Idle and Stalling Problem Solved!

[ToplessPony94]

For at least 4 years I've had idle and stalling issues that everyone who knows me knows about and has probably seen at least once. Over the past few weeks I believe these problems have finally been solved.

After some engine work about 4 years ago, I had multiple issues, including a distributor that wouldn't fire correctly no matter what. After getting a few issues like that resolved, The car got dyno tuned. There were still severe stalling/idle issues after the dyno tune and it went back to the tuner for a week to get that resolved. It came back somewhat better, but there were still issues. The car would randomly stall after stopping, I had to rev it way to high starting off from a stop to ensure it wouldn't stall, it sometimes bucked for no apparent reason, etc.

My car has now been dyno tuned again and drives great on the road. It also has more HP and torque than with the previous tune and runs much smoother. The bucking and random stalling has also been addressed and fixed. There is still a short period at cold start - no more than the first minute - when the engine still tries to stall on occasion, but I don't care much about that. It may or may not get some attention next time the car is at the shop. This is heaven compared to what I've been dealing with for four years!

Many thanks to ProTree, Dana and Alex for sticking with this over the past few weeks and getting the tune right for this very difficult to tune engine when no one else could! I give them a standing ovation - they deserve it!

[Michael Plummer]

Glad everything worked out for you but what camshaft do you have? Did the shop give you any details as to what was causing the problem?

[ToplessPony94]

Glad everything worked out for you but what camshaft do you have? Did the shop give you any details as to what was causing the problem?

Michael, I have the TFS mildest cam. That's what was so puzzling when it just refused to run well. I was told that the car was just really, really starving for fuel at idle and, while other things were changed as well, basically they dumped fuel on the problem. It's still starving when totally cold, but very quickly straightens out with just a bit of warm-up. While they want to fuss with that a bit more, I'm happy with it as is compared to what it's been doing for years now!

[Jibber]

I'm glad that its better and more tolerable for you. Congrats!!!

[SmokinStang]

Glad to hear it's sorted out for the most part. The SN95's can be quite challengeing as you had mentioned. Along with the prior Idling / Stalling issues....did you experience any "Surging??"

Keep us posted as I'd be curios to hear if the new found positive changes remain consistant.

[RED5.0MUSTANG]

yes they are great had my 86 fror 7 weeks,but they fixed it ,cant wait till spring,,,,,

[ToplessPony94]

....did you experience any "Surging??"

Hell, yeah, Bob! It would hunt between 500 and 1K, sometimes surge from around 500 all the way to 2K.

[Cobraman1024]

True, the 94/95 cars are difficult to tune but I can't help noticing the mismatch of parts you have for a combination.
What I'm noticing is a very mild cam with a very large throttle body and intake inlet. You kind of tried to compensate for the extra air by providing extra fuel with the 30# injectors and larger fuel rails. Unless your heads have extensive porting, they don't really justify the use of that extra fuel and air. What was your fuel pressure set at with the new regulator?
With what I normally see, the heads would probably work best with a 76mm MAF, 65 or 70mm throttle body, 24# injectors with stock rails.

Are you planning on replacing these heads with some larger later? or forced induction?

[ToplessPony94]

True, the 94/95 cars are difficult to tune but I can't help noticing the mismatch of parts you have for a combination.
What I'm noticing is a very mild cam with a very large throttle body and intake inlet. You kind of tried to compensate for the extra air by providing extra fuel with the 30# injectors and larger fuel rails. Unless your heads have extensive porting, they don't really justify the use of that extra fuel and air. What was your fuel pressure set at with the new regulator?
With what I normally see, the heads would probably work best with a 76mm MAF, 65 or 70mm throttle body, 24# injectors with stock rails.

Are you planning on replacing these heads with some larger later? or forced induction?

Well, I could write a short novel about how the combination came about, but Dana at ProTree ran the numbers (and so did I independently) and we agreed that the 30# injectors were the right ones - that 24# injectors wouldn't cut it - and I returned the 24# set I had bought and got a 30# set. Dana doesn't feel there is a serious mismatch here; in fact, at the time he said I had obviously done my homework before choosing parts given my goal. This will stay an N/A car - no plans to go any further there. My intent is a road course corner carver (hence the suspension mods) not a dragster. I also note that the TFS top end kit combines exactly these heads, cam and plenum with the same 75mm intake that I have in what used to be called their "Street Heat" kit. I don't remember what they call it now, but it's the same kit.

The issues began when the larger exhaust system happened (which was when the entire stock exhaust fell apart over the course of several days) and I decided I wanted everything to be ceramic coated or stainless. So I ended up with the Borla, Catco H-pipe and BBK 1-5/8 ceramic headers. The car ran very poorly until I replaced the intake system as well, with the parts you see listed.

At that point I (temporarily) still had the 19# injectors and band-aided things some by boosting fuel press to around 46# and things were pretty good. Later came the heads, cam, 30# injectors and fuel system. I'll admit that the larger rails were a bit of vanity. I know I didn't need them, but I just love the look of the Aeromotive rails and did not like the look of the stock rails. I paid for my vanity by needing to replace the distributor with a taller one to clear the new rails.

After the initial tune, the new fuel press was set around 34# at idle, which I always felt was too low. Now that things are running well, I note that the idle fuel press is now back in the upper 40s even with the 30# injectors. Other than now being richer at idle, the A/F for the rest of the rev range is flat and perfect.

Honestly, you would not believe how well the car runs now that Alex and Dana have tuned it. It's a dream to drive now, and I don't have to rev up to 3K just to be sure I don't stall getting moving after a traffic light stop. It has enough power to keep me happy, sounds bad enough to keep most of the ricers from bugging me, and lets me play when I have the chance. On the other hand, I'm not saying it's perfect or ideal, and I never mind receiving advice from anyone. But I admit that it has been an ordeal and now that it's running very well, I'm somewhat reluctant to change much.

[Cobraman1024]

Do you mind if I look at the dyno sheet for your combination? I'd like to see what your combination tuning did for your power and torque curves. I don't have any professional experience in tuning or anything but I like to try to understand how certain combinations work when certain changes are made.

You mentioned having to rev up to 3k to prevent your car from stalling out while accelerating which would lead me to believe that there was a noticeable loss of low end torque---did you by any chance add the aluminum flywheel around this time also? Very strange how the exhaust system improvements caused this to come out though. You may have regained some lost torque with the new tuning along with a more noticeable high rpm horsepower gain with the larger intake setup and lightweight drivetrain stuff. I've got the aluminum flywheel and driveshaft on my car too.

My exhaust modifications started with an off road h-pipe, then shortie headers and then a catback. When I added the longtube setup to my car I didn't notice anything start to go downhill; my computer pretty much self adjusted for it. I didn't start to have any really bad issues until I got the E303 cam and the ported GT40 heads with an Edelbrock RPM II intake. This is when I couldn't even get the car to start up and idle on its own. I added the PMAS conversion harness with the A9L computer and I was able to at least drive the car. I had Lou Manzo do a tune for me and then the car was a little better with the exeption of it stalling out when coasting to a stop, turning a corner and when turning on the A/C. It got to the point where I couldn't deal with it anymore and this was about the time that I was moving to Florida. Right before I moved out there, I installed the original Cobra intake but with the lower half ported. Once I got to Florida I had Jay Meagher at Real Street Performance take a crack at the tuning. The car came out feeling like there were some slight improvements. Some of the stalling issues went away but not everything was taken care of. I took it back to him and Jay gave me a refund and told me that it wasn't worth his time to have to continue to make slight/incremental changes to get my car perfect---there would always be something that was just off. It was decided that the E303 cam was the issue because of the 110 LSA-----94/95 cars generally like 114 for the best idle quality for the computer.

Because I am overseas right now, I decided that I wanted to add an ON3 Performance turbo to my Cobra. I also decided that a cam change was needed if I ever wanted the tuning to go as smooth as possible without it being the worst pain in the ass for whoever was going to dyno tune it----probably Mike Dez. I'm going to have to discuss with him how he feels about using an FTI (FlowTech Induction---Ed Curtis) cam for the 94/95 cars and how he feels about tuning it to work with a turbo.

For right now my car starts up, idles and drives pretty well. Gas mileage is crap because of the cam and I chose the cam because of how it sounds more than for its power potential. It dynoed at 275rwhp/305rwtq with a pretty flat/wide torque curve. It's a pretty fun car to drive but I have to keep my budget open for premium gas and.......well, tires lol

I was hoping to set up my '95 Cobra for the dragstrip and my '96 Mystic Cobra for road course type stuff. My '93 LX is sort of a combination of both cars I guess lol.