911 turbo II 3.6 problem. Can anyone help?

[SimonHarrod911]

My car has an issue whereby the engine cuts out. It is not an immediate total loss of power, the revs just steadily fall until the engine stops. If I restart the car it fires, runs for about .5 of a second, then the revs fall until the engine stops. This continues until (and I know this is bad) you hold the key in the fire position. The car will then drive fine.

This usually occurs on full boost, dying at the top of the rev range, however it has happened once driving 'normally', but then restarted immediately. Another time was when the car had been left overnight in heavy rain.

Any ideas would be greatly appreciated.

[James s]

I am no mechanic simon, though your symptoms sound v similar to the failing air flow meter I had on my 964.

From memory I think it comes up on diagnostics if this is the problem.

The advice I had when it happened (which was very intermittant), was to reach round the back of the aribox when the AFM is located and give it a bit of a jiggle. This always worked and would get me home. Eventually replced it at a cost of around £250 plus fitting.

I may be well of the mark, there are probably many thinkgs it could be. Even if it is this, I don't know if you could get at it on a turbo.

good luck

>> Edited by James s on Monday 24th January 12:12

[SimonHarrod911]

Many thanks James, I'll look into it.

[zanzibar]

There is a lot of plumbing on the intake side, intercooler pipe work etc, fist thing to check for is anything loose, hole it etc which is causing a pressure drop.

[SimonHarrod911]

zanzibar said:

There is a lot of plumbing on the intake side, intercooler pipe work etc, fist thing to check for is anything loose, hole it etc which is causing a pressure drop.

Thanks for that, doesn't appear to be the problem.

[aceparts_com]

sounds to me like losing fuel pressure. check relay, maybe fuel pump(s)

[SimonHarrod911]

Spoke to someone earlier who thinks it's a faulty overboost switch. Anyone agree?

[aceparts_com]

well find it, either disconnect it or bypass it and see if you still have the problem.

[SimonHarrod911]

aceparts_com said:

well find it, either disconnect it or bypass it and see if you still have the problem.

Sounds a bit technical to me. Over to someone with a bit of talent, it's off to Woolley's. Thanks Aceparts.

[leosayer]

Try replacing the DME relay. You should be able to pick one up for around £20.

[SimonHarrod911]

leosayer said:

Try replacing the DME relay. You should be able to pick one up for around £20.

Thanks Leo, but there's no DME relay in the 3.6 turbo. Mechanical injection. I know that because it was the first thing I thought of, order it, then looked for it to make the simple replacement.......

I got my coat.

[ultra violent]

I doubt its the overboost switch. If you experience that at full boost it is like hitting a brick wall. My bet would be a vacume or boost leak. Check the intercooler hose.

[aceparts_com]

It MUST have a fuel pump relay!

[turbobloke]

ultra violent said:

I doubt its the overboost switch. If you experience that at full boost it is like hitting a brick wall. My bet would be a vacume or boost leak. Check the intercooler hose.

I'd go with that too, a badly re-fitted intercooler (OPC, tut tut) with an o-ring not seated properly did this to me. Managed to find it before more expensive diagnostic stripping or parts replacement (phew). Any similar cause of the same effect would do it. Good luck.

[turbobloke]

SimonHarrod911 said:

zanzibar said: There is a lot of plumbing on the intake side, intercooler pipe work etc, fist thing to check for is anything loose, hole it etc which is causing a pressure drop. Thanks for that, doesn't appear to be the problem.

May be difficult to tell - if a seal / ring doesn't leak until the car is moving and on boost where pressure forces movement, hard to spot...easier to spot when the turbo hose gets blown off...

[SimonHarrod911]

Many thanks to ultra-violet and turbobloke, I'll pass your comments on.