new b here with obd1 tuning ?s

[christuned]

I'm in SoCal .

[badluck]

They don't have egr on 91-95 jeep 4.0.

[badluck]

Could a tune be written to fix the problem? I've been told the timing is not adjustable but it sounds like it is. Can I do this with a dbr2?

[christuned]

They don't have egr on 91-95 jeep 4.0.

Yes, that is what I said previously, 4.0 Jeep motors in XJ's did not have EGR from 1991 on up. Just because they don't have EGR does not mean your engine does not need EGR.

[christuned]

Could a tune be written to fix the problem? I've been told the timing is not adjustable but it sounds like it is. Can I do this with a dbr2?

If you look at the images in the previous post I made on this thread, I am showing the adjustment that can be made with a standard DRB2 to retard the timing up to 5 degrees, this is done in the EE area of the ecu. Can it be remapped, sure, but the time, and money spent may or may not get the NOx low enough. Remapping involves removing the board from the ecu case, getting the eprom out from within all that nasty isocyanate potting material, then reading the eprom, edit mapping, burn new chip, socket ecu, seal everything back up.

[sidewaysstarion]

Runs well except for a little ping and high nox.

I have to agree with Christuned, it looks like you have too much ignition timing, I'd see if you can find someone local with a scan tool that you can use to adjust the timing. Also by any chance do you know if you have a high altitude CPS in the jeep?

[badluck]

How would I know if it has a high altitude cps? Is that cam or crank position sensor?It definitely could. It was used in tahoe. I like the timing idea.For some reason 28 deg sticks in my head.

[christuned]

How would I know if it has a high altitude cps? Is that cam or crank position sensor?It definitely could. It was used in tahoe. I like the timing idea.For some reason 28 deg sticks in my head.

The two sensors in the link are offset to give the extra timing, a stock one would have the sensor in the middle of the bracket.

http://www.naxja.org/forum/showthread.php?t=1112644

[badluck]

It looks like the cps in the photos mount by the flywheel. Mine is mounted by the harmonic balancer on the driverside at about 3 o'clock.Would it need to move closer to 2 or 4 to retard it?I'm not moving it. I'm just curious.The dbr to reduce timing is where I'm headed first.

[Cheromaniac]

It looks like the cps in the photos mount by the flywheel. Mine is mounted by the harmonic balancer on the driverside at about 3 o'clock.Would it need to move closer to 2 or 4 to retard it?

The engine spins clockwise when viewed from the front so moving the CPS clockwise would retard the timing.