low compression

[killer_eclipse]

so im helping my buddy with his new 91 gsx... He is complaining its not pulling very hard. So i did a boost leak check and found a bunch of little leaks and one big one the throttle body seals fixed them all did another test still not holding pressure so i did a compression test and this is were shit went south..

no.4 60
no.3 40
no.2 35
no.1 30
???????????????????????
how is this car runing
anybody else seen anything like this from a running car???? and its not like i dont know how to do a compression test i have done hundreds and rebuilt plenty of these motors and im lost...

 

[zhjiln]

if you have rebuilt so many dsm motors ... rebuild your friends motor.. problem solved... with those compression levels.. it cant be drivable..

 

[Dewayne Waldron]

I don't understand how it is running, a car needs at least 75 compression in order to start. Has he done anything to it like cams, ,valves, etc...

 

[96eclipzGsT]

I had an n/t that a friend ran hot and burnt up the piston rings or something and it did the same thing. It would run only when it was warm outside, otherwise you would have to put a squirt of oil in the cylinders to get it to start. That sux man.

 

[1AWD90]

I would say check your gauge! Either this thing runs like total crap if it even runs or your gauge just took a dump on ya. If not the gauge maybe your friends timming is off or the motor is just shot.

 

[JesterJess]

I would check your gauge with a known good engine. Squirt a little oil in the cylinder, and see what those numbers show. If you were working on it leaned out, any chance it fuel washed the cylinders and you lost some compression due to no oil on the rings?

Just a couple ideas I would work with.

 

[killer_eclipse]

i am going to rebuild it i am more stumped as to why this thing is running and running good at that... it idles perfect pulls ok sense i fixed some of the boost leaks.... and what really confuses me is those numbers were a cold compression test( i know i know do it when the motor is at op. temp. only did it to get an idea) but after seeing those numbers i got the engine up to temp and did it again and got
hot
no.4 30
no.3 30
no.2 30
no.1 30

im going to tri a diferent gauge and just hope

 

[JesterJess]

WOW, I can't believe it even ran at all!

 

[killer_eclipse]

it still is he is out driving it right now like i said i dont understand it....

 

[LittleBear]

He is going to make my problems driving it like that

 

[BryanCenterfitt]

you need to get another gauge and check that bro cause thats not even right.. i dont see how that things is even running, let alone driving up and down the road...something's not right.. good luck

 

[popwarbunny111]

I am having the same issue. I did a compression test warm and cold and it didnt make to much of a difference.
My compression was 60 psi across the board and it runs and drives pretty good when it's warm outside. I had the same question posted on here earlier. I was stumped as well. ..

 

[ts90gsx]

i have the same problem with mine, mines 50 across but it doesnt start.. one day it was 120 and i found out the timing was off by 2 teeth fixed the timing and now it wont start.. the compression dropped down to 50..

 

[popwarbunny111]

i have the same problem with mine, mines 50 across but it doesnt start.. one day it was 120 and i found out the timing was off by 2 teeth fixed the timing and now it wont start.. the compression dropped down to 50..

ahhggg that sucks man. I've also heard if the timing is off like 2 teeth it's not to bad, as in like 1 or 2. I have also heard if it slips once that it will continue to slip.
that sucks though.

 

[rEclipserGST]

Maybe, just maybe... you did the compression test wrong. That is always a possibility.

 

[shift2drift38]

posting on this one because it's almost the same story with my motor. it's a 420a (95 eclipse). Just had a reman short block come through, had my shop put the head and all together and drop it in. Now...... this is my fault entirely but I was just too pumped to think about it. The car had sat for 2 years, with a full tank of gas. I drove it home, took forever to start, but it fired, exhaust smelt like crap but i didnt think much of it. Next day same thing, and i had only put like 8miles MAYBE before I shut it off ### i was getting worried... 2weeks later I try to show my mechanic whats up, and it wont start... Compression is now 100-110-100-25......... chance that fuel washed the rings?

I'm asking because I see alot of this "squirt a little oil in it" fix. I have drained the gas tank entirely and replaced the filter, and pump just because. Timing is dead on, but like I said after reading around, it sounds like my hype and forgetting the simple things screwed me... any insight would be great before I try this oil trick.. Thanks all.