View Full Version : LM-1 possible issue

10-06-2008, 11:45 AM
If the O2 sensor goes bad for the LM1 would it read rich or lean or either?

The story. I had 87 gas in the car to drive long distance and had about 5 gallons left over at end of trip. So I let the car idle for about 2 hours total with the lm-1 on to run some of the 87 out. Would that goof up the O2 sensor? If so could I just recalibrate it or have to get a new one?

I ran at the track and it was reading 12.5:1 on first pass 2nd pass took head lite out and was reading 12.8-9:1 blew the IC tube of just after 1000'( broke the clamp) got clamp fixed 3rd pass to see if I was making more boost to see if that was why it was runnin lean, 13.5:1 got out real early for that pass didn't see any more boost than normal but didn't wind it out. Car normally runs 11.8:1.

Checked a plug the easy one on the side with the wide band and it was fat like normal.

So is this a O2 problem or a fuel system problem, will check fuel sys anyway?

Car was running like a beast more on that in the racing section!:cool:

10-06-2008, 11:58 AM
What does the sensor say if you just give power to the LM1 but don't start the engine? Should be around 20.7 or so. If it's not close, you may want to re-calibrate.

More likely you are leaking some air in around the sensor. Check the exhaust pipes for any cracks, make sure the sensor is tight in the bung.

10-06-2008, 09:39 PM
Thanks Mike, I checked it with engine off and its 52:1. Guess I'll recalibrate it.

10-06-2008, 11:01 PM
Let us know if you improve in this cool air!!!!

XR7 Dave
10-07-2008, 07:49 AM
It's possible the sensor is bad. Best way to check is to monitor AFR while cruising down the highway. It should be switching right around 14.7 AFR. If it is then the sensor is ok.

Check your alcohol injection. Sounds like it might have misfired...

10-07-2008, 09:45 AM
When the car idles it stays around 14.7 to 1. Checked the alky just by the initial key turn on and it pumped so the nozzles could be cloged. Or the controller could have went bad. How likely is it that the controller crapped Dave?

I'll turn the dial down so it comes on quick and see if it sprays.

I'll change the fuel filter and check the fuel pressure. Pumps older that the rest of the fuel system but only has about 20k miles on it. Its a 255HP unit.

No N2O on any of the passes. I was brake stalling it to 2k instead of 1700. This was also at track I've haven't been to in about 7 years. Not a fluke though cause Dads car was runnin what it should. It was 75* and about 33% humidity.

First pass the car went 12.05 at 110 with a 1.67 60' i was on and off the throttle cause the AFR was lean.

2nd pass went 11.999 at 110 with a 1.65 60' IC tube popped off just after 1000'.

3rd pass 13.5 cause AFR was way lean.

60's where best ever with or without N2O. 60's are .1 better than normal. The car was haulin, glad I still had the wide band on it if something is wrong.