Hey gang,
I've got an '84 Mitsu Montero with a conquest 2.6 stock motor/turbo with a MPI intake, 42# injectors. I never built this truck to be a daily driver, but now it is. I recently had to drive it many hundred miles on the freeways, to relocate. On the drive, I noticed a few things.
It got hot... not the coolant temp, but the exhaust/turbo (no cats).
It smells like gas, pretty much all the time. I think these are related. It smells like it's dumping fuel in, yet my mixture meter does not run that rich. If I back the knob way off, it will help with the heat, but it still smells gassy at times. I get really poor mileage.
After long periods driving, the mixture meter will go from hunting lean/stoich, to suddenly reading very rich. (No adjustments from me.) If I then adjust it to where it's hunting nicely, drive awhile, it'll go back the other way, to reading really lean. Re-adjust... same thing, back and forth for sixteen hours. I've tried open and closed loop. Seems to act exactly the same.
I get a very lean reading under light throttle, light to medium loads. Anywhere from around -.1 to -5 in the map range. It isn't consistent at all, and not really repeatable. If I step on the throttle, it will usually go rich.
I'd really like to get this thing tuned for some basic economy, and unplug all the "stuff" on my dash board and just drive this thing. I didn't buy this system with hot-footing it in mind. I just wanted reliable, easy to drive, and not constantly tinkering.
Thanks!
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I bought the WMS one when I purchased my SDS and to be honest it's useless. I see SDS have stopped supplying this brand as they must have realised it's no good.
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During cruise you can safely run as lean as the motor will let you, so like 17:1 A/F.
If your car was not warmed up then that could be why the fueling was changing. On that same note if you have numbers in the eng temp values in the motors operating range then that would be the cause. As you should have 0's from 140deg on up, then maybe some numbers on the high end for hot restarts.
I'm not a fan of narrow bands but they should work for cruise anyway.
Also you can run higher timing in vac, so program some advance in in vac cruising values this will make the temps go down a little also(EGT's).
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Forgot to say, on that lean cruise. Just cruise on the highway, then keep removing fuel till it lean misfires(no harm done), then add a touch of fuel back so it doesnt do that like on a hill. That will be the best economy you can get.
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