7.3 pump in a 6.9

quickster · Nov 17, 2020

Just wondering if my slight smoking issue could be from the pump putting out too much fuel. I remember reading another post saying the 6.9 pumps were underfueled. So when I put in the rebuilt I used the 7.3 pump. It runs good but gets a little smokey on acceleration. Not black, but gray. Wanted to see what the IP guru's had to say.

Philip1 · Nov 17, 2020

its more likely the timing is a little off then the issues of too much fuel

Isaac Ristow · Nov 17, 2020

Second timing adjustment was it timed properly when you replaced the pump? Is it just a slight haze of smoke?

quickster · Nov 17, 2020

I get a good haze when I accelerate hard. Not black, but a dark gray. I picked up a pulse timing unit that I use with a timing light. I set the advance to 8 and It's dead on @2000rpm. Was wondering if I was over fueled. Maybe turn the pump down a half a flat. Runs great though.

Philip1 · Nov 18, 2020

If your truck is still na, and is timed correctly, under heavy acceleration i can see there being some slight smoke. (Although for me, I had slight smoke while I was still na on my truck with all stock parts) if you let off the throttle slightly does the smoke disappear?

Thewespaul · Nov 18, 2020

There’s more of a difference between the 6.9 calibration than the 7.3 and 7.3t calibrations for fueling. 6.9 runs smaller plungers and fill ports, you’re probably over fueling slightly, if you don’t have a pyro I would recommend getting one.

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quickster · Nov 18, 2020

Thanks Wes. I only put 600 miles on the truck since I've got it together. I think I'm still blowing chunks out of the fuel system that have been in there for the 6 years it sat. Just replaced the rear tank cause it was rusted out and spreading super fine silt throughout the motor. Just put in my 4th fuel filter.
Philip, the truck does not smoke at idle. But you can smell fuel.

quickster · Nov 23, 2020

So an update. Turned the fuel down one and a half flats. Smoke is 95% gone. Get a little bit when I accel hard. And It actually feels a little bit peppier. It responds a little quicker when I accelerate. We'll see how it goes.

Isaac Ristow · Nov 26, 2020

quickster said:
So an update. Turned the fuel down one and a half flats. Smoke is 95% gone. Get a little bit when I accel hard. And It actually feels a little bit peppier. It responds a little quicker when I accelerate. We'll see how it goes.

I've always noticed with my 6.2s that when I go WOT then back off ever so slightly you find the sweet spot and actually get a little power boost. I turned up the cucv half a flat in my na 6.2 service truck when I put head gaskets and studs in

7.3 pump in a 6.9

quickster

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quickster

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