Hey guys, this is an odd one

2 Nights ago, on the highway, it felt as if one rotor just cut out, the car started backfiring like crazy and I was forced to pull to the side. About half an hour later, it started right up and ran as if nothing had gone wrong.

Then, later that night on the journey back, it did it again but much more severely. Clear fireballs constantly shooting out the back, pulled over again and called a tow truck.

The wideband goes really lean (17:1) when this starts happening, so I figured maybe a fuel injector not working properly, but yesterday I moved the secondaries to the primaries (all 550s), and it ran fine for maybe 30 mins before acting up again.

I've checked the megasquirt grounds too, they seem to be fine.

So failing that, what else does it sound like? What would cause that intermittent failure?

Injector wiring? or coilpack wiring?

Thanks

 

Intermittent problems like that are a pain to trouble-shoot. Could be a problem with the MS box itself, but most likely it's a connection problem in the harness somewhere. Given you say it sounds like it's running on one rotor, you may want to check injector connectors and associated power circuits first. Next time it happens, pull over and pull both leading plugs. You may be able to tell which rotor is intermittent by appearance or temperature of the plug.

 

it sounds like to me if it's blowing fireballs when you have that problem, and the wideband is reading lean, you might actually be dumping so much fuel in that the wideband can't see it all, reading lean.

The only time I've ever seen this happen is when your injector wires to the MS are shorting.

Ken

 

Does this happen under normal driving condition or under acceleration?

 

Alright, figured it out- turns out the leading coilpack was going out. Replacing this corrected everything!

Thanks!

 

RPM to the rescue! LOL. Good to hear its running good again.

 

I have a question did it do this at any certain rpms just trying to find other outlets here after trying everything else ive read on this site . You guys are talkin about injectors wires and I am suspecting my rear secondary is not working . When I check the wires for continuity i get nothing no reading . But it is gettin continuity on the front secondary . I need new injectors wires and can't find some anywhere . Or maybe my leading coil pack is going out to .

 

After the VIR North event, my car was exhibiting these same symptoms. I just drove it with a newly flashed y4 code, and it runs like crap. A timing light shows me that only one trailing plug is firing, and the leading plugs are occasionally intermittent.

Are the ignition settings we are using for the MS burning up our coils?