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Calling all Z31 Gurus - Looking at buying another Turbo


attworth

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I tried posting this over at Zcar.com, but only got one or two responses, nothing definitive. I was hoping maybe you guys could help me.

 

Here is my original message from Zcar.com

 

I went and looked at an 87 Turbo this evening, and have a few questions.

 

Previously I owned an 88T that unfortunately was T-boned and totalled.

 

This car has me scratching my head.

 

The body is super straight. The suspension, steering and brakes all seem very good. The tires are practically brand new along with some somewhat ugly, but newish wheels. The interior is nearly immaculate with the softest leather seats I've ever sat on. The engine bay looks very nice and unmolested. Everything looks to be in order and it is very clean.

 

However....

 

When the owner started the car, I'm not sure if he had it floored, but the valve that blows off boost if it reaches about 6psi (or whatever stock is,) popped open emitting a nice loud POP. There was also some sparking of some sort in the area. I'm not sure if this is a factor, but the battery was dead so it needed to be jump started. The charging system seems to be ok, because as soon as the car was running it stayed running just fine.

 

Now to the test drive. It seemed not to have any boost. I looked at the gauge during several moderate to high load launches, 20mph pulls, etc. and it was only reading about 3.5-4psi. I know the stock gauges aren't known for accuracy, but it didn't feel like my 88 at all. In addition, the speedo was not reading correctly (analog gauges.)

 

The motor sounded pretty good. No real abnormal lopping or missing. The clutch felt just fine, and the transmission and rear end felt pretty good.

 

I think I want to run a compression test on the motor and see if it's good there. I may also see if the owner will let me dismantle the intake enough to get to the turbo shaft and such.

 

The tailpipe was not spitting oil nor was there any accumulated. It smelled like a turbo car at idle, while I was driving it, etc. (Not sure how to describe it, I just know my turbo smelled the same and smelled different than any NA I've owned.)

 

Any ideas what could be wrong with the car? His asking price is a low $1800, however I don't want to waste money on another car that's going to cause me problems. The guy selling it apparently doesn't know anything about Z's but is the 2nd owner and inherited the car.

 

Thanks, and sorry for the long post.

 

I went back today to take a better look in the daylight. I also poked around, ran a compression test and tried to do a leak test of the turbo system. I brought my own battery and it didn't have any problems with starting or running well. The POP from the POV happened again at the initial startup but no other time. There was also no spark in the area like previously. I noticed some of the wiring in the area looked questionable, so I think that's where the spark came from.

 

Still impressed by the cleanliness of the car. I did find one hole in the floor about the size of a golf ball. It's not a rust hole, but is a puncture, like somebody ran over something they shouldn't have. There was surface rust in the spare tire hold, but nothing serious.

 

I've checked the VIN and the car has not been claimed a total loss, nor is it currently stolen. I have yet to check the carfax, but it's high on my list. I did notice a slight "buckle" in the radiator support, but nothing else looks out of the ordinary. The bumper and fenders still look perfectly aligned.

 

Compression test came out good. All 6 cylinders were within 2 or 3 degrees of 150. Cylinders 2 and 3 read the lowest, but I think the fact that I couldn't get the gauge in there all the way may have something to do with that.

 

I tried to test the turbo system for leaks using this method - http://www.audizine.com/forum/showthread.php?t=104080 I couldn't get the system to pressurize. I think the bicycle tire pump I was using didn't have enough oomph to fill the intake. I didn't want to lug a compressor over there and don't have a smaller car tire inflator type compressor. Oh well...

 

I also got the car on the highway this time. It still pulls extremely well, but it's not boosting above 3-4psi like stated above. I noticed once the turbo is fully spooled out, something emits a high pitched squeel, almost like a pinhole in an exhaust pipe type sound. The sound is not present until the turbo is fully spooled. The turbo also seems to hesitate a bit while spooling.

 

Worst case scenario I'm thinking the turbo may need to be replaced/rebuilt. Although I still think there could be a leak somewhere.

 

Other issues I noted:

- Speedo was reading 25 mph sitting still and went up from there

- Temp gauge wasn't working

- A/C does not power on (common problem from what I hear.)

- Not sure if it was nearly out of gas or if the fuel gauge wasn't working, was below 1/4 but the 1/4 gauge did not read anything.

- Passenger side intake manifold was leaking slightly (no biggie, at least the driver's side did not appear to be.)

 

I'm sorry if this should be in the Z31 forum. I figured it should be here as my main questions are regarding the turbo system in this car.

 

I appreciate any advice you folks can offer.

 

Thanks!

 

Tony

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Was looking through pictures and had a few more questions.

 

Is this how this is supposed to look? I seem to remember my 88T's POV being fully closed. The car was not running when I took this picture, but it looked the same when running. Could it be faulty, and maybe that's why it pops open when first starting the car? Could also be leaking off vacuum?

 

SDC10079.jpg

 

This doesn't look good. Looks fairly clean in there, but I assume it being broken is not good. Could it be causing any problems? (This is the AFM by the way.)

 

SDC10078.jpg

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sounds like a vacuum leak not letting it build boost try removing the pov and plug it with a 1 inch pipe plug and the MAF doesnt look normal either. I dont remember mine looking like that, from what your saying sounds like a nice car.!

 

edit that definatly looks like a puncture in the MAF and they are very sensitive worst comes to worst just get another if you dont take it I will :D

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