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Discussion Starter · #1 ·
Hey guys i just recently purchased a 1994 Toyota Twin turbo supra it has 45K miles on it right now. I havent had time to put any pics up because ive been so busy. I went to a performance shop today in DE. I had a compression test done and all the numbers came up around 175-180 excpet for cylinder #4. They checked it 4 times and it was 135 one time then maybe 175. They said theyve never seen this in Cylinder #4 before and there could possibly be just something little or as much as a rebuild of the stock engine. If i could get any feedback or what you guys think i should do i would greatly appreciate it.
Thanks
Dan
 

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Discussion Starter · #3 ·
Should I bring it to the Toyota dealership to have them check it out? and see if they can find the problem because i just brought it to a perofrmance shop and they dont have the tools to find out exctly what is wrong with it and to fix the problem.
Thanks
Dan
 

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i think he meant that the testing equipment wasnt sealing to the engine correctly....given that one time it did read 175. Have it tested again with another tester.
 

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was the engine hot when they tested it?
also you might want a leak down check done it will tell you if you have a real problem.
 

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Discussion Starter · #6 ·
Iam not sure i drove it for 40 mins and it sat for about 20 mins before working on it and i watched them work on the car and they did say some parts on the car were hot. They did do a LeakDown test. 1-10%,2-17%,3-5%,4-82%(checked 4 times)5-7%,6-8%.
 

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You might just have a ring in #4 that is gummed up and sticking, or carbon buildup on the back the #4 intake valve that holds the valve slightly open. Or there may be dirt at the #4 plug interfering with a good seal on the compression tester.

Before you panic you can:

1. Get the motor warmed up and drive the piss out of it. High RPM, 2nd, 3rd & 4th gear pulls. Italian tune-up. As always, be safe, don't get a ticket etc. This would be most effective if it is a sticky valve.

2. Try one of the top end cylinder cleaners made by Mopar or GM.

3. Try adding Rislone or Auto RX. This would mainly free up a sticky ring.

4. Test again.
 

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Lagtime said:
You might just have a ring in #4 that is gummed up and sticking, or carbon buildup on the back the #4 intake valve that holds the valve slightly open. Or there may be dirt at the #4 plug interfering with a good seal on the compression tester.


None of these would be valid potental issues based on the leakdown results he posted for his #4 cylinder.

Brad
 

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banton said:
Lagtime said:
You might just have a ring in #4 that is gummed up and sticking, or carbon buildup on the back the #4 intake valve that holds the valve slightly open. Or there may be dirt at the #4 plug interfering with a good seal on the compression tester.


None of these would be valid potental issues based on the leakdown results he posted for his #4 cylinder.

Brad

Come on, an intake valve held open wouldn't leak like crazy? Or a ring not fully seated against the bore wouldn't either?

The things that cause poor compression are the same things that cause poor leakdown. The difference is that a leakdown test lets one pinpoint the problem, while a compression test just lets you know there is one.
 

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Dman3 said:
Not Good.....??Whats ur input on it?
If the shop did a leakdown, they should have been able to tell you what the issue is? What was their diagnosis upon completing the leakdown test?

Where was the leak traced to?

Intake manifold (intake valves)? Tailpipe (exhaust valve)? Crank case (rings)? Other (headgasket)?

Brad
 

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Lagtime said:
banton said:
Come on, an intake valve held open wouldn't leak like crazy? Or a ring not fully seated against the bore wouldn't either?

The things that cause poor compression are the same things that cause poor leakdown. The difference is that a leakdown test lets one pinpoint the problem, while a compression test just lets you know there is one.

Lagtime, I was incorrect in my earlier statement, sorry. I will blame my brain-fart on last night's activities :)

Brad
 

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Lagtime said:
You might just have a ring in #4 that is gummed up and sticking, or carbon buildup on the back the #4 intake valve that holds the valve slightly open. Or there may be dirt at the #4 plug interfering with a good seal on the compression tester.

Before you panic you can:

1. Get the motor warmed up and drive the piss out of it. High RPM, 2nd, 3rd & 4th gear pulls. Italian tune-up. As always, be safe, don't get a ticket etc. This would be most effective if it is a sticky valve.

2. Try one of the top end cylinder cleaners made by Mopar or GM.

3. Try adding Rislone or Auto RX. This would mainly free up a sticky ring.

4. Test again.
Very good advice.

Ken.
 

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has the car lost any coolant? if so might be a BHG BUT might be blown on a part that coolant does not pass
is there smoke coming from the oil cap? if so could be a bad piston, rings or BHG
 

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Listen to Lagtime.. and Ken. Do everything in that list he posted, then take the car back to another shop for a more thourough leak down test. Try to find a shop in your area with a decent rep when it comes to supras :)
 

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Discussion Starter · #19 ·
I live outside of philadelphia. I had the Compression/leakdown test done at CarV2 in DE. Anyone know a well known place that knows a good amount about supras?
Thanks again guys for your suggestions.
Dan
 

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Discussion Starter · #20 ·
Do you guys have any sites or stores where i could find the cleaners for the cylinders and free up the possible sticky ring?
Thanks
 
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