misfire

[volksdragn]

Hello, I am having intermittent misfire from #1 cylinder at Idle, I changed the plug and it corrects the problem for a minute and then the issue becomes progressively worse. I have checked it with a timing light and it is intermittent. I have swapped coils, wires and plugs and it only does it on #1 cylinder. in my data log I can see that the dwell increases when the engine speed slows down, does anyone have any opinion on this, I am at a complete loss. i know enough about refi to get into trouble and thats about it, it is a 2276 and I'm running ms3- EVO wasted spark at the moment. Thanks for the help

[sideshow]

Go back to the basics, what does the plug look/smell like? What is the leak down or compression compared to the other holes?

[grelland]

Have you checked valve adjustments?

[Chip Birks]

What kind of coil? Smart or dumb?

[volksdragn]

I haven’t checked the valves, it’s really odd because I had the issue a while back and then I tore the engine down and out new bearings in it and it’s doing the same thing. So I’m thinking it’s an electronic problem not mechanical but I could be wrong. They are gm ls coils. I’m waiting on a part for my cam sync so I’m currently running wasted spark until the part comes in

[volksdragn]

They are dumb coils

[Chip Birks]

Ls coils are smart coils

[grelland]

I haven’t checked the valves, it’s really odd because I had the issue a while back and then I tore the engine down and out new bearings in it and it’s doing the same thing. So I’m thinking it’s an electronic problem not mechanical but I could be wrong. They are gm ls coils. I’m waiting on a part for my cam sync so I’m currently running wasted spark until the part comes in

I was messing around a lot last summer also, with misfires and popping. I checked all eletronics and fuel issues, but it turned out to be the valves in the end

I am also using LS coils, but wasted spark with a trigger sensor on the flywheel.

[volksdragn]

I have to apologize, the valves were way out of adjustment. it seems to be better now but it still has a sporadic misfire, when its not misfiring it idles perfect. When it misfires it jumps around i.e misfires on different cylinders. It almost acts like a vacuum leak but it isn't. I'm not sure what else to look for. i do appreciate all the help so far.

[Ol'fogasaurus]

Have you checked the cap, rotor and the dist. itself? Stories I could tell you on them .

Just a thought.

Lee

[volksdragn]

its fuel injected there isn't a distributor

[Ol'fogasaurus]

its fuel injected there isn't a distributor

What you are describing is something like that part of the ignition system can cause. Had similar problems like that before and those parts ended up being the problem!

Lee

[Jadewombat]

*Edited* try doing some data collection also. It should show up on cylinder #1 if it's just that.

Then try swapping smart coils with another cylinder, etc.<<

Sorry, I had a couple of drinks. Compression check?