Perry 951

Figured I might get a little more action over here.

So I continue to try and figure out my misfire. To update, EVERYTHING ignition wise is new. I've tried different chips, different FQS settings, and different DME and KLR. No KLR blink codes.


I get a misfire under full load, 3/4 to full throttle, above 3000 RPM. It is an ignition misfire.

I think it is a multiple cylinder misfire. Load dependent, it must be 3/4 throttle or above, 3000 RPM or above. Misfires at any boost setting over 5PSI, 12.5 AFR at 15/18PSI. NGK BPR6ES plugs read fine, .025 gap. Using a TE-WBO2/2A-1 with 9 inputs (3 in on 3 rotary switches). The LED output is what drives the diagnostic plug in the engine bay; for KLR blink codes. IIRC, it is KLR-3.

So logging the LED output (KLR-3), I see a constant 4 volts while running. When I go to full throttle and it begins to misfire, the voltage drops to 0. When I let up, it goes back to 4 volts. Is this an indication of anything? Anyone log this output?

Anyone know what the full load output from the KLR to DME should be? I plan to log this for activity tomorrow.

Anyone?

Ski

would you clarify ignition - all new? Have you replaced the TPS with spare?

Perry 951

I've not replaced the TPS, but it has less than 10K on it, idle contact is good, and it sweeps clean. I had planned on swapping for giggles but can't find my spare.

You think TPS could cause the misfire?

fast951

Perry951, Whay not come by, we can hookup the Motronic Monitor and monitor (and data log) everything in real life mode. You'll be able to view the all the variables on real live mode.

Ski

there you go.

I guess you two Atlantians (if you go) will probably be at Road Atlanta next weekend instead of Barber Motorsports.

fast951

What's going on at Road Atlanta? How about Barber?

I was thinking of going to the Boat show this weekend, but I might have to change.

Perry 951

I'll be in Munich this weekend, and then Amsterdam next week. Can't wait!!!
John - We'll get together when I come back. Thanks for the offer!

Ski

Barber - DE and Club Race, I think Road Atlanta as well, not sure but that's pretty close for two races in the same weekend.

fast951

The PCA Club Race at RA is at the end of March.

xtaC

Mate, this is IDENTICAL to whats happening to my car, except I have a Wolf3D.

I would be really interested in the solution when you find it!!


Lee.

special tool

I have experienced this before.
Exactly the same situation.
It was solved with a new engine wiring harness.

Perry 951

Harness huh? Not what I wanted to hear but might make sense as I was up under the dash before this started. I also completed a tune up, so this is why I went to the ignition stuff first.

Before I go tossing a new harness in, I'd like to know what is failing to cause the misfire. Hopefully the MoMonitor will show me!

fast951

Brian, The MotronicMonitor will show you the variables as seen by the KLR/DME. If you have a wiring problem, coming IN to the DME KLR, we might be able to detect it. However, going OUT it will not be possible to detect.


I doubt a wiring problem will be triggered on boost only! Your ignition system (plugs, plug wires, coil, dist cap & rotor) might act up under load.