Stalling After 1 Minute Of Warming Up...

[Bassman 1]

My GTi starts every time and idles fine after about 20 seconds. If I drive off it goes for about another minute and then dies without warning and blipping the throttle has no effect.

 

I tried testing it today and started it from cold and held it at 1500 rpm for about 1 or 2 minutes and it was fine and then suddenly with no warning died. It will re-start straight away but as soon as I let go of the ignition key it dies again and depressing the throttle does nothing. After about 4 or 5 re-starts it is then fine and drives like a dream with a pretty good idle and does not stall when stationary.

 

What could this be? There are lots of articles on the SAD but, I don't see why this would be the problem as it is supposed to gradually close the air supply and surely holding the throttle at 1500rpm would not allow it to stall instantaneously like this regardless of the extra airflow supplied by the SAD?

[pugrallye 0]

is fuel pump running?

[Bassman 1]

is fuel pump running?

 

I presume so, because it runs happily for a minute or two before the problem and I can re-start the engine straight after it stalls and after a few re-starts all is well again.

 

I wondered whether it may be a fuel blockage somewhere becuase I had a problem with debris in an old Polo, but this was intermittent as the debris was floating around in the tank. With this it is a regularly occurence about 60 seconds after starting which makes me think that perhaps the ECU is trying to do something at this point and getting upset because something is not working?

[pugrallye 0]

trouble is engines normally idle quite happily with a dribble of fuel in the line, make sure firstly your getting fuel,can normally hear pump whining away, maybe something silly like a bunged up fuel filter. And air, no intake blockages. also check all vacuum pipes are connected then go from there, yes may be probs with air flow meter or sad if its an intermittant fault though, more than likely electrical...

Edited February 22, 2006 by pugrallye

[Bassman 1]

trouble is engines normally idle quite happily with a dribble of fuel in the line, make sure firstly your getting fuel,can normally hear pump whining away, maybe something silly like a bunged up fuel filter. And air, no intake blockages. also check all vacuum pipes are connected then go from there, yes may be probs with air flow meter or sad if its an intermittant fault though, more than likely electrical...

 

Thanks, but I'm sure it is not a fuel pump or filter issue. As I said it starts and runs fine and I can hold it a quite high revs (1500) and also drive off and it is fine. It is only after about 1 minute that something happens to cause it to suddenly stall. The airflow is fine as the car runs fine all day after this initial problem. It only points to something that happens as the car is going from cold to warm.

[fiji bob 0]

what rpm does it idle at when warm? maybe raising the idle speed a touch might help?

[Bassman 1]

what rpm does it idle at when warm? maybe raising the idle speed a touch might help?

 

... ... but it doesn't make a difference if it is idling or I am hard on the throttle, it still just instantaneously cuts out after 1 or 2 minutes when starting from cold. After a few re-starts it is then fine and will drive all day.

 

Puzzling.

[jonah 1]

Very strange. It's definitely not the SAD or anything to do with idle adjustments, has to be an electrical problem I think. Possible that the fuel pump relay could be playing up, or perhaps not receiving the ignition pulses that tell it to run the pump. Turning the key to Start overrides it which could explain why it starts and immediately stalls. Worth swapping it for a spare if you can get hold of one to rule it out.

 

Failing that, does that car have an immobiliser / alarm? Could be disabling the fuel pump or ignition when it shouldn't be for some reason?

[ALEX 98 1 Cars]

The SAD could be closing too early.

Or it could be gunged up so much that when it's half closed the muck seals the opening.

I've Never seen this happen but it's what I think is happening to mine as the idle is very rough for about 5 mins, 5 mins after warm up.

Hardly ever bad enough to stall though.

I'd check my SAD but it's such a pain to get to.

 

Edit:

Mine dose pick up with the accelerator though so like Jonah said yours does sound somthing not SAD related.

Edited February 23, 2006 by ALEX

[Bassman 1]

Possible that the fuel pump relay could be playing up, or perhaps not receiving the ignition pulses that tell it to run the pump. Turning the key to Start overrides it which could explain why it starts and immediately stalls. Worth swapping it for a spare if you can get hold of one to rule it out.

 

Where is the fuel pump relay?

 

I ask because I started it about half an hour ago and left it ticking over at 1300 rpm after a bout a minute I could hear a relay clicking two or three times somewhere in the driver's footwell, possibly near the ignition barrel. Next second it cut out.

 

After two re-starts I was off and away as normal.

 

When the key is turned to "Start", I can rev the engine briefly, but as soon as it is back to "Run" it dies. Could it be this relay?

 

 

Edit:

 

Quick search on the net and I found this:

 

"Up to 88 model's it is in a small plastic box near the battery, on the new style interior (phase 2) models it should be attached to the side of the ecu, above the drivers cubby hole - it's known as a tachmetric relay. Pull a spare from the scrappy as they are £40 from pug dealers."

 

As my GTi is a 1990 Special Edition it is really a Phase 1, but I will have a look on the ECU as this would be around the area I could hear the clicking.

 

Are they really £40 for a bloody relay!?!

Edited February 23, 2006 by Bassman

[jonah 1]

Yep yours will almost certainly be by the ECU (roughly behind the right hand air vent in the dash). Sounds quite promising for tracing your problem if that's what you heard clicking before it cut out.

 

There's more to it than just a relay which is why it's so expensive. It detects pulses from the ignition system to control the pump, switching it off if the engine stalls. It also runs the pump regardless of ignition pulses when you turn the key to start. So if it wasn't registering (or receiving) the pulses reliably, that would explain why the engine will run breifly when you restart it and then stall again.

 

One other check, did you notice if the rev counter does anything strange when it stalls? Especially if it happens while you're driving along - if you keep it in gear when it cuts out, does the rev counter drop straight to zero or does it continue to show engine speed as you coast to a stop?

[Bassman 1]

Yep it's the tachymetric fuel pump relay. I hadn't had chance to look at this as my 405 is off the road, but last night and this morning the car was cutting out after a minute as normal but then refusing to stay re-started for more than a few seconds and I could hear the relay clicking away like mad.

 

Took the relay out (in the rain), got on the train and brought it into work and sure enough I have a scorched pin and an obviously dry joint as mentioned in lots of previous threads. I am going to try and reflow it today (I work for an electronics company) and see if it improves tonight.

 

The PCB that the relay is mounted to looks like it has seen some heat which is why the joint has reflowed and become dry. I presume this is probably due to increased contact resistance in the relay, but it seems a bit of a swine to get to and clean up. Anybody know the part number for the actual internal open frame relay? (not the overall G Cartier number).

 

If it plays up again I will try a standard 12V nornally open relay from RS (~£3) and swap them over on the little PCB.

 

Will take some pictures if I can as this could be useful for anybody else with this problem.

 

Rob

[Bassman 1]

Pictures of relay before I re-worked the solder joint are here:

 

Tachymetric Relay

 

 

I reflowed the joint using lots of flux and fresh solder and gave the PCB a general clean-up. It is hard to get to the internal relay contact without de-soldering the device and I needed the car today and I didn't want to risk damaging the PCB.

 

Plugged it in last night and it has been fine. Not a permanent fix, but should keep me going for a while.

 

Thanks for the help.

 

 

Rob