1989 1.6 Gti Running Problem

[lando9000 2]

Have a 1989 1.6 GTI.

 

I recently did a timing belt/WP job on the car and it hasn't been running correctly since.

 

The timing seems fine as it is running as it ran before. First time I started up the car from cold, she started fine. I leave the car running for a few roughly ten mins and go back out the car is not running any more and won't start. She'll turn over fine, she won't catch though. It appears to be when the car gets warm, it doesn't want to start. I tried a second time today and again, she started up fine and ran for about 5 mins. I went to get in to test the car in the yard and as soon as I put my foot on the accelerator, she cut out and wouldn't start back up again and there was a big backfire from the exhaust.

 

It's worth mentioning that I had an issue with the throttle body originally as I had not put it back together correctly but that appears to have been fixed as the car runs and starts fine from cold and will drive fine.

 

If anyone could shed any light on where to look next, it'd be appreciated. Would be great to get her back on the road after doing the TB + WP!

 

Thanks.

[Anthony 1,000]

Are you sure the cam timing is correct, as that's the obvious one if you've changed the belt? They will run one tooth out.

[steve@cornwall 100]

Usually run fine, but down on power when 1 tooth out, but rough with 2 out. Too much fuel on idle perhaps eventually flooding? Check wiring to coolant sensor or maybe too little air once sad closes? Will it idle longer with air filter disconnected?

[lando9000 2]

I don't think it's the timing. We marked up everything and turned it over twice to be sure the our marks lined up.

 

The car runs perfectly for 10 mins. I was able to drive the car 2-3km's from where I did the work down to my house and got the car home. I parked it up and left it running and it was fine for a few mins. I went back outside and gave it a small blip of accelerator and it nearly cut out. I then gave it a big one and the car conked to cut out. Then the car won't start after while it's warm.

 

The car started first time, no problems from cold.

 

I had someone say to me possibly a sensor into the thermostat?

 

I'll try disconnecting the air filter and see if it starts then. Is the coolant sensor just under the distributor?

Edited February 9, 2017 by lando9000

[steve@cornwall 100]

Yes blue one with blue loom plug

[toolie72 67 1 Cars]

Sorry to jump onto this-please accept my apologies

But what does coolant sensor do/how does it work? Does it power sad/tell it to open,shut fiik!!!

 

Yours nicebutdim

[steve@cornwall 100]

Tells the ECU to squirt extra fuel in the cold (basically) if open circuit it tells the ECU it's minus something stupid degrees and starts filling the bores up with go go juice. First time I had a failure it took ages to find. Got taken to independent garage, main dealer and couldn't be found so I bought it for peanuts!

[toolie72 67 1 Cars]

Ah right

So mine will just be open all the time then

-3 and getting colder yippee

[steve@cornwall 100]

If it's totally open it will most likely fire a few times, die and not restart. And you can fill the sump with fuel!!! But with age resistances increase, I often wonder how much increased resistances in wiring and corroded connections over time affect this component.

But replacing them often has a dramatic effect on running and economy.

With the one I mentioned above, to get it home it was tow- started and driven at high revs up the A30! It bloody flew! but conked out at the first roundabout and had to be towed.

Often the cause of hot start problems as they start to fail

[welshpug 1,621]

nothing at all controls the SAD, its a simple valve that gets 12v ignition feed and is also bolted to the thermostat housing, as it warms up the valve closes, very very simple very very reliable.

[steve@cornwall 100]

nothing at all controls the SAD, its a simple valve that gets 12v ignition feed and is also bolted to the thermostat housing, as it warms up the valve closes, very very simple very very reliable.

Is it not closed by bi-metallic strip heated by 12 V supply? So resistance drop affecting supply can slow the operation? IMO this is what can lead to stalling at junctions when the car is between cold and operating temperatures.

 

Saying that, the above is my conjecture, not in any way a proven fact

[welshpug 1,621]

yes they are, as well as the heat from the engine.

 

I doubt these are that refined that a bit more resistance in the wiring will make that much difference to how quickly it closes, i fit stalls too easily its usually part of the while setup of the system than a single part, including the charging system.

[toolie72 67 1 Cars]

Yeah always thought sad just got fed power but you wonder when they're both on the same bracket

So cold start injection time is set by temperature (would make sense I suppose) really pretty similar in principle to bimetal autochoke on carbs

[Telf 222 2 Cars]

Andy did you solve this?

 

It sounds like a timing belt issue to me- I rebelted mine last year and it slipped 2 teeth about 6 months later as I hadn't tensioned it correctly. Symptoms exactly like yours. I would start then got really rough as it heated up.

[lando9000 2]

Andy did you solve this?

 

It sounds like a timing belt issue to me- I rebelted mine last year and it slipped 2 teeth about 6 months -

Hi,

 

Sorry for the late reply. The car magically or not has fixed itself. I've been driving it all week - got about 250 miles on her.

 

When the suggesttion to check the blue coolant sensor came in, I decided to have a look at the thermostat as it was in there as well. I looked at how to get it off. While doing so, I think I messed around with the blue coolant sensor and it seems to be working now. I'm going to get a replacement one at the end of the month.

 

All seems to be working just as it was before now which is excellent. It's been a long time..

 

Thanks for all the help, everyone!

Edited February 18, 2017 by lando9000

[jackherer 543]

It sounds like the wiring or plug to the blue sensor is causing issues, it probably isn't the sensor itself if disturbing it has improved things.

[steve@cornwall 100]

The fog light plug from later peugeots makes a good replacement for this plug, I have a 306 item and wiring soldered/ heatshrink wrapped further back in the loom on my gti. (because mine was corroded inside and I was breaking a 306).