99 6.5 Blowin Coal (Want to fix it)
 

Hello, I reciently purchased the truck, after a PMD and Neautral Saifty Switch she is running great. (its bone stock except for a 3 in stainless exhaust and relocated pmd)

I noticed reciently she seems to be running a bit ritch, i know the previous owner tinkered with it trying to figure out why it died after 5 min.

Basicly when she is ideling i can tap the pettel and a ton of black smoke comes out, driving anything over 1/2 throttel is just rolling smoke! (yes its black smoke) under 1/2 its clean.

Any ideas? it also has new filters/lift pump on it.


Don

p.s. I also have a slip in the tranny when trying to shift from first to second, if it does it and i let off it goes in gear and is fine. then i can floor it with no slipping, also it dosent slip if shifted manually

Im guessing the Neautral Saifty Switch is bad:tttt: or it is running ritch agian. You coold try adesting the pettel for the throttel:humm:

the trany suonds like it neds some mor fliud. it might bee loow. I wood just add soom

If it blows black smoke when you step on it, your turbo system is probably not working to spec.

Here's what you need to check:

Quick and dirty - with your truck idling, try and move the turbo wastegate lever by hand (careful, it may be hot):

http://i40.photobucket.com/albums/e2...Turbos_GM8.jpg

It should not move and should be rock solid. If it does move, you have a problem in the turbo wastgate system.

So, now:

1. Pull the trouble codes out of the PCM. You'll need a code reader to do OBDII (1998)
2. Test the output of the vacuum pump. pop in a vacuum gauge, it should read somewhere around 20-ish in/hg. If you have vacuum, the pump is good
3. Use a hand held vacuum pump and pull the wastegate vacuum pot closed. If it works and holds, it's good.
4. Now for the likely fix for most bad vacuum wastgates - the wastgate solenoid. It's on a bracket above the drivers side valve cover. It will have a green dot on it if you have more than one solenoid there. There's a little steel ball inside that rusts and then won't seal. It's about a 55 dollar part. Like so:

http://www.turbobuicks.com/forums/at...wg.jpg%3C/a%3E

5. If all this is good, the vacuum lines might be leaking. They're hard plastic lines and go bad over the years, get brittle and can leak.

The other option is to install a turbo master for around 100 bucks from Bill heath, install a shorter serpentine belt and and you can forget about ever worrying about the vacuum system again.

You can "make" a turbo master by gutting your vacuum pot and installing a spring with some threaded rod and nuts. Google will turn up a few how to's.

If non of this works, it's probably a mechanical failure of the turbo (wastegate frozen, bearing failure, etc) and replacement is the only cure....

turbo master all the way:jump:

Wow man, thanks! No Codes Listed. Is there a vacuum pump on this engine? Ill run out as soon as its quit raining and pop the hood.

The Neautral Saifty Switch has been replaced, I did that knowing the tranny is electronic, and R N D D wouldn't light up, that improved it. I have driven it for 2 weeks daily with the new one in it and all the indicator lights light up although it still hangs going into second unless I let it take its sweet time shifting.


I'm honestly starting to think I have a valve body problem, or a shift solenoid problem.

Yes it has a fluid and filter change when switch was done, and its right where it should be.

P.S. Its a 4l80e Opt MT1

Bottom lower passenger side:

http://i40.photobucket.com/albums/e2...tinebelt-1.jpg

Shift solenoid a or b usually sets a code.

Slow shifting would indicate those, but you have no codes.

Low line pressure is another cause, but that usually also sets a code.

All Automatic 6.5's are 4l80E's, except for some very early 90's that might have come the 700r4. I've seen one 6.5 burb with a 700r4. Coincidentally, it was on it's 3rd rebuild.....:w2:

Not really sure what else to tell you right now about the transmission. I know my way around, but they're not my strong suit...:ouch:

I might read through a few 4l80e factory manuals I have this weekend if I get some free time and see what I can come up with for ya......no promises though......