matador

I was wondering what adjustments I could make to improve mileage by making adjustments to the injector pump. When I started having probs with black smoke was when I put in new injectors with stock replacement injectors. I did rotate the star wheel which improved preturbo smoke but still seem to maybe have too much after turbo has kicked in smoke. I get quite a cloud sometimes if I step her down hard. How much is too much? If you can see a constant wisp of smoke at say holding steady at 55 mph is that too much for the 12 valvers? I get about 14.5 to 16 mpg average at 75 mph empty. I hear of some getting 21 or better fairly consistantly. Are they stretching things.
Any suggestions?
I have 200,000 miles on the truck with about a quart of oil being used in about 3000 miles. I have also adjusted the valves lately with no improvement, they were very close to spec at 10 and 20 thousandths. Overflow valve has been replaced also and timing is set to appx 14* bftdc by using the pump pin and cam pin method by a shop in town rather than the lift pump setting method. I also have the 3.54 rear gear ratio.
Matador

98rammer

you shouldn't see smoke coming out of the tailpipe just cruising unless you have really big injectors/fueling mods. it sounds like you have a bad set of injectors--are those stock hp or do you mean they are higher hp replacement injectors?

is your plate moved forward? if it's too far foward, it'll pour fuel in a little late in the combustion cycle and give you black smoke with high boost situations.

to me, it sounds like you have a bad set of injectors.

Tom

DieselDaze

Have you checked all the intercooler boots and clamps?
These clamps can come lose and/or the boots could be cracked allowing the boost to excape before reaching the engine.

Have you checked/replaced fuel and air filters?

Start simple, go from there.

Rich

matador

The reason I replaced the injectors was because one or more was slobbering and causing clouds of white smoke at start up and after idling for a couple minutes, replaceing the injectors cleared up that problem immediately but now I have what seems to be too much black smoke. Adjusting the star wheel almost took care of excessive black smoke before turbo spooled up but it seems excessive after the turbo kicks in now. I replaced them with supposedly the same rating injectors as what was in there before.
The plate has not been moved.
thanks for your response.
Matador

matador

boots and clamps seem to be tight. fuel and air filters have been replaced too.
Matador

DieselDaze

Have you noticed any change in performance? (better/worse).

Also, I know these trucks all seem to get slightly different mileage, but your numbers seem to be a bit on the low side at 14.5 for running empty.

Rich

infidel

Tricky boost leak to find is at the lower intercooler inlet. The boot expands under pressure and rubs on a sharp fender seam on many trucks. It can be cut and you wouldn't know it unless you looked at it under pressure. Also check the intake manifold bolts for tightness.

Cummins66

I'm a little concerned about using a quart of oil every 3K miles. Maybe someone who knows more about it could say, but that seems like a lot. I don't use anywhere near that much, and I have 260K. The injectors would have been my guess as to a problem, I'd contact the place you got them and see what they say.

matador

I was told a qt to 3k isnt bad at all. I will check for those hard to spot intercooler boost leaks. Thanks infidel.
Matador

doug60

I have 170000 on my 96. 400 HP # 800 torque b&d injectors. Pump work. All mods were done 130,000 miles ago. You dont need to buy any parts your pump can be worked to deliver fuel up to 3800 rpm. mine does and its been doing it
since 98 before any cam plates or governer spring plates were available. But you have to respect that power. ( tore my imput shaft in half ) .AS far as oil consumption, a quart every 3000 is not bad, you can bring it down to less than a half quart by using two quarts of Lucas Oil treatment per change.
Bad news is the locating pin on your timeing cover can work its out , and cause the timeing cover assembly to break. Im not sure but I think the 97 is a canidate for this problem.there is a $100 fix if you do it before it breaks.
Next Your block may be one of blocks prone to cracking between the freeze out plugs .( the dreaded #53 block issue ) Look it up !.
My CTD has cost me plenty . and now I cant even sell it ( leaking coolant )
But Im cumming back for more. New one one the way!

DZLPWR

What kind of boost are you seeing at full power? If you dont have gauges, they sure do help in situations like this. They help to figure out or prevent any problems more than anything in my opinion.

matador

I am running about 25 lbs of boost if I floor it and let her spool up. At 70 it is around 10 depending on wind etc.
All the boost fittings etc seem tight with no apparent leaks.

Matador

DZLPWR

Thats seem right inline with how my truck is. 10psi at 70mph. And you say it smokes at this speed? Or slower?

matador

It seems like it has a slight haze at an even speed anywhere in that range of speed. Sometimes I think it may even be my imagination. If you step on it even slightly you can definitely see a little bit of smoke. Are you guys seeing smoke when you step on the accelerator about halfway down at anywhere from 60 to 75 mph?

I know a guy with a 24 valve that says his doesnt smoke when he steps on it. Do the 12 valvers smoke if set right ?

Matador

DZLPWR

Yea, mine will smoke a little while when the pedal is pushed from a crusing position. Just needs to build some boost to eliminate the extra pre-boost fuel. My AFC housing is full forward. You can eliminate smoke if you want by turning the starwheel. I wouldnt unless you REALY want too, cause youll notice the boost builds slower when cutting down the pre-boost fuel.
Constant haze is not correct. I would make sure that your realy seeing smoke before trying to fix it.
Smoke is quite fixable(granted you dont have big injectors) since these lovely p7100s are so adjustable.
Just making sure, air filter is clean? Fuel filter too?