take the head off

[jayb903]

I'm still trying to figure this misfire out. I can't get more than 7 8 Psi and my turbo and pipes are fine. I've checked inj pt coils wires plugs and maf. All tested good. My misfire keeps getting worse. So I'm thinking about taking off the head to look at the valves. Any ideas? Timing is good and my compression was good last time I checked about 3 months ago. I'm on my blackberry so excuse my punctuation.

 

[jayb903]

Anyone? I know this basically covers a broad spectrum of things when dealing with misfires. But I think I have narrowed this problem down pretty far by eliminating certain things that tested good.

Could my problem be a stuck valve or something like that? I mean if I'm getting very little boost(7,8psi) either its my A/F or something dealing with combustion somewhere, correct?

Maybe I should just open up a blog on my progress....

 

[cheap90gsx]

you can somewhat check the condition of the valves by taking the valve cover off and inspecting the roller rockers, valves and valve springs while turning the engine slowly by hand. You should not be able to wiggle the rollers, they should be tight.

 

[evileagleawd]

I think you need to take a step back for a second! You do not need to take the head off in less you defiantly know something is wrong! You said you have a misfire. Do you know what cylinder. Is your car a 96 or newer and do you have codes such as p0300,p0301,p0302,p0303,and p0304. The last number will distinguisher what cylinder is misfiring. I would defiantly retest your compression. A compression and cylinder leak down test will definitely give you allot of information on what is going on your cylinders. Does the car misfire at idle or just under a load?

 

[jayb903]

I think you need to take a step back for a second! You do not need to take the head off in less you defiantly know something is wrong! You said you have a misfire. Do you know what cylinder. Is your car a 96 or newer and do you have codes such as p0300,p0301,p0302,p0303,and p0304. The last number will distinguisher what cylinder is misfiring. I would defiantly retest your compression. A compression and cylinder leak down test will definitely give you allot of information on what is going on your cylinders. Does the car misfire at idle or just under a load?

Yeah I get the p0300 code on my 99 GSX, but as for which cylinder I can't narrow it down. I go to unplug plug wires and the miss is still present. Also if I unplug my o2 it sounds fine at first then misfire comes back. It misfire under both load and idle.

I will try to do another compression test in the next day or so. It rained today so I didn't want to get wet.

 

[stevo911]

Did you check for vacuum and boost leaks?

 

[jayb903]

Yessir! I've had this misfire problem for a few months now. And now I'm motivated to track this monster down and see whats what.

 

[Kastigir]

Have you checked your fuel pressure?

 

[jayb903]

Have you checked your fuel pressure?

Yup, fuel pressure is fine. I've tried raising it and the same problem persists.

 

[jayb903]

Just got back from checking my compression 190 across the board.

Unfortunately I still have the misfire and the little boosting problem

I took my turbo(fine), w/g(fine), looked at my manifold and still the same results.

Now when I changed my plugs to the "NGK BPR6EKN" the misfire code(p0300) never came up, yet it sounded worse than when I had my NGK BPR6ES in. But when I put the BPR6ES in, the misfire code came up again???

So now I'm down to rechecking my MAF and replace switching out my CPS. The misfire I believe is causing me not to boost. Even though I still have no official boost gauge(LAZY) hooked up, I'm using the Boostest off of DSMLINK and before it worked pretty good.

Any help would be nice.

 

[stevo911]

Check your intake manifold gasket? Still sounds like unmetered air getting into the engine.