Dead Miss

[Whistlin'87GN]

Alright, I've had an intermittent miss for a little while, but now it just got to where it is there about all the time and all the way through the RPM range. I've tried an another Ign. Module and Coil, and that didnt fix it. I pulled the plugs and # 3 was carbon fouled, so I replaced that once since it was pretty bad. I need to check the wires. I did a compression test, and the numbers seemed pretty low, ranging from 75 to 85. I have the cylinder # and psi if it would help. My boss at work, the shop foreman, thinks it could be a burnt valve.
I'm going to try a new set of plugs. The guys at work think I should put in a hotter plug?? Im running a cr43ts. Also what should I set the FP at with a Thrasher 92 chip (I think its set at 45 static, havent checked in a while). It has seemed to be running rich lately, and I have always gotten real poor mpg. When its missing, most of the times the O2's fluctuate in the 021-070 range or basically down below 100. I do not know what is causing this either, it has a fairly new O2 sensor (AC sensor)
I've been meaning to get a new chip and now i'll probably get new wires also. Also it has popped a couple of times through the intake I think and there is also what seems to be a loud knock sometimes back above the #6 lifter.
I'm confused on whats going on, any ideas, tips, anything at all would be greatly apreciated!
-Jeff

 

[scottyb]

Tired injector(s) maybe?

 

[Whistlin'87GN]

Im going to try to check those tommorow. What is the best way to check them, I'm going to ohm them, than do voltage drop across them. I'll also check the wires.
Thanks
-Jeff

 

[Whistlin'87GN]

TTT

Anyone???????

 

[Ray R]

You might want to check the cam. Almost sounds like a wiped cam lobe. Good luck.

 

[Whistlin'87GN]

I was kinda afraid of that.
Is the only way to check it by pulling the intake and doing a visual? I do have a knocking noise occasionaly from what seems to be above the #6 lifter??
What are the symptoms of a wiped cam?
Thanks
-Jeff

 

[Ray R]

The easiest way I found is to pull the valve covers and start the engine. look for one rocker arm moving less than the others. If the lobe is as bad as I think it is, you will see the offending lobe pretty quick. As far as symptoms valve train noise is one, the dead miss is another, this might not be the problem, but if I were you I would definetly check it.

 

[Whistlin'87GN]

Thanks for the info guys!
Do you think it'd be worth it to check anything else (ie injectors, wires) or should I go straight for the valve covers? Hopefully this weekend I'll be able to check most all of the electrical side, than at work I might pull the valve covers.
Also when a cam lobe is wiped, is it recommended to pull the motor and do a rebuild since there obviously will be lots of metal in the motor?
Thanks again
-Jeff