Help - Too much cam?

[JL1958]

I bought this car so I am trying to get her tuned and straightened out.
302 bored 30 over, roller cam, (no I don't have specs) EFI, aluminum heads, MSD distributor and ignition.
The car runs too rich, backfires, runs rough under 2800 rpm.
Bogs down, hestitates, generally runs like crap. If you get her out on the highway and open her up she could run forever.
Low rpm range is horrid.

I was recomended to an EFI expert who really knows his stuff. He hooked up his equipment and we took her for a spin and he said I have two problems, that also have too much cam.
Unlike almost everyone on here, I am not a mechanic, but a lover of beautiful automobliles and I love my car, but I do not know if he is taking me for a ride or I have too much cam.
My brother in law says BS, if the car is not tuned right, it will make the cam act stupid. He is a mechanic, but lives out of state and knows carberators, not EFI.
His recomendation was buy an intake and a Holley and throw out the EFI system, but I'm not looking to do that just yet.
I would prefer a poperly tuned EFI car.
So, should I tune the car and see how it acts with the current cam or is it actually possible to have too much?

[skullandbones]

You should check your basic timing. Disconnect the SPOUT at the distributor. It is a oval shaped plug and allows the computer to advance the timing but you want to know what your basic timing is so disconnect. You may want to start with about 12 degrees. If it is a really wild cam, maybe 14 or so (that will lean out the fuel mixture). I'm not a ford expert but I have not seen a 302 that didn't have a roller so that isn't unusual. Also look for any vacuum leaks. Is it an OEM EFI or an aftermarket? BTW: a radical cam may not idle very well but it should run better than yours. I would start out with a clean slat and clean the plugs if it is fouling them. Also, if you have a MAF system, it and the injectors have to match up (calibrated for one another). Otherwise, the computer can not compensate for the different components. I'm making assumptions here because you said it's "too much cam" so I figured it was not stock. You could also have a bad ignition box but you need to do some basics to rule out the simple stuff first. You didn't mention what your two problems were according to the EFI expert. I'm with your brother in law on this one. Good luck, WEK.

[Bob Cowan]

The nice thing about EFI is that it will really tame a radical cam. You can run a really huge and radical cam, but a properly tuned EFI will make it purr like a kitten at low RPM's, but scream like a banshee when you mash the go pedal. Been there, done that. No matter what cam you have in there, as long as it was installed correctly (or even close), it should still run well.

The engine parts have to work together as a whole. It's a whole package, and not just some parts that sounded good, or maybe the builder had left lying around in the garage that he threw together. If you have a huge parts mismatch, the engine may not run as well as you'de like it to, and may not make the power it should/could. But it should still run fairly smoothly.

Take a step back, and take a look at the package you have now, and how it's assembled. Assume that the collection of parts may not be perfect, but will be at least fairly close. Don't change any parts just yet, but make sure the parts have been installed correctly and are working correctly. Look for something simple like a vacuum leak. Maybe the intake manifold doesn't fit the heads properly, and is leaving the port partially open? I'v seen that before.

Go through the systems one at a time, and check them carefully. Look for the simple stuff first - the so called "low hanging fruit".

[tcoon]

agree with all the above. The fact that it runs poorly at low rpm is suggestive of injector/MAF/computer mismatch. As stated above they have to work in concert. also, the computer needs to advance the timing at high rpm. are you using the stock A9L computer? What injector size? which MAF? I would start with a matched MAF and injector set, then tune the computer to the proper air/fuel ratio. Most people run an adjustable fuel pressure regulator. Also, don't forget to check the IAC (idle air control) and TPS. It all has to work together as a system.

[JL1958]

Thank you! I think the 92 Mustang computer and the MSD Ignition are not in sync and I need the computer programmed to give it the right message before I start replacing the cam.
the fuel / air mixture is all wrong. I think this is why I got such a deal on the car. I was about to order a kit when I found this one for what I felt was about what it would cost to build it.
And instant gratification witha few bugs was better than waiting 18 months! I will let you know how it goes.

[Jeff Kleiner]

Are you willing to travel about 200 miles to get it done right? If so plan a trip to Enterprise Alabama for a session with Wayne Presley.

http://www.verycoolparts.com/

Give him a call.

Cheers,
Jeff

[JL1958]

I got a name from a friend who deals with high performance cars and he said this guy is the best EFI man around. I think my problem is he saw blond woman with expensive car and he is trying to take advantage. But I research what I don't know and I will discuss more with him when his shop opens this morning. After more reading I think it sounds like a leak somewhere.
I am getting too much fuel as the computer is calling for it due to the leak.
I know my regular mechanic was getting a MAF sensor code, but could not do anything with the computer and recomended I take it to a shop that could reprogram it to the aftermarket MSD Ignition and distributor. He is good for routine stuff, but could not figure out the different pieces of this car.
I love this car and do not mind traveling to get her right if this shop does not want to be on the level with me.

[Garry Bopp]

JL,

You might send a PM to local guy, Joe Camire. He is called "The Cobra Whisperer" by many around here. He knows his stuff! His screen name is JoeC. Perhaps he will chime in if he sees this post. BTW, what part of Atlanta are you. I'm out East in the Covington area.

Garry

[skullandbones]

I also have a 92 GT EECIV system. I never put a EFI system together before this one. It is a reliable and stable platform. The MAF error code was a huge red flag.

If I were you, I would take the advice and have a cobra guy have a look. The pro mechanics and technicians are in unfamiliar territory when they deal with custom systems like yours (some exceptions). They are used to OEM related issues so it will cost you more for them to figure out your system and then diagnose ($$$/hr). IMO, you don't need to have your computer reflashed. When you get your basic problems fixed (leak or bad MAF sensor), the system will start behaving much better.

[Mustang Man]

Wayne is very good, yes, but if you're looking for someone closer (as it sounds like you might be towing it). Give my pal Tim Matherly at MV Performance a call. He's one of the top Ford tuners, including EEC-IV (what you have), EEC-V, Spanish Oak PCMs, etc in your area.

MV Performance-Tim & Lisa Matherly
816 Tucker Ct Winder, GA 30680
(770) 725-7862

Mark

[JL1958]

No way Garry! I am in Covington. Small world.

[tirod]

Yes, the wrong cam will screw up an EFI system. Carb and EFI have completely different cam requirements.

It's all about the Lobe Separation Angle and how that affects vacuum. A carb generally has less problems with low vacuum because it has bandaids to cover up it's lack of sophistication - like an accelerator pump, to squirt more fuel in when the throttle is tipped in. That's not a metered or interactive response, it's straight mechanical. The designers knew they had no better way to cover up sensing what was going on and having the carb respond. After all, with low vacuum, there's nothing to work with.

In EFI, the system requires much higher vacuum, especially with Mass Air Flow. Mass Air senses the amount of air passing thru it to calculate the fuel rate delivered by the injectors. If the vacuum is low, the amount of air passing thru is low, and the sensor can't function. It doesn't see any air. Tip the throttle open and there's no accelerator pump to cover it up - it stumbles and runs stupid.

Get the specs on that cam by any means. If the LSA is less than 110 degrees, it's definitely contributing to the problem.This is where the large number of "I can't get EFI to run so I tore it off and installed a carb" posts come from. EFI and carb motors are two different tuning setups, and saying "they should run regardless of the cam" isn't a fully informed opinion.

Check this out for yourself - look at the specs for EFI cams vs carb cams. You see it very quickly with the roller cam specs, because most of those are going into EFI motors. 115 degrees + and smooth idle is common. Carb, less than 110, lumpy idle, and "will require assist for vacuum accessories" is common.

Don't build an EFI engine with carb tuning and it works ok.

[myjones]

a lot of good advice so far and I want to throw two more on the pile
Sometimes a big cam's driveability can be helped a bit with a cam timing adjustment IF PTV clearance allows
lining em up dot to dot isn't always the best combo, If all else is cleaned up first you should pull it down and
get a degree wheel on it.
The EFI tuners I know say that if it pulls under 13 at idle it can't be tuned for street use period
That threshold comes from them dealing with quite a few on the edge combo's and learning what works and
what never will.

[JL1958]

Lots of good material here and I felt much more comfortable discussing this with Speed shop#1 this morning. Bottom line was he said he could not tune the issue out of my car, it was the cam.
I thanked him and advised I would get a second opinion and if they said the same thing, I would be back to see him. I have an appointment at speed shop #2 Saturday.
I have left a message with the original builder that I could really use the cam specs. I will let you know what they find.
Thank you all for your input.

[Garry Bopp]

JL,

Sent you a PM ...

Garry

[tcoon]

The info that it runs well at WOT and you have a MAF error is very helpful...at WOT the computer runs it as an open system, bypassing the info from the MAF. At partial throttle it uses MAF to adjust A/f ratio. By logic, you have a problem at partial throttle, seems likely to be a malfunctioning or mismatched MAF. Check your MAF and injector match, they come paired together...ie a stock MAF uses 19 lb injectors, bigger injectors require a modified MAF. Once you get the basic functionality right, you can tune the EECIV with an add on chip such as SCT or quarter horse to fine tune the drivability. The EECIV cannot be flashed.

[JL1958]

Great results today. The guys raised the hood and saw my MSD Distributor and then described to me exactly what my car was doing.
They did not have an Autolite on hand and could not get one on Saturday, so they just tuned to the one that was on it. They did recomend I switch it out as it will start running like crap again and potentially leave me stranded. I asked them to get one in stock and I'lll take her back over in a few weeks.
They put a chip in the car, dyno tuned it, relocated my coil from the block to the side wall to keep it away from too much heat, tightened the knuckle on my rack and pinion to take out some slop in my steering wheel, and anything else I could think of. I got out of there with a great running car and the drive back was a blast. The guys were awesome and they loved my car. They kept going on and on about the paint job on the car, so I'm feeling pretty good about my purchase. Oh, and the dyno results were 280 hp at the rear wheels. That's enough to keep her drivable on the street and still have fun.

[Garry Bopp]

JL,

That's great news about the "new tune" working out for you.

You may want to consider this September cruise with the Deep South Cobra Club. Several ATL area folks will be attending ... please join us!

Re-scheduled from May, 'Randy's 24 Heures De La Cobra'. Same locations, same great drives, same awesome restaurants, just a different time of the year.

September 19-21. Arrive in Jacksonville at the Crowne Plaza for registration; participate in planned cruises on Friday and Saturday.

Registration on the Deep South Cobra Club website will begin soon. You can call the hotel now to reserve your room at the club rate of $89. 904 741 4404. There is plenty of parking for your trailer.

Ricky
______

[JL1958]

Sounds fun. I sent you a pm.

JL,

That's great news about the "new tune" working out for you.

You may want to consider this September cruise with the Deep South Cobra Club. Several ATL area folks will be attending ... please join us!

Re-scheduled from May, 'Randy's 24 Heures De La Cobra'. Same locations, same great drives, same awesome restaurants, just a different time of the year.

September 19-21. Arrive in Jacksonville at the Crowne Plaza for registration; participate in planned cruises on Friday and Saturday.

Registration on the Deep South Cobra Club website will begin soon. You can call the hotel now to reserve your room at the club rate of $89. 904 741 4404. There is plenty of parking for your trailer.

Ricky
______