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Compression and starting questions

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Old May 4, 2009 | 11:17 AM
  #1  
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Question Compression and starting questions

Hi,

I just bought a 88 GX as a project car and am having issues getting it to run.

When I picked it up, I noticed that the leading and trailing plug on the rear rotor were reversed and believe it to be flooded.

So I swapped them, ensured that all the fluids were good and although it tries occasionally to fire, it won't catch.

I did a compression test and on the rear rotor saw 3 even bounces at 85 psi. The front had 2 at around 60.

Is there a blown seal somewhere that shows that I need a rebuild? Should the engine run?

I'd really like to get it on the road this summer but with baby on the way, a rebuild is a long way off.

Thanks for any advice!

Mike
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Old May 12, 2009 | 09:10 AM
  #2  
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Hi,

Quick update, I have the engine running now, but it only idles between 1500-2000 rpm then dies after 3-4 minutes.

It will only start after it cools down.

Any ideas?
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Old May 12, 2009 | 03:55 PM
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Aaron Cake's Avatar
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Do another compression test now that you have it running to make sure compression came back up. 60s is basically a dead engine.

Check for huge vacuum leaks like at the black intake tube which leads to the throttle body. One the car warms up a bit, the mixture leans out and a vacuum leak may cause it to end up too lean to run the engine.
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Old May 12, 2009 | 08:45 PM
  #4  
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Hi,

Quick update, the car will start at will now, replaced the air filter as it was the worst I've ever seen.

However, while running, the pedal needs constant attention. Over 2500 rpm, it bogs and tries to stall. Let it go too low, it stalls.

I did a quick check of the vacuum lines and they all look ok however its hard to tell as quite a few disappear into the depths.

It seems like an intake issue but the haynes manual lists so much and it really is a rats nest.

Will redo the compression test on the weekend.

Thanks for the advice!
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Old May 14, 2009 | 10:14 AM
  #5  
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If the car is very hard to start, floods easily, and requires full throttle to keep it running you may have an injector that is locking open.
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Old May 14, 2009 | 04:21 PM
  #6  
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Originally Posted by mikeyjay
Hi,

Quick update, the car will start at will now, replaced the air filter as it was the worst I've ever seen.

However, while running, the pedal needs constant attention. Over 2500 rpm, it bogs and tries to stall. Let it go too low, it stalls.

I did a quick check of the vacuum lines and they all look ok however its hard to tell as quite a few disappear into the depths.

It seems like an intake issue but the haynes manual lists so much and it really is a rats nest.

Will redo the compression test on the weekend.

Thanks for the advice!
Other than the bogging at 2500 r's, my problem is EXACTLY the same as yours. My compression is 70 on 1, and 50 on 2. I just hope I did the test right, i have a thread awaiting approval with more details. No vac leaks, and the BAC passed both tests with flyin colors. What I dont understand is how my car can still run as strong as it does with compression being so bad. And when I say strong, Im talking 13.2 sec 1/4 mile strong. Owner had the time slips from 2 weeks ago. I just bought it this past weekend. No smoke out the rear at all. Can smell heavy fuel though out the exhaust. Would that be an indication of anything?
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Old May 15, 2009 | 09:55 PM
  #7  
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hi,

quick update, i just discovered there's a thermostat in the bottom of the rad that's disconnected. as the gauge works, i'm not sure what this does.

is there a link between this and the problem?
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Old May 15, 2009 | 11:43 PM
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Check for vac leaks. I had the same problem as stated earlier in this thread, and today I found the throttle body vac line discon'd. I dont have to keep pumping fuel anymore and she never stalls and the car idles great. Hope this helps.
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