T4 2.5 petrol drama

[slugger95]

Hi Guys

Had this 1995 T4 for about two months now,has done about 280k so far. Good service history. Runs quite well most of the time. Had the oil cooler replaced the other week @ $400. Had the fault codes reset in the computer at the same time and did run better.
Took a trip up the coast over the weekend 650k round trip and on at least a dozen occasions while travelling at 100k the engine cut out but only for a second and then carried on as usual.

On one occasion after turning engine off in a car park it would not start again, turned over all right but would not fire for about 5 mins. Gave it a rest again and tried again and then it stated again no probs.

When driving it does seem a little sluggish at certain times but not all the time and you can feel it stuttering a bit....

I had been running premium fuel in it and added a fuel injector cleaner as well.

Any thoughts on what it might be, I was thinking maybe a fuel pump prob??

Many thanks

Steve

[Bora Sport]

I would be thinking coil pack.

[gregozedobe]

Any thoughts on what it might be, I was thinking maybe a fuel pump prob??

I know someone with a petrol T4 that had a similar sounding problem - it went on (intermittently) for a couple of years before someone smart finally figured out what it was. The engine mounts had either gotten loose or started to break up, this allowed the engine to move around more than it should, this caused a problem with something electrical (either shorting something out or pulling a connection apart so that the engine wouldn't run).

Sometimes when cranking it over the engine would shift back to roughly the proper position and it would go again (until the next time it shifted to the "bad" location).

Sorry I can't be more specific about which elecrical bit was the cause, but the owner was very non-technical (but very happy to have her van fixed at long last).

Should be pretty easy to see if your engine can move around too much.

Good luck with fixing your van, intermittent faults are a real PITA for all concerned.

[aprr32]

Sounds like an ECU current relay(30) to me.

[slugger95]

Thanks for the suggestions guys, I will take them on board and see what happens.
Cheers
Steve

[Jmac]

Yeah go into measured value blocks if you know someone with vag com and you can watch the ecu voltage. When warm this will show up, very sluggish with a surging supply, these vehicles are tempremental with 12volts, and i have to say it sounds like it.

[Golf Loon]

Try the 30 relay first. Easiest and very common.

[slugger95]

Just a quick update, the T4 stopped today a few times and is worse than ever before. Took it to the VW mechanic here in O'connor and it looks like it might be fuel pump problem, I can now hear the fuel pump running inside the cab which I couldnt before it is quite noisy...will find out for sure later tomorrow. The computer said that the knock sensor was faulting and some other code that I cant remember, I will keep you posted..

Cheers

Steve

[Golf Loon]

Have you changed the 30 relay?
That controls the fuel pump and is cheaper and easier to change.

[slugger95]

Yep tried all things suggested including second hand computer but it still runs like a slug intermittently????? Someone suggested cranck angle senor?? This is about the only thing not tried at this stage..what are you thoughts???

Cheers

Slugger

[Golf Loon]

Did you change the 30 relay?

How about the coil?

[Jmac]

Mate i would probably disregard the knock sensor as it is doing its job, if you are saying you are having fuel dramas the system might be leaning off and causing it to ping , knock sensor can only retard the ign so far. Like the guys are saying try 30 relay this only needs to drop a volt or fluctuate voltage and it causes dramas - if you connetc a scanner you can actually watch it doing this.
Jmac

[Transporter]

Yep tried all things suggested including second hand computer but it still runs like a slug intermittently????? Someone suggested cranck angle senor?? This is about the only thing not tried at this stage..what are you thoughts???

Cheers

Slugger

How did you go with VW mechanic?
Was it the fuel pump?
If not did he check fuel flow and fuel pressure. Fuel flow is as important as fuel pressure. You can have a good fuel pressure and bad flow.
How old is the fuel filter? Partly blocked fuel filter would give you good fuel pressure reading but not enough flow your engine would start missing and even stall. And at the same time knock sensor would retard the ignition timing.
To diagnose the fuel system your mechanic should have Inter-Ject fuel flow and pressure measuring equipment or similar.

[slugger95]

Still working on a solution, will get it back to him this coming week hopefully, fingers crossed..............will update you all when we find the gremlin

Ta

Slugger

[slugger95]

2.5 petrol drama still

Tried everything suggested and more. Mech suggests it may be tension leads??? Cant see why that would stop motor from running completely on the odd occasion??? Running out of options now. It really should not be that hard should it, the mech is very knowledgable but even he is getting more and more frustrated..

Slugger