Howdy,

I have a 93 F250 7.3L diesel no turbo, it has 134,000 miles.
I have noticed that when I haul a
load up a hill, no black smoke comes out.
From what I can see no smoke at all comes out.
Nothing comes out when I floor it either.
When I first start it in the morning
it blows out some white smoke. I think
the engine is running a little lean, if
so where is the adjustment screw and which
way do I need to turn it.

Thanks ahead of time,
G8ride.

 

well it sounds like you have a great truck. you really dont want to see black smoke at all. black smoke means that the engine is getting more fuel than it can burn in the amount of time it has to burn it, low pump pressure or not enough air to mix with it.the white smoke you see in the morning is not bad as long as it goes away once the motor warms up. it is created when the temp in the combustion chamber is too cold, as a result the fuel is igniting so late that combustion is incomplete at the time the exhaust valve opens and fuel goes into the exhaust in an unburned ot partially burned condition, producing white smoke. no big deal,in other words. if you see white smoke all the time it usualy means low compression. thats all.

 

I agree with stroker96 - don't change a thing. It sounds like yours is dialed in just right. Running too lean will cause hard cold starts; if yours has no starting problems, don't touch it. About a thousand guys with smokers and lousy mileage would trade places with you.

 

Hi,

Thanks for the responses everyone. I just wanted
to ask what is considered hard to start?
In the morning I let the wait to start light
go out(which only stays on for 3-4 sec.) and
then crank it for I am guessing about 10 sec.
While I am cranking, it sounds like its about
to catch several times but doesn't quite get there.
Another question I have is, I went out this morning
and started it up and the high idle speed didn't kick in until
I put it in gear. I started it up about 4 hours
later and it didn't want to start at all. I went
through 4 cycles with the glow plugs before it started,
It was about 90 degrees out so you cant say it was cold out.
It has never been that hard to start before.
Any ideas???
One more thing, does holding the accelerator down while cranking
do any good at all???

Thanks
Gr8ride.

 

well,,, if it is hard to start and you see white smoke right after it starts, does it idle rough until it warms up,then smoothes out? with only 134k miles on it i wouldnt just say glowplugs and end it there,but it does sound like at least one glow plug is a defect.however, there are other things that are easier to check and cheaper to replace.1) air in the fuel 2)injection pump isnt timed to the engine 3)injector nozzles sticking open usually accompinied by a knocking sound 4)fast idle solenoid inoperative or incorrectly adjusted.thats about all it could be.when a truck is brand new this happens for the first 2000 miles of break in, but i am guessing in your case glowplugs or thier nozzles. and dont let anyone tell you you might as well replace all of them they can check each one without removing them and replace the bad ones only and it may only be one that is bad.if it is a good shop it may even be the nozzle that needs replaced. let me know.

 

I would put my money on glow plug problems. 3 to 4 seconds for wait to start is a little too soon; 8 to 15 is considered "normal". You may hear 5 to 10 seconds of loud clicking from the controller after the light goes out; this is part of the pre-heat cycle - dont start cranking until all the clicking stops. Go pick up Haynes Diesel Engine Techbook #10330. It's easily worth twice the $13.95 price. More than 100 pages on the Navistar 6.9/7.3's alone. It covers glow plug curcuitry, testing, and fuel systems extensively. Yours is doing exactly what my '91 F-250 started doing. I went through the controller/harness testing sequence and found two dead plugs and one poor harness connection and now she fires up in about one second every time. DO NOT replace all 8 plugs without testing them unless you like wasting money. The fast idle solenoid is too weak to overcome the throttle return spring without help - give 'er about half throttle while cranking and that should set the fast idle. Hope this helps

 

Hi,

To answer your question Stroker96,
it starts up and runs pretty smooth.
I haven’t noticed any knocking like your
talking about. What’s a good way to check
the injection pump timming??
Also how do you check the glow plugs??
I would like to do most of the work my self
rather then take it to a shop if possible.
crumudgeon thanks for the tip on the book.

Thanks,
Gr8ride.

 

well, the injection pump timing can be checked by checking the timing marks on top of it and seeing that it aligns with the mark on gear housing. if there off that is your problem. glow plugs require using a test light, with the key off remove the wire from the glow plug. connect the test light to the pos. side of the battrey and the glow plug end that is exposed. if the test light comes on that glow plug is fine then check the rest of them. good luck,let me know.

 

If you have a volt/ohmeter, with ignition off disconnect each glow plug wire and touch one meter probe to the top of the plug (where the wire was) and the other probe to the metal shell of the plug. Replace any plug that shows a reading of 2 ohms or more. Less than 2 ohms is OK. This will detect dying plugs instead of just dead plugs. With all the wires still off, check for harness and fusible link problems by touching one probe to the glow plug controller output terminal and the other probe to the end of each glow plug wire. If any reading is 1 ohm or more, replace the wiring harness.

 

Hi,

I tested the glow plugs and
it turns out I only had 3 working
glow plugs. I ordered all new glow
plugs. I will post again once I get them
installed.


Thanks,
Gr8ride

 

good job!

 

Hi,

Today I got the glow plugs installed,
and what a diffrence it made it just
starts right up.
Has anyone ever had the a glow plug
fall apart while taking it out??
and I don't mean like the metal tearing
or the threads stripping I mean the top
of the plug came off the threaded part and
the tip of the plug stayed in the block. I
had this happen twice.I luckly had a pair
of vise grip and a can of WD40 other wise
I would have to take the engine apart I guess.

Thanks for all the help,
Gr8ride.
PS.
everyone needs to say a prayer for
the people in NY and DC.

 

Have never had one break above the threads, but have pulled plugs out that the bottoms have been broken about half way down the element, leaving the broken part in the pre chamber. My experience.