1G Zero Compression in cylinder #1

[DSMFLipp]

Hey guys,

I could use some help and advice as to what you might think is wrong with my
1990 Eclipse GS-T.

Its only got 133k on the mileage. The head only has 4k mile on it.
I picked the car up with a misfire, thinking it was an electrical or coil issue.

After replacing the spark plugs with the correct ones( original owner had denso plugs??) and upgrading the wires and going thru multiple coil packs, I went to see about the ecu being the issue. Found out it has a 92 ecu in a 1990. Tried running my friends 1990 ecu and nothing changed. There are no CELs at all.

We then went onto a compression test and checking the timing. Timing marks were all on point and there were no boost leaks at all.

The compression test came back as so:
#1 o #2 152 #3 153 #4 155

we watched the motor crank with the valve cover off and looked at the rocker arms and tried wiggling them, everything seems tight and opening/closing corectly.

The car idles(like crap) in open loop and misfires. It still pulls good, just not full power.
The car is all stock except a 16g and a walboro. The exhaust back fires once in awhile also.

I did find a small hose clamp under the valve cover just sitting in the head. COuld it have wedged the lifter springs and kept a valve open? The car does not smoke at all!

Is it a bent valve or burnt valve? We checked the injecotr seals, well wiggled them around while the car was running and no change. I been draily driving it the last 9 days. SHe fires right up and everything.

 

[fallenauthority]

You answered your question already. Cylinder 1 has 0 compression. Time to pull the head and check for bent valves and any further damage.

 

[Bo0sTdTsI]

Yea bro if you get no compression even in one cylinder, that is not good, id pull the head also and check whats going on in there because i doubt itd b a wiring issue, ive seen cas's rewired for the 92 ecu and it ran like crap til the ecu and cas was rewired for a 90 als the ecu being swapped out back to a 90. My bro had a poblem like that with his 90. Let us know if you find anything else.

 

[drewbuddy]

Similar thing happened with my '91 2l turbo. only had 50lbs in my #3(except it would smoke when boosting). when i pulled my head apart didn't notice too much, took off oil pan and had a few shavings, but when I took my #3 piston out it came out in pieces. rings were broken and piston separated from itself. Luckily there was no damage to my walls. so i agree with fallenauthority, you must open it up and see whats goin on

 

[DSMFLipp]

Well, I'm just driving it too and from work right now. I'm grabbing a new head
And piston, rtv, and head gasket. Me and the team will pull it apart
Within the next two weeks. I'll keep updates on here if I find anything else.

 

[bryanwheat]

Before buying anything do a leakdown test. You will know exactly where it is leaking before you even pull the head of and know what you need.

 

[92AWDHX40]

Well at least youll have a list of parts, but you may find more things you need as you proceed.

 

[eross92304]

I agree with bryanwheat do a cylinder leakage test before you pull the head off. Make sure you are at tdc and check at your throttle body, tail pipe, and dipstick for air leaking that will tell you if your valves are messed up or if you have worn rings. Also check the cooling system for bubbles could have a cracked head causing 0 psi on cylinder 1.

 

[DSMFLipp]

Would it be cheaper to replace the bad valves or buy a new head?

Ive decided ill do a leak down test.

 

[Mischif]

Zero Compression? Even with shot rings you should still get some sort of compression. Your valve's must be bent pretty bad in that cylinder.

 

[DSMFLipp]

Update: started pulling things apart. No shavings in the oil. That must be a good
Sign. Pulling the head today hopefully if weather allows. Will keep you guys posted.

 

[DSMFLipp]

Replaced the head. And all gaskets. Used a felpro permatorque. Installed Arp head studs.
She's running good and strong. Pushing 15 psi. All four cylinders had no dents or nicks
At all. Problem was a chipped exhaust valve on cylinder #1.it took me all of labor day weekend
And then some, in between working. I also put in a new head with ss valves this time.
I'll update with pics tonight. Thanks guys!!