Hi gang,


I have a 96 chev 1 ton srw 4 door 4X4 with automatic trans approx 250K I have been lurking on this forum lately and with your help I replaced a dying injector pump. Yesterday I was driving down a gravel road and hit a pothole so big it knocked my rearview mirror off and knocked the battery cable that goes over the fan shroud into the fan it cut it shorted it out and the truck soon stalled. I opened the hood, discovered it and repaired it. When i was driving home the transmission would not shift into od only up to third. after about 20 miles it shifted all has been well after that. why? was this related? also the idle speed is about 1k now where it was about 650. The engine makes a different but hard to describe noise as well. It doesnt sound bad but it is different mostly at idle.


Second unrelated problem, sometimes i get a great deal of black smoke from exaust when pushing the truck hard i also get a ses light when this happens. the code refers to the turbo or wastegate. other times the truck has minimal smoke and has more power and better fuel economy.


Any help would be appreciated


Justin

Tempature sensor curcuit fault will make it idle higher and smoke. check for a bad connection
See if jiggling wires on top of the motor makes it idle lower.

And wg,solenoid,vacuum system fault. Edited by: quantum mechanic

Did you check to see if any of your other ground wires were broken loose at the same time? GM wiring harnesses are notoriously troublesome, and a big enough pothole could jar them and give connection/ground problems. I suspect either ground or 5volt reference is the problem, since they are shared by the wastegate actuator, MAP sensor and I think the temp sensor in the IP, improper voltage or a weak ground or weak connection would give you an off reading. I'd say best bet, hook it up to a scanner and have someone read your data from these inputs and see if they are 'believable' values, i.e. like your fuel temps says 210 degrees, or MAP says you've got boost pressure at idle, things like that. Then unplug the sensors and check to see if you've got 5v and 0 resistance to ground at the plug. While you've got them unplugged, try and clean and stroke out the contacts if they look weak, at the sensors then the PCM.Edited by: Texas Diesel Guy

I checked wires at temp sender to no avail. I will have codes scanned tomorow and give an update. Thank you both for your time.


Justin

OK, gang I had codeds scanned and Quantum was right the temp sensor was broken off. the other code was a misfire on cyl #7 i replaced sensor and cleared codes all is well for now. Thank you so much for your help.


Justin

Justin,
How stock is your truck? Your signature doesn't say.

It is stock all the way. Heres what I know about it


1996 black 4 door 1 ton single wheel 4X4 automatic trans 245K Ranch hand stuff gooseneck hitch amsoil duall bypass. I use the truck now and then to haul cattle to the sale,vet etc. I also play steel guitar all over TX so most of the driving is empty highway. My gear fits in the back seat nicely. I do have some overheating problems and some turbo issues so i need to do some mods to the truck. I am new to this forum and didnt know all the mods existed. so keep me headed in the right direction. I also have a 92 dodge dually that i use for heavy work it is ugly and uncomfortable but it does anything I need to do without mechanical issues and it keeps me from tearing up the chevy. Not trying to dis the chevy i like it better i just sometimes get frustrated with it


JustinEdited by: justin25taylor

Do a search for RPO codes here in the forum there is a list in your glove box that lists whatb yout truck came with new, match it against the code list to decipher it.

more problems, turbo doesnt seem to be working. no vac at wastegate at idle is this normal? also please explain the spring i need to add to the wg arm. thanks in advance for your time


Justin

Hey justin,


The system should have 25" Hg vacuum before the wg solenoid and 15" Hg vacuum at the actuator at idle. The wg solenoid sticks when bad letting limited vacuum through. The stock vacuum lines should be replaced, if suspected. I went with 1/4" id vacuum hose. 15' for $5. Solenoid is as cheap as $16 www.gmpartsdirect.com (http://www.gmpartsdirect.com) #01997227


If you want to meet a fellow 6.5er I can drive out and donate my extra solenoid/vac line.





Edited by: quantum mechanic

sounds great is the actuator where the vac hose connects at turbo? i dont know where the solonoid is located. ill be happy to drive to meet you as well and maybe you could drive the truck and give me your opinion id be happy to pay you


justinEdited by: justin25taylor

The actuator is where the line plugs into the turbo. follow the line from there back to the solenoid.

Truck is fixed! Quantam drove an hour to my house brought a solenoid and installed it. he also showed me how to put a resistor on the map sensor to increase boost pressure. He threw a fit when I tryed to pay him for the part and his time. What a great forum this is. Thanks again Quantam!


My Best,


Justin

Justin,


Anytime. That's a real perty truck you got there. And anyone who would go through all the hastle of replacing their own IP is OK in my book.

JT,


flowmaster has a downpipe and crossover for the 6.5 for less than $90 if you buy the kit from summit racing. kit #17220.


I forgot to throw one of my old stock downpipes in the back to show you it's a real piece of work.


http://www.dieselplace.com/forum/uploads/Z3D_downpipes.jpg


That's a '94 up top and a slightly less crimped '96 below. A 3" mandrel bent pipe looks like a champ next to these chumps.








Edited by: quantum mechanic

WOW Can't wait till I get mine installed. I have heard alot about the GM4 vs the GM8 turbos I think. WHats the difference and which should I want on my 94 6.5 ? WHY?

WOW Can't wait till I get mine installed. I have heard alot about the GM4 vs the GM8 turbos I think. WHats the difference and which should I want on my 94 6.5 ? WHY?








I doubt that you can really tell the difference between them but the GM8 is supposed to be the best. It is the newest and changed slightly for better flow. If getting a new turbo, the GM8 would be the one to look for. The vacuum line will need to be rerouted slightly or if you have a turbomaster, I think you would need a new one.


Someone that has had both may have a different opinion. I only have the GM4 on mine so was never actually able to compare them myself.

I havn't taken my dad's GM7 apart but it is sapposed to have a better turndown, the part that bolts up to the wg/turbine housing and the downpipe and ofcourse the shorter wg arm. vertical instead of horizontal.