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-   -   Boost spike -> Oil leak (https://www.miataturbo.net/general-miata-chat-9/boost-spike-oil-leak-15016/)

olderguy 12-25-2007 11:10 PM

Treat the oil leak first. You may have compromised the PCV, blowing enough pressure into the crankcase/valve over to push oil into the turbo and blow out the front of the valve cover gasket.

Check the PCV.

Check the valve cover gasket.

When you do the compression test, just pull all the plugs and unplug the CAS.

bryantaylor 12-25-2007 11:15 PM

if its running ok, and you have oil in all of your turbo pipes, you might just have a blown turbo.

FHS 12-25-2007 11:24 PM

Thanks for all the input guys! I do have a turbo rebuild kit waiting for me back home if I manage to get my car back to it. :)

XxGoKoUxX 12-25-2007 11:27 PM

well rest assure ur head gasket's most likely ok :)

good luck on the trip back... i know i'd cry if my car was doing that on a trip out of town :(

Braineack 12-26-2007 08:53 AM


Originally Posted by FHS (Post 189668)
Thanks for all the input guys! I do have a turbo rebuild kit waiting for me back home if I manage to get my car back to it. :)

In this situation you'll find that rebuilding the turbo and curing the problem will be as effective as changing your tires to solve the same issue.

FHS 12-26-2007 03:56 PM

Compression numbers on an Acton tester from Autozone:

#1 = 155
#2 = 150
#3 = 150
#4 = 155

A bit low overall but does it indicate compromised pistons?

Changed the valve cover gasket. The PCV was pushed about half a centimeter into the grommet so I replaced both the PCV and grommet.

Braineack 12-26-2007 04:08 PM

i suspect you didnt test with the throttle wot?

warm the engine 160* coolant. turn off. unplug the coils and injectors.

test #1 - 4, WOT, crank until the gauge stops building compression.

pour 1/2 teaspoon of oil into #1, test again, the pour in #2 test again, etc.

post the wet/dry numbers

FHS 12-26-2007 07:14 PM

Never done the test before but I was at WOT and I warmed the car up for ten minutes.

I ran each cylinder three times so I'm at least confident that the ratio between cylinders is as good as it is going to get under the circumstances. I just want to get my car back home and into the hands of a mechanic who can do a proper diagnosis.

I know you thing I compromised my piston rings but what will the second round at wet and dry tell me that the numbers above don't?

Bryce 12-26-2007 07:21 PM

Putting oil in there will help the rings seal better if they are bad, thus resulting in higher compression numbers.

FHS 12-26-2007 07:33 PM

Ahh, I see. Thanks man.

bryantaylor 12-26-2007 08:12 PM

i always hear to hold WOT for a comp test, but every test i have ever done, it hasnt made a difference at all.

FHS 12-26-2007 11:04 PM

Here we go:

#1 = 160 dry/ 185 wet
#2 = 160 dry/ 190 wet
#3 = 160 dry/ 190 wet
#4 = 160 dry/ 205 wet

Ran each cylinder 3 times dry and wet, final numbers are averages. Lowest raw value was 150 at cylinder #3. All the others just didnt have much variation within treatments (wet or dry). Biggest variation was obviously between treatments.

Any input at all would be appreciated. I'm hoping to leave Vegas around 10 AM.

Thanks!

Braineack 12-26-2007 11:56 PM

looks like your rings are all worn. use an oil additive before you head out.

FHS 12-27-2007 08:54 PM

Yeah, looks like the replacement engine I got might have had a few miles. Made it back to LA fine. It looks like most of the oil leak was coming from the front of the valve cover gasket because I didn't lose any oil on the trip home.

Thanks again for the help!


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