tommy944

I have a 1987 944 Turbo equiped with the following:

*new TiAL wastegate (with all new seals)
*55 lb injectors
*new vaccum lines
*venturi delete
*LR MAX Chips (DME & KLR)
-set for:
55lb injectors
k26-8 turbo
*new J - Boot
*new intake manifold seals
*new Bypass Valve "Forge" (Blow off valve)

I recently had a turbocharger spin apart and got damaged, the turbocharger was sent to Lindsey Racing for a full rebuilt (seals, bearings, new compression wheel, rebalancing, etc.), The turbocharger was just returned a few days ago and I put it back on the car. The car idles as it should.

The issue is when the car gets into boost, some times the car boosts quick and strong as it did before the turbo went and had to be rebuilt, and other times the car experences no boost and you can hear what sounds like the turbo spinning a million miles an hour. The car randomly decides when it wants to boost nomally and when it wants to make a loud whistle like sound with no boost. Even when the car is parked and you rev the throttle by hand from under the hood and you can hear the turbocharger spinning loudly.

I checked the vaccum lines and made sure they were all attached correctly. When the old turbo went it poured all my oil directly out my exhaust leaving puddles of oil in the tail pipe. when I had the Turbo out I tried to blow most of it out with a shop vac

Any Ideas why the turbo would works for 5 minutes then just spin like crazy making a loud noise with no boost?

Paulyy

check all the connections to the intercooler pipes. make sure the bypass valve dosn't leake.. take it out inspect it.

tommy944

I just bought a new bypass valve today and put it on, it doesnt leak, my old one had a small leak in it but that didnt cause the issue. and I believe all the connections to the intercooler are tight and the rubber connections are in like new conditions.

clangjr

Is it possible that when your turbo blew oil everywhere the back end that the oil went into the wastegate and now you've got a non-functioning wastegate? It sounds to me like the system doesn't know when to build pressure or hold it or release it.
Chuck

Black51

Good point. I'll bet if there is oil surrounding the piston in the WG, it will stay open after it opens once, and will take a long time to shut, as is the sludgy characteristic of used engine oil.

JBrown

check your WG and if its not that and you have a stock exhuast they are duel walled and they collaspe. i had that problem and i checked every were and it was the exhuast. the turbo sounds like it is spooling but your getting no power

fast951

Did you verify the Tial WG is installed properly? They get installed differently, orientation wise, than the stock WG.

tommy944

the exhaust was all redone recently, on my old turbocharger I had the downpipe collapse so I know that is all good as of now. Would oil in the wastegate cause it to malfunction? the wastegate worked prior to the rebuild and is still in "like new condition" looking at it on the car. I figured since the WG works off of pressure that it wouldnt matter if a little oil got in it, i assume it would just blow it into the exhaust?

tommy944

I just hooked up the main vaccum line from the wastegate that goes to the right angled hard pipe to a shop compressor and cranked the compressors regulator between zero and alittle over 15 psi. I heard the wastegate open and close like it should. when zero psi is added and the engine is reved up alittle you can hear the turbos spinning loudly (when the wastegate is in the closed position), when i add 15+ psi to the wastegate to fully open it the turbo sounds perfect when the engine is reved. Im guessing the diaphram in the wastegate is damaged causing the boost to cycle back to the turbo's hot side; resulting in no boost.

Does anyone know how difficult it is to replace the wastegate seals? or if it is a do it yourself project or needs to be sent out for a rebuild?

the wastegate is a tial 38mm wategate purchased on http://pauertuning.com