Won't Cold Start, Won't Warm Idle Very Well, Stalls...

[strikeeagle]

OK, I need help!

I put almost $2K's worth of parts into my buddy's (my old) 87 GN this summer and the thing will not cold start without giving it (some) gas (no fast idle at all), can't be moved before it's fully warmed up, doesn't warm idle especially well and stalls when you get out of the thing after a part throttle excursion.

The IAC readings seem to be all over the place - from 0 to 175. If you increase minimum air the idle drives to 0. If you back off it remains at 0. Now and then it jumps to 175. IAC *never* seems to make sense.

The car has a newly ported Steve Monroe TB, a new IAC, a new vacuum manifold, a new Angle Boss, new gaskets, new vacuum hoses, a new PCV and Tomka check valve, etc. In short, things have been gone through. I did disconnect the EGR and vapor canister this summer, and capped the associated vacuum lines. I even changed out the PROM, then the entire ECM - no difference.

What am I looking for, guys? Vacuum leaks? Spurious magnetic fields? I'm really stumped?

Thanks for any help.

strike

 

[strikeeagle]

Come on, guys? I *need* your ideas, please?

strike

 

[johnnyttype]

what kinda MAF u running? if stock i would try unplugging it to see if car will stay running. my last MAF was replaced because it would not run on cold start, IAC readings try to drop, engine stalls or comes close, IAC goes up to 150 and repeats cycle until car was warm. unplugged MAF and car ran as it should when cold. hth!

 

[strikeeagle]

The MAF is a NOS unit we bought from Steve Y. last year. It only has a few hundred miles on it now, but I'll give it a try.

Thanks for your response.

strike

 

[artrenee10]

Is the IAC an AC Delco? If not you may want to try one...

 

[strikeeagle]

Yes, the IAC is an A/C from Caspers...

Thanks for your response.

strike

 

[TurboDave]

Here's something to try for the sake of troubleshooting.
There's obviously a reason for the angle boss (large intake tube).

So, remove the intake tube, replace angle boss with a stock unit/IAC motor.

So how that behaves. It wont hurt anything for the turbo to be sucking directly as long as you don't drive much and not in dirty air.

I just noticed you're still running a maf, so try and reduce tubing size to allow for the temporary use of a stock style IAC setup.

The reason for all this is to point to, or eliminate the angle boss as a source of the problem.
Some of them have been very problematic, especially if it's a complete unit.
The ones that just rotate the stock IAC housing are much safer.

 

[strikeeagle]

Dave,

The car uses a NOS MAF I purchased from Steve Y. last year (?). I suppose it only has a few hundred miles on it now?

The car uses a new Tomka 3-1/2" cold air kit, hence the need to rotate the IAC. I used an Angle Boss for this purpose.

The TB is a "new" 62 mm unit from Steve Monroe.

What kinds of problems have folks been running into with the Angle Boss?

Thanks for your response.

strike

 

[TurboDave]

Dave,

The car uses a NOS MAF I purchased from Steve Y. last year (?). I suppose it only has a few hundred miles on it now?

The car uses a new Tomka 3-1/2" cold air kit, hence the need to rotate the IAC. I used an Angle Boss for this purpose.

The TB is a "new" 62 mm unit from Steve Monroe.

What kinds of problems have folks been running into with the Angle Boss?

Thanks for your response.

strike

It has to do with improper pintle seating. No specifics since it's been too long for my "old" memory to recall all the details.

Your issues seem to be IAC related which is why I recommend removing the angle boss to confirm or deny it's part in the issue.

 

[strikeeagle]

OK. I also vaguely recall seating problems. I'll give that a shot when the car gets back from Ohio - Vince Janis is straightening out the "backyard job" my buddy's "mechanic" did on the tranny over my good advice - the tranny hasn't been right since. Big surprise...

strike