Back to stock

[plumbers crack]

I need to put my truck back to stock so I can pass the emission test, right now it has a slight haze at idle. I know that the pump has been played with but the PO doesn't know what he did, he basically swapped the engine and drove it for a month and parked it, than came me. The ksb and grid heaters are not wired, I found a 89 ram in the bone yard that I'm going to pull wiring/parts from. Can I pull the pump from it and use the stock afc housing to pass the etest every 2 years? My end game is to have 2 afc's, one stock for etesting and the turned up one to run on the truck.

The truck is a 90 GMC 2wd crew cab with a 90 cummins.

[DMan1198]

As far as I know nothing you do with the pump itself will affect your emissions at all. Timing will though (more timing means more emissions) luckily your truck only has to pass the emissions regulations of the trucks production year. If your getting a haze your injectors are worn out

[CumminsPower59]

Depends if they do a snap test. I'd neuter the hell out of it...no need to swap AFC tops when a few turns of a screwdriver can do the same

[Tacoclaw]

Yup, spin the fuel pin to its shallowest side, bring the star wheel to the top of its threads, thread the high idle screw way in to limit throttle travel, if you're really serious you can back out the fuel screw and raise the idle screw to compensate, but that idle screw is such a bitch I'd rather fail the test.


Less timing would make more smoke, it gives less time for the fuel to burn in the combustion chamber. A timing bump should actually clean up the exhaust.

You need to have 12v going to the KSB on a non-IC'd truck, otherwise the timing will be all screwy. It's also supposedly rough on the pump itself.

[CumminsPower59]

that idle screw is such a bitch I'd rather fail the test.

That's why I always turn them around so I can get at it from the front. The jam nut goes on the back side then, but it's easy to get at with a long punch. That, or use a super long skinny cabinet type screw driver, one of the ones in the set I bought from $nap on years ago is perfect for idle adjustments. Fits behind/between the injection lines easily.

[PToombs]

Instead of adjusting everything on the AFC top remove the boost tube and plug the hole in the head. Then it has no boost fueling and your settings are the same when you pass the test and put it back.

[plumbers crack]

I don't think boost is an issue because the test up here is a snap to the governor, I have already talked to the tech doing the test and he said that he'd only run it up to 22-2400rpm for the test, so I don't have to pull the 366 spring. They also read opacity during the test.

Is there anyway to set the pump back to stock timing? What about the other adjustments, I'd like to start back at zero with it, PO didn't seam to know what was turned up.

[DodgeFreak]

on the afc top there is a boost line for the fuel pin. The fuel pin gives it more fuel according to boost. Pete is saying to plug the boost reference line so it won't fuel more. is the pump to the head???

[CumminsPower59]

Timing...if it hasn't had the gear skipped a tooth, loosen the three pump mounting bolts up front, the lower rear one (if it's still there) and the six injector lines at the pump, and pull the pump back towards you till the timing marks line up.

I'd still pull the fuel screw back some, make sure the throttle linkage is in the outer hole on the throttle arm
, and put some slop in the accelerator linkage. Just because the tech says he only takes it up to 2200-2400 doesn't mean it still won't soot up the place. I'd be positive the thing is a turd before taking it in.

[DMan1198]

Star wheel to the top, smoke screw as far out as it'll go, and the afc line blocked should give you no smoke, and no power with stock injectors.

[plumbers crack]

Thanks guys. I'll pull the said adjustments out of the pump and get the ksb wired, that should be fine.

To the trained eye, how does the setting look on the pump?





This is the driver side pump bolt, is there a mark on the timing cover under the gunk to match the one on the pump?