New with a few questions about a 92 W250, 5speed, extra cab

[hungrycyclist]

Love the truck. Had a 91, 4x2, auto, single cab but my new truck is so much nicer.

Several things. Stock engine with K@N, 100% biodiesel all the time.

1) Black smoke - I have read about the low speed smoke adjustment (Low manifold pressure (boost) fuel delivery adjustment.) but still have smoke.

Uses a little oil but not out of th ordinary for this engine. I adjusted the smoke nut OUT (on the fuel pump as per this websites instructions http://dodgeram.org/tech/dsl/more_power/Power_ve.htm )

ANY IDEAS?

My goals are fuel mileage and NO Smoke.

In the process I bunged up the cover to the low manifold adjust nut and can not seem to find anyplace that has them. Any ideas?

2) Does anyone know the stock lift of these trucks. Mine has a 6" lift block.


Thanks for help in advance. I am proud to own this truck and plan on keeping it for as long as possible.

Peter

[oldestof11]

NICE!!

On the smoke issue, is it at idle, start-up, hard acceleration, or all the time?

I have a 6" block under my back wheels too. I notice some have'em ad some don't. Mine look like they have been there since factory. On a side note, do you have over-load springs?

Jon

[Begle1]

Does your truck smoke under acceleration or at idle? (Or both?)

My truck, stock, couldn't smoke black no matter how much you flogged it. A little puff if you caught it in the middle of a gear on a hot day with low humidity. That's a sign that the pump settings were stock and I had 100 HP (i.e. stock).

At idle, however, it did (and still does) haze at idle every once and a while. That can either be caused by really big aftermarket injectors (which I don't have) or by worn down and ready-to-be-replaced stock injectors (which I do have). (And it's also a possible sign of bad compression or retarded timing.)

So good-running, stock trucks smoke under very limited conditions, if at all.

However, there's no reason why you can't have your truck set up so that it can smoke, but only ever drive it so that it doesn't smoke. If you want mileage, buy a $40 boost pressure gauge and drive it so that it never gets above 8 PSI. You'll probably get 25 MPG.

(Another good fuel mileage mod is an aftermarket torque convertor that's 65% more efficient than the stock one, but in order to do that you need to tune the truck to the point that it'll smoke if you get on it.)

[wannadiesel]

You don't need that little tin cover, it's just there to discourage taampering.

When is the black smoke happening? I'm sure we can help you tune it out if that's what you want.

[TWorline]

Hey great looking truck!!! I don't think the Torque converter will help you any! Is the adjustment limiter still on the full power screw? If not somebody has probably tweaked the pump a little. Buy yourself a 16cm exhaust housing for your turbo and a 4" exhaust so it can breathe. With the mods done on my truck I get 20mpg on a big road @ 70 and 16-19 around home.

[hungrycyclist]

Thanks for all the replies.

Before I backed out the screw (to reduce smoke) it had a bunch of white smoke at start that went away after a few seconds then a pretty good cloud of black smoke when I got on it. I don't recall much smoke other than that.

NOW, after the adjustment, a huge belch of black smoke at start up along with a spew of black tar like stuff. It smokes at lower RMPs, stops smoking at higher RPMs just before the shift (5-speed) and then smokes at the change of gears and lower RMPs. Still a pretty large cloud of smoke when I punch it.

Not much smoke at idle.

It got worse after backing the screw out (see first post). I was under the impression that the tin cap kept air from being sucked in. So I temporarily sealed it.

I am going to return the smoke screw to were it was originally (several turns clockwise) and see what happens.

I am pretty sure the truck engine is stock, but really do not know.

As far as the springs go, the owner before put on the 34 tires and had to add two leaf springs in the front. Other than that it looks stock even with the 6 inch back lift.

[Begle1]

It really sounds to me like you have the "power adjustment screw" turned up a little bit. You can see the screw in this picture.



Now, if it is stock there should be a black sheet-metal anti-tamper cover on the back of the pump hiding the screw . If you can see the screw, chances are that it's been tweaked (turned in). You should be able to turn that out to the point that you have no smoke.

If that screw is turned in, in my experience with my truck, it's impossible to eliminate smoke with the fuel pin/ star-wheel/ smoke screw, and the smoke screw is the most ineffective of of them all.

But really, that's going to decrease power to the point where you are right now with no smoke. The time it's spending smoking right now is time making power that you won't be able to access with the screw turned out. In other words, just driving it easy now has the same result as turning out the screw, only you now have the power if you ever need it.

If you have a manual, a 12 cm w/g housing for the turbocharger (under $200) will really cut down on how much it wants to smoke after shifts. (And as a fringe benefit it'll let you accelerate 50% faster...)

The cloud of smoke on start-up is unavoidable with the VE pump. Just the nature of the beast.

[oldestof11]

Try advancing the pump about 1/8". You should see less bottom end, more top end power, and a little more mpg. Then back the power screw out a little.

With it smoking white a startup, I think that is a sign of the pump being retarded way too far or bad injectors. I will let other people decide that.

Jon

[Begle1]

With it smoking white a startup, I think that is a sign of the pump being retarded way too far or bad injectors. I will let other people decide that.

Jon

Correct. Or, if it's particulary cold out, it'll haze a whitish-blue. It's summer, though.

I should have said, "the cloud of black smoke on start-up is unavoidable with the VE pump".

[hungrycyclist]

Thanks again for all the help fellas.

Last night I returned the smoke screw to near the original position (about three turns clockwise), and I noticed that the fuel adjustment screw still has the tamper cover over it.

Although I did not get to test drive, I did notice a decline in the smoking.

I forgot to mention that the pump is a very recent rebuild. The previous owner said it was leaking a little and he had it completely gone over.

I might need to tweak it some as I am running 100% biodiesel. Anyone know what kind of adjustment I would do? Biodiesel has a much higher cetane. I read on another thread that it burns a little different and you can reduce fuel injection timing to compensate? That sound correct?

I have heard about going with the smaller waste gate? housing. That will be my next fix. And of course the leaking vent that is getting the floor wet.

[Begle1]

Maybe the shop that rebuilt it made it a little "hot".

Biodiesel's higher cetane means that it ignites sooner after it's injected, and takes less time to burn; that means that it can burn just as well with retarded timing as #2 Diesel does with advanced timing.

So no matter how the pump is calibrated, biodiesel should smoke less than #2. With biodiesel you should be allowed to tune the pump to inject more fuel while still getting the same smoke levels as with #2.

So heck, 4 options:

1. It might be that you're injectors are really worn out; that'd cause smoke.

2. Or maybe your turbocharger is on it's last legs, or you have a bad boost leak somewhere.

3. Perhaps you have really bad compression; that'd explain the smoke as well as the blow-by your seeing.

4. Or the pump was configured hot from the shop.

If you could post a video of it smoking, that could help the diagnosis.