[96lt12011]

I recently replace plugs and wires on my stock lt1, i switched to the MSD 8.5mm super conductor wires. Now my problem is that it starts up fine and runs fine in park and nuetral, but when put in any gear it sputters. Could this be a swithced wire on the optispark? No CES codes either

[GaryDoug]

Try running the engine again. Make sure (....gas tank is over 10% full and .. oops probably not pertinent to a 95 or 96) that you keep the throttle steady for a few seconds at least. That way any misfire codes that might be pending will get set. It takes at least two ignition cycles to set the MIL for misfire codes.

This post has been edited by GaryDoug: 11 August 2012 - 11:23 AM

[96lt12011]

Ok ill try running it again. I was burping the coolant system since i replaced radiator, started and shut it off mulitiple times. Will it throw a code if it is misfiring?

[GaryDoug]

See this document for an explanation of all the trouble codes for your car: http://service.gm.co...6c57P_FY_yE.pdf

[96lt12011]

Thank you SO much for that link. I printed it off and gonna wait till tomorrow to where i can get my friends obd II reader. Thanks once again!

[GaryDoug]

Those readers are great... but somewhat limited. Consider two other possible ways to go:
1. If you use a smart phone, get a $20 Bluetooth OBD2 adapter (http://www.amazon.co...f=pd_sim_auto_2) and download the Torque app ($5), or
2, If you have a laptop PC, get a $15 USB adapter (http://www.amazon.co...f=pd_sim_auto_5) and use a "free" app like OBDWiz or mine (GDScan) and do the same on a much larger screen.
Either way will give you way more information than a simple code reader. For example, you will get misfire counts by cylinder# even when there are not enough to light the MIL. Also graphs, virtual gauges (not on mine), and data logging.

[96lt12011]

Nice to know. So if the codes come up as example " cylinder 8 and cylinder 6 misfiring" Would that just simply state that the wires are put on backwards on the optispark?

[GaryDoug]

96lt12011, on 11 August 2012 - 11:52 AM, said:

Nice to know. So if the codes come up as example " cylinder 8 and cylinder 6 misfiring" Would that just simply state that the wires are put on backwards on the optispark?

That would be a very likely possibility.

[96lt12011]

Ok thank's once again for the tips and links. I'll post an update once i figure out the code.

[96lt12011]

p0300 cool. Anyone know where to start?

[Injuneer]

"Multiple misfires" doesn't help much. Can you access the misfire count by individual cylinder? That's where you find out if it's truly random, or related to one or more cylinders - e.g. cross-firing plug wires.

[96lt12011]

No. The wires were all correct. Can you show me a pic of how you routed the msd 8.5 wires? I have them running through the same "hell hole" as the stock one

[GaryDoug]

My guess is that one or more wires are DOA, or that one or more terminals aren't pushed in/on all the way. BTW, when I was testing my OBD scanner software, I unplugged one wire to force the cylinder#1 misfire code and the engine idled pretty much normally also.

[96lt12011]

Checked all the wires on both sides, and all of them were connected properly. It ran fine, but as the more i drove it the worse the sputtering came back. Next thing i know the CEL light was flashing then stayed on. Could it be the gap on the plugs that can cause the P0300 "multiple misfire" code? What is the correct gap to be set at .50?

[96lt12011]

96lt12011, on 12 August 2012 - 01:23 PM, said:

Checked all the wires on both sides, and all of them were connected properly. It ran fine, but as the more i drove it the worse the sputtering came back. Next thing i know the CEL light was flashing then stayed on. Could it be the gap on the plugs that can cause the P0300 "multiple misfire" code? What is the correct gap to be set at .50?

I bought the E3 plugs, thinking i would of saved fuel and gas mileage. I think they just don't run right. Looks like i wasted some money.

[GaryDoug]

Which ones did you buy? I see the standard replacement is the E3.44. With E3.40 and E3.62 as optionals.

[96lt12011]

I can't remember, plus i threw away the boxes. :angrysoapbox:

[96TA]

Not sure if it applies on the older cars like ours but its worth a shot, disconnect the battery and while the battery is disconnected clean the throttle body and blade then reconnect the battery and let it idle with the a/c off for a few minutes. A lot of newer vehicles require this as part of the spark plug replacement.

[96lt12011]

I've tried that. Im thinking it could be the gap, but then again the E3 plugs you cannot gap. Everything ran fine before i changed out the plugs and wires. I never had any codes or problems with the EGR valve or any vacuum leaks.

[96TA]

When I changed the plugs and wires on mine I spun the wire the wrong way and burned it on the header and had a p300 code for the #4 and #8, changed those wires and all fine. But the saving grace was the misfire count feature. On a older bird I had the MSD 8.5mm wires and they worked pretty bad, ran a 8mm set from Autozone and it ran perfect. The other thing to check is if the coil wire is all the way on and if the coil is working properly. I just had to change mine last week for the same issue you are having. $60.00 at Bennett for the AC Delco unit with a 1 year warranty.