1997 3.8L Won't Start but Has Low Compression

[TBULT97]

THIS CAR WILL NOT START. I HEAR SOME DETONATION BUT IT IS NOT ENOUGH TO ENABLE THE ENGINE TO RUN FOR EVEN A SECOND.

History of this vehicle: supposedly the car ran, but when I got it - thinking it was just a fuel pump - I found that there was a large amount of water in the tank and fuel rail. I have replaced the fuel pump, fuel injectors, fuel regulator, fuel rail and fuel filter. Additionally, I have checked that each cylinder is receiving spark (but not that the spark is occurring near TDC).

I have checked the dry compression on cylinders 1 and 5 on Bank 1 and cylinder 2 on Bank 2 of this V6 3.8L. I have been told by many others that even with low compression an engine will start if the only issue is compression. I am about to head down the path of taking the timing chain cover off to check the timing mark alignment due to the fact that the low compression is on cylinders that are on both banks, but I thought I would get these questions answered first.

My questions are:
1. Should the car start even with these low compression readings?
2. Due to the fact that the readings for all three of the checked cylinders (the easiest to get to) are between 50 and 70 psi, is there a greater probability that either the timing chain has jumped/or it was assembled incorrectly OR that it has poor sealing rings/valves (on both banks)?

 

[melsg5]

did you do a wet compression test to see if the low compression is rings or valves? why would you suspect an incorrectly assembed chain? try doing all the cylinders both dry and wet.

 

[TBULT97]

Wet Compression Test

I have not done a wet compression test yet. I was leaning toward the timing chain as the culprit because I know it is easier to fix than removing the heads and still within what I am willing to put into it both time and money wise.

If I do a wet test and the compression goes to say 90 psi leading me to believe the rings are the issue, what liquids are out there to temporarily provide a better seal for the rings?

If the compression doesn't go up, then is there more of a possibility that it could be a timing chain issue?

Tim

 

[melsg5]

your local auto parts store carries various suppliments for oil but if it's as low as 50 I doubt they will help. If it doesnt go up I would say burnt valves. You never mentioned how many miles are on the engine.

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[TBULT97]

Miles on Engine

The vehicle has 130,000 miles and I believe it to be the original engine.

 

[R_T_71]

Sounds like you need to take valve covers off and turn the engine to make sure all the valves move.