Any Ford EFI gurus out there?

[kraftee]

You probably read my recent thread concerning being jerked around by IST on my mass air upgrade. Well, it gets worse. I put it all together and tried running the car today. Well the mix is so damn rich you can't even stay in the same vicinity. Black smoke coming out of the exhaust, uneven idle, wants to die. I adjusted the fuel pressure down to about 38 lbs. - and that improved things a little. But still WAY too rich.

The engine is a Blueprint Engines HO 5.0 with flow-honed intakes halves - otherwise stock. I had been running it with a speed/density EFI system, but wanted to upgrade to Mass Air. The Ron Francis harness I have been using has provision for a mass air sensor connection. Here's what I put on the car (the "kit" IST sold me): Professional Products 75mm polished throttle body with polished 75mm EGR spacer, 30 lb. disc-type (as opposed to the original 19 lb. pintle-type) injectors (flow-matched - supposedly), new O2 sensors (OEM, I guess), new OEM air idle control, new "improved" BAP sensor, Ford EEC-IV A9L (it's a manual transmission car), and....what is SUPPOSED to be a 76mm mass air sensor calibrated to 30 lb. injectors. When I measured the inside diameter of this new MAF, it came to a whopping 82.5mm. Obviously, I called IST immediately. "That's correct", they said, "76mm is just the EFFECTIVE diameter of the MAF, the ACTUAL diameter is going to be much more." Sounds ridiculous now, but I bought it then. So, I bought a huge aluminum elbow and connectors. Had to buy a special reducer sleeve to mate everything to the 75mm throttle body, of course.

So here are my thoughts - hopefully someone with way more knowledge than me can help: I think I got screwed on that 82.5mm MAF. My guess is that it should ACTUALLY measure 76mm inside diameter. I am also not sure about the sensor itself. The numbers on it are AFH60M-19. If that '19' denotes that it's for 19 lb. injectors, that might be part of the problem. The sensor reads the quantity of air and sends a signal for the 19 lb. injectors to open for a designated amount of time - but if it is actually sending that signal to a set of 30 lb. injectors - well, a whole lot more fuel is going into the engine! Does that make sense?

Anyone have a recommendation? Thanks. Eric

[DaveS53]

Maybe these folks can help. They seem to offer a lot of MAF sensor options. If you buy one of their products, they calibrate it for a specific fuel injector size. Yours may have been recalibrated for 30 lb. injectors, despite the part number on it.

http://www.promracing.com/mass-air-meters.html

The seem to have a lot of interesting options, but their offerings sure are pricey.

[Jeff Kleiner]

... If that '19' denotes that it's for 19 lb. injectors, that might be part of the problem...

If you have a 19# meter with 30# injectors it isn't "part of the problem" it IS the problem. Unfortunately it sounds like you may have a hard time getting this vendor to give you much help determining exactly what you have.

Jeff

[kraftee]

That's correct. So I'm trying to figure it out. I guess my best bet is to bite the bullet and buy another mass air sensor that I KNOW is a 30 pound meter. Of course, that assumes that I really have 30 lb. injectors... Not good.

[Jeff Kleiner]

Sounds like you're working with a freshly rebuilt but basically stock 5.0, right? 30# injectors in an otherwise stock 5.0 aren't gonna' gain you any power but will make for driveability issues, even with a matched MAF meter. In the long run I think you'd be best to go with 19s and a matched meter.

Jeff

[Svtfreak]

Mr Jeff is right. 30 lb injectors are way too much for a basically stock 5.0. And if the ecu thinks it is 19's, and the MaF is tuned for 19's but you have 30's, then it'll be way pig rich.

The quick fix would be to throw 19's in it and see how it runs. If that solves it, have a ball.

The hard fix is to get something like a Moates quarter horse and go into your computer and see what injector slopes are programmed in and then change accordingly. Check out your maf transfer functions and change accordingly. Then tune correctly.

I find it highly unlikely that they tuned your ecu. Chances are they just didn't match the hardware (either by accident or haste), so dropping 19's in just might fix it.

[kraftee]

Thanks for the input, guys. My gut instinct here is to yank the 82.5mm MAF and the 30 lb. injectors and replace them with 19 lb. injectors and a 76mm - 19 lb. MAF.

[michael everson]

I would put everything back the way you had it. Almost no need to update a stock motor to MAF. If you want MAF then just install the mass air meter and the A9L and see how it runs.
Mike

[kraftee]

Gentlemen,

I cannot thank you enough for the rational, measured ideas and responses. As you could probably tell from my initial post, I was kind of in panic mode about this problem - and all over the board as to what to do. Though the responses varied somewhat, the underlying thoughts were that the 30 lb. injectors were ridiculous on a basically stock 5.0 and that the MAF might very well be calibrated for 19 lb. injectors. So, as several of you suggested, I yanked out the 30 pounders and reinstalled the ancient, beat-up, broken end cap, original 19 lb. injectors. reinstalled the MAF (supposedly 76mm - 30 lb.) and fired her up... The car runs PERFECTLY. I still have a few issues to deal with - notably the throttle cable - which is hard to modulate (too much friction? sh1ttty cable?) Also a high-pitched whistle at idle that seems to be loudest at the K & N (vacuum leak in the plenum?) But otherwise, she starts, idles and accelerates beautifully.

Thank you again guys! Eric

[michael everson]

Some of those 75MM throttle bodies are known to whistle.
Mike

[kraftee]

You're correct Mike. And it was really two distinct whistles. An extremely annoying high-pitched whistle and a lower pitched whistle almost like a turbo spooling noise. I removed the TB and used a Dremel to gently chamfer all the sharp edges on the inside holes. That got rid of the higher pitched (most annoying) whistle. But the lower pitched one is still pretty much there. The larger problem is the gas pedal issue. It's VERY difficult to modulate up from idle smoothly. It feels like the cable "catches" at idle and as you start to gently push the pedal, suddenly all the power is there right now. However, the TB plate does not stick in the bore at idle - like my stock one did. But the cable still seems to be catching. Thinking of upgrading to a linkage type throttle. I know one of you guys makes a linkage for the carbureted 5.0. Does anyone make one that works with the EFI motor?

[michael everson]

I would first try a new cable. It doesn't appear you have any sharp bends so maybe its frayed somewhere
Mike

[Svtfreak]

Glad you got it, Eric!

You got the whistle. Good. Mine still does it. I need to chamfer mine more. No idea on the second whistle! Maybe the pcv system?

As far as the catch, I've never seen one catch that wasn't a throttle blade. That would be a new one for me. I agree with Mike though. Try a new cable or even just rerouting that one slightly. Also make sure the cable is in the right place so it is pulling straight on th ball and not at an angle, possibly forcing it to jump passed 90 degrees (if that makes sense).

[kraftee]

It seems that the problem with the throttle is that the return spring is WAY stiffer than the original. So, just for grins and giggles, I put a really weak little spring facing the other direction (trying to OPEN the throttle.) Problem fixed. However, I really feel like that spring is a bad idea. Any other suggestions? Obviously, if I could increase the mechanical advantage of the throttle pedal, that would do the same thing...

Also, I did some research into my "flow matched 30 lb. injectors". Seems they are actually 36 lb. injectors! So, I got a little chunk of money back from my AMEX dispute (although I am still way upside down on this deal - STAY AWAY FROM THE CROOKS AT IST!) Does anyone have a need for a once-used set of Mostplus 36 lb. injectors? They are exactly like these: https://www.amazon.com/MOSTPLUS-36lb.../dp/B00ZR5NVUY. I'd sell them for $100 - including freight (I paid $350...)

Thanks again for all the help and advice! ERIC

[Svtfreak]

If you have a dual return sprint, remove one. Or you can buy lighter springs in the "help" section at auto parts stores.

[kraftee]

Well here's a quandary for you EFI experts. The 33 has been running flawlessly. Starts right up, idles beautifully, accelerates cleanly. In short, everything you would expect an EFI car to do. So last night, my wife and I take the car out for its first real outing (wife's first ride, actually.) Drove (flawlessly) to a restaurant about 5 miles away, parked in front, went in and ate. About 45 minutes later, we came out, got in the car, turned the key, and cranked the engine - but no start. Just crankety, crankety, crankety. Did this four or five times before I realized that the fuel pump was not coming on for a few seconds when I turned on the key. Opened the hood, got out, turned the key on. Sure enough, no spike on the fuel pressure gauge. Reached up under the dash and checked the inertia switch. It was still set and fine. Pulled the cowl cover off to look at the fuses. All fine. Flat bed ride home. It's in my shop - and still no joy on the fuel pump. The Ron Francis EFI instructions tell you that to build pressure for a first start, you can ground the test wire labeled ECM 22 VIP to run the fuel pump. Did that (key on, of course) and when I ground the lead, I can hear the fuel pump relay click. So bad fuel pump or short or wiring issue? Weird that it ran perfectly until I turned it off and then would not restart. Suggestions?

[wallace18]

jump the fuel pump relay first. It may just a bad relay.

[kraftee]

Well, took the waterfall off and there IS power at the fuel pump. So, I'll call the guys at Boyd tomorrow morning and go pick up a new fuel pump.

[kraftee]

Tried tapping on the tank, on the fuel pump plate - could not get it to come on. Of course, as soon as I removed it from the tank and reconnected the leads, it works fine. Going to head down to Boyd's today and see if they will replace the electric motor.

[Svtfreak]

Something doesn't add up. You have a running fuel pump when grounding the pin, but no run when 12v is at the fuel pump normally? With key on, of the ecu doesn't get a engine running signal, it doesn't keep 12v to the fuel pump. It kills that after about 5 seconds.

If the pump runs and builds pressure when uou ground the pin, it's highly unlikely it's the pump.

I know you don't have one, but sounds like symptoms of a dead battery in the old quarter horse emulator. Which could be a fritzes ecu. But the pump not running with 12v at it is weird still.

Edit. Had a thought. This after market company you got this from didn't possibly change it to make/break on fuel pump ground instead of hot, did they?

Did you check for spark?

[kraftee]

Hey SVT. I think you're misunderstanding what I wrote, since the problem was very simple. Here were the symptoms: No pump running. At all. Not when jumping the test pin, not even the three seconds when you first turn the key on. Believe me, with the pump about ten inches behind your head, you can hear it on the 33! When I pulled the waterfall off, and put a test light across the pump leads, then turned the key on, the test light came on for the three seconds and then went out. Just like it should. But the pump was not running. So, obviously, it was a pump issue.

Then, when I pulled the fuel pump out, it seems like I must have jarred the connections, because suddenly it would work fine when I connected it to the leads. I took the whole unit down to Boyd (builder of the tank) and he replaced the pump at no charge (AWESOME customer service - this was a 4-year-old unit!) He gave me back the old unit and once home, i set it on the workbench and the crimped on, heat-shrunk positive ring terminal simply fell off. The crimp was not complete and was not holding it - just the heat shrink. I am about 99% sure that was the actual problem.

The new pump is back in and everything is all buttoned up. Car starts and runs perfectly.

[Svtfreak]

Oh! Yes I misunderstood!

Good deal. Glad you got her going.