por4ever

I have been having an ongoing intermitent problem talked about here:

https://rennlist.com/forums/944-turbo-and-turbo-s-forum/212523-vapor-locking.html

When I start the car for the first time in a day it idles like its on 3 cyl for about 30 sec then it runs fine. Then after about 30 - 45 min of driving the engine loses power and eventually dies.

Well now after upgrading the following parts: 55# injectors, 3 bar FPR, Vitesse chip, Accuboost. I am still having the same problem. After doing some reading I am thinking about the TPS. I don't have my multimeter and the car died on the way to Radio Shack to get another one It has also been suggested that I listen to the fuel pump. When I start the car the pump is rather loud then quiets down. But back to the TPS. Could an improperly set or a failing TPS give these intermitent symptoms?

Ski

Yes. \

There has also been a recent rash of injector wiring going bad on some cars, although the cars will run with three injectors firing if everything else is getting proper signals. But if one of the injector ground wires is going bad/grounding, then your going to have serious issues with the injectors firing.

But after reading, with what Chris has been saying, I would also check my rotor and cap, check my coil voltage as well.

As far as the ISV, if you go to LR site, technical, they give you a nice simple explanation of how to set the idle. You have to short out the ISV, just give it a read.

Did you clean your grounds? Also, someone mentioned the speed and reference sensors on a previous post - square plugs, back of the manifold, give these an unplug and plug back up - simple and can't hurt, but grab the plug and not the wire.

por4ever

I will definately set the idle tonight and also check out the TPS. The way it is acting really makes me think it is an electrical problem. When the car is running it runs great, all the power and no hesitation or stuttering. Also after changing all the parts the problem is not AS bad when it happens. It takes longer for the car to die. I reall do need to carry my multimeter with me until I can get this sorted.

hosrom_951

por4ever,
Yes, you need a multimeter to properly check the TPS on the TPS itself and on the DME connector. You could also check the injectors using a multimeter (will PM you some tricks).

PS: Nice car SKi

por4ever

How about this? What parts would you replace? It takes me about 5 - 7 days to get ANY part so I have to really think in advance about what I need. It is easier fo rme to replace then diagnose most of the time. So far I am thinking I need a TPS, and maybe a new injector harness from LR. Any thoughts?

ehall

I hate too say this, but I know I don't have electrical problems. I'm certain that I'm slowly losing the head gasket. The car will start, not be warm and want too die without A LOT of gas. Once warm it's fine. Block meet head. It's always a bit worse if it sits.

Peckster

The rough idle on cold start-up soubnds like a classic head gsaket [proble. Are you losing coolant? Check to see if one plug looks extra clean immediately after it's run rough.

por4ever

That is not what I wanted to hear . When it first started that was what I was afraid of too. I have checked the oil and I don't see any signs of that but I will check the coolant again tonight after work. Just so I can prepare for the worst does anyone know the hours for a headgasket replacement? That is way beyond my skill level.

por4ever

But wouldn't the symptoms be something that would happen with more predictability? Like I have said before all other times the engine is really strong.

hosrom_951

por4ever, did you get the e-mail i sent you??

Signs of a blown head gasket:

-Runs on 3 cylinders when cold, runs on all 4 after a few seconds
-White smoke when cold
-Always low on coolant
-Running hotter than normal
-Oil/coolant mixture

Better get a leakdown test/compression test to verify this, i doubt you'd find someone in Bahrain with a leak down tester (don't ask me why), but the dealer may have one.

por4ever

Hosrom, yeah thanks. As for the other items:
Yes
Have looked but don't see any smoke (but is it ever really "cold" out here?)
Coolant looks ok but I will look tonight
No coolant in the oil as of two nights ago

I will ask the dealer tomorrow. They have worked on my car a little lately so maybe they have noticed something.
It's just that when my 924 HG blew it really blew. Engine died, white smoke everywhere, coolant leaking. My only other experience is with 914's and they don't need to worry about this.