2.1 DJ Wont start when hot and possible fuel issue

[burnzdog]

Thank you that's a new one to check, defintely similar issue.

[Robsey]

Have you looked here - easy reading about the DJ set up.

http://syncrosport.com/info/wiring/VW_T ... -92_DJ.pdf

I am wondering if it had air-con in the past, but has since been stripped out?

Or is it a digifant loom?.. in otherwords for an engine with an oxygen sensor.

If the van previously ran okay, and you have not made any engine bay wiring changes, I would not look for issues with the connectors that have been tied up out of the way. It is too easy to become paranoid about "spare" connectors.

The one thing that I can answer with certainty is the sensor question.
Yellow wire with red stripe is the temperature sensor for the dash temperature gauge.
If the dash gauge works as it should, and appears to be reading approximately correctly, then it does not need any further investigation.
-‐-----------------------------
Now that I have read it all again...
If you can smell fuel, and it 'appears' to be struggling, it could indeed be a fuel line issue.
Leakage causing an air leak (poor mixture)
or partial blockage causing restricted flow -
Especially if you are running old fuel lines.
Not sure if it is relevant whether you have been running on E10 yet. (?)

[burnzdog]

As a quick reply....now you mention fuel.

The day the problem first started, I had E5 in the tank and I topped up for the journey and it may well have been E10. I can't be certain but it may well have been.

Would the mixture cause the issue?

[Robsey]

Not so much an issue, if you have only just put E10 in.

I was referring to the blurb about E10 rotting out fuel lines.
Probably a time to look at renewing the fuel lines with ethanol safe hoses, if you haven't already done so.

But old fuel lines was my thought overall.

[burnzdog]

Have you replaced the temp sensor ?

Temp 2 sensor replaced and still no different.

Give your pride and joy a proper service first. Including plugs, leads, dissy cap and rotor.

When you waited for engine to cool before restarting did it run normally again?

The Temp 2 sensor is easily tested. Its in Bentley. As are various tests around the DJ to establish the fault.

However, aside from my previous post about checking injectors, I would start checking colour of spark plugs and by testing spark plug leads (again in Bentley).
Then check dissy cap and rotor for wear.

If fault continues plug together the two leads connected to the idle control magic (by coil) box then try starting again.

Picture of spark plugs ... Any feedback on these?


 

[Robsey]

The obvious (to me) observation is that the plugs on the left look blacker at the tips and the threads look wet.

Blackness inferring a rich mixture, and wetness possibly being oil.

The right pair of plugs don't look too bad.
A bit of residual blackness from fuel enrichment when cold, but the electrode tips themselves are a nice colour.

Those plugs have clearly been in a good while.
At the minimum they need a good clean and re-gapping.

Although, ideally if the rest of the ignition system is in a similar age and state, then I would be lacking if I did not say "just fit new plugs, leads, rotor and dizzy cap".
Easy to say, as it is not my budget.

If you are watching your wallet, check, clean and wipe dry all the parts.
That includes the plug lead ends.

It will give your engine a better fighting chance.

[burnzdog]

The obvious (to me) observation is that the plugs on the left look blacker at the tips and the threads look wet.

Blackness inferring a rich mixture, and wetness possibly being oil.

The right pair of plugs don't look too bad.
A bit of residual blackness from fuel enrichment when cold, but the electrode tips themselves are a nice colour.

Those plugs have clearly been in a good while.
At the minimum they need a good clean and re-gapping.

Although, ideally if the rest of the ignition system is in a similar age and state, then I would be lacking if I did not say "just fit new plugs, leads, rotor and dizzy cap".
Easy to say, as it is not my budget.

If you are watching your wallet, check, clean and wipe dry all the parts.
That includes the plug lead ends.

It will give your engine a better fighting chance.

Leads are fine and I replaced the plugs today. I cleaned and checked cap and rotor. From cold it fires first time and sounds fine. The issue is, it seems, is the fuel air mixture when the engine warms. Throttle from cold is fine, as it warms up throttling becomes worse.

I don't really have means to test injectors so I will need to send it somewhere.

If anyone can recommend someone in the wiltshire/Gloucester/oxfordshire area.

[Stesaw]

I forget the place in Hull that refurbs injectors. But everyone who uses FI swears by them.

[ajsimmo]

http://www.injectorcleaning.co.uk/

Can't see that anyone answered the other question - it's your temp gauge sender.

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[burnzdog]

OK thanks for that, that's all working. Will look at cleaner but I think if there was a issue with injectors it would effect the overall performance. I think it's something to do with balance of air /fuel when warming. I've no idea what that's means but thats what I see.

[ajsimmo]

Yeah, i agree. I didn't say it was your injectors, I was just answering previous question of who's that company in Hull?

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[ajsimmo]

Just looking through this thread again, seeing what I can glean. It's a Syncro, with a lambda probe connector but no probe, and fuel hoses wrongly routed on the engine. The hose connector is most likely a fuel tank breather connection designed to keep water out while wading.
Can't see the dissy, so can't tell if it's vacuum or not (digifant or digijet). The behaviour you describe suggests a Digifant setup, as the Digijet with lambda input is quite a rare beast (mostlu US spec 1.9s like GW or DH).
Can you confirm your dissy has vac, and does your ecu say digijet on it?

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[burnzdog]

No vac on the dizzy

[ajsimmo]

Right, so not strictly a DJ (although engine number may say so) as it's running Digifant. Your problem may be due to a spurious back voltage in the lambda probe cable (or its shielding) causing the ecu to alter fuelling/timing away from the default map. This can happen if you have a bad earth elsewhere, or a cable clipped to an ht lead inducing a pulse to irritate the ecu.
I'd look at fitting an O2 sensor, checking the loom for breaks/corrosion etc. and making good all earths. That diagram you have is an early setup with twin throttle switches. Check the pinouts against a late Digifant diagram, and that the ECU is the correct one.

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[burnzdog]

How can you tell if its running digifant or digijet? I'm not sure it has a lamba problem as I thought you only have these on specific engines not the DJ?