dash lights are dim
    ?
    Here are a few things that come to mind:
    I would check the battery - is it old? What voltage does it read with ignition off, on, and engine running? Is there corrosion on the terminals preventing a good connection? Are your spark plugs new?

    Do you have a fuel pressure gauge? This would help troubleshoot if you're controller and pump are supplying the right fuel pressure. Also, you could try data logging your injector duty cycle.

    I don't believe the ECU has an internal voltage regulator. It runs off of 12V from 2 or 3 fused wires. But ECU's are relatively cheap if you wanted to swap in another one, I see several on ebay from $55 to $100.

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    Hi Stiwrd thanks for the reply

    **i should mention that I did have the car running properly before I shorted a wire with no battery light or emergency brake light displayed, or a P0230 code

    1. Actually the car will fire right up on second crank, however, it seems to stall and once it has stalled it becomes more difficult to start afterwards.
    2. The battery light is on and I am wondering if that battery light can indicate a poor battery or just no charging/bad alternator? The battery voltage sits around 12v and it is about 5 years old but was perfectly operable prior to me shouting out that wire. It does charge at 14 volts as well indicating the alternator is working
    3. The dash lights dim once the car is running, which is ironic because I would assume they would be brighter with the alternator power than the battery power.

    I do have a spare ecu but I am wondering if my I initial short of a wire has caused another short and would cause me to potentially fry the new ecu I put in place? From your response The ecu should be protected from the power side by fuses but I am wondering what happens to it when I have supplied the ground terminal power. I also have a fuel pressure gauge and can watch that to see if it drops, thanks for the tip.
    .
    Last edited by iblackwe; 07-24-2018 at 06:35 PM.

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    Senior Member Just puttering's Avatar
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    Disconnect the alt or regulator and check the ac volts again. See if it changes?

    Dash lights should be powered just from the bat. I think after you start the car and the key goes to run, something is pulling the voltage down that dims the lights?

    Also, a picture of the ground you fried.

    If you jumpered 12v to ground you missed the other fuses. Only the circuit with the switch and the ground should be effected.
    You may have an open ground that is causing you grief?
    Mk3.1 347 AFR 205cc Race Heads EFI siemens deca 60lb injectors MSD 6AL ignition Vortech V-3 3 Link PS/PB

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    Unclear exactly what you connected to where. This will make a difference. What were you trying to connect? A switch to run what? And "main ground terminal box"? Without more specific info, we're just guessing.

    I've always told my customers that guessing isnt fair to your wallet or my reputation. Let's prove what's wrong.

  6. #6

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    Brad gives the best questions and advice I think. But some comments ahead of your answers to Brad -

    About ECU regulators - The ECU does have a 5V regulator (maybe even two) that outputs pretty accurate +5V to a number of the sensors. This gives the sensors a tight voltage supply that doesn't vary when the battery/12V circuits move around between weak battery (say about +10.5V), charging (about +11.5 to 13.5V), full charge (typically +14.5V). The ECU and it's sensors need a good reference to be accurate in measuring engine conditions - and a varying battery voltage doesn't provide that, so regulating down at +5V takes care of that (and +5V is a long standing favorite in many sensor designs automotive or otherwise). BUT that said, if the ECU's 5V internal regulator was damaged, the sensors might not behave well enough for your engine to run well at all. The sensor inputs back to the ECU can then be referenced to the +5V inside the ECU for accurate measuring of the inbound info. If the engine runs, and does so fairly well (tune in question though) the ECU is low on your list to worry about. Of course until you find the problem, you don't know 100%. Get on one or another of the engine sensors - temp sensor for example (or whatever is easy to get at first) and check the supply pin to ground - expect real close to +5 (verify in the wiring diagram of course). ECU should put that +5V out any time it has ignition on - engine not needed to be running.

    If you do check +5V with igntion on and engine not running, check it again with engine running - should be almost exactly the same, maybe drop I suppose a tiny bit, but I don't have background on this. Given your dash dims, if I saw +5V drop to say +4.95 or even +4.9 I'd say probably ok, but +4.5V for example or lower = some sensor or wiring problem is pulling the regulated voltage down = problem to find.

    Once you go through the more typical inspections, tests, etc. that the guys have mentioned, if you are still stumped, I'd bet you have fried a wire or connector (maybe more than one). Try this route -

    Going back to what you said happened - I understand that you tied +12V battery wiring to a block or group of grounds. That is either a block you put together, or maybe you are referring to the sensor ground group that is part of the ECU wiring? Regardless, if you had +12V on there for 10 seconds, I'd expect you did burn open either one or more wires, or cooked a push on terminal in a connector, or toasted a crimped wire in a spade lug - that sort of thing. The end result of this is often a wire that may connect when cold (albeit poorly) but as it warms up with electric current flowing through it, it loses connectivity (often a result from it getting hot). It cools off and works better again - i.e. car runs better. Dim dashboard - suggests a similar possibility - poor ground due to wiring or connector that got fried. Get your volt-ohm-meter on lowest ohms range and try to check the various ground wires coming in-out of that ground block you mentioned - see if you can find one that reads any resistance other than right at zero ohms. Visible inspection of the wires in that block must include all along their length - looking for odd appearance in the insulation, discolorations, and pull the connectors they go through and inspect the male and female pins and the plastic shells for those wires - looking for discoloration.

    About connectors - over-current through wiring that has connectors - often results in the connector being the damaged part. Depending on the connector design, contacts in the connector, especially when aged, are often more susceptible to failing when subjected to higher than design current (or even within design but on the high end). This is challenging because a "cooked" connector may deteriorate such that it is very hard to disconnect - either the contacts are burned together (and yet not connecting electrically very well now), and/or the plastic shell parts get melted together. Usually if you can get to the ends of the connector pair and look closely you'll see the wire entry and shell body opening for the wire that got hot - just looks a little different than the others around it. Need good light and look carefully. You may find the problem by snooping with your eyes if you get in the right place.

    Spent my life chasing medical, industrial and consumer electronics problems. I troubleshoot both by looking through the circuits with instruments, checking voltages and signals that should be good - trying to find what is not as it should be. But also by visual inspection in areas that might be suspect, and depending on the problem of course, I find that in probably 30% of the things I chase out, I can spot physical evidence as fast or faster than using test equipment and chasing signals and wiring continuity. One thing visible inspections give you - you don't have to be an electrical/electronics wizard to find things - if you can spot visible damage, but to test electrically you do have to have understanding how to split up circuits and chase the problem with instruments. Every chase is different though and that is just how my luck has run.
    Last edited by aquillen; 07-24-2018 at 10:42 PM.
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    Thanks for the advice everyone. To be more clear on the grounding box I have made a terminal for any grounds that occurr from the front end of the harness, but nothing for the harness in the engine bay as I have left that one untouched.

    Some good news and some bad news: the good: I had to replace my alternator yet again due to the brushes hitting the commutator in an uneven fashion causing a loud clang each rotation. With the newest alternator both the battery and emergency brake light went out! So even the last new alternator might have had issues.

    However I took aquilins advice and measured bolts through the system:
    Speed sensor: 4.79v off and 4.81v running
    MAF: 4.79v off
    Throttle position sensor: 5.04v off
    IAT: 5.04v off

    There is a difference in voltage between the two components which should have the same power source. I don’t know if cable length and ground quality would make up that 0.25v or not? So I am thinking I still have a short somewhere that I don’t yet know about. I did another visual inspection of the wires at my grounding terminal and none of them seem to be fried or damage or even show signs of melting. I think what might have happened is the ground terminal I have made is directly connected to the car battery via a ground cable and it’s a 8 gauge wire so I am assuming when I put power through the ground it travelled the path of least resistance to the battery and that might explain the short circuit frying my alternator internals which is directly connected to the battery.

    Let me know what you guys think though on the difference in voltage between sensors.

    Thanks again for the advice wouldn’t have been able to trouble shoot it otherwise

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    1) Is your code gone?
    2) Your ground terminal, was it grounded, or just bundled when you fed it power?
    3) We're the grounds on the engine grounded at the time?
    4) Year & model of your engine harness?

    What you are seeing between the different sensors' reference voltage is called drop. 5.?? volts comes from the ECU, but will drop as it encounters resistance. (the ?? is because this is not that precise) You may have corrosion in a splice. You may have two different reference voltage feeds. Give me #4 and I'll look over a schematic.

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    Hi Brad,

    The code is infact gone, once I cleared it the first time it hasn’t shown up again

    The ground block was grounded via the negative battery cable and frame

    Yes the grounds on the engine were grounded at the same time

    2003 wrx wiring diagram

    Okay sounds good thanks for taking a look at this much appreciated!

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    According to the schematic, these are 12v sensors. The have a 12v feed, a ground circuit, and the signal wire. You may see voltage on the signal wire even if the sensor is disconnected. Reason being is the ECU uses a bias voltage to read the signal (basically opposing voltage)

    Have you tried it since the alternator replacement? At this point I cannot say what you are seeing is actually a problem.

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    Senior Member STiPWRD's Avatar
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    Ian, did all of the electrical problems go away once you replaced the alternator? Is the only thing you're still trouble shooting the difference in voltage between some of the sensors? You should be able to trace each of the pins running from the sensors to the ECU. For instance, the MAF has 4 wires that eventually make their way to the ECU and one wire to the shielded ground. Measure voltage at the MAF and at the ECU at each of those pins to see if the voltage drop occurs in the wiring in between. The speed sensor only has 1 wire that runs to the ECU - measure voltage at the sensor and at the ECU.

    I'm using an 02 wrx harness and ECU and I believe the wiring is nearly identical to the 03. I can verify that the TPS sensor runs off of 5V coming from the ECU because I remember troubleshooting it at some point. The sensor is just a variable resistor that outputs a signal voltage (Vo) based on position like so:
    sensor.jpg

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    32F11FF5-6B51-443D-916F-EFB7CE5A5DCB.jpeg402F5A73-9BE8-486B-B6A8-AC8D8B3C7529.jpeg


    Hi stiwrd

    Unfortunately no. I thought they had but low and behold when running the car at night you can see that the battery light is still lit up but so faint. I was wondering what this means? If it’s not as bright running as it is when it’s not running does that mean that I potentially have a faulty resistor, switch or something within the cluster/combination meter? I had put a 2004 cluster in and I actually had replaced every bulb in that cluster with blue leds lights and although I never had this issue before I am wondering if it’s too low of a resistance to provide the alternator switch to activate the charging system (see diagram). I have measured the battery and it is charging though while the car is running. So I tested this with another combination meter (the original 2003 one) where I haven’t replaced that battery light bulb and it goes out fully with the car running so that almost leads me to believe that there is a short within the 2004 combination meter I was using.

    Another issue is when the car stalls/shuts off. I thought it was an improper tune but I now believe it has to do with my aquamist water meth system and fuel pump controller. What I believe happens is the fuel pump controller shorts out through my water meth level tank sensor, I’ll explain.

    The level sensor in the water meth tank is normally an open circuit when full(it’s full right now). When it’s empty it’s a closed circuit and essentially shorts it’s self to communicate that to the controller box and it shuts the system down and puts the ecu into a limp mode. What I noticed is when the car stalls my water meth system also shuts down and even when I am able to start the car again The unit doesn’t power up and still considers the water level empty (would be considered a closed circuit and this shorting itself) then when I disconnect the level detector permanently creating an open circuit and thus tricking the system to think it is full, removing that grounding opportunity, the unit powers right up. Should also point out that when I have the level sensor disconnected I have yet to have the car stall out on me. Another thing I noticed is as soon as the car stalls I try to turn the key right away and I don’t hear a fuel pump priming, I don’t know if that’s a function of residual fuel pressure in which the system doesn’t need to prime itself but I find that fishy because I don’t remember there being a pressure sensor to dictate that and if I wait a few seconds and then turn the key the pump turns on to prime the system. So somehow the two are connected and I have yet to determine the exact timing but I am almost certain the water meth shuts down because the tank level sensor has shorted (Maybe but not likely from the sensor itself) and thus somehow shorts my fuel pump controller and then I have no fuel pressure and it stalls. The fuel pump controller and water meth share a common ground at a terminal block at the back of the car near my firewall and that is all. (I have attached the wiring diagram for the water meth system too as there is a relay to enable the pump mechanism for the water meth which is the only way I can see it getting power)

    On a side note I have also read that the water meth sensor can be affected by magnetic currents, such as a pump etc. this may also be the case as I have my electronic coolant pump for my motor mounted less than a foot away. But even if it were to trigger the level sensor as a closed circuit and short the system why would it somehow send power through the ground to short my fuel pump controller (or something like that). Could a faulty relay do that? There is a fuse on that relay and it is not blown.

    So then the final question is, are these two issues connected or related in anyway?

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    Okay, for the charge light, there's definitely something up with the 04 combination meter. Did you run it with the led's in it BEFORE the incident? The light is turned off by opposing voltage, but is designed to have a bulb. An led might act improperly in this application. Try putting the bulb back in the batt indicator of the 04 meter and see if it goes out.
    As for the stalling, are you losing spark or fuel to cause the stall?

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    Hi Brad,

    What do you mean by opposing voltage? Is that equivalent to shorting it out? I had the LED’s in there before the incident without issue. I have yet to determine what Is shorting out to cause the motor to stall yet but I still think it’s fuel because I did have a P0230 code when the problem first started and that was eluding to the fuel controller not having the correct voltage

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    Either spark or fuel is going away, establishing which one is essential at this point. We can't depend on anything being solid right now.
    When it stalls, does kind of sputter down and die, or does it just quit like it was shut off? Fuel issues typically sputter down as pressure drops, ignition will usually just quit in a blink.

    Opposing voltage is with key on, engine off the charge light has a path to ground through the alternator allowing it to come on. When the alternator begins charging, this ground path becomes battery positive, cancelling out the path to ground and turning the light out. LED's are MUCH more sensitive to current flow, even tiny amounts will cause them to light up where the same current in a bulb would do nothing.
    Last edited by Brad Smith; 07-30-2018 at 02:32 PM.

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    Okay it is definitely fuel then because you can hear it slow and then die, likely as fuel pressure dies off as you indicated. I am pretty sure somehow the fuel pressure controller is connected to the water meth system or it’s somehow relate to that grounding process and them both being shorted somehow over time as something heats up as you mentioned. Because they both don’t fail right away so there has to be a cause. I am wondering how that relay indicated in that water meth system might be related to that? Or is that even possible?

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    It could be starving the controller of it's ground. Make SURE the ground they share is solid. Hook a test light between the shared ground and battery negative, then trip the Meth system and see if the test light illuminates.

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    Yea I can definitely hook the controller and the water meth up to separate grounds to see if that makes a difference. Would that explain why they may be receiving a ground and after a while that ground somehow heats up and fails?

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    Yes, the ground could be a restriction. Sometimes resistance only happens with current flow, what's called "hot" resistance. Take a light bulb. Check its resistance with an ohmmeter, it will say 0.0 ohms. But if theres no resistance, how does it not blow fuses? The resistance comes as the filament heats up. Something similar could be happening here.

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    This issue sounds very similar to my intake manifold ground connection because I powder coated the manifold and the phonelic spacer under the intake to the head. I added ground wires from the negative battery cable at the engine block and ran to the intake manifold. Intake grounds were re cleaned. The resistance check to the from the dash to the intake to the negative battery terminal showed a huge resistance.
    Hereís the original post!
    https://thefactoryfiveforum.com/show...-and-poor-idle

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    Thanks for the input guys. I actually have done the same thing with painting the intake and installing phenolic spacers between the intake and heads so I am definitely going to try ground the heads to the main ground strap as the engine. I am not sure if that will solve my problem or not but I definitely think it might be contributing. I am also going to wire separate grounds for the fuel controller and water meth system to see if that helps at all and I’ll get back to you guys.

    Thanks again for the input and ideas, definitely would have never thought of the phenolic spacer causing issues
    Ian

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    Okay I have some theories and pictures to help diagnose this. So I grounded the intake manifold with an 8 gauge wire to the main engine ground where the starter mounts so that should solve that problem if any. I have also replaced the entire gauge cluster set as I was still seeing that faint battery light with the led lights in the 2004 cluster. The first picture I posted is the ground block on the backside of my firewall. That blue wire is a grounding wire that travels through the console to the main grounding block I have at the front of the car and also unfortunately where i shorted the wire in the first place. So there is very little doubt I sent the wrong current through this wire into my rear grounding block which is where there are the components that isnaren't working correctly now. Both my water meth and fuel pump/fuel controller ground to that terminal block. So I am thinking I should just reground everything from that terminal block directly to the frame or a different grounding wire that isn't connected to the original one that fried. Why I think the water meth level sensor cuts out is that the terminal block at back isn't providing enough grounding for the fuel pump/controller and water meth now (Somehow, which may be related to that blue grounding wire running to the front) and it heats up, like Brad indicated, and then stops providing the proper grounding for the components. Its odd though because the water meth level sensor seems to ground out or fail and once I get the car started and running again the unit doesn't come back on as the water level sensor essentially is still "grounded" or closed loop to shut down the system to indicate a low water level. I am wondering if there is a possibility I fried the relay associated with the water meth system and if that could cause any of those issues as well?

    Thanks for the advice,
    IanIMG_0838.jpgIMG_0839.jpg

  24. #23
    Senior Member STiPWRD's Avatar
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    Are you running an aftermarket fuel pump? If so, these typically draw more current than the stock unit and may need thicker wiring for the power and ground. I would just run your ground wires into the chassis where possible. I don't really see the point of running a ground wire through the console to the front of the car when the frame can easily carry those electrons for you. Also, it seems your issues stem from the water meth system - I'd focus the trouble shooting on that or just consider removing it. Sorry, I'm only anecdotally familiar with these types of systems.

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    Yea I am running an aftermarket fuel pump, so that could be the issue But it didn’t have that issue prior to me shorting the the wire so I am suspect as to it now being an issue of an undersized pump ground. No problem, I realize that not many go the water meth route for good reason... they are sometimes complex. I don’t know for sure the water meth is causing the issue because initially when the car is turned on it works perfectly and also had worked perfectly before the short. But what I think might be a part of the problem is that blue wire that supplies the ground from the front might have got some damage that’s not visible from the outside and isn’t supplying enough ground and then the system hunts for a ground and finds a short through the water meth level sensor which would be a closed circuit with ground supplied and why the unit shuts down. However that doesn’t explain why the fuel pump shuts down. Once I start the car again after it has stalled the water meth unit won’t come on because it still sees a closed circuit on the level sensor, so once I disconnect that level sensor, even while the car is running all of a sudden the unit turns back on and the short is gone. So I think it has to do with something finding a ground through that system. I will test that theory by isolating and removing the water meth from one of my tests to see if the problem still arises and if it doesn’t then it could even be a faulty level sensor shorting the system.

    Thanks again for the advice, if there is any other advice or see something wrong with my logic please let me know and when I get a chance to diagnose the system a bit more I will keep you updated

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    https://photos.app.goo.gl/DShfZTQK2xuxtrSdA

    Okay so I have found out why the car is stalling, it seems to be that the fuel pump quits and car stalls from lack of fuel (video is oftge fuel pressure gauge dropping. So it is either the fuel pump controller, fuel pump relay or the fuel pump. I am thinking it is the fuel pump controller as it was grounded on the same block I had the blue wire running to that shorted. The water meth was also grounded to that block with the fuel pump controller and after I had moved all the grounds to a different location and ground them to the frame the water meth unit doesn’t shut down after the car stalls so I think there was a short running through that from the fuel pump controller. Does the fuel pump relay run through the ecu and then to the fuel pump controller? Or is there a connection between the two that could also be faulty? Does anyone know how to test the fuel pump controller? There wasn’t anything in the diagnostics section of the wiring manual that I could find.

    Has anyone just bypasses the fuel pump controller and ran the fuel pump 100% of the time?

    Thanks for the advice

  27. #26
    Senior Member STiPWRD's Avatar
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    The fuel pump relay provides power to the fuel controller via a black-yellow wire. You could try measuring the voltage at this BY wire at the moment you lose fuel pressure to see if the relay cuts power. This relay is independent of the ECU:
    fuel pump relay.jpg
    You can test the fuel pump controller by hooking up 12 VDC to the BY (black-yellow) wire, ground the B (black) wire and providing a 0-5V signal to the VW (violet-white) wire. Then just hook up a load such as a 12V fan to the BW (black-white) and BOr (black-orange) wires. These two wires will put out a modulated 12V output with 3 different duty cycles - 33%, 66%, and 100% as you adjust the voltage going to the VW wire.

    You could also bypass the fuel controller altogether by running a thick gauge wire from the battery directly to the fuel pump. Some builders have done this but it will mess with the fuel pressure at low load (such as idle) because there may be more fuel pressure than the injectors and ECU are used to. It definitely helps that you have an aftermarket fuel pressure regulator but just be aware that the car will likely need to be retuned from the extra fuel pressure. It should still run but will idle rich.

    In your video, what causes the loss of fuel pressure? You're just reving the gas?

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    Okay I’ll test the relay to make sure that works and then I’ll monitor the power going trough to the fuel pump controller before it dies. With that test you mentioned i wonder if the fan would draw enough current to get it hot enough to quit? Actually that was just idling, when it started burping is when I hit the gas pedal a bit to see if I could keep it going and it wouldn’t, so the initial drop I am assuming is when the fuel pump controller or relay failed or short circuited.

    I have also read on the forum somewhere that walbro pumps are grounded through the external casing, is that correct? I wonder if that might be causing the short, I have to remove it from the tank to seal it better anyway so I will take a look while I am in there

    Thanks again for the continued advice, it definitely helps to bounce ideas off another builder

  29. #28
    Senior Member STiPWRD's Avatar
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    So it idles for a few seconds and then just all the sudden fuel pressure drops and the engine quits? Are you sure you have enough fuel in the tank?

    I don't have a walbro but you can measure whether the case is grounded by checking continuity from (-) to the case. Glad to help anyway I can.

  30. #29
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    Actually it runs for about 5 minutes and then dies, not super consistent either, it ran for a bit longer a previous time I had it going. I definitely have enough fuel in the tank, and it will start again after stalls. Before when I had the water meth grounded to the same terminal I think it would somehow use that system as a ground or would short it out somehow because the water meth wouldn’t turn back on once the car was started again. But now that they are on different grounding points the water meth comes back on and it’s shorted out.

  31. #30
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    This sounds very intermittent, which can be a real pain to troubleshoot. I would break down each part of the system that can cause loss of fuel pressure and troubleshoot them individually until you isolate the problem.

    1. Fuel pump relay: Measure output voltage to make sure it's providing power to the fuel controller. Should be 12V.
    2. ECU: Measure voltage on the VW wire to tell the fuel controller what duty cycle to run at. Should be 0-5V.
    3. ECU: Measure voltage on the LgR wire from the fuel controller to inform ECU the controller is alive. Should be 12V.
    4. Fuel controller: Run a 12V fan as I described above to make sure it functions properly. Run for a half hour to see if it over heats.
    5. Fuel pump: Try hooking up the 12V battery to the pump and running it for a few minutes to see if it over heats or quits. See if you ever lose fuel pressure.

  32. #31
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    Definitely. I will try isolating each component to see if that’s the problem. One thing I forgot to mention and I don’t know if this help is that I got another P0230 which is an indication of low voltage or improper voltage and that signal is sent to the ecu from the fuel pump controller? This to me sounds like a poor coil in the relay or the pump controller and heats up which then causes the switch to lose continuity. I am assuming that since the car runs for the most part that the Ecu isn’t a factor... i hope

  33. #32
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    https://www.iwsti.com/forums/2-5-lit...lfunction.html

    I came across this thread on another forum and the issue you're having sounds very similar. Some fixed the problem by replacing the fuel controller, some fixed it by hard wiring the pump directly to the battery. Most that posted about this problem were running an aftermarket fuel pump.

    The P0230 CEL can be caused when the ECU gets a signal from a diagnostic line on the fuel controller for more than 2.5 seconds. For instance, if the voltage drops below 8V or reads open, this will trip the code.
    P0230-1.jpg
    P0230-2.jpg

    Practically speaking, the diagnostic line is telling the ECU that there's a problem with the fuel controller. This line, I'm guessing is the light green-Red wire on the controller. I suspect that running an aftermarket fuel pump draws significantly more current and can degrade the stock fuel controller over time since it was never designed to handle that extra current. So, the solution would be to either run an aftermarket controller or just hard wire the pump to 12V.

  34. #33
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    Okay so I had a chance to test everything you have mentioned in the previous post and I believe the problem to be my fuel pump. I had a volt meter on my controller the whole time checking the voltage and continuity. When the car began to die it was the fuel pump I heard shut off and not turn back on. The pulse width wire VW Was a constant 1.2V almost the entire time as you can detect the actual pulses with a voltmeter however when the pump had shut off it had increased its duty call to 3.6V with no response from the pump. The pump had power at 13.5V the entire time and the LgR wire sat at 8.7V with the car not running but the key to the on position and with the car running it averaged around 10.7V. I am not sure if that is supposed to be exactly at 12V and if it is then that may be the problem as well, or that tells me I have a large voltage differential through my pump as it is being supplied 13.5V but only returning 10.7. In the end I know for sure my pump quit working as I couldn’t hear it any more and there was a loss of fuel pressure and the car stalled. I didn’t have time to do a run time test on the pump directly connected to the battery to see if it failed but that’s another test I am going to try.

    I am now wondering if when I shorted that wiring that I somehow didn’t cook or damage the windings in the pump or somehow cause this issue. I am going to start looking for a new pump to test this theory as well, does anyone have any recommendations? I was using a walbro 255 before hand

    Thanks!

  35. #34
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    The LgR wire runs from the fuel controller to the ECU, it is independent of the fuel pump. I would bet that it is supposed to be close to 12V or higher, so 8.7-10.7V is concerning. Is there a chance it intermittently drops below 8V and causes the CEL? I would suspect the fuel controller as well as the fuel pump. You may want to check if there's a voltage drop in the wiring by checking voltage near the fuel controller and then near the ECU (on LgR wire). By the time this voltage reaches the ECU, it may be below the 8.7-10.7V you're measuring at the fuel controller. I think you're zeroing in on the problem tho. The fuel pump hard wire test would bypass the controller so you can isolate the pump.

  36. #35
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    Okay that is a good idea. I think the fact that the code says to initiate a cel when the voltage drops below 8V indicates that there is some variability within this voltage. The code also didn’t go off until the car started sputtering and died as there was still voltage coming from the LgR to the ecu indicating 10.7v or so. I will measure the resistance from the ecu to that wire to see if there is potential to get a voltage drop as well.

    Essentially the fuel pump was getting the signal to turn on and the controller was supplying the right voltage to the pump but the pump just wouldn’t run/turn on. I think the test you mentioned with directly connecting it to a battery and seeing if it will run and for how long is the next step. I honestly might just avoid the fuel pump controller anyway just to make life simpler.

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