KickSS

So i just emptied my pockets to buy a 98 SS camaro, thing looks great and has some great things done to it, most notable are the z06 cam, after market heads (not sure of the brand) weiand intake and full header back exhaust. The Service engine light was on when i bought it but my experience with muscle cars tells me that it is common for a modified car to be throwing codes every so often. I drive the car home from the gentleman's house and the light begins to flash, which i know is not good. I bring the car to my mechanic and he tells me ive got 4 random misfires and the plug wire for cylinder #4 has been burned through by the header. Furthermore every cylinder has 175psi on the pressure test expect #4 which is reading a really healthy 0 psi. What happened and whats the problem? mechanic said its either the valve(s) or theres a hole right through the side of the piston or the rings are fried, with everyone's experiences which one of these options is the most likely?

01ssreda4

iTrader: (96)

sounds like I would be taking it back to the gentlemans house.

KickSS

Tried that... no dice next time i go it will be with gasoline and matches

bjamick

iTrader: (31)

"0" psi in one of the cylinders? Sounds like there was a reading or test error there. Just change the plugs and wires and call it a day. If there was a hole in the piston you would know it.

Please go get your car from the mechanic and change the plugs and wires yourself.

Zach79Z

iTrader: (21)

Change the wires and plugs like said above but put those plug wire protectors on the wires that are burn proof from the headers.

fergymoto

iTrader: (129)

I completely disagree with that. I fixed a LS1 a while back for a guy. I had run a compression test on his motor and #7 rear ZERO on the gauge. Upon tear down the piston was burnt.

PAGregSS

iTrader: (10)

Did the mechanic say anything about hearing air coming out of the throttle body when doing the compression test on the cylinder with 0 psi? A qualified mechanic should have no problem telling the difference between a leaky valve and a busted piston when doing a compression test.

Like the others mentioned, change plugs and wires, clear the codes, and see how it runs then. Were the only codes for the misfires?

deelong4002

iTrader: (8)

Flashing mean Lean condition RIght? Maybe have fried a piston. Perhaps he didnt tune it correctly for all of the modifications.

Zach79Z

iTrader: (21)

When my 02 went out my motor would misfire and the service engine light would flash. A mechanic told me it was falshing because of the misfire. But it could also mean other things i really dont know

TWS

iTrader: (63)

One of the codes for which the SES light will flash is misfire.

If a piston was "burnt" or cracked or rings were bad, I would expect the car to run rough. I've never had a cylinder read 0 psi, but have had some low ones like 35 psi when I had rings butt ends and break off the ring lands.

KickSS

The only codes were misfire codes and the car runs fast, i had a 98 mustang cobra and this thing in the shape its in out runs that 2:1 in the event that it is a fried piston any estimate in what im looking at in repair costs? also are there any tell tale signs of a burnt piston because with the exception of the SES light it doesnt seem like theres any issues with the car.

TWS

iTrader: (63)

If it is running strong now, then all you probably had was a burnt plug wire.

Because (no offense) it seems you are new to this, you may not have a good feel for how a healthy LS1 runs. You should recheck compression in that cylinder. May have been a false reading, or your guy may not have had the fitting screwed in right or the quick release on the hose leading to the gage, etc. Don't know, I wasn't there, but you should recheck.

Mumbles

iTrader: (5)

As previously stated, when the SES light flashes at you it means the PCM detects a misfire and is telling you to do something about it before you ruin your cats. (I had this happen to me with my 99 Sonoma. I ended up replacing my cat after I fixed the misfire.)

Fix the simple problems first. Change the plugs and wires. Talk to 99BlancoSS. He is a sponser on here and can get you some NGK plugs and a set of MSD wires for a really nice price. With the MSD's you can shape the wires so they aren't touching the exhaust. I agree with the above posts stating if your #7 was at 0psi, the car would not run worth a ****. If the plugs and wires don't fix the misfire, then I guess I am wrong and you have a bigger problem on your hands. But start simple and work up to big things. Good luck, man.

bjamick

iTrader: (31)

Yes if there is a hole in the piston, you wont be wondering why the SES light is flashing. Your going to be wondering what that loud noise is. Most likely the compression test on that particular cylinder was not correct. Either you can recheck it or just replace the plugs and wires. Simple as that.

KickSS

You are correct i am new at this haha, had experience with mustangs but never with the LS1, i changed out the burnt wire hasnt changed the engine performance. I did notice the SES light is solid except under load, my guess is that it is happening because the unburned fuel is dumping into the cats more so. I assume it is possible that the test was administered improperly but assuming it wasnt would a bum valve cause a zero compression reading or is it likely rings?

TWS

iTrader: (63)

Rings or a valve not sealing will result in low compression, but not zero. Definitely not if you think the motor is still running decently.

Get someone with a code reader and see what codes it is throwing.

DaddySS

A couple of thoughts.
First, in most states the seller is liable for 30 days - car should be free from problems unless they are stated on the bill of sale.

Second - you seem to be leaning toward a bad cylinder but as stated above it is not likely that you would have 0 compression without smoke out the exhaust and a very poorly running engine.

Third - pull plug #4 see what it looks like and did the mechanic put new plugs in there while he was doing the compression test?. With a z06 cam you should not be getting misfires. Fix that problem first. BTW the codes usually mention the cylinders - which ones are misfiring?

hammertime

iTrader: (1)

Your mechanic should have known that a leakdown test would quickly indicate where the air is leaking. If you have zero compression in that cylinder, the air leak will easily be audible at the throttle body (Intake Valve), tailpipe (Exhaust Valve) or through the oil fill hole (Piston, Rings). I've got money on rings washed out by unburned fuel since #4 cylinder had the plug wire burned. I would guess it had been that way for a while.

Your mechanic should also have known that a squirt of oil into the cylinder is a good way to see if ring seal improves enough to see a change in cranking pressure or leakdown. Unless he has a bore scope, you're probably looking at pulling a head off to inspect the damage. Depending on what you find, you may be able to replace that sleeve and the piston & rings. Otherwise you may shop around for a good used shortblock.

Second thread I've read in two days about a new purchase being soured by internal engine damage. Hope things work out for the best!