E303 cam and Idle fluctuation

[yaheew68]

Is there a solution to the idle "hunting" with the e303 cam? only mods are the cam, headers, off road pipe, and mufflers. all else is stock. idle fluctuates from about 1400 to 600 and back and forth and back and forth!!1
Anybody know how to cure this, or is it natural with the cam?
Thanks.
:read:

 

[psucobra]

In my old cobra, I had limited success with an idle adjustment plate and TPS voltage adjustments. The only real solution is to get a custom chip, tweecer or some other type of EEC tuner.

 

[Scream'nCobra]

Its actually natural for that cam. My bcam did about the same thing for a few weeks. Just screw around with the idle and see how it goes. All it really takes is time for the computer to get used to it.

Where in the midwest are you?

 

[MICH_427_Cobra]

Screamin Cobra, Please tell me more about the idle adjustment (how and where do I do it?)
Also, how can I get the computer to "learn" the cam, or is it an automatic thing. If it is automatic, how long should it take?
BTW I am in SE Michigan.

 

[93Cobra#2771]

You will prob. end up having to raise the idle a little bit to compensate. The idle adjustment plate is the easiest way to do this, as you don't have to mess with the throtte set screw and readjust the tps every time. TPS voltage should be set between .93-.97. No higher than .97, as you can cause problems.

Also, double check for any vacuum leaks.

Quickest way to learn the new cam is to disconnect the battery for 20+ minutes. That will clear any long term fuel trims.

Tell me a little more about the surge:
1. Only at startup up, or does it do it all the time?
2. Any other bad behavior with the cam?
3. Does it buck at part throttle/no throttle?
4. What other times does it exhibit any bad behavior?
5. How many mile on the car?
6. What is base timing set at (spout pulled out)?

 

[Xstanger]

My Black 93 did the same thing and I did not want to raise the idle to compensate. I changed the maf sensor and switched over to a A9L ecu.

 

[jibbers93gt]

The best thing you can do is raise the idle to around 1000rpm.

Good luck with it!

 

[Scream'nCobra]

I went to auto zone and bought a bunch of springs for the idler, tried a few and found one that worked with adjusting the idler. Also, another thing that helped it idle better was the new manifold i put on.

Try what 93Cobra said, that should work.

my idle with the bcam

Thats how my idled after we tried out the springs and adjusted the idler and put on the ported GT40 intake.

How far are you from US41 dragway? Check out the link in my sig, let me know what you think.

 

[MICH_427_Cobra]

okay, here is more info.

The car runs fine. When I am into the throttle there are no issues.
When I am rolling (coasting to a stop) in nuetral, it is okay.
Within 2 seconds after being stopped at light, it starts to hunt for an idle.
The slightest pressure on the gas pedal will take care of the hunting.

Please keep your tips coming. I will keep trying things until I solve it. Does anybody know of very descriptive directions on how to make these idle adjustments?

I am in metro detroit, so if anybody has any expertise locally, let me know!

 

[MICH_427_Cobra]

Can anybody local suggest a good tuner? Again, Metro Detroit area....

 

[02_Lightning]

Originally posted by 93Cobra2771
TPS voltage should be set between .93-.97. No higher than .97, as you can cause problems.

Why is this? I have had mine set at .99V since I got it the car, and it has run quite nicely.

 

[93cobra#3326]

do you have a k&n filter? is the mass air meter close the filter? ive seen for myself and have heard others speaking of this: the oil from the k&n can over time build up on the mass air meters sensor wire causing erratic idle and false rich or lean(cant remember which) conditions. i dont know anyway to safely clean (because im scared to try) other than blowing compressed air on the sensor wire. ive also heard of "clocking the meter" but havent seen nor tried this to prove its effective. -this is all in addition to what was already said above.
oh yea, how many miles on your engine? maybe check your IAC to see if its carboned up.
just some thoughts, good luck
bryan

 

[psucobra]

Here is a link to the procedure for resetting the idle. http://www.corral.net/tech/maintenance/idlereset.html It helped me. This is just a band aid fix though and probably will not completely solve the problem. The dynamics of your new cam are beyond the stock ECU's ability to compensate for the changes. To fully solve the hunting idle, the ECU's parameters need to be updated and customized to that cams idle characteristics.

 

[93Cobra#2771]

Originally posted by 99Lightning
Why is this? I have had mine set at .99V since I got it the car, and it has run quite nicely.

Some cars, the .99v works OK, but some causes problems. Basically, its a computer thing. Any voltage over 1v is considered to be on throttle and causes the computer to change from idle strategy to acceleration strategy.

Sometimes, setting the voltage an .99v was so close to 1v that a digital voltmeter's calibration cold be off by just a tad. So then, the EEC sees 1v or more and starts behaving erratically.

It has also been shown that as long as you are in the factory voltage range, the car behaves as it should. In fact, there is no hp/throttle response difference.

Since your's is acting fine, don't worry about. But if you start having drivabilty problems in the future, that's where I'd look first.

It was an early trick from the old days, but has fallen out of favor for the most part.
;-)

 

[JimJr]

Originally posted by 93cobra#3326
do you have a k&n filter? the oil from the k&n can over time build up on the mass air meters sensor wire causing erratic idle and false rich or lean(cant remember which) conditions. i dont know anyway to safely clean (because im scared to try)

This is a common problem and can be caused by over oiling the air filter. I use normal household rubbing alcohol and a Q-tip to clean my MAF, and clean those wires GENTLY. You will need to buy a antitheft torx bit, which is a star bit with a hole in it, to get into the MAF. You can buy these at any auto store. I clean my MAF, throttle body, and blade about twice a year. Don't forget the TB, it can get built up with oil/dirt and affect your idle also.

 

[trey193]

THere is an idle setting procedure with quite a few steps involved, I had the E in my 93 with just bolt ons and it surged at first until I went through this procedure then it was rock solid at 900-1000 and sounded wicked. DO a search on Corral for idle setting procedure, you have to follow every step exactly for it to work and it will work at least it did for me!

 

[93Cobra#2771]

Yep, the idle reset procedure that psucobra linked to in his post is the one you want to use.

 

[Speedfreek]

Ok started mine up today and the damn thing is pig rich. ANy ideas? All vacume lines look fine, stock FP regulator, could the reg be stuck? I've never had this problem before?

 

[93Cobra#2771]

I would lean more toward a vacuum leak. An exhaust leak will also cause a rich condition, believe it or not.

Rich at idle only?
Is this the s/c'ed car?

BTW, I'm so close to finishing your replica window sticker, I can taste it... ;-)

 

[83gt5.0]

I just installed EFI on my 83 and started it for the first time last week. I too am having this problem. I also get the bucking at part/no throttle. I looked at the TPS, and it looks liek it's been cut and bored out for more adjustability. I can only get .90 out of the damn thing though. I guess I need to buy a new one. But it will also die occassionally, like when I put it in neutral while driving (as to come to a stop). I do have an F303 comparable cam in it.

I think I will buy one of those idle adj plates, and give it a try.