MY CAR IS STILL RUNNING CRAPPY PLEASE HELP MEEEE!!

[98tadriver]

well last night chummmmmmmaa came down and scanned my pos car, was showing alot of misfires from cyl 4. 6 was showing a couple but not too bad. actually i think that whole side showed a couple here and there. the other bank was at 0 most of the time. anyway the coil packs are good, we swapped them around, they were fine. new plugs, correctly gapped, new wires too. but stilll misfiring like hell. no other sensors threw codes. just that damn P0300 code. we checked the pushrods, they were ok.

another thing i noticed was that the intake runner going to the #4cyl was hot compared to the rest of the others.. wtf?

so im gonna do a compression/leak test tonight

my thoughts before that test--

bent/stuck/burnt valve?
bad lifter?
timing chain skip a lil? only 49k miles on the motor.

[su_maverick]

Wouldn't an increase in heat possibly be related to running lean? Could you have a clogged injector on that side or possibily a fuel pressure problem?

If your exhaust runner is alot hotter then the rest then it means that too much air and not enough fuel is getting into that chamber. For that it would either be.
a.) not enough fuel- injector
b.) too much air- valvetrain

[98tadriver]

im sorry i forgot to add that its the intake runner on the intake manifold

[su_maverick]

well, the only way that intake runner should be hot is if your intake valve is stuck open a little and some of the combustion is leaking out into the intake tract. That could be catistrophic since the injectors are part of the intake manifold. The last thing you want is ignition in the intake. I would take off the manifold and check for combustion residue in the intake tract for that cyl. If it is darker than the others then you have an issue.

[98tadriver]

UPDATE!

#4 cyl sparkplug was clean as a whistle while the others were not. the compression on every cylinder but #4 was 150lbs. #4 was 90lbs. I would think that means the valves arent opening correctly. possible collapsed lifter? valvetrain damage? Its a stock jasper engine so it has a 3yr 75k warranty. thank god!

also, the rear main seal is leaking, i think the front seal might be leaking, and theres a lil oil leaking from under the intake manifold as well.

[su_maverick]

if it is low compression then I would say that your valves arent closing correctly. I would check the intake side first as the heat would explain a valve that hasnt closed all the way. A collapsed lifter would cause the valves to not open correctly but that doesnt sound like the case.

[98tadriver]

cool, its all starting to make sense now. if i get bored enough, i might pull the valve cover off and check it out. if not, im going to take it to the shop where my motor was installed in june of 05, for i still have a warranty on it.

[su_maverick]

I would say your best bet is to yank the intake mani. That way you can see if there is any discoloration in the intake port. If 4 is alot darker than the rest then that could explain it right there.

[Bandit]

Could be a few things, does the car hesitate or feel weak at launch and not as strong as it use too?

I think it could be 1 of 4 things

Bent pushrod
Bad spring
rocker arm issue
Lifter gone bad

[su_maverick]

but how would those explain a heated intake runner? Actually, if there is something keeping pressure on the rocker arm then the valve will remain open a little bit.

I would check the #4 rocker and the intake side pushrod and lifter. Or am I totally off base?

[98tadriver]

Originally Posted by Bandit

Could be a few things, does the car hesitate or feel weak at launch and not as strong as it use too?

I think it could be 1 of 4 things

Bent pushrod
Bad spring
rocker arm issue
Lifter gone bad

Chummmmma and i checked it out the other night,

pushrods are ok

rocker arms looked fine and were torqued to proper setting

springs didnt look damaged

lifter ? could be but im not pulling the head off to get to it since its under warranty lol. and i think im gonna pull the intake off today to check it out and also find out why oil is leaking from underneath it. (knocksensors probably)

[bubba428]

Its is posible the valve its self is bent, which could be from abuse(no not ron, never) or from a tap that went unnoticed or "fixed itself" BUT a bent valve would cause it to not seat right and the way the LSx heads are its wouldn't cause any noise but it would cause lose of compression and a misfire code from having the cylinder fire but no power output from it.

[su_maverick]

wait wait, where is oil leaking from???

[98tadriver]

from earlier in posts by me-

also, the rear main seal is leaking, i think the front seal might be leaking, and theres a lil oil leaking from under the intake manifold as well.

[su_maverick]

Are all your bolts from the intake manifold tightened down to the block all the way?

[WildBillyT]

Originally Posted by Bandit

Could be a few things, does the car hesitate or feel weak at launch and not as strong as it use too?

I think it could be 1 of 4 things

Bent pushrod
Bad spring
rocker arm issue
Lifter gone bad

I agree. Probably a bad valvespring or broken lifter.

[98tadriver]

It was a bad valvespring, she broke!! its fixed now and runs like raped ape

[su_maverick]

cool, glad you got it fixed

[98tadriver]

me too lol

[bubba428]

Yea that wasn't to bad, we cleaned out the intake ports on the heads and I sprayed the hell out of the intake manifold with 2+2 and you wouldn't belive the crap that was in there. Its a damn good thing I got the spring compressor it would have been a female dog with out it

[su_maverick]

so, was it firing into the intake manifold?

[bubba428]

yup just about

[foff667]

consider yourself lucky you didn't cause any major damage at least none that you can see.

[bubba428]

yea man...like i said...your lucky them reatainers didn't pop out...cast steel piston vs aluminum head...take it easy man