Engine Start then stall

[Sportriderseattle]

Does anyone know what's the deal with starting your MKIII and it will not go into nomral idle and simply stall out on ya? I've had an 86.5-n/a and an 87-turbo and both have done this on occasion. I'm sure you guys have had the same thing happen and it seems to only do it when the engine's warmed up and you restart it and the only way to get it going without stalling again is to hold down the accelerator for about 5-10 seconds manually, then releasing it to prevent it from stalling again?

 

[ChadMKIII]

Yeah, exact same prob right now. Have you ran your codes? If you don't know how its really easy. (Click here for instructions) I just had a HG job done, and I'm throwing code 51. My guess off the top of my head is that my mechanic made a mistake in re-wiring the TPS circuit. Dunno yet. Also, if you get a whole bunch of codes, reset the ECU (also on that link) and drive around for a while, then recheck after about an hour of driving under varied conditions. See what you come up w/ for codes then.

Just to double check your problem, what mine is doing is after same situation (restart after its only been sitting shortly and engine's still warm) it will flutter around between 0~650ish RPMs for ~5 sec and then just die. Holding the gas down and keeping it at about 1700 for 10+ sec will save it. Thanks for the thread cuz I was considering asking too ;-)

I'm really not good with electrical stuff, anyone have recommendations for how to see about the TPS and what to check in the wiring, or somewhere they can point me for good tips? Thanks guys.

 

[CRE]

Sportriderseattle:
Chad's right, check for error codes and then post back. Otherwise there are several things you'll be looking at, taking up more time than needed.

ChadMKIII:
If your mechanic only did the HG, not an engine swap then he shouldn't have had to rewire anything. Either you've got a short (alot of people's engine harnesses ave become brittle and as such prone to shorts when moved around alot) or you're TPS is misaligned/faulty.

I can't recall clearly, but I think I may have had a code 51 when my afm died.

The procedure for testing both of those is pretty straight forward and easy to do. Just pick up a cheap multimeter if you don't have one and follow the TSRM. If you run into a problem post up the specifics and we'll be better able to help.

 

[ChadMKIII]

CRE: Thanks, yeah a short sounds more likely than incorrect wiring in that case, I didn't know whether it involved removing it or not. But it didn't do it till after he replaced the HG, it started perfectly and purred right about at 700 before. It idles a bit higher now, too, so perhaps he just jostled it by accident and messed up the alignment? Don't know. I'll try to pick up a multimeter tomorrow. If I can get one I'll post up results, hopefully I can take care of this w/o too many n00b-ish questions for you guys . Still learning though, so I appreciate the help!

 

[CRE]

No apologies.... I'm learning everyday... Hell, I just made installing a MAFT Pro on a N/A look like the world's worst undertaking... hindsight, it wasn't that bad, just the delay in finding out which wire I mixed up made it tiresome.

PM me if you need help. You'll also need a feeler gauge.

 

[Sportriderseattle]

ChadMKIII: Thanks for the response and link to the diagnostic codes. It may be a few days before I get the time to check the codes. Anyways, it's really no big thing as my car only does this maybe once a month or so and like I said, the 2nd car that has done this and yes, you pinned it right explaining the issue and how you get the car to return to a normal steady idle. Also neither of my cars ever had a HG redone or any major work. FYI, I have never checked any codes on my car so that might be kinda fun.

 

[ChadMKIII]

SRS: Heh, yeah, first time I did was just a few days ago to check this problem out. It was kinda fun . Mine does this at least every day, so it bugs me a lot!

CRE: Just to let you know, my oil press gauge wasn't working either, the mechanic couldn't get it hooked up again (he's an oldschool guy, and hates electronics) so he referred me to a friend who does auto electronics and told me he'd pay the bill cuz he was sick of working on it lol. So I'm just gonna ask the guy if he could run the tests on the TPS at the same time, I just don't have time to right now. Maybe another time

 

[Figit090]

i thought this problem was called "heat-soak" and its really just a confused CPU that cant understand temp readings....thus improper fuel mixture that is only saved with application of the throttle. mine did that before my BHG fix...rarely.

usually it was after driving around, shutting it down, shopping, and starting it up after 30min/hour of sitting.