Timing question

[keimmmo]

I bought my '92 new. It has smoked when you stomp it from day one. I spend most of my time above 6000 ft. At this elevation it is hard to keep the smoke down even at light throttle. If you hit it hard, it looks like it is burning a mixture of corn cobs and shredded tires instead of #2 diesel!!! The motor is stock. It runs fine and still gets good economy. This is NOT a new problem!



Mexico is trying to improve it's air quality, which it certainly needs to do. The crooked cops down here look for ANY reason to stop you, and excessive smoke is high on their list of reasons. I am tired of getting stopped and hassled! I HAVE to cut down on the smoke!



I have read that advancing the timing will help. When we rebuilt the injection pump at 249,000 miles, we set the FYI timing with a gauge to 1. 5 inches instead of the factory 1. 33 or whatever. I understand this advanced my timing.



Now, I have read about advancing the timing by rotating the pump about 1/8 inch above the factory setting. If I understand correctly, that would be with stock FYI settings. Can I SAFELY advance the timing any more? I do get down to sea level fairly often. I DO NOT want any blown head gaskets or melted pistons!!!



I am seriously considering losing the muffler and pulling the head for some porting and polishing to make her breath a little better. What do you think?



Thanks for any help and advice you can give me.



Steve

 

[formula]

new turbo

Steve,

From your signature, I assume the truck is basically stock? (exhaust system, air filter, turbo, etc) If you're gonna get rid of the muffler, make sure to take care of the nasty bends in the tailpipe too. Check air filter and change fuel filter. To reduce smoke further, add more air. While porting and polishing will probably help, I think that you'd be better off to spend your $$$ on a new turbo. I like mine a lot it's a huge improvement over the factory turbo. A 12cm exhaust housing would be great for you too. It will provide much better spoolup and low end boost which will definitely cut down on your smoke. As for the timing, if it's already at 1. 5mm that may be far enough, but I'm not really sure how far you'll have to go before your head gasket is in danger. Perhaps it's better to leave it where it is. Another thing you can do to reduce smoke (but with some loss in throttle response) is to adjust the AFC. Back out on the smoke screw a turn or two and back out the starwheel a turn or two as well. Hope this helps a bit.



Cheers,

Sean

 

[keimmmo]

I change my filters often. New filters make little difference in the smoke. It is what I always tell a diesel owner when he has excessive smoke, so a good thought since you don't know me and I did not include that information.



I understand I need to move more air or less fuel. Yet, I don't want to spend much money on an old truck with over 300,000 miles on it. I do virtually all my own work... except the actual injection system. I do lots of custom fabricating, so that type of modification doesn't bother me. I can also learn new things! (That is what I am doing here!) If I add an extra air inlet into the filter box and drop the muffler, it would be virtually free. I can do my own porting, so I am looking at less than $200 and my time to port the head. That is why I am thinking that way. A timing adjustment would have also been free, but I will leave that alone unless I get other information.



Do you have an idea how much a new turbo and bigger outlet would cost? I understand your logic... but the words "new turbo" make me think expensive! I don't want to lose power, but I'm not really looking for more power either.



Thanks for the input. Point well taken!



Steve

 

[BushWakr - RIP]

keimmmo,



Just a thought, but before you spend any $$$ why not try adjusting the pump a bit first.

If you have that much noticable smoke there is obviously room to tweak "down" a bit. ... . geeezzz I never thought I'd say that...



Since you are "at altitude" you will have smoke due to the air/fuel mixture, and less boost overall.



You should consider making an adjustment to the starwheel. I'd go counter-clockwise with it maybe 3/4 to 1 full turn. That will help hold back your fueling until you get a bit more boost built up.

Basically it adjusts the amount of fuel per pound of boost being developed.

Next a quarter turn CC on the smoke screw will ease your initial off idle smoke. Kinda like the first 50' of launch so to speak.



Give that a try and see how it affects your smoke/boost/power levels.

On some pumps the smallest adjustment will immediately have an effect, on others, they almost refuse to respond no matter what you do so don't be too surprised if it goes either way.



Here is a link to a fairly good look into the workings and effects of changes regarding the VE pump we use on our trucks... ...

http://dodgeram.org/tech/dsl/more_power/Power_ve.htm



bob.

 

[keimmmo]

Thanks Bob for the good information! I have read and pretty well digested it. It makes sense! I am a little fuzzy on a couple of points, but I have a friend who owns an injection service. I'm going to talk to him! I'm sure he can straighten me out!



By the time the truck was a couple of months old I had noticed that if it was dogged around, the soot would build up in the exhaust and there was no possible way to keep it from smoking noticeably. If I take it out and "flog it forthrightly" once in a while it REALLY helps! Once the soot is blown out, the full throttle smoke isn't bad. But, that first punch will produce enough smoke/soot to block the sun!



I have ALWAYS looked in my rear view mirror before starting it to avoid choking anyone who might be passing by the tail pipe. I get stopped most often for smoke at moderate throttle pressure before the boost comes up. Sounds like there is a fix for all that.



I have just recently found this site and am really learning a bunch! I'm sure I wouldn't have left it stock all these years if I had had this information before!!!



Thanks again to all!



Steve

 

[Philip]

"flog it forthrightly"

Most of do this all the time. I was tought it wasn't working unless you heard the turbo whistling.



This site can run into a lot of money. LOL

But it can save you a lot also and you get to know your truck better.

 

[formula]

Steve,

You can find good deals on used exhaust housings and turbos if you check out the classifieds here in the TDR. Also, I've heard that if you frequent ebay, you'll find some good deals there too :-laf



Sean

 

[Midnite]

Steve,



Two really simple things you can do to reduce smoke for next to nothing are:



1. get rid of the stock muffler and replace with either straight pipe or a straight-thru type muffler. (which you already mentioned)

2. remove the stock airbox



The first mod I ever made to my truck was to have a local muffler shop remove the stock muffler and replace it with a 3" ID glasspack. While I didn't really notice any performance or milage improvement, it darn near completely eliminated all smoke except for a light haze at wide open throttle. (note that this was before I did any pump mods or replaced my injectors)



While the stock air filter flows lots of air, the air box on the '92 is a little restrictive--all the air must flow through a space that's less than the cross-section of a two-by-four. If you notice any improvement in the smoke situation when you remove the airbox, then you can either leave it off, or drill holes in it to allow more airflow.



I'm betting those two alone will help your situation tremendously, but good luck however you chose to attack it.



Mike