Cold start problems, then wont start when warmed up!

Hi,

I am in the process of fixing one of my Golf's and am having an issue trying to get it running properly.  

The problem comes when trying to start the car cold.  It fires up straight away, but dies more or less straight away.  If i hold the gas on for a few mins at around 2000rpm it warms up and will then rev freely without cuting out (it is a little lumpy though).

Today when i warmed the car up i thought i would have a look to see why the heater fan wasn't working so i stopped the car to have a look at that then when i tried to start it again it wouldn't start!  I thought i had broke something but when i went out to the garage this evening it went back to the same problems i am having trying to start the car from cold!

It's an 83 GTI with a DX Engine and is completely standard if thats any use.

Any help given will be greatly appreciated!!!

have you been messing with the fuel injection setup?

No, haven't touched the fuel injection, other than replacing the fuel pump…

check the aux air valve out ?

I'll have a look to see what an aux air valve is, and where to find it! I'm sure a haynes manual should tell me. Is this a part i should replace or clean up and use? Am i looking for anything in particular?  Sorry i'm no technician, i just give things a go and get my hands dirty.

Pulling my hair out now!  Taken off the aux air valve and cleaned that up and it has made no difference. changed the cold start valve recently, and i had a look at the WUR and cleaned that up too.  Does anyone know why the car wont start with a warm engine???

All help greatly appreciated!

Disconnect the cold start injector plug and see if it starts any better, the thermotimeswitch may be faulty, it will be a little slower to start when cold but will start after a second or so of turning over.

I tried starting the car with the cold start plug off, and it wouldnt start.  put it on again, let it run for 15 mins or so then stopped it for a few mins. tried to start it again both with and without the cold start valve pluged in still no luck… any ideas what else it might be?  could it still be the WUR or the aux air valve?

have you checked the fuel pump is working correctly? check the connections are sound at the pump,
failing that  probably either the coldstart valve is faulty or the thermo-time switch

they are the usual suspects with cold or hard starting probs.

then its time to check fuel pressure.

go thro methodically and you`ll sort it :wink:

Hi mate.

I had a similar problem with warm starting, (leave it 5 mins and it just would not start. it was always fine when cold though) which turned out to be the fuel metering head leaking and not maintaining enough pressure in the system. Put a replacement on and it was fine for a while, but the problem has reared it's head again. Not quite so bad this time as it usually starts after a lot of cranking with the throttle planted down, but frustrating. I've been told it could well be the WUR. I've got a replacement but not fitted it yet so cant say. I do have the old filler neck problem and I know that the tank is contaminated with a bit of water so thought I should sort that first.

Anyway, good luck and please post it up if you find a cure !.

Paul

its cold starting i think is the prob? not warm :dontknow:

check the pressure relief valve in the metering head it might have seized.

Sounds like its way too lean but that could be caused by a lot of things including the WUR :-)

It should be able to start cold without the cold start injector, will just take a few more cranks than it normally does (unless it is properly freezing ;-) ) I think you really ought to do a fuel flow test like described in one of these pages, and also see what CO levels are at the moment to see if you need to richen up a little

sounds a bit like the injectors to me for the cold start problem, worth doing the old faithful injector test on them (linky for it is on the left)

I've got the same hot starting problem (that I've been trying to fix for far too long now).. mines down to a complete loss of fuel pressure once the car is switched off (although I can get it started again upto 5-10 minutes after turning it off… after that it's a no no)

probably worth checking that the fuel system holds pressure once it's switched off

thanks everyone, i have a lot to check now!  Dont know how to do most of it, so i'll start with the simple things and then have a look for some guides on here.  Gonna be a while..

If anyone else has an idea of anything else i should be doing as well let me know.  Ta

i had a hot start problem once it was warm it wouldn't start, i replaced the starter switch, seems fine now.

i have got the same prob and cant get to the bottom of it yet . its when been out and the car is hot and you switch car off it will not start until cold.can start it by putting wire from battery to wire to the start and it will start iam banging head on wall . the way i start it one day same will think i have nicked it lol asking for help to fix the problem please .thanks dek

Little bit of an update.  i have just changed the fuel lines as one had a leak in it.  at the same time i replaced the WUR with one from crazy quiffs that was tested, i also replaced the AAV with a tested one from crazy.

Engine cold, turned it over, and it fired up straight away.  It seems the WUR was possibly the root of the cold start problem.

if i let the car warm up, turn it off, then turn the ignition fairly quickly it will start.  If i leave the car for 10 mins or so it will not start until it has cooled down completely.

Still some investigation work to do here i think, but if anyone else has had this or a problem that sounds like this and overcome it, let me know how you did it!

Thanks

mine is in the garage now with a hot start problem so once i have it back i will let you know what they have done