Using a resistor to richen part throttle?

[b4black]

I have always had some part throttle knock. Mostly while crusing down the highway. I recently bought a Casper's 10-LED knock gauge and a AutoMeter Air Fuel gauge (cheap off ebay - it's a 20-LED circus). It easy to see with these two, that the part throttle knock mainly occurs when the O2 sensor output is oscillating between lean and rich. When I give some gas, it goes to Power Enrichment mode - no knock.

The other thing I notice is that when the AFR gauge is oscillating, it doesn't really go rich. It goes very lean (0.00 V) to barely rich (~0.65 V). And it's spends more time lean side, then spikes up rich and then back down lean. (The sensor is new, and I've confirmed these readings with a scan tool. Burning a new chip isn't an option I have with a non-EFI car)

Instead of varying around a 0.45V midpoint, my ECM seems to be controlling around a lower value, like 0.30V average. Can I put an in-line resistor to lower the O2 sensor ouput and trick the ECM into making the mixture a little richer? Any suggestions on the resistor size. (Is this what those "O2 Sensor Recalibrators" on ebay are?) It seems to be able to go rich just fine in PE mode and I don't think the resistor would effect this function.

THANKS!

 

[larry33kc]

I don't know if this helps but I do remember seeing a thing on this in a book called (GM fuel injection) or something like it, it was a big book and I think it was put out by Hynes, but it had some info on this same thing. It is a very good read I also think that Summit has them HTH

 

[Darkside]

Don't know if this helps, but I have a 2200 ohm resistor in place of a mat sensor. It stays at about 76 degrees. Had no probs so far. I got this info from another board member.