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Breakdown

My 1985 mk2 8v kjet Gti has become totally unreliable and has broken down twice on me in the last week.
The 1st time doing appropriate 60mph the engine died, just completely shut off.
After maybe 45mins it started again and I just about got it home. Took it to my local garage but because at the time it was running he suggested a new fuel pump relay,which I've now replaced.
Tonight it did the same totally died but this time it wouldn't start(just turns over), I returned home on the back of a recovery truck.
To say am annoyed with it is an understatement, I pushed it into the garage a couple of hours later the rusty tart starts.
Am at a loss what to try, I only understand the very basics. Could it be the coil?
Thanks for any advice I appreciate it.
Trying and mostly failing to keep a rust old tart of a golf on the road.

Re: Breakdown

Reply #1 –
We would need to know more, do you have a spark and no fuel, or fuel and no spark or nether?  How did it fail, gradually or did it feel like you had switched it off?  Are there any security devices fitted?

Re: Breakdown

Reply #2 –
Quote from: tabbie on
Quote from: PWardy on
We would need to know more, do you have a spark and no fuel, or fuel and no spark or nether?  How did it fail, gradually or did it feel like you had switched it off?  Are there any security devices fitted?
Am not sure about spark or fuel as I had no tools at the side of the road.
There are no security devices fitted, it's as if the engine is just switched completely off.
It's done it afew times over the last month but usually starts up again.
The last week tho its totally broken down twice and wouldn't start.
Thank you!!
Trying and mostly failing to keep a rust old tart of a golf on the road.

Re: Breakdown

Reply #3 –
My GTi is a Digifant, if the fuel pump failed I wouldn't expect it die instantly, it would struggle on for a short distance as the pressure in the rail reduced.  You know it is not the fuel pump relay and based on your description of how it failed I suspect an ignition failure.
First off I would check all electrical connections around the dizzy and coil.  You are looking for fatigue and broken strands and or corrosion.  If you find nothing carry a basic tool kit so you can investigate while waiting to be recovered.

Re: Breakdown

Reply #4 –
Quote from: PWardy on
My GTi is a Digifant, if the fuel pump failed I wouldn't expect it die instantly, it would struggle on for a short distance as the pressure in the rail reduced.  You know it is not the fuel pump relay and based on your description of how it failed I suspect an ignition failure.
First off I would check all electrical connections around the dizzy and coil.  You are looking for fatigue and broken strands and or corrosion.  If you find nothing carry a basic tool kit so you can investigate while waiting to be recovered.
Am at the point I can not even trust it to drive to a garage,  I might have to get a mobile mechanic to look at it or at least take out a yearly roadside recovery (apparently some don't accept classic cars)
Hopefully Eddypeck will be along soon as he knows the kjet injection better than most.
Thank you PWardy I appreciate your help.
Trying and mostly failing to keep a rust old tart of a golf on the road.

Re: Breakdown

Reply #5 –
Breakdown cover, we have Auto Aid at £70 personal cover or whatever you're in. Use it once and you've saved. Like most though I think they won't cover the same fault.
Mk2 Golf Riviera
Other toys

Re: Breakdown

Reply #6 –
@Eddypeck does a KJet just switch off or does struggle for a short distance as the fuel pressure drops following a fuel pump failure?
If you type @ before a members name your question will be notified to them.

Re: Breakdown

Reply #7 –
K-jet is super dependent on the correct fuel pressure.


Some factors and considerations:

The in-tank fuel pump 'lifts' the fuel out of the tank and creates a syphon to continually feed the swirl pot where the main pump sits. The under-car high-pressure pump then sends fuel to the front of the car so that there's something like 10 times the amount of fuel needed, permentaily available at the injectors - hence, the Continuous Injection System (CIS) unused fuel is returned to the tank and the cycle continues.

If the in-tank pump (the cheap one) fails (this is the same part regardless of Digi or K-jet) it can go unnoticed as the high-pressure pump (the expensive one) does have the ability to pull fuel through. However, this put the high-pressure pump under additional strain and it will likely not last long under these conditions. - The car will become unreliable and you'll have symptoms of poor running, and fuel starvation.

You can crack the large nut on the fuel pipe at the front of the air box and turn the car over to confirm you have fuel at the engine bay. If you have no fuel there's obviously a problem but if there is fuel this is fairly inconclusive without testing the pressure.

The cold start (or 5th injector), gives a quick squirt of fuel straight into the intake chamber past the throttle body. To aid with starting from cold, this has no impact on continuous running, however, some people have reported that unplugging this helps the car to run better. It never made any difference to me.

The Warm Up Regulator (WUR) has a biometric strip which adjusts the pressure when the engine is up to temp - a 16v one is adjustable an 8v one isn't, it either works or it doesn't.

The metering head, is the big metal flap under the rubber boot on top of the air box - an easy check is to undo the jubilee clip and lift the boot and check this is clean and free moving. A can of carb cleaner can be useful to remove any built-up grime. If it's particularly oily check the breather hose which feeds from the cam cover back into the airbox, this may be gunged up, it's worth removing and cleaning but be warned it's very brittle if it's still the original hard pipe.

Vacuum and air leaks are the next biggest issue, the vacuum system needs to be sealed and in good order, with it idling spray WD-40 or carb cleaner around the engine bay, following all the pipes and tubes if the revs go up then there's a leak, the engine has just sucked in your spray, and it's acted as a catalyst to give the engine a quick extra burst of power. The larger rubber Y piece behind the intake manifold can be a problem.

This chart is good for diagnostics, and should help narrow things down



And of course more info here. But in short, unless you hook up to a fuel pressure tester anything else is guesswork.

https://www.vwgolfmk2.co.uk/clubforum/index.php?topic=114.0

Re: Breakdown

Reply #8 –
Thank you for all the replies.
Considering the low cost of the in-tank fuel pump it maybe worth trying? I've replaced the expensive one afew years ago.
I'll be checking the metering head for sure and will check the  WUR if possible (Haynes manual might be worth looking at)
Am praying its not a vacuum leak as that will be a bitch to find.
Thanks @Eddypeck I will work through your list I appreciate it alot.
Trying and mostly failing to keep a rust old tart of a golf on the road.

Re: Breakdown

Reply #9 –
One thing to bear in mind, most fuel/k-jet related issues will not be intermittent (unless related to the WUR, where the issue is only when cold/hot), the symptoms are normally hard to start, rough running, or lack of power.

I'm tempted to think your issue is not related directly to the fuel system. It could be indirectly related, say a broken wire to one fuel pump which makes contact, and then doesn't.

As per your original comment you mention coil. Ideally, you need to determine which you don't have fuel (pressure) or spark.

Re: Breakdown

Reply #10 –
Agree with the above, but to add my 2 cents -

I had the same symptoms on my Kjet, I changed the fuel pump relay and it was fine, briefly - but then the issue came back. I think the recurrence was caused by a loose battery negative lead, since tightening it up and cleaning the earth there for good measure, it seems to be fine. Touch wood.

Will keep an eye on your updates, hope it’s straightforward for you.

Re: Breakdown

Reply #12 –
Quote from: Eddypeck on
One thing to bear in mind, most fuel/k-jet related issues will not be intermittent (unless related to the WUR, where the issue is only when cold/hot), the symptoms are normally hard to start, rough running, or lack of power.

I'm tempted to think your issue is not related directly to the fuel system. It could be indirectly related, say a broken wire to one fuel pump which makes contact, and then doesn't.

As per your original comment you mention coil. Ideally, you need to determine which you don't have fuel (pressure) or spark.


thinking about it Eddy it has been a pig to start once warm for awhile, when it's cold first turn of the key.
Not sure if this is related.
Once again thank you peeps much appreciated for a the advice, it all helps.
Trying and mostly failing to keep a rust old tart of a golf on the road.

Re: Breakdown

Reply #13 –
OK it looks like its got no spark but only seems to happen when warm, am I correct in thinking maybe it's the coil that's breaking down when it gets hot?
Please remember I only know the very basics, I have a mechanic that's knowledgeable about mk2's and K-jet but I'd have to trailer it to him,  the way it is at the moment.
Thank you for any advice on the rusty tart.
Trying and mostly failing to keep a rust old tart of a golf on the road.

Re: Breakdown

Reply #14 –
I’m still sticking with the advice I gave previously.  Check all of the wires around the coil and dizzy. All you have to do is start the car, stay clear of the moving parts snd start pulling wires. Only touch HT with insulated tools. If the engine stops you have most likely found your fault.
Only once the simple stuff is eliminated move on to more complex things and spending money.