I need major help :/

[yayo01]

1987 GTi
PL 16v with 143k miles

The car runs fairly well, unless it's warm/hot outside which really sucks because I live in San Diego.
The motor has New Bosch plug wires as well as plugs,
New coolant temp sensor,
New o2 sensor,
all vacuum lines have been renewed,
injector o-rings and cups have been replaced,
it has a re-manufactured fuel distributor,
new transfer pump and main pump,
new fuel, air, and oil filters
all ground connections have been cleaned and coated with dielectric grease
new fuel pump relay

yesterday it was pretty warm outside and my car would not start, I let it sit for about 5 minutes and it started and ran fine. Today it started fine then 2 minutes later it shuts off and doesn't want to start, I let it sit for a minute then it starts and again just shuts off. WHY??
(This is not the first time this happens)
Any help would be greatly appreciated.

[Jones84]

Fuel pump relay.. When they get hot they stop working sometimes. I have had this happen to many customer cars and mine.

[ps2375]

You need to determine if you are missing fuel or spark when it fails to start. An easy way to do this would be to carry around a timing light. Then you can throw it on to check for spark. And I also did not see an ignition switch on the list, those are known to fail and cause weird problems.

And you can also pull the fuel pump relay and jumper it to see if it is the relay or not, at least you could rule out the relay.

[antichristonwheels]

replace the check valve on the output of the fuel pump. it is supposed to maintain system pressure with the car off. about 15 bux

[EL GOLFO DE MEXICO]

sorry for not really be helpful but could you tell me all the grounds locations please

I'll really appreciate it

[broke..]

a bad fuel accumulator will cause this problem too... or so i was told.

[8716vrocco]

Fuel pump relay.. When they get hot they stop working sometimes. I have had this happen to many customer cars and mine.

This. Mine would run for a while, relay would get hot and car would die out. Wait a little bit and it would fire right up, then die again. The relay is pretty cheap and you could probably walk into the dealer and get one.

[yayo01]

Thanks for the input, I will try the fuel pump relay first then go from there.

[Youngfonza]

Does anyone have a diagram that shows the correct temp sensor switches in the rear of the head? And I would like to know the proper wire configurement as well. One of mine came off while at the shop and I don't know if I don't need the connection and they removed or w/e the case is.

Furthermore my fan has not been coming on lately, at what temp should my fan come on? I just wanna make sure so the summer does bite me in the arse. Thanks for time: and sorry for thread jacking.

[ps2375]

Does anyone have a diagram that shows the correct temp sensor switches in the rear of the head? And I would like to know the proper wire configurement as well. One of mine came off while at the shop and I don't know if I don't need the connection and they removed or w/e the case is.

Furthermore my fan has not been coming on lately, at what temp should my fan come on? I just wanna make sure so the summer does bite me in the arse. Thanks for time: and sorry for thread jacking.

All that info is located in a Bently Manual.

[Jones84]

All that info is located in a Bently Manual.

The best tool you can have in your tool box...

[yayo01]

So I replaced the fuel pump relay and started the car, it all seemed fine until the car reached operating temperature then it turned off. This time it fired right back up and didn't turn off anymore. I don't know if I should call it fixed yet though... could this issue be caused by timing in any way?

[ps2375]

doubtful

[shraouf]

So I replaced the fuel pump relay and started the car, it all seemed fine until the car reached operating temperature then it turned off. This time it fired right back up and didn't turn off anymore. I don't know if I should call it fixed yet though... could this issue be caused by timing in any way?

are you sure that the mixture is set correctly ? try enriching it if that happened again but keep a record of the old setting in case it didn't help
The fuel dizzy should lean the mixture whenever it reaches the operating temp, if it was already lean when cold then that would shut it off.

[yayo01]

So I've driven the car these past few days and nothing related to what I described has happened.
I'm going to knock on wood and say that it is good to go

[Glegor]

if the terminals in the fuse box are dirty AT ALL then the fuel pump relay can act up, just like you describe..

my 86 GTI used to do the SAME THING as yours, so i pulled the fuel pump relay, checked it, and there were a few dirty terminals, mainly the TINY one, and thats the one where the coil signal goes to. if the relay has no coil signal, it shuts the pump off.

i cleaned the fuse box connection, and the relay connection, and plugged/unplugged the relay a few times to get any junk out of the connector that i could.. then i eventually just replaced the relay with an audi 4k relay (to remove my rev limiter, im running CIS-lambda) and i havent had the issue since then.

i would lean HEAVILY towards a fuel pump relay as the culprit..