It's an 87 TII, and it starts right up when its cold, but once i get it up to normal temp, it refuses to restart after I shut it off. I've installed a fuel injector cutoff switch, because I thought maybe the water temp sensor was screwed up (but wouldn't the temp guage also be?), and it was just trying to start it rich, and it seems to work a little, but its still not where I'd like to have it. Any ideas? Thanks

 

The water thermo-sensor and your temprature sending unit are two different sensors.

Can you shut it off and immedialy restart? Does it have to sit for a few before it floods?

Rat

 

check your compression.

 

And how would this be affecting his hot start as opposed to his cold start? Generally speaking, if compression is an issue, the cold start would be more difficult then the hot start.

HOWEVER, checking compression is not a bad suggestion. I just dont think its an issue.

Rat

 

sounds like it's flooding. I would check the compression. strong engines won't flood... build a fuel pump cutoff, instead of your temp sensor one

TPS is also a factor for warm starts. but that usaly just makes the warm idle lumpy. should still start.

 

Hi:

There was a fellow with same problem. Can't find the thread since search not working. Also, don't remember if was s4 or s5 or na or t2.

In any case, assuming it's not actually a true flooding problem as others have suggested, the problem may come from a mal-functioning BAC valve.

If I remember correctly, the BAC valve is asked (by ECU) to supply maximum air possible upon hot startup. If you BAC is not working, then this could be your problem (it was the problem for this guy). To check the BAC, just follow instructions from FSM which you can get at www.fcs3s.org under tech->manuals (get section about fuel and emissions).

HAILERS may know a tad more about this so you could PM him for details.

Hugues -

 

If it isnt flooding then you are not getting enough fuel.

Try richening the idle mixture slightly. Dont do this if your car is flooding or has low compression though.

 

On that compression thing hot and cold. I do not know facts just using mechanical common sense.

When metal is cold it contracts. When metal is hot it expands. When a cold engine cranks the clearances should be tighter, hence more compression. When an engine is hot, clearances should be fractionally larger. Less compression.

The reason you do not compression check a cold motor. Unaccurate results.

Also, how are you using your fuel cut off switch?
I would think you would use it to shut the car down when hot. Is this how you are using it?

James

 

So you think the thermal expansion of aluminum is great enough to almost wipe out compression when the motor is warm, as opposed to when its cold?

 

I'm using the fuel cut-off when I start the car when its hot, and it seems to do a little bit towards easing the starting process.

hugues: the site wouldn't work, so I'll try PM'ing hailers

Thanks guys

 

Sorry for the typo

the site is www.fc3s.org

fsm is under how-to->manuals

Hugues -

 

I would think you would use the switch in this situation. Car is hot and you are ready to shut it down. So instead of using the key to turn it off. You kill the fuel pump. The car starves it self of fuel. Now no fuel is alowed to trickle into the engine via faulty/leaking injectors.

J-Rat - Not enough to kill compression. But enough to make it lower (hot compression). Hence, you do compression checks on warm engines. Unless you are trying to sell the car J/K

James

 

If you look at FSM section about fuel and emissions,
you will find a sub-section about "hot start assist system". Pages are 4A-80 and after.

This tells you how to check intake air temperature sensor and the solenoid that controls vacuum to the fuel pressure regulator, and maybe a few other things.
Please, check it out !!

hugues -

 

what wankel7 said. if the compression is already on the low side the expansion of the metal when hot, could bring the clearences beyond an acceptable level. thus low compression.

 

Okay, lets not hijack this thread. We can discuss this on AIM. I am not convinced, and alot of other people arent either.

Rat

 

Good call

James

 

I got this exact problem, I will try some of your solutions and come back and tell you if it works

 

Most likely, you are not getting enough fuel when you are starting your car (when engine is hot)

from FSM88,
the fuel pressure regulator raises fuel pressure for 90s when the ECU detects a hot start situation (via the intake air temperature sensor)

If the the fuel pressure is not raised during hot start, you may experience difficulty in starting a hot engine (some pple have removed all their emissions solenoids including the FPR solenoid, and it did not make a big difference, so I guess everything is relative)

The cheking procedures are well explained in the FSM

Hugues -