Just bought a 7.3L IDI, What now?
 

I just bought a 91 F250 7.3L diesel for $1750. It has 111,000 miles, so I think (the gage only reads up to 99,999). It has a 5 speed manual, and a C6?? rear end. It seems to run good, and drives pretty well too.

Some things that I have noticed; When braking heavy from a high speed, it shakes a little bit. Other than the the ride is just fine, and braking at lower speeds is also fine. Another thing I have noticed is that I get a bit of white smoke in the exhaust, particulary when I get on it. I dont really notice it unless I am really accelerating from a stop, or accelerating alot in higher gears. One more thing is that there is a slight whine when I turn the steering wheel, so i think power steering fluid is low.

With all that being said, what are some must do's for this pickup? Obviously, I plan to change the oil right away. Any other suggestions. Fuel filter, transmission oil, rear end lube?

warped rotors possibly?

i would buy that truck in a heartbeat for 1750 as long as it was mechanically sound. congratulations on that find! post up some pictures of it when you get a chance :rocking:

..old ford pwr steering pumps tend to whine,but check for leaks.With the 5 speed you have you wont have a c6...that's a auto transmission..maybe you meant dana60 rear end.The pump maybe getting a little worn and the advance is off.Try some standyne pump lubricant...wont win a drag race but them old idi's keep going..:tu:

I looked on the sticker inside the drivers door and it says C5, not C6. My dad did some checking and told me that he thinks that is a 4.10 gear ratio.

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As far as the white smoke, should I be concerned. I read that it could be caused from coolant getting into the combustion chamber. I noticed that the coolant was about half way up in the overflow reservoir, so I don't think I have a coolant leak. Could it be something else? Lack of fuel? Bad Fuel?

Here are some pictures of the pickup.
91 F250 7.3L IDI - Imgur

...your father would. Be correct axle code c5 is a 4.10 gear set:tu:

Would it be easy to swap out the 4.10 with something geared a little higher. I only intend to pull my boat with the thing and will put mostly highway miles on it, so I want something that can get a bit better mileage.

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...with the 5speed you should be good.....if not look for a c6 automatic truck in the wreckers some came with 3.54 gears

It doesnt really cough or struggle to run at all, just blows some white smoke with heavy accel.... it revs just fine in the process.

Have someone check the timing on the pump....also add the standyne pump lubricant

my truck smokes too, but with heavy accel, i get black smoke, i havnt noticed anything wrong with it. you have toi remember, it is a diesel, they do burn "dirty" if that makes sense. i would only really be concerned if you smell somthing burning, or if you notice your truck acting weird. as for the gear ratio, you wont notice too much of a difference with the fuel mileage. yes there will be but not much, whatever you are comfortable with. dont mark my every word, because i am too newer to IDI's, but from what i have read about them and from what ive seen performance wise out of my truck, they are EXCELLENT engines. my truck is 20 years old and still running strong. just pulled 9,000 lbs of rocks and work equipment a few days ago, pulled like a beaut

Your white smoke sounds like it could be a timing issue. Shouldn't cost more than an hours labor to have it checked/adjusted. One thing I would do is change the coolant, unless the previous owner mentioned SCA's in the coolant. Do a search for "cavitation" and you will see why this is important. You will want the proper coolant and SCA level if you want the most life from your motor.

Thanks for the reply, I have heard of cavitation, but it was at the back of my mind. I will look into it.

Thanks for the advice.

these engines love synthetic oil .... I've been running 15/40 Royal Purple oil in my truck along with Z-max ... been getting 18+ mpg .... 3.55's and 35" tires ..... pulls good .... another thing to watch out with the coolant ... get a 160* t-stat if you do intend on pulling ... these things will heat up quick if you lug them down on big climbs... ( just fyi )
and most definatly gonna wanna monitor your SCA's for sure...

IMO, that's a great find! After all the basic services, oils, lube, etc, there are a couple little things I'd do. First, have the pump timing checked as stated above. I had an 89 7.3 5spd, 410 ratio that i sold a couple years ago with 285k miles and the best bang for your buck is an after market air cleaner and some exhaust mods. I gained a couple mpgs and got noticeable power gains by doing this. I love my Cummins, but the i.d.i.s are very good runners with little maintenance.

I agree , change the oil regularly , keep you coolant SCA'S in spec, and keep the fuel clean and they will run for a long time ... just don't get tempted to slap on a turbo on a N/A engine ... will be a bad thing

Man, I actually really wish I had a turbo. What is the downfall of putting one on a N/A engine?

Good thing I'm broke as a joke and can't afford one.

I just turned over 200k in my 93 IDI 5-Speed. Timing issue sounds about right. Keep up on the basic maintenance and this truck will serve you quite well for a long time. SnowBiz is right as well. Fix up the exhaust, and mod your air intake into the air cleaner box and you'll notice some decent power gain and a few extra mpg. Awesome truck mate, reminds me of my 87 f250 with a 460. Loved it! minus all the big block maintenance... haha

make sure u check you're SCA levels.