1997 VW Passat 1.9 TDI revs to 2k instantly on hot start and no power

[Biped]

This has been intermittent and was gone for approx last 12 months. I was doing servicing myself. Car has 164k miles and timing belt was replaced along with water pump, full service, fuel filter etc at a garage recently.

Collected it and it ran fine for about two days then the gremlin returned.  In the past this is what would happen.

Start from dead cold, no problem and if would pull really well. Stop and restart when hot and the engine instantly hits 2k rpm for a split second and drops back to normal idle but no power like it was in limp mode.

Previously this went away even though I changed air mass meter but it didn't fix the problem and eventually it went away.  No excessive smoke but as the revs eventually climb the engine sounds a little rough.

This time however after the timing belt and fuel filter change the problem started again after about two days. This time though it never comes out of limp mode. So start from cold no instand revs just normal idle but no power.  Start from hot 2k revs the normal idle and no power.

Back to garage on diagnostics. Solenoid valve on fuel pump showed issue so took it to a diesel fuel injection specialist. On diagnostics again, fuel solenoid came up, he put in a new air mass meter and swapped the solenoid with another one (not new) faults cleared in ecu. He thought it made an improvement and to be fair it did but it's still way down on power and still revs on starting when hot.

Any suggestions welcome, I will try and pressurise the fuel system tomorrow as per another thread to see if there is an air leak using the rag in tank neck and compressed air.

I know she is old and has big mileage but when on song it pulls really great and everything else is perfect so if it's a few hundred to fix it's cheap motoring for another year or two.

Thanks in advance.

[nathan_b]

If the Ijnection quantity is way high it will do funny things when you first start it, also, is the timing set 100% right? with vag com? if not, it's wrong and theres no point in continuing diagnostics with a known problem.

It could be an injector leaking down and dribbling fuel into the cylinder on shut down. I would recommend nozzles at those miles if they aren't already done.  It's not using up too much oil is it?

[Vincent Waldon]

Evidently another common cause of a "rev to 2000 on start" is a leaking 0-ring on the stop solenoid...not the plunger rubber plunger itself but the o-ring that seals the solenoid to the high-pressure head.

Several cases of this fix reported on TDIclub.com... might work for you.

[Biped]

Thanks for replies, she doesn't seem to be using oil and rarely needs to be topped up between indicated services.

Don't know about the injectors being changed as I have changed them while I have owned it, last 80k. Would the garage have checked the timing after the service / timing belt install to make sure it was 100% although I have noticed they didn't change the sir filter as its still the one I fitted in October - put the date on it.

I'll check out tdiclub.com and take a look at the suggestions so far.

Took a vid of whats happening and will stick on youtube for ref here, there is a puff of black smoke from the inital start rev but then clear and the car will rev all the way up with no smoke but its under no load.  I'll need to get someone to follow me to see if its smoking while driving as I can't see any in the mirrors

Thanks

[Biped]

Did a search on TDIclub and found this thread - sounds identical so new solenoid ordered and will try and have it fitted today http://forums.tdiclub.com/showthread.php?t=241746&highlight=revs+hot+start

Fingers crossed and will update on the out come

Thanks!

[Biped]

New solenoid in last night. Running like a dream since. €40 for the culprit and it's all sorted. Took a video on my phone of the problem so will upload it in the hope of saving someone else some effort and expense.

Thanks for the help