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cdn_w_sr20
05-13-2005, 02:20 AM
For the last week i've been trying to help my friend figure out why all of the sudden he had some blowby, mysterious actually.

Tonight I did a compression check on his engine, the cylinders were 155-154-155-153. Seeing as the compression was good I was a little stumped as to what would cause this blowby. The one day he had a good teaspoon or two drop onto his exhaust manifold via the breather.

So I start looking closer, and happen to notice he has no TPS sensor on his throttle body at all and the wiring that was supposed to go to it is cut off, immediately I asked him what the hell he did. Apparently the place that sold him the engine said this was "normal".

Now i know i drove my car for 1 day without this being hooked up just so i could drive it to the paint shop. Would driving the car at full boost with no tps possibly cause blowbly to occur since the air/fuel ratios and timing would possibly be all screwy because you'd be running in safe mode? That is the only real thing i could think of that could cause the blowby to occur, and even that seems wierd. Any ideas?

Is it possible that the blowby shot out of the valve cover and not the crank case?

insndrvr
05-13-2005, 07:55 AM
It's possible his is having PCV issues, is that still hooked up? How are his vacuum lines, are they all in the right places? Have you done a leak down test?

cdn_w_sr20
05-13-2005, 10:00 AM
the pcv was still hooked up from what i could saw. Right now he has the T in the valve cover hooked up to a big coke bottle, next to nothing in it.

Kingtal0n
05-13-2005, 10:29 AM
So I start looking closer, and happen to notice he has no TPS sensor on his throttle body at all and the wiring that was supposed to go to it is cut off, immediately I asked him what the hell he did. Apparently the place that sold him the engine said this was "normal".

Now i know i drove my car for 1 day without this being hooked up just so i could drive it to the paint shop. Would driving the car at full boost with no tps possibly cause blowbly to occur since the air/fuel ratios and timing would possibly be all screwy because you'd be running in safe mode?

Is it possible that the blowby shot out of the valve cover and not the crank case?



Disconnecting the TPS will not cause blow-by. Nor will it cause your ECU to run in "safe mode" .I drove my SR20 around for 5000miles without realizing the TPS was disconnected, the only thing it does for you is Acceleration enrichment (to prevent tip-in stumbles like off idle) and advance your timing in various places, such as during sudden let-off or a sudden stab. It really doesnt affect much else, performance wise, Although I did run the car at the track without the TPS connected and went 14.3 @ 101, where after I connected it with a 2.6 60' I went 14.1 @ 104, so it does help to have the thing connected.

If your compression is good, it doesnt always mean your rings are good, the only way to check that is to check leak-down with a leak down tester. Sometimes the oil in a cylinder will help seal a bad ring during a compression test, fooling you.

But there are other places oil can come from, actually LOTS of other places on these motors. Things to check off the top of your head would be Turbo Oil-feed, catch can turn down (Where it goes back into the block), check the oil cap tightness (duh), make sure you feel suction where the catch can feeds in (throught the T in the valve cover), ensure your oil filter is the correct one (blacktop and redtop SR oil filters with both thread on the same motor, but installing a blacktop filter on a redtop will result in oil leaking, possible filter failure), and dont forget the seals in the motor that may only leak during boost, such as the oil pan seal, or just below the head gasket where the variou s fittings are. Use your imagination, I have had oil come from just about everywhere.

cdn_w_sr20
05-13-2005, 10:37 AM
how much oil came out of your TEE when you noticed the blowby? Did it spray all over the place or just in one small place? I'm beginning to think this was normal. This happened the 2nd time he started the motor and the first real time he gave it a little gas at full boost. Maybe just the engine cleaning the gunk out lol. engine could have been sitting in japan for god knows how many years afterall.