Ok, it's almost the end of the line for my car. Here's the deal:

Plain and simple, it's loading up on fuel for no aparrent reason.

224/230, JPR heads, SVO 30# squirters.

Open loop, cold start, it's fine for about a minute. Then the O2 mV start to take a climb from the nice 450 up to the 600-700 range.

Once the car gets into closed loop, you can see how all hell breaks loose.

LTerms just plummet to 108. STerms plummet down to 50 give or take.

I'm pulling 15 In Hg of vacuum. Plenty. Can't find a leak.

Have put in new A/C Delco O2's, plugs, wires, MAP, Hypertech AFPR with pressure set to 40 at idle.

My IAC shows "0" and the car is idling at about 950-1100, when the target idle is set to 800. I have done the copper pipe mod to the TB (BBK 58MM tb) and closed the blades via throttle stop. Have NOT run it yet, will do so later, but I'm not expecting a fix.

History: The car ran FINE on the first tune. A/F was very close to perfect, juts a little lean up top. On the dyno, the opti seal failed. Off came the opti, and crank seal was replaced. Then the opti seal was found to be the leak, and it was replaced. Put tune #2 in after car was back together, and it was pig rich. 10.5 AFR at tip in and leaned to 13.0 at 6K on the dyno.

This loading up on fuel is also causing a fast throttle movement stumble/cut out/hesitation, which is only momentary, but enough to throw you forward as the car falls on it's face.

I can't find any vacuum leaks, don't have any exhaust leaks, and can't find anything. My cat will glow red if I run the car around long enough. The car drives fine at part throttle, I just can't get into it. It's rich everywhere, and I can't figure out why.

Has anyone ever dealt with such a situation and fixed it, or does anyone have any advice? I'm quite sure it's something mechanical at this point as the car is fine coming off of a cold start, and as it warms up it starts to load up on fuel.

 

Is the stumble not there in open loop?

Also, change the plugs out.. I've actually had a bad set of plugs from the factory. When I rebuilt my last motor it had a horrible shake and I thought the machine shop didn't balance it correctly

Turned out to be 2 plugs. Both primary's would glow red at night and when i pulled them it looked like the plug had never fired before even after 500 miles.

Had a simular situation in my beater honda.

 

The stumble happens during open loop. It starts after about a minute of running off of a cold start, right at the same time that the O2 mV starts to take a climb.

The plugs are new NGK TR55's gapped @ .040 and all 8 are firing. The car idles fine, light throttle revs fine, fast throttle stumbles then revs fine.

None of the exhust pipes glow other than the cat, and it only glows if I've been driving the car for any length of time.

 

Start by adjusting the throttle stop screw until you get the IAC between 30-45 counts...

Adjust the injector constant accordingly...

what constant are you using??

raise the inj constant a bit..

the rich thing could be a bad calibration for the MAF too...

check all that out..

recommendations;

start with a stock tune and put 32# on the inj constant and then adjust the throttle stop screw.. see if that works

 

I did adjust the throttle stop and it adjusted the IAC, but then as the car warmed up the IAC would drive shut and the idle would come up anyway, a good indicator of a vacuum leak.

It doesn't matter at this point. I dropped the car off at the shop on saturday.

 

Have you tried hooking up an OHM meter to the injectors. I know it's at the shop now but I'm still suspicous of those injectors. I hope whatever it is that they find it for you. Good luck.

 

Well, I told the shop to put the car through a very full thorough diagnostic. So, we'll see......

I just hate the fact that I couldn't find/fix it myself. That's what's killing me the most at this point.