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Discussion Starter · #1 ·
Hey guys, I finally got my hands on a cummins. Had an old 7.3 Ford for years, but just recently picked up a nice 1st gen for my current truck.

The truck currently has 224,000 or so miles, but starts easily even in cold mornings here at 7,000 feet. I drive a lot between 4,200-7,200 feet and up to 10,700 on occasion. When I start up, I get quite a bit of grey smoke. A little less when it's warm. This was pretty common with my old Ford when not plugged in. However, this truck continues to smoke longer. It seems to run well, no problems heading over mountain passes keeping up with traffic.

When it's cold, I get black smoke if I get too deep in the throttle, but it goes back to grey if I'm stuck idling in traffic down in Salt Lake City at 4,200 feet for extended periods.

It does not appear to be using much if any oil, and I have not seen any blow by with the oil cap off.

The injector pump looks new since it's quite clean compared to it's surroundings, and I do not think the truck is completely stock since I can hit 25psi of boost easy on mountain grades.

I'm not familiar with Cummins yet, so I was wondering if there was any easy tuning to be done or if I should just take it Rocky Mountain Cummins to get it set up properly while I'm on the learning curve from International to Cummins.

Also, it's a 4x4 auto extended cab 250 and I get ~14mpg, which seems low. My Ford was the same, but 5 spd and usually in the ~18mpg range, so I am wondering if the truck is running rich at my altitude producing smoke and keeping the fuel mileage a little lower.

Any input is appreciated.
 

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The PO might have turned up the pump, or have a fuel pin in it, thus the black smoke and your little bit lower MPG.
These trucks on start up do smoke, but your's does sound a little excessive.
If you look in the tech guide for 89-93 Cummins you will see instructions on how to turn up the pump, fuel pin, adjust throttle linkage, etc. Before you do any of that get a Pyrometer.
Have fun with your new truck, and also Welcome =)
 

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If the PO put in some bigger injectors,done the pump mods and installed an aftermarket fuel pin thats probably fuel haze, mine does it and alot of others do it with these mods. look on youtube and put in fuel haze and you will see some to compair yours to.

Dar
 
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Discussion Starter · #4 ·
Thanks for the info. Looking up fuel haze on Youtube was definitely a good call. I think that it may be a little fuel haze, and it is less than some of the heavily modified trucks on there, but a little bit more smoke on start up than some of the stock trucks.

I would not be surprised if the truck's been turned up some. I can go up a steep 3k vertical foot mountain grade without really getting my foot in it at 60-65 and maintain over 70 easily but then the EGTs start getting up a little higher by the top. It definitely has a lot more torque than the old Ford since I unexpectedly ended up powersliding around a switchback on my way home one evening without much throttle.

Is there any easy way to ID the injectors without pulling one so I know exactly what's in the truck?

I think I'll go ahead and start saving up for a new tranny and drive it gently in the meantime.

Rocky Mountain Cummins is offering a tune up special for $150 over the summer, so I'll probably have them go ahead and set the timing and valves, but it doesn't sound like it's anything pressing.
 

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Make shure they don't go more than an 1/8th inch or so timming bump, that will give you a little more zip also, you can check it your self just look at where the I/P mounts up to the cover there should be a small mark on the timming cover that should be lined up if it's stock, if it's been turned already the mark on the pump body will be above the mark on the cover an 1/8th or so. As for the trany have a good trany shop put a heavy duty rebuild kit in it and get a good T/C from one of the vendors on here. And i don't know of a way to identify the injectors with out pulling one, but if there is a way i would like to know also.

Dar
 
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