I normally can figure these things out myself by searching. This one has me a bit confused. Got the letter for emissions the other day. So I put a stock TB back on. Got rid of my codes and put the egr pipe back on. Zeroed out the cam pulley. The car then spectacularly blew the headgasket (I guess it didn't like the stock crap). Car has 140k on it. Stock internals. Did headgasket (want to get it thru before I pull engine and do a bigger rebuild). Now I have a strange low idle problem. It does NOT waver between rpms (maybe by 30 to 50 but nothing like normal intake leak style waver). Stays at around 500. Sounds as if it has race cams. Almost like all cylinders aren't firing (they are). I'll give you a run down of my process:

1. clean and check iac
2. check tps (used the oven to warm up but should be ok)
3. Comp check 150,150,150,152 real good for all the coolant that I smoked through those rings)
4. New wires
5. new ngk's set at .045
6. No cel's at all
7. Checked spark. Strong blue and affects all cylinders.
8. no intake leak.

Here's the real confusing part. It picks right up from that low idle. No hesitation at all. No popping, no lag. Falls back down to idle without a cough or a waver. The only problem with this is at that low idle it gets smelly. Rich smelly.
I still have the AFX/ECU on there so I called Howell to try to get info on it but all I could get (when I finally got someone) was "I don't think we play with the idle" and "it runs leaner up top". Wow what info! He did repeat that they aren't emissions certified.

So I wonder if the maps on that ECU do make it run rich at idle. I don't know I am at a loss right now. If I need a stock ecu then fine, I'm in the market for a 97 mtx ecu.

The only other thing that I noticed was when I pulled the #4 spark plug wire it ran a little smoother (at idle) but, of course, it would stutter it's way up on the rpms. Probably just an anomaly.

I made this so long so that I could hopefully cover some of the "usual" answers. Right now I am anxiously awaiting any help at all.
Thanks, MB

Oh yeah, and Brian if DJ does not want those cams let me know. I'll need them for the winter rebuild.

Is the timing bang on?

I eat emo kids for breakfast

1995 Eagle Talon (SOLD)
72' SuperBeetle
72' Standard Beetle
56' Deluxe Beetle

This happened one time when my upstream 02 went out, i was getting like 8MPG and it was so rich at idle it was ALMOST stalling. uhh I'm hoping your asking this question *post* replacing the HG? if so any oil leaks at the head? A car will idle like shit if the HG is blown or leaking

///97 Eclipse GS\\\
-Greddy Header-Greddy Evo Catback-AEM Short Ram-3 Angle, P&P (AMM Work)-B&M short Shifter-Symborski Kit-

One more thing; I replaced the UDP with the stock unit. Any more takers? Does anyone know if the AFX/ECU even reads the downstream o2? No cel but maybe this is the problem at idle? Still grasping. Anyone got a 97 ecu for me to check with?

MB

Could be a result of you resetting the ECU. I'm not sure how quickly the af/x will be able to relearn the many miles you put on her before hand. Goodluck!


Wouldn't be a tank of bad gas would it? Premium, corect?

Good shot on the ecu reset. I have found that the AFX does take longer than the stock to "learn" the engine. But normally 100 miles is more than enough.
Yeah, nothing but 93 in there. Possibly bad tank of gas but that would normally affect more than just idle. I've got about 250 on it so we'll see in a little bit here.

Thanks for the help. It makes me think about possible fuel filter? Usually a clogged filter is a top end problem but it would not hurt to change.
MB