R2FU

Hi there, I'm looking for some advice...

Earlier this year I bought a 993 turbo with factory 430bhp upgrade. The car was given a clear bill of health during a PPI with only a couple of minor things to sort as and when.

In due course the car became due for a service so I booked it in with a respected specialist locally. On its return from the service I noticed quite significant smoke on startup.

About this time I also noticed a slight dulling of the car's performance, and sure enough checking the boost readout showed I wasn't getting above 0.5bar. I booked the car back into the specialist to get checked out.

Long story short, a month later the specialist has run out of ideas and I now have the car back having had a slightly cracked distributor cap replaced, an injector that wasn't flowing 100% replaced, and all oxygen and knock sensors replaced, but the car still not generating full boost. The garage tells me they have been right over the engine and it is fundamentally sound and it would seem to be an ECU related issue that results in the Motronic backing the boost off. Their recommended next step is to get the car on a rolling road for a diagnostic session and remap (they do not have a rolling road themselves).

I have noticed that the car no longer smokes on startup (I seem to remember early in the time they had the car the garage mentioning they would change the oil filter as a precaution, though it is not mentioned on the invoice anywhere that they have done this).

Having read the "993 turbo much posted problem" thread on here, I'm wondering if it is too much of a coincidence that the oil smoke coincided with the lack of boost. I certainly want to eliminate this before messing around with the ECU.

I would appreciate hearing thoughts from you guys as to what I should do next. Also what specialist would UK based people recommend within reach of the NW London area? I'm reluctant to go back to the same place given their apparent inability to diagnose.

Thanks in advance!

Felix

Don't trust the factory in-dash boost gauge. The senders are prone to giving faulty readings, particularly if it's the original sender. Your 430 ECU should result in 0.9 to even 1.0 bar but the factory gauge is limited to a reading of 0.8 bar by design. Go figure.

Has the ECU listed any check codes, even without triggering the check engine light?

I've had good service from JZ Machtech; Steve and his team look after at least a couple of Rennlister's 993tts. When my engine issues were being diagnosed one of the first things he did was put an external boost gauge on the engine to get an accurate reading.

A properly running engine with the 430 ECU should stay strong and eager right up to the redline such that it's almost too easy to find the rev limiter. Except perhaps in 6th. :evil:

bb993tt

+1 for JZ Machtech. Give Steve a call. He even has a new and improved (more accurate) external boost gauge now.

R2FU

The garage looking at it did put an external boost gauge on so I'm pretty confident it's not running as it should. The CEL is not coming on, not sure about ECU check codes though - I'll try to find out.

Regardless, sounds like a trip to JZ Machtech is in order. I only ever hear good things about them and as you guys are confirming that extends to 993TT's I'll pay them a visit. They are pretty close to me.

The last place I used have a good reputation but I'm beginning to think maybe normally aspirated is more their thing.

Thanks for your help.