Joocid

Hi. I took my girlfriends car to the mechanic today to get our lack of power issue figured out. In short, they told us we needed a new engine, which is too costly for us. I also feel like they could have pinpointed the exact problem instead of saying I needed a new engine. Here are the symptoms

P0107 & P0108 - MAP Codes(Replaced still throwing codes)
P0122 - TPS(Replaced still throwing codes)
P0171 - Running Rich
P0300 - Random Cylinder Misfire

Cylinder Compression Low
Cyl 1: 95 psi
Cyl 2: 55 psi
Cyl 3: 85 psi
Cyl 4: 105 psi

Under Throttle (about 1/3 or more) it hesitates. Idle is rough(Bad IAC) but it will move under 1/3 throttle. At WOT the intake shake. Took off the intake and put my hand over the opening. It seems to be sucking AND pushing air at WOT. Engine lopes and runs at the 1/4 temperature mark as well. Any suggestions?

Here is a youtube video of the problem, duoplatinum's Channel - YouTube

kevinkpk

Put a rag on the exhaust like you did your hand, is it also sucking in? If so that could explain the lower compression on a couple of those cylinders. Post back, might just need a valve job.

Joocid

I dont think the exhaust is sucking in as well.. I could be wrong though. I've read that timing could cause low compression as well.. I asked the shop if they did a timing test and he just told me, 'It needs a new engine.' felt like I got blown off after paying them. A different mechanic that took a look at it said something about 'hearing' a valve problem before I even got the compression test done.

Timing and valves? Seems like possibly a slipped timing belt caused some bent valves. Which leads me to another question, is the Corsica's valves protected from a slipped belt?

It seems 3 of the cylinders are around the same loss, seems like whatever is going on is affecting all the cylinders. The fourth is probably a bad ring.

Does any of this make sense or am I on the wrong track?

kevinkpk

You don't have bent valves, timing has nothing to do with a compression test whatsoever. With it running, take the oil fill cap off, and see what kind of pressure you have comming out of it.

Joocid

I dont have any kind of tester for that but I just checked it out. Put a piece of paper over it and it pulsates in-out. It shouldn't do that correct? Sound like you are onto something.

Joocid

Just looked up the symptoms. Head gasket and/or rings. Doesn't show symptoms of a head gasket, could all the rings be worn that bad? 127k miles. Why do you say the valves are not bent?

kevinkpk

Valves being bent, maybe on a hi compression engine that flew apart. It runs? Rings could be the problem being worn, but think about how come half of the cylinders are low, and the others are "ok"? Even wear, break a ring possible, but broken rings on half the cylinders? Being pratical here. Look at what it is, and evauluate what it is telling you. Yes a new engine would shurley fix your problem since it does have one or more of these problems. The engine under anything normal is going to wear evenly. Head gasket, I didn't see any smoke, white, black, or blue out of the tail pipe, I still think it needs a valve job.

Joocid

Ok makes sense. Quick rundown.

Intake 'Gurgles' Air Pulsates when it 'hesitates' over 1/3 throttle. Which seems like air coming out intake valves from compression correct? It seems like only the intake side is messed up, the exhaust seems fine.

Lack of compression = Random misfire?

Air in oil dipstick(Not a lot) worn ring most likely in the cyl with 55 psi.

Valve job meaning, bad valves due to buildup or bad boots? Please elaborate what you think happened to the valves. Could I run a buildup cleaner through it? Or are they 'shot'.

Also forgot to mention oil has a gas smell to it, which could also be a bad ring. Intake manifold smells like gas as well. Also the intake had black dry 'flaky' buildup behind throttle plate.

Thanks for the input and advice, I need to get this car in working condition. I don't want to have wasted my money getting this car for cheap.

kevinkpk

Burnt valves will cause low compression, and hi blowby in the engine, also wit "bubbles" in the oil. You might even get a new PCV valve install it, but with the low compression on the cylinders you have, I'd still say valve job.

Joocid

I've had some time to research more on this and valves seem to be in accordance. Thanks for the help, I'll get those repaired and see if that is the magic trick.