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turbo failure on 240[850/1995] posted by Craig on
Monday, 23 March 1998, at 6:32 p.m.
A few weeks ago while going over a mountain pass, I noticed my turbo quit boosting and smoke was coming out of the tailpipe on my 82' 240 (oil cooled) turbo. I thought the converter was plugged, so I removed it and installed straight pipe. The turbo still only barely has boost, though it does not smoke anymore-?? The gauge still works as usual, wastegate is fine, but the car is gutless.
-What would cause a turbo to not produce boost other than a leak between the inlet side turbine and exhaust side? And if air could get through here, why would'nt oil? I went over the same mountain pass yesterday and there was no smoke and no boost, though the turbo gauge was pegged. Any ideas would be appreciated. -Craig
Re: turbo failure on 240[850/1995] posted by john on
Monday, 23 March 1998, at 11:33 p.m.
Have you checked for a split hose in the air system? That would wipe out your boost and let the turbo overspeed. That may have something to do with the smoke but if nothing changed on the air side why did it go away?
I drove a Paxton supercharged Avanti that was having rather sluggish performance
for no apparent reason. The boost gauge wouldn't go but up to slightly above zero. Finally noticed a split in the underside of the hose connecting the blower outlet to the carb inlet. The engine was doing the work but not getting any of the benefit.
Re: turbo failure on 240[850/1995] posted by Craig on
Tuesday, 24 March 1998, at 11:53 a.m.
The boost guage is normal- right where it has always been adjusted by the wastegate linkage. If the line to the wastegate actuator was cracked or broken, the guage would peg and the fuel pump would cut out. So the problem is with the turbo, or some other air restriction. I have installed a new air filter, but that didn't do anything. The turbo seems to just be a deadweight parasite in its present condition. -Craig
Re: turbo failure on 240[850/1995] posted by Bill on
Wednesday, 25 March 1998, at 6:28 a.m.
If your gage is showing boost, then the turbo is doing its job. If the cat had plugged, it would not build boost as it could not get rid of the exhaust gasses. Centrifugal devices like this can be controlled by regulating the discharge pressure. From experience: my cat plugged from excess oil thru turbo and the boost dropped more and more as the cat plugged more and more. Is your timing belt ok: has it jumped a tooth? Retarded cam or distributor timing will make for a very sluggish engine. Is your fuel pressure correct? Have you done any other work on the engine lately? The last work done is often responsible for latest symtoms. More diagnostics needed!
Re: turbo failure on 240[850/1995] posted by Andre Corriveau on
Friday, 27 March 1998, at 11:13 p.m.
Craig, I ran into very similar symptoms a few weeks ago.
Reason: Head gasket blown.
I replaced it and it has been fine since. It exhibited large amounts of white smoke (antifreeze leaking into cylinder) and the boost gauge was pegged. I had seen water droplets on oil dipstick but once I saw the white smoke I knew it was gone. The engine and turbo were working hard but all power was lost due to water leak into the cylinders. Also, the ECU was probably over-compensating by running extra rich mixture. All piston tops and combustion chamber were covered by black soot.
I would suggest getting it checked ASAP.
Though all your symptoms are similar, mine got progressively worse. More smoke but still no power until it finally would hardly idle on its own.
Probably worth the cost of a professional diagnosis. You wouldn't want to replace anything (head gasket, turbo, etc.. ) and then find out it wasn't the cause.
P.S. Also check compressor bypass valve (adjustable valve unit on corner of head). Mine got unseated and leaked, drained any boost the turbo was making.
Good luck,
Andre.
Re: turbo failure on 240[850/1995] posted by Craig Murphy on
Monday, 30 March 1998, at 1:46 a.m.
Andre, I thought about the problem you mention, but my car hasn't smoked since the day I wrote the first post, I have no water loss and the oil has no color difference or water beads on dipstick. I ran into a problem a few years ago, when I couldn't get the car timed, and it turned out to be the "star" on the distributor rotating on its crimped colett. I could turn it back so it passed the points on the cap correctly by hand. I think this may be happening again, throwing my timing slightly off and cutting the overall power in half.
-Craig
Re: turbo failure on 240[850/1995] posted by Craig on
Wednesday, 1 April 1998, at 8:42 p.m.
Andre; I may stand to be corrected in my response to you about my loss of turbo boost being related to timing rather than your head gasket explanation! Today, I noticed that my coolant overflow reservoir was empty, and there are no leaks visible anywhere. The oil dipstick appears to be dry, but the water definitely drained somewhere. I had quite a bit of white smoke this morning, which reminded me of your response to my post and prompted me to check the coolant level. I think I will have it checked soon. Did you need any special tools to replace the head gasket? It is not a job I look forward to, but your explanation seems to be fitting the problem more closely now and at some time, I will have to "face the music". -Thank's for the insightful post! -Craig
Re: turbo failure on 240[850/1995] posted by Andre Corriveau on
Wednesday, 1 April 1998, at 10:44 p.m.
Thanks for your response Craig.
I did notice that my head gasket was leaking for a while before I changed it.
One day it just decided it had enough and blew heavy smoke all the way home.
On the head gasket change, it's not that hard just time consuming. Took me 4 full days to remove and replace. I also changed thermostat, waterpump, timing belt, 3 shaft seals in front timing cover and all new gaskets for intake & exhaust areas. One caveat: Exhaust manifold remove/replace is no fun. There's not enough room for hands or tools at the manifold nuts, get swivel extensions or universal-joint socket or extension. Turbo oil return pipe is fun too.
I would recommend the FelPro head gasket kit. It comes with head, exhaust, intake, throttle body and tons of other stuff (even injector seals). Price is reasonable too. Also make sure you've got yourself a good torque wrench.
Good luck,
Andre.