Hello,
First, I should say that I have been a lurker for the last couple of months. It seems like this is a very good forum, so I thought I would post a question about a bit of a problem I am having with my 98 6.5 LTD. I have had the truck for about a month and a half. I bought the truck with 200,000 kms on it, and it now has about 209,000 kms. Now what is happening, is that when driving, say for example, you slow down and turn a corner, then if you are trying to accelerate, but very gentley, the truck will buck a bit and will let off some light colored smoke. If you turn the corner and accelerate a little harder, it doesn't do this. Any ideas as to what could be the culprit? It is not giving me the light on the dash, but I haven't had it plugged in yet.

Greeze if you have been lurking for a while, then you know what is coming, soapbox speech again.

"update sig with truck info per welcome note sticky and have you been to FAQ stickys yet", if so let us know if you did not find your answer there so I can turn this into a new FAQ if need be.

Sounds like a fuel delivery problem with what you have supplied as info, several tips in FAQ on how to diagnose, do those then report back with results

Sorry about the sig. It should be there now. As for FAQ, I have been through them, but one thing I missed is the chance of a bad ground. Will try that this weekend. It got me thinking that on Moday, while at an accident, the truck sat with the flashers on for about 3 hours. When I went to start it, it was like a dead battery. I just wiggled the ground on the passenger side battery and away it went.

I just wiggled the ground on the passenger side battery and away it went.
Bad battery cable grounds (and engine grounds) are a very common problem on our trucks and cause all sorts of headaches.

Definately going to be looked at this weekend. One common thing in the FAQ I noticed is that it keeps mentioning stalling. My truck has never stalled, but it has done that stumble, so I am not sure whether it applies or not. The smoke is throwing me for a loop, but I guess we'll eat this apple one bite at a time.

Consider yourself lucky so far on stalling, sort of a matter of when it will happen not if, IMO. remote mount is best way to insure longevity, I have had good success to date with the Heath remote, it's higher than some solutions, but 7yr warranty was decidintg factor for me. Remote mount on heat sink is low buck solution that many use with homemade harnesses.

Better IMO is the a remote harness from Kennedy or Heath which uses factory style weather resistant plugs, Kennedy also sells a cooler for old style FSD & also new driver which is testing well as replacement design over GMs(REMAR-Q) only negative there for me is 5yr warranty vs 7 with the Heath, if REMAR-Q had a 7yr warranty I'd be more in favor of that solution

Apples are best eaten individually you get a belly ache trying to eat the whole bushel ):h do the ground & fuel delivery checks report back results, then do another thread on smoke, FYI partially blocked filter is just as bad as fully blocked and will cause stumble when was last filter change.

For smoke thread what kind of smoke lots, on heavy accel only or heavy all the time you are on throttle. White or black smoke, smoke at start up again heavy/light & color, be as descriptive as you can

Filter was changed when I bought the truck, so about 9000 km's ago. Am going to change anyway, but I doubt it will be the problem. It seems more like a feedback error between the accelerator and the PMD to me (not really sure how that system works), which could explain the the puffing of grayish smoke when it stumbles. That is the only time it smokes, other that that just a little black puff when first starting and a little black puff when kicking down into passing gear. For alot of people, they would not even find the stumble, but I drive with feather foot, so I hit it from time to time. This is my first GM ever, so it will take abit to figure this thing out.

Bone stock & staying that way, hmnn says you, just don't ever ride in one with some tweaking done to it then :D , it gets real addictive, I'd at least do the basicaly free mods, as it will help improve life of your engine, more boost can lower EGT, you just don't have to go as far as some of us have tread.

Smoke level seems normal, but run the turbo & fuel delivery checks, could be getting early sign OPs or lift pump problem, I also had a "new" filter bite me once, towing epmty GN trailer I couldn't hardly make 40 mph though with no trailer, ran like raped ape to 100 mph. Got a bad load of fuel somewhere within 5K miles of the "new" filter change which partially blocked it under load causing "fishbiting" on acceleration. After that I went to Racor pre lift pump filter in addition to the on engine filter (see FAQ)

A slight update. I talked to a service guy and he said that it may be the pedal. Since this system uses that "fly by wire". Anyone ever have to change this? I am still going to eat this apple a bite at a time, but I like to have as many maybe's in my head as possible before I start. It helps me make sure I don't overlook something.

I've read about that being replaced a lot but never read about it solving a problem

Yes APP could be the cause but not often do the other stuff 1st, know anybody with a Snap On MT2500 or GM tech 2, APP volts can be read there to know if APP is the problem, also run with cruise control that takes APP out of the loop and see if it still does it. Hill climb in cruise control would have same result as you driving by advancing the APP with your foot.

Turbine Doc,
Free mods? hmmmm, I'll have to search and look into those. I spend more than enough on my other bad habits, I don't need another one. Plus I prefer to do all of my own work, so not alot of time to monkey with this thing, and it needs to be my daily driver. It is going to have an easy life, basically pulling sled trailers, boats, etc. I would like to get a fifth wheel so that would be it's biggest load. As I stated, I am new to owning GM's. We had one we used as a service truck on the farm, but it was obviously a Friday truck.

Yes APP could be the cause but not often do the other stuff 1st, know anybody with a Snap On MT2500 or GM tech 2, APP volts can be read there to know if APP is the problem, also run with cruise control that takes APP out of the loop and see if it still does it. Hill climb in cruise control would have same result as you driving by advancing the APP with your foot.

It never does it while driving, only after slowing down to turn a corner and then gently accelorating, so I don't know how to do the cruise thing. It does seem like if I push the pedal past a certain point, it takes off, as if it missed a certain throttle position range.

Greeze you are where I was back in 2000 lot of things to bump up performance in a L56might want to go PM with me though as some require "special modification" for off road use and then be reconfigurable to be smog engine (L56) legal when no longer offroading your K1500

It never does it while driving, only after slowing down to turn a corner and then gently accelorating, so I don't know how to do the cruise thing. It does seem like if I push the pedal past a certain point, it takes off, as if it missed a certain throttle position range.

Intermittent you may wnat to find a scanner and watch while driving, with cruise control on you can accelerate/or slowdown using the control features, or just set it for say 65mph then climb a hill/bridge etc. it should maintain without stumbling, if it stumbles or "fishbites" I don't suspect APP.

Fish biting is a slang term used in 6.5 community where when cruising along or accellerating where truck just out of the blue starts jerking sort of line a fish on the end of a pole trying to spit out a hook rtthen it settles out on its own or with deceleration on your part.

Sometimes it is early sign of PMD sarting to go south, this may be your only indication of PMD fail before leaving you stranded. no codes set with bad PMD generally. But before going there need to rule out other things like grounds (fly by wire trucks need clean grounds and full voltage to work BTW), OPS, filters, lift pumps, wastegate/vacuum issues (need gauges look cool and great troubleshooting aids)

If all above checks out I'd almost bet PMD over APP, with your miles PMD is highly suspect.

I will try the cruise control/ hill thing. Can't hook up to the scanner right now as my hours and the shop's hours are basically the same, meaning they are closed by the time I get there. Might have to pick up a scanner for this thing next time I am anywhere that sells them. Called and dealer 60 miles from here has a PMD for $500 cdn, so that seems livable, but will have to do all those other checks before.

Nah don't go dealer on PMD too high, somebody will chime in where is best source in Canada for those things CR, Firefighter, & TDG have the "Canada connections" maybe you want to PM them.

My truck does the same thing when it is somewhat cold (warmed up for 10 min ideling) in the morning. It lets out a big puff of smoke when I start it and it stumbles once or twice. When I get in it to take off it stutters and jerks and smokes for a few seconds then it takes of good. Anybody got any ideas? IP and PMD replaced under warranty by stealer a month ago. New injectors.

I guess my truck does have a simple mod done to it. I added it to my sig. I don't really consider it a Mod, just an option, but I'll add it anyway.

Well, a quick update. On the way home from work, I tried leaving the cruise on going up a big hill. I had the cruise set at 65mph, and there was absolutely no fishbiting what so ever. In town when I was driving around, I noticed the stumble again when accelorating, and the truck would also give a light grey puff of smoke out, then it would be ok. The only way I can describe this is it is like when a gas engine is flooding slightly and you hit the throttle and it clears out. I should note that there is no smoking when idling and it idles fine.
I looked at it briefly, but it is raining. Anymore ideas? Like I said a new filter is going in tomorrow. Checked the cables and they seem ok, but I'll clean them tomorrow.

The gas engine flooding and clearing out when you hit the pedal is the same feeling I get. Hopefully what ever you find will work for me/

Greezemonkey, try wiggling the wires going to the solenoids on the solenoid bank. They can give you a kind of stumble when they are broken. I don't think that's the problem because your getting the stumble only on slight acceleration, but it's easy enough to try.

Wiggle them thoroughly to make sure you'll find a position that causes a stumble, if there's anything to that at all.

I found this topic here. It seems to me to be more of what is happening. Changed the fuel filter, and no luck. Here is the link:
http://dieselplace.com/forum/showthread.php?t=36739&highlight=waste+gate

Just a slight update. Still no solution at this point. LP is putting out about 4psi at idle, never did the drive test. Talked to dealer's diesel guy, thought it may be a weak LP or that the EGR may be opening on manifold pressure and may be faulty. I booked it in for next Friday at 8am. Will find out then. I am still using the truck daily, so I hope I don't screw anything up.

Just an update at this point.
Took it into the dealer today and it seems like they fixed my problem. All the tech did was put in the patch that is for the surge at idle into the program as well as updating the program. Works like a charm now. End result was $34 cdn.