quickWS6

EDIT:

Under 2000 RPM, #6 doesn't fire, above 2000, #2 doesn't fire. Would a bad crankshaft position sensor cause this?

Z-Rated

Are you sure your getting fuel? How do you know that the injector is getting fuel? And do you know for sure that its getting spark? could be a bad coilpack... because I know you checked the plug wire a thousand times Id change the injector and the coilpack and see what happens

Ryan K

iTrader: (11)

Also, I would recommend a compression test. Check your oil level and smell the oil. If it smells like gas, you may have a bad slug in that hole...

Ryan K.

Slowverado

yeah, when i had my bad misfire the oil smelt like GAS, my plug was dead though.

quickWS6

I pulled the wire off the plug and started the car, had a friend hold a screwdriver near the end of the wire, and it got spark. I pulled the fuel rail off and put a towel under it, turned the car over some and saw #6 is getting fuel. I also switched injectors before to no effect. I swapped plugs between cylinders also. I'll do a compression test, what numbers should I be looking for on it?

White_Hawk

iTrader: (3)

I don't know the absolute numbers for compression, but the cylinders next to it should be at about the same compression if that helps. If there is a problem you will see a big difference cylinder to cylinder. You can also swap the coils out with another cylinder and see if there is a problem there. You might have low spark energy or something too. I'd run compression first, though.

-Geoff

quickWS6

Okay, when I start the car, it idles okay at 1800. When I put it in gear, I get a flashing SES and the car tries to die, the idle goes below what is set in Edit. I hear a noise like a hollow thud when it is in gear at times. Any ideas?

quickWS6

Does this sound like it could be the crankshaft or camshaft position sensor?

Bugblndr

It could be. I had a problem with misfires on Cylinder 7 when under light load between 2500-3000 RPM. Tried changing the wire, plug, coil, fuel injector and no change.

When I had the motor in for a rebuild, ARE discovered a messed up crank and reluctor wheel which was causing the problem.

ne14a6t9

id check the valves springs, you may have broken one or 2. a brocken ex valve spring will give you a thud noise, with your 600 lift cam that is the most likley thing. what springs do you have, pop the valve covers and look at the springs, sometimes its hard to find the crack, so push down on them with your palm and see if you can move the valve off the seat easily, more than likley it woul be an ex spring, they get hotter and fatigue. good luck hope its a help

quickWS6

I checked the valve springs, they looked okay. I am running 918 springs, they only have 40 miles on them tops, and 4000 RPM is the highest they have seen. Which side is the exhaust valve?

Pro Stock John

iTrader: (34)

I don't think it's a messed up crank or crank sensor.

My concern is that you have broken valve springs. Flashing SES can point to pcm detecting very poor running conditions, ie 1-2 cylinders not firing.

quickWS6

Okay, I'll check them again. In a way I hope it is, I can go to some Revs. I couldn't see any cracks, would I be able to tell by removing the rockers and pressing down on the springs like was mentioned above?

Gold Phoenix

iTrader: (1)

Are you still running the stock short block? I had some misfiring when I over-reved the motor on a 3-2 shift at 6000rpm. I changed my pushrods and got the car running but there was noisy clatter. I just got done putting new valves, springs, titanium retainer, and lifter in the head. I learned that all 8 of my intake valves were bent. I did the compression check and got anywhere from 170 to 185 psi. The bent valves found another way to seat and seal themselves. The bend was only a couple thousandths, but it was enough. I am just wondering if your big cam may have made contact with the pistons.

quickWS6

Yes, I am still running the stock shortblock. I plan on changing back to the stock cam and I have a set of stock heads here that I will slap on. Hopefully it will cure my problems.

Reboot

iTrader: (5)

Are you sure the coil pack harness didn't get reversed? I've heard of similar situations when they're plugged in backwards.

quickWS6

No, the coil pack harnesses are correct.

ne14a6t9

Gold phoenix has a good point, your cam is big and being on a 110 lsa has alot of advance in it over stock or a 112 lsa. maybe you did tweak the valves, this is what you do, remove the intake valve covers and rockers on the missfiring cyl, put air in the cyl using a compressor, fill the port up with a little brake clean to cover the valve, if you see alot of bubbles, you have bent valves, I did this on my 69 camaro a while back and found a bent valve, except there is no missfire data to narrow it down, so i had to do them all, it works, good luck finding your problem