MK3 Golf GTI not starter/runner help needed.

[bababoom]

So i bought a none running Golf on impulse, on the face of it, it should clean up and make a decent car. 
Its a MK3 2.0 8v 
140k
What ive done so far. 
Compression test all 4 cylinders are 150psi plus. 
Drained the tank and filled with fresh fuel. 
Have a good spark on all 4 plugs. 
had the injectors out and they are working as they should ie not stuck off. 
fuel pump cuts in and out as it should. 
cambelt timing checked and correct. 

The problem is it keeps flooding the plugs hence not starting. It was last run in September so its not been sat a long time. 
Ive fitted a new coolant and crankshaft sensors but still nothing. 

I'm at a loss now, really want to get it back on the road but starting to lose the will with it now. 

 





Thanks in adavance for any info 

[zeberdee]

Does it flood all 4 plugs , or just 1 ?

Could it be a stuck fuel injector or fuel pressure regulator ?

[bababoom]

All 4. From what i read a faulty pressure sensor it would cause poor running ie low fuel pressure and not enough fuel. 

[vitesseefi]

Coolant temperature sensor busted and making the ECU think it’s much colder and thus over-fuelling?

Also, have you tried a noid light on an injector to confirm that they are pulsing and not just “on” when cranking. Used to be a thing with GTIs (though possibly mk2, not mk3) that if engine earth was lost it would earth via injector wiring and cook the injector drivers with exactly that effect.

[bababoom]

Managed to read the codes today and this is what i got.
Is it telling me the ECU is gone or just that its reading it?

[welshpug]

did you hit the OK button?

[bababoom]

Yes lol it just takes it back to the main menu which then points to engine speed sensor that i changed yesterday. 
But Google says it will always show this until the car starts. 

[ejenner]

I've found what happens with my old car is as follows:

1. Leave it sitting for 6 months without starting

2. Try to start it, does not start on the first few cranks so keep trying

3. Dump a ton of fuel into the cylinders

4. It will never start


The fix is to:

1. Disable the fuel pump and ignition system

2. Take out spark plugs and burn the tips with a blowtorch or on a gas cooker. Initially the flame will be yellow which indicates you are burning off the petrol. When the flame goes blue like the gas flame the plug is clean and ready to refit.

3. Before fitting the plugs spin the engine over 10-or-so times to blast all the excess fuel and any other curse word out the holes.

4. Refit the plugs, reenable fuel and spark and try to start it again. Hopefully successfully!

[bababoom]

Nov 22, 2023 15:44:23 GMT ejenner said:

I've found what happens with my old car is as follows:

1. Leave it sitting for 6 months without starting

2. Try to start it, does not start on the first few cranks so keep trying

3. Dump a ton of fuel into the cylinders

4. It will never start


The fix is to:

1. Disable the fuel pump and ignition system

2. Take out spark plugs and burn the tips with a blowtorch or on a gas cooker. Initially the flame will be yellow which indicates you are burning off the petrol. When the flame goes blue like the gas flame the plug is clean and ready to refit.

3. Before fitting the plugs spin the engine over 10-or-so times to blast all the excess fuel and any other curse word out the holes.

4. Refit the plugs, reenable fuel and spark and try to start it again. Hopefully successfully!

Yep ive done this several times but no joy. 

[ejenner]

Back to basics then... you've done the compression test so that's good.

You may have checked these things already but have you verified that:

1. Exhaust is clear all the way through and no blockages?
2. Intake is clear all the way through and no blockages?
3. Fuel return line is not blocked and can vent fuel back to the tank?

[kevins]

you could see if it will run for a few seconds on easy start with the fuel pump fuse out, this would rule out the ignition side of things, next as sugested above I would put a light or scope on the injectors and check they are pulsing and also check the fuel pressure, bridging the coolant sensor with something like a 200 ohm resistor usually simulates a warmish engine and will rule this out.

Is this the era of VW where the ecu sits in a small pond? if so might be worth checking it for signs of water ingress.

[vitesseefi]

Like the easy-start suggestion. Have you ever had so
much as a cough from it?

We did own a P-plate one of these for several years which was mostly fairly well behaved, but did go through a period of random refusal to restart when hot. That was eventually tracked down to a dry joint on the fuel pump relay/engine management relay (though not before its eviction notice had been signed), so unlikely to be the problem in your case. I don’t recall any ECU pond/wetness issues while hunting down the problem.

Only other thought is that I’ve found dome NGK spark plugs to be rendered useless by a single fuel flooding event. New/lightly-used being worst affected.

[turbogeek]

With the Digifant mk2s, the check/fix for cold-start issues was to disconnect the coolant temperature sensor in the top hose, and see if it starts or tries to run any better. You'd probably generate a fault code for it being disconnected, but the ECU should default to a "safe/best guess" value for enrichment.