question for guys with aftermarket cams?

[x182dan]

How badly does your car surge? My car surged like crazy without a tune. I would have to hold my foot slightly on the pedal so it wouldn't stall because thats how bad it would get. It would surge for about 20-30seconds on a cold start then it would get better and idle somewhat normally after that. If I restarted it when it was still somewhat warm it would idle fine also. I only have a trickflow stage one cam. I have heard many people say that they have put much bigger cams in there 94-95s and it didn't surge nearly as bad. My question is do I have a problem that know one can pin point? At first I was thinking a possible vacuum leak but wouldn't that be constant and not stop after 30seconds? Any ideas?
Dan

 

[OnyxCobra]

Did you try raising the idle a little? That seemed to be enough to stabilize mine before the tune, I have a computer friendly cam though.

 

[x182dan]

Did you try raising the idle a little? That seemed to be enough to stabilize mine before the tune, I have a computer friendly cam though.

I had it idling around 1100ish and the tuner got to down to 900ish. It surged no matter what I did stock. The tuner calmed it down a lot.

 

[Venom351R]

I have an aftermarket custom cam and it does alot of the same things your saying. Just needs a tune thats all.

 

[LAFENATU]

On the SN95 you generally have to keep the idle raised due to the vaccum with the aftermarket cam.

I have my car tuned to idle at 1000rpm

 

[OnyxCobra]

My car idles around 800 steady now... after a tune the car should idle fine regardless of cam.

 

[LAFENATU]

You also run a steeda 19 that was designed around the SN95 PCM.

 

[mikey94gt]

I installed the TFS top end kit (street heat) and the car surged like crazy, didnt matter what tune I put on it. I finally bought a AFM PMS and that seemed to fix it, but it still surges when it is cold. I am looking at swapping in the A9L from the 87-93 cars so I can loose the PMS (not road race friendly) and use a Tweecer.

 

[94kingcbra]

mine surges first thing in the morning too, it goes away as soon as I give it a little gas....

 

[NoMercy94]

my surge seems to be completly random, wont do for a week sometimes then i'll hit a red light and stop it will surge like crazy till i turn the car off then its fine again WTF.

 

[OnyxCobra]

You also run a steeda 19 that was designed around the SN95 PCM.

true but it shouldn't matter after a tune.

 

[x182dan]

Well I guess I am not worse off than any of you guys. Thats good to know.

 

[topless95]

After the tune, mine idles perfect at 800 rpm's.

 

[x182dan]

the tuner got my car down to 900rpms

 

[x182dan]

Its just that I was on another forum and there were some guys with 9495s saying how they have huge cams in an sn95 and never had the surging issues like I had thats why I was questioning my surging. This past week even with the chip it starting surging like it was stock again. I emailed the tuner and he asked me to unhook the battery for 5mins and then restart the car and see what happends. The car restarted and idled perfectly again. He said take it to him any time and he will fix it, its a simple tweak in the tune he told me. Today after work I am going straight there and hopefully he fixes it. He doesn't even need the whole car just the chip.

 

[95-stang]

The 94-95 ecu will always try and adapt which is where the problem lies, my Tweecer has pretty well got the idle sorted but no matter what i try i still have to keep my foot on the gas when its cold. As soon as its warm it will idle all day drives superbly so its a trade off i can live with.
Some people seem to get away without a tune, it may be down to different combinations of parts giving different results, but the idle surge problem is common to virtually every mustang forum i have read. I found several people including me who could'nt stop the surge even using a PMS so i know its not down to just cleaning the maf as many seem to advise.
If you have money and do'nt mind learning, the AEM ecu which replaces the stock unit seems to take control of all the annoying functions but at $1599.00 its not cheap, and for most people including me its probably more than you need.

 

[x182dan]

I just got back from the tuner. I will let you know the difference tomorrow. He made it seem like theres some flaw in the 9495 computers that made it start to run crappy again. He also said when he tuned it he made it so he closed the window on it being able to adapt. He said it can still do it but the window was closed a lot. I asked him about the foxbody computer and he basically said its like going with an older technology computer but its easier to tune with.

 

[mikey94gt]

The AEM computer is an overpriced POS. I went through 3 of them trying to get them running in my car.

if you wanna go aftermarket, go DIYautotune.com and get a Megasquirt 2. much better, more reliable and easier to tune. The new ones (MS2) will control spark too.

 

[302N20]

i got the trickflow stage 1 cam and it idles nice @ 800 rpms after my tune

 

[Inspector13]

I installed the TFS top end kit (street heat) and the car surged like crazy, didnt matter what tune I put on it. I finally bought a AFM PMS and that seemed to fix it, but it still surges when it is cold. I am looking at swapping in the A9L from the 87-93 cars so I can loose the PMS (not road race friendly) and use a Tweecer.

I got the same kit on my car with a tune (just a generic tune cause the ignition box was fried and the car was breaking up) and mine used to surge bad for about a minute when it was cold. I was meaning to get the car back to the tuner now that the ignition is fixed but I had a bit of a nitrous backfire (totally my bonehead fault) and pulled the heads off to make sure it was just the lower intake manifold gasket and not also a head gasket. After I did that and put it back together it has yet to do it again. No idea why. Still taking it back to the tuner so that he can do a custom dyno tune for it.