LS7 ZO6 misfire ????

[bada]

I installed a LS7 from a wrecked ZO6 in my 32 frod pro street truck. My ??? is I am getting a misfire code. Speartech did the PCM for me. I am running a turbo 400 auto tranny. I am running a weldon 600a fuel pump with a bypass regulator.PSI is set at 58. The motor idles fine, an seems to run OK. But the trouble light comes on. When we put a scanner on it to check codes it says misfire. Now before I got the motor, we went and listened to the motor run. It sounded fine. Any help would be appreciated.

[IT L GO]

What year Corvette is the PCM from?

Send a PM to RC45, he installed a LS7 into his C5

[bada]

Originally Posted by IT L GO

What year Corvette is the PCM from?

Send a PM to RC45, he installed a LS7 into his C5

2008 ZO6

[GR8 WHITE]

Call me crazy, but the last MISFIRE I had, was a defective spark plug that wound up to be cracked. Since you installed the engine, is it possible a spark plug was cracked when you re-installed them? A simple check.....

Can't hurt to check it out..... Hope it is as simple as that.

Possibly a fouled spark plug wire or, when the wires were pulled off, maybe the wire itself was pulled and not the boot, so maybe the wire is frayed inside the shield and not 100% in contact with the boot connector anymore?

Just some suggestions....

Try new plugs and new wires. Are the spark plugs the correct ones for the LS7?

Good luck -

[extanker]

if you are using the z,s oem ECM it will tell you what cylinder is missing

[bada]

Originally Posted by extanker

if you are using the z,s oem ECM it will tell you what cylinder is missing

The misfire is not on any one cylinder. Its like a random misfire. Thats what has me stumped. I have solid motor mounts not like the factory ones with rubber in them. I am making new ones that I will have urethane in. I was thinking maybe the knock sensors were causing the code. PO300 is the code I am getting. IF the new mounts dont solve the problem I will be stumped for sure.

[bada]

Originally Posted by GR8 WHITE

Call me crazy, but the last MISFIRE I had, was a defective spark plug that wound up to be cracked. Since you installed the engine, is it possible a spark plug was cracked when you re-installed them? A simple check.....

Can't hurt to check it out..... Hope it is as simple as that.

Possibly a fouled spark plug wire or, when the wires were pulled off, maybe the wire itself was pulled and not the boot, so maybe the wire is frayed inside the shield and not 100% in contact with the boot connector anymore?

Just some suggestions....

Try new plugs and new wires. Are the spark plugs the correct ones for the LS7?

Good luck -

The motor has the factory plugs & wires.

[extanker]

the emc might not be able to pick it up .like you said random. you are on the right track ,solid mounts can do it as can rotors,driveshaft and crankshaft position sensor relearn. good luck

[bada]

Originally Posted by extanker

the emc might not be able to pick it up .like you said random. you are on the right track ,solid mounts can do it as can rotors,driveshaft and crankshaft position sensor relearn. good luck

Thanks. I am getting urethane poured in my mounts now. I have customs mounts that we made just for the truck. So we modified them the accept the urethane. Hope that does the trick. If not the tranny mount will be next.