JRB 9966

I use an AutoXray EZLink. I just changed plug wires and was doing some routine monitoring while driving to check for misfires.

Odd thing, I periodically get "Total misfires" counts that are always divisible by 8 such as 512, 1024, 1536 while all 8 cylinder counts stays at 0.

It usually happens at or shortly after starting the engine and sometimes during the drive when I downshift.

I get no SES light, no codes.

So what is it counting as a misfire if it sees no misfires on any cylinder?
Is my scan tool hosed up?

When I first changed the wires I took it for a spin around the block and it seemed fine. No misfire counts. When I started to bolt the shock tower brace back on I noticed that the #6 boot had come off the coil pack. I'm beginning to wonder if this tool can even read a misfire.

Anybody seen anything like this?

Thanks,
John

2002_Z28_Six_Speed

iTrader: (19)

I found out that while logging with EFI LIVE I would get misfires on the Dyno but the power graph never showed a loss of power or dip in the power. I would get 1-2 misfires per cylinder per dyno pull.

Therefore, I am listening in...

eallanboggs

iTrader: (1)

Misfires are to erratic to be an exact binary power of 2. That sounds more like a software aberration.

JRB 9966

Yeah, that's what I was thinking. The first time I saw it, it said 1536. That didn't ring a bell. The next time it was 512 and then 1024. 512 + 1024 = 1536. I have swapped enough computer ram for that to ring.

But what if something in the PCM is suddenly seeing a misfire on all eight in batches that add up to these total counts. I would think that would throw a code or two but have gotten none. I hope it is a scan tool problem. I wish I had another to check it with.

John