My car did that when I had the automatic tranny in it.The torque converter just wasn't up to the task and the car would die every time I came to a stop unless I kept one foot on the brake and one on the gas.The 5 speed took care of that.

 

get a tune....I ran a E-cam forever with a blower and had a rock solid 800 rpm idle. Even with the AFM B21 ...94-95 are just more sensitive than the 93 and earlier

 

i have been fighting this same problem in my 91 after i put an e303, i was going to try and fix it with a tune.

 

quoted and saved for when people knock the 94-95 computer and praise the fox comp's....


I've always had a way to tune the computer so i cant help ya. Until you figure out the problem, cant ya adjust the idle screw so it idles higher?

Just an idea...

 

When I first installed my E303 it did the same thing you mentioned. My problem was caused because I had put an idle air restrictor plate between the IAC and TB to fix the between shift surge I was having with the stock cam. After I took the plate out, I drove for a while without a tune and my only driveability issue was chitty MPG.

 

My 331 e303 10.5:1 with lightweight flywheel had The Stall.
It would idle ok, but when coasting in a parking lot, a touch of the brake or turn of the wheel caused the motor to die.
The garage retuned the thing, and it is improved somewhat, but I still occasionally have the problem.

 

Vacuum leak???? Spray some carb cleaner around the intake, any where there is a mating surface.
Can try and adjust the air bleed valve on the TB and raise the idle a little.

 

A few simple things to check/do would be the idle air controller, TPS voltage, clean the MAF sensor, reset base idle, and check the ECT. I have the voltages if you need them. Most can be found in a Chilton manual.

OP, do you have a means to datalog or edit the tune of the car? Either way, let the car sit until it's completely cold, start it and use a stop watch to see how long it takes to act up. Reason being, if you tell me how many seconds it takes to act up, I can cross reference that time with some scalars within the tuning and possibly narrow down what's happening to make it idle surge.

People will tell you left and right that the 94/95 computers are more sensitive to cam changes, and that's true; however, with all the sensors working near 100% the computer is not as sensitive. A bad TPS, IAC, ECT, MAF, etc. will wreak havoc on the 94/95 computers. The good thing is, if you know what the computer is trying to do, you can look at what sensors it’s looking at and narrow down what it could be.

 

Honestly, it depends on the day. Yesterday it held idle all day long. it was 90*F outside, but low humidity. Today it won't hold idle for ####, its around 80*F right now, but more humid.

This morning when I cranked it, to warm it up, it held idle for around a minute, then it started to surge and wanted to die. I haven't checked any of the sensors, but I have a friend who is going to check TPS voltage, fuel pressure, IAC, MAF, and set the timing for me. I really don't have a way to datalog or tune it right now. How do I go about resetting the base idle?

Most likely, I'm going to swap out this cam for a Trickflow, in the near future, since they seem to run better.

 

I had "The Surge" and "The Stall" with my '95 Cobra. It has the A9L and the E303 with ported GT40's and a T-Moss Cobra intake. I dropped the car off with Jay at Real Street Performance out here in Orlando, FL. It was determined that the tune on the SCT chip was stupid rich at idle so that problem was corrected and then that also fixed the stall that occured while making a U-turn. My car now idles at about 1050 but I don't have those driveability problems anymore. I'm going to see if its possible for him to put a tune on there with a lower idle speed. My car sounds like a freight train at the stoplight lol.....
Absolutely nothing was wrong with the mechanical or electronic parts on my car. The tune just needed to be adjusted.

 

Not sure if anyone mention the IAC motor but it might be worth cleaning or replacing. It might be stuck/clogged and not able to feed some air in when the car starts to stall.

Ross

 

bump idle up to 900-1000 rpm's

 

honestly, all this troubleshooting crap isn't going to get you anywhere. take it from someone who was just there and did just that. The e-cam is only good for one thing; a lopey, mean sounding idle. it sucks on gas mileage and there are other cams out there that make better torque and power all around and are easier to tune with depending on your cars overall attitude. My next cam will be a custom grind or an AFM cam but for now, I'm stuck with the E because thats what I chose to run.

 

honestly, all this troubleshooting crap isn't going to get you anywhere.

That's crap advice.

 

keep trouble shooting thats what we are here for to try to help.

 

I have a 94 with just an e cam ,auto and had a problem with it . I bumped up the timing , played with it and found a sweet spot. A tune with a e cam sounds like a waste of cash that i didnt have and only had cash for a cam at the time.Also bump up your idle . If this doesnt work I have ran the ac just to get idle increase. Just dont give up.Also do a search on this topic because if I remember some folks where drilling a small hole in their throttle body butterfly. Just dont recall how big.

 

If this doesnt work I have ran the ac just to get idle increase.

That's a thinking-outside-of-the-box idea. The a/c and defroster settings should yield the same result. FWIW, aside from any airflow specific increases with the a/c setting, the stock tuning raises rpm by 48. Other tuning within the eec may take over an raise idle more if the increase in 48 affects another function (almost like a domino effect, but not extreme).

So, the point I'm trying to make is the a/c setting increases rpm by 48 minimum.

EDIT: Well I just checked and the J4J1 (Cobra) computer does not increase idle for the a/c. I'll have to look as it may increase idle some other way, but for now I'd assume it doesn't. The 94/95 GT 5-speed T4M0, raises the idle 48. Sorry for any confusion.

 

Try this.... this solved my stop sign stall issue after H/C/I swap... Try unplugging the IAC and see if it helps the stalling... if so then the full idle reset could solve...Its easy to do..

http://www.muscularmustangs.com/maintain.php

 

E-nuts, I had not heard that one before. Don't worry, they are not swollen yet, thanks for the concern. Just an FYI, if I had the ability to tell you to your face your advice sucked, I would have. That's not trying to be a hardass by any means, I don't have a problem disagreeing with people and telling them, that's just how it is. However, there is a geographical inconvenience with me talking face to face with you so the internet is going to have to work.

I used "calling out" only as a phrase for disagreeing with your advice when I thought before hand you would type back with some response which attempted to support your crappy advice, which you did.

I got my QH primarily because I just wanted to learn how to tune and so in the future I don't keep paying people to tune for me. I hate paying people to do stuff I would rather do myself. I can be somewhat picky on how I want my car to behave and when I got my first SCT chip I didn't like some of the characteristics but also didn't want to pay a crap load of money to pay someone to get everything the way I wanted it. Plus with the QH, I can datalog, which is also something I wanted the capability of.

 

I got my QH primarily because I just wanted to learn how to tune and so in the future I don't keep paying people to tune for me. I hate paying people to do stuff I would rather do myself. I can be somewhat picky on how I want my car to behave and when I got my first SCT chip I didn't like some of the characteristics but also didn't want to pay a crap load of money to pay someone to get everything the way I wanted it. Plus with the QH, I can datalog, which is also something I wanted the capability of.

I can at least agree with you on that much. I briefly considered the Moates tuner myself but realized with my car being a daily driver, I wouldn't be able to dedicate the necessary time required to learn how to properly tune it myself between week and home times.

 

Question for both Ryno and Cobraman.
I've read internet disparagings of the "cobra computer"... my question is, when we get a chip burned, isn't the "cobra computer" out of the equation?

 

In short, no. Correct me if my interpretation is wrong, but are you basically saying that the chip replaces the computers tuning? Depending on what computer you start with, that computers programming is only modified, not completely replaced. Thats why it is said that its more difficult to tune 94/95 computers than it is to tune the A9L and that tuning the J4J1 is more finicky than tuning a T4M0. Also, an SCT chip is "married" to the computer family that it is piggybacking until it is completely wiped. The chip in my '95 Cobra right now was originally burned for my '96 Cobra. Since it didn't work properly for the '96, the tuning was wiped and the chip reburned for the '95. One other thing; when you have a 10-position switch for one of these SCT chips, you can only burn modifications of one computer tune on the chip; tunes cannot be put on the same chip for multiple engine computers.

 

P63:

The chip intercepts the stock computer's commands and replaces them with the chip tune's command. Basically a chip is a middle man who swaps commands to what the chip wants to happen. The computer's original tuning is not modified or erased on a hard-drive level; so if the chip was removed, it would be exactly as stock.

However, to answer your question, the cobra computer is not of the question. You could have a cobra tune burnt to a chip, put the chip in a T4M0 (94/95 5.0 GT 5-speed), put the computer in a Cobra and you'd never know the difference; the same is true for putting a Cobra computer in a GT. This is possible because both tunes use the CBAZA strategy.

On my QuarterHorse, I can put 8 different tunes on it and either use a rotary switch to change tunes (limited to selecting 1st four tunes) or use my computer (usb connection) and pick between eight tunes. I don't actually use 8, but I could. Also, I can disable the QH (basically a 9th tune spot) and the QH copies the computer's command and sends it out. So, I do not need to tie up a tune spot to select the stock tune. Which makes it very easy to figure out how much progress I'm making over the stock tune.

I could put an A9L and a T4M0 tune on the QH at the same time, but since they run different strategies, they would not work interchangeably. To clarify, a CBAZA-family computer will not fun with a GUFB (A9L) strategy. But as far as being on the chip at the same time, that would easy.

Cobraman:

If you do fine the time, you could have your SCT tune pulled from the chip and have the binary file loaded on to a quarterhorse. That's how I got my base tune. Since then I have started over with modifying a stock T4M0 file, but that's just because I got more comfortable with what I was doing.

 

P63:
Cobraman:

If you do fine the time, you could have your SCT tune pulled from the chip and have the binary file loaded on to a quarterhorse. That's how I got my base tune. Since then I have started over with modifying a stock T4M0 file, but that's just because I got more comfortable with what I was doing.

I've got other questions about this but I'll PM them to you.

 

1) Why did you buy a car that had these problems????

2) your ####ty idle is probably not because of your cam, my sn95s idled just fine with, e, tfs1, crane 2031...a tune wont fix a car that wants to die, theres issues at large, i would...

a) check timing with spout on
b) put a vacuum guage on it tell us what it's pulling for vacuum
c) do a tune up, new plugs, wires, cap, rotor, fuel filter, air filter. cheap stuff to do, and you can never tune a car up enough...

 

Does anyone ever read the previous responses to a thread before posting a response anymore??

 

Some of these guys are going ot have you running in circles... if you guys don't understand efi basics and operation than you shouldn't reply to the post because you're just going to give misleading info.

Some of these guys have touched on this a bit, but here's what my thought is...

The cam is most likely going to make the car run lean at idle and cause a surge, however, that is not the issue you're experiencing. My bet would be either the IAC is dirty or not working, or the tps is set out of range. Check to make sure the idle air control motor is not filled iwth carbon, if it is clean it out with some brake clean... Check to mkae sure your tps voltage is between .9-.99 if you do all this and you still have no idle speed changes than your iac motor is probably shot.

Don't get discouraged, you'll be up and running right in no time.

 

Try this also: If you can get the car to idle well at your desired RPM with the IAC disconnected (ie: temporarily raise the idle to desired with the set screw), it probably means your computer is confused on how to run the motor and the surge is caused by the computer overcorrecting then under-correcting RPM with the IAC and/or spark, or the IAC is bad.

The computer controls idle using two methods: Spark advance/retard and airflow through the IAC. The method above troubleshoots air flow, the following troubleshoots spark: With the IAC disconnected, check the timing. If the timing bounces around, the computer is probably confused. Connect the IAC and check timing again, if it's bouncing around, again, the computer is likely confused. By bouncing around I mean by more than 4 degrees in either direction. If the spark does bounce try disconnecting the spout (locking the timing) and if you still cannot get the car to idle with or without the IAC connected, you probably have a vacuum leak. When looking to vac leaks, don't forget to look at the PCV system and the garbage in the passenger wheel-well.

If you are confused with what I tried to say, trying doing every combination and post your results. ie: spout connected/iac connected-check timing; spout disconnected/iac connected-check timing. ect. It may be a pain, but you can eliminate some possibilities and narrow in on others.

My guess is your idle is set too low or you have a vacuum leak somewhere. If you don’t have a vacuum leak, I’d guess the IAC is bad. Do you have an intake spacer? If so, check that. I just saw the ugliest intake manifold spacer the other day which caused a mean vac leak. It was so bad I'm surprised some spacer pieces didn't fall into the motor when it was removed. I don't know the brand, I'm guessing he bought it off of eBay.

Check to mkae sure your tps voltage is between .9-.99

That's a good rule of thumb, but the .9-.99 is an internet myth. The TPS should be under 1.02,. Everytime the car is started the computer looks for the lowest TPS voltage and uses it as a base. Within the programming you can set the voltage increase to where the computer sees part throttle. Stock is .03-.04 volts depending on the computer. So, if the lowest voltage was 1.02, the computer would sense part throttle at 1.05-1.06. 1.02 is still a rule of thumb, but you could go slightly higher and be fine. IIRC the computer flags the TPS as bad at 1.2 minimum volts. - Don't quote me on that, but I know it's far above the internet myth of .9.

 

ryno is spot on...

 

Both of you are correct. The TPS has nothing to do with idle as long as the computer sees the TPS's minimum value is within the tolerance limit for closed throttle. If it detects a failed TPS, I don't know what would happen forsure. The computer has numerous fail modes which would be the equivalent of entering "Safe Mode" on a Windows based computer - only uses the necessities. It's possible the TPS could cause the computer to enter a mode like that.

For example if the MAF fails, the computer enters a fail-mode similar to Speed Density, but it's only meant to run the car long enough to limp along until you can get somewhere to fix it.

 

Thanks for the help everyone. I think I got it fixed, I went through and replaced all the vacuum lines that looked cracked or dry-rotted. I found a few of them weren't even tight, so I'm thinking it was a vacuum leak somewhere. But it's idling fine as of right now, I just gotta lower it a little bit because its set ~975.

 

I fixed mine also, turns out it was the pickup coil!!! when the car warmed up it started malfunctioning(thank you captain obvious). I never would have thought if the thing didn't stop working altogether.