the427chevy

i have a 98 sonoma with a 2.2, it dropped compression on 1 and 4 cylinders; can't see any physical damage to valves; pistons in good shape; i'm thinking that maybe its a stuck lifter? i tried compressing them, i had to put them into a vice in order to force the oil out of them, it didn't take much in a vice but i couldn't begin to do it by hand; is it possible they were stuck? the engine only had 98,000 miles on it

Turn this car around

Did you do a leak down test?

far2grumpy

What led you to compression test? Would engine run? Did you have SES light ... did you check codes, if so, what were they?

Edit ... sorry if it sounds like I'm second guessing ... its your engine and you know more about it than me.

I'll attach service manual extract regarding 2.2 compression testing to next post - hope it'll assist.

Good luck!!

far2grumpy

I've attached FSM extract regarding 2.2L compression test. It says Chevy but I had that part of manual pulled up for another reason.

EvansBlue

Did you check all the valve seats for hairline cracks?
Also check the head gasket to make sure there wasnt any cracks or weaknesses. If you have the head pulled, you should replace the head gasket anyway...
It could have had a stuck lifter, I wouldn't rule it out.

the427chevy

engine would run, very rough at idle, could unplug cylinder 1 and 4 and barely change idle, so i pulled the plugs, both were very carbon covered and wet, did a compression test, about 15 lbs on both cylinders, and they didn't hold no matter where the engine was positioned. add oil, no difference, ad a lot of oil, still no difference (haha) so i pulled the head, pulled all the valves out, check all the seats, nothing. i pulled all the lifters out, i couldn't comress any of them without the use of a vice the first time, but they all freed up nicely, i soaked them over night in oil again before putting them back in, i pushes all the air out of them under oil. put it back together with a new headgasket, now i have about 30lbs of compression on those cylinders and adding oil boosts the compression above 200psi
i always thought 1 and 4 cylinder were getting floooded out so my thought was that fuel wore the rings out washing the cylinder out.
i took the ECU out of it to put in my other truck because i have two of them, and it won't even start the other truck, it just pops and backfires and cranks slow like its out of time, all the numbers on both ecu's are identical.
put the original ecu back in my other truck and its fine again.
i'm thinking that i should find another motor or do the rings in this one. and the MIL light was constantly flashing the whole time this truck ran. fuel pressure is dead on where it wants to be

far2grumpy

If adding oil boosted compression to 200+ its almost certain you have bad rings, bad cylinder wall, or both. A blinking MIL generally indicates misfire, and probably lots of raw fuel dumped into the catalytic converter ... that guy is most likely fried ... and partially clogged.

Regarding ECU ... do I recall many of the parts houses having a ECU tester? Maybe I'm thinking of simpler times.

EvansBlue

You can get a code reader/eraser at most auto parts stores. Don't know about an ECU functionality tester... I have never seen one at an auto parts store.

Definately want to hone cylinder walls if not bore it .030 over.

the427chevy

i have a modis; it was throwing constant missfire codes due to the no compression; and the 1st and 4th injectors were off the chart throwing fuel; my theory is somethin int he ecu went, overloaded the cyldinders with fuel and the dude that i bought it form just kept er pegged
i got a 96 sunfire engine somewhere in my pile of parts its a 2.2L any reason why i can't use that motor?

Turn this car around

I would bet the injectors or bad,pissing and that the computer is alright.But it is possible it could have got damaged after a period of time dealing with the problems.Need to test the injectors this is your real problem.You can test the injectors by removing the fuel rail and plugging the return line. You will need a Electronic Fuel Injector Tester so you can pulse the injectors to see their spray pattern .The two in question no doubt are just pissing. Otc has this tester their old part number for this is 3398 .I don't know if the number has changed for it .Other manufactures may have the same tool. So you could verify the bad injectors.You will have to power the fuel pump to pressurize the fuel rail .Your modis may be able to help you there.