Mk2 16v fuel issue - advice required!

[Ad16v]

Hi all,

This is my first post on the forum - apologies that i need assistance straight away!

Bought a 1990 Mk2 GTi 16v six months ago. Haven't had any major issues with it until last week...

Had driven all round South Devon for the bank holiday weekend with absolutely no problems. But on Tuesday morning on my way to work the car momentarily lost power. It picked up again but then began to lose power again (engine was still running - but revs were not holding) and eventually after a lot on kangaroo-ing up the road, it gave up. It started a few times but i could not maintain any revs and the engine would cut out again. It very much felt like it had run out of petrol. This was not the case as I had filled up the previous evening.

So Mr AA man came to my assistance an hour later. He was unsure of the problem, and as I had conveniently broken down around the corner from my mobile mechanics house - he towed me there.

My mechanic had a look and by the end of the day he seemed to have cleared the issue, putting it down to an airlock. Ran it about 10 miles with no issue. So i picked it up and drove home with no issues. Next day - on the way to work again - it did exactly the same thing.

Its now back with the mechanic. I have scoured the forum for solutions to what seems to be a fuel issue. There are loads of people that seem to have had similar issues but i cant find a post where they say how they fixed it!

So i have a few questions:

Can the fuel pump be partially working? By that i mean can it be pumping the fuel through but not at a high enough pressure because it is faulty?

What pressure should it be? My Haynes says Injection System Pressure should be 5.2 to 5.9 bar but just want to double check.

The fuel seems to be getting to the fuel distributor with no problem- but not getting any further i.e not coming out of the injectors which is why im wondering if it is a pressure issue..

Im desperate to get the car sorted but dont want to pay out for parts i dont need i.e. new pump.

Any advice would be great.

Cheers, Adam

[Diamond Hell]

Swap out the fuel pump relay for a known good item, as a first port of call.

[DarnPB]

Or connect the fuel pump directly to the battery. The car will rev a little, but its a good way of fault finding. Worked for me years ago.

[monzablue16v]

Few thoughts.
You can bridge the fuel relay as well sounds like it is that but... When was the last time the fuel filter was changed? wonder if it's some crap in the fuel you have put in that is causing it? Fuel accumulator or lift pump in the tank, metering unit on the airbox could be faulty, intake leak letting un-metered air in.

[Ben Lessani]

How do you know the injectors aren't getting fuel - did you disconnect a line from the metering head? Some of the metering heads I've noticed have a valve that stops flow when the banjo bolt is removed - so you can't visibly inspect.

Have a flick through here .... http://www.golfgtiforum.co.uk/index.php?topic=99852.0

[Conker]

As already said, search the Mk2 section for "Lift Pump", it could be that.

Ignition/electrical problems could also give the same kangarooing symptoms, so don't assume its definitely fuel realted.  When my leads were shot I had exactley the same issues as you. Look at distributor, hall sender, dizzy cap, rotor arm, leads, spark plugs, coil, earths, battery leads/connections, TCI module, ECU, corrosion on the ECU lead connection.

Also check very carefully for air leaks on all the vac hoses.

Finally, does it do it from cold straight away, or only when the engine is hot?

[Ad16v]

Thanks for all the advice guys. I've been passing all the info on to my mechanic, as i havent actually been with the car since last Thursday when it broke down again. Both the AA guy and the mechanic said that fuel was reaching the fuel distributor but it did not appear to be coming from the injectors.

New fuel filter is first job to be done today.  Not sure when it was last changed but has not been done in the past six months i have had it. I changed the distributor cap / rotor arm / plugs about 8 weeks ago.

In regards to when it was doing it, it started up fine but after about a mile it started to lose revs and power. Managed to get about another mile stopping and starting. But then it gave up. Im not sure what temp it was at but i would assume not very high as hadnt been far. Hasnt started since.

Will keep up to date as different things are tested!

By the way, probably a stupid question, but where is the fuel pump relay?

[Ben Lessani]

Its in the fusebox - look at the Fusebox FAQ.

On mine, its no. 62 and position number 2 IIRC

[rubjonny]

90 16v will have it in the bottom right slot, #67, 80 or 167. unlkess its a late reg pre-90 in which case it'll be slot 2, same number on the relay tho.

I had exactly these symptopms with a blocked fuel filter, cold it would fire on the button, would all be well for a while then itjust wouldnt start at all, fuel to metering head but gets no further.

[Ad16v]

Thanks. Thats encouraging as the filter is being changed as we speak i think, so fingers crossed!!