dragonriot
08-29-2007, 15:26
Been a while since I posted, so I'll update the group with the situation first.
I bought a 94 Yukon 6.5 Turbo from a guy in September of 2006... From day 1, it blew black smoke when I got on the throttle, and never really had much in the way of "balls"... it would still go anywhere, but it would go there slowly, and with not much power to spare. In December, I took the truck to the shop I used to work at, and they sent it off to Diesel Injection Service for diagnostics. DIS returned a quote for $2200 for an Injection Pump, Wastegate Solenoid, Intake Cleaning, and new HD Gasket to remove the EGR Valve.
After the work was done, I was still blowing soot, but not as much, so I thought everything was great... It had more power, got better mileage, and felt like a "new" truck... or so I thought.
A couple months ago, I hooked up a trailer to tow some (2-tons) of Lannon stone, which is basically big flat rocks taken out of the Lannon Quarry near here. The first 45 miles of the drive produced billowing clouds of black smoke, and my mileage dropped to probably 14mpg from 18mpg average. I was constantly on the throttle, and not gaining any speed. I think my top speed was about 60mph, on the freeway, with my friend calling me every few minutes and telling me to speed up, with me replying "I can't"...
We stopped at a farm store on the way back to my house, and while we were there, left the truck running to cool everything down, as I had been running hot almost the whole trip. When I got back to the truck after about 45 minutes in the store, the engine sounded different, and I couldn't put my finger on what it was.... until I got in and hit the skinny pedal... If I thought my truck felt "new" after the repairs, this was like getting an entirely different new truck.
Suddenly, after idling for 45 minutes in a parking lot, my turbo began to audibly spool and make a ****load of power. It no longer blew black smoke, and if it blew smoke at all, it was white and clean looking. I had hill-climbing power that I didn't realize I could have, and my mileage went back to about 18mpg for the remainder of the 45 minutes home. I unloaded the rocks, took the trailer back to its home, and thought my truck had somehow fixed itself permanently...
Then a couple weeks passed, and the spooling was intermittent... if I stopped and punched it, the spool and loud whistle would come back for a while, then slowly fade out again. This effect was noticeable in the harmonic vibrations of the truck, sounds of the engine when the turbo was spooling and whistling, as well as sounds and vibrations from the engine when the turbo was not spooling. Now, the turbo only spools in the first 10 minutes after I start the truck, and then goes away leaving a rattly, noisy, smoke blowing non-turbo'd engine. Nothing I do can get it to come back anymore, except letting it sit overnight, and having a small amount of boost - though enough to stop the smoke and give me a bit more power feel - when I start it up again in the morning.
The codes it had in the history were related to too much MAP volume, Accelerator Positioning Sensor #1, and the Wastegate Solenoid inoperable. I am looking now at taking the truck back to DIS and saying the WG Solenoid is broken again, less than 9 months after you replaced it... what are you going to charge me for this time?
My mechanic thinks I need a whole new turbo, but I'm very hesitant to believe that the WG doesn't separate from the turbo and that I can't just replace that part, and not spend $1000 on a turbo.
Any advice would be appreciated, and yes... if I am capable, I do plan to do the work myself this time.
***EDIT***
I forgot to mention - that's a big forgot - that I attempted to wire the wastegate actuator towards the firewall... Not all the way, but enough so that the solenoid wouldn't have to push as hard to get it to open all the way... I think this is when the WG Solenoid and MAP sensor codes were thrown, as there were no current codes when I plugged it into the tester. While the thing was wired that way, I got no better performance, and in fact blew more smoke - in my opinion - than when it wasn't wired. Also, the lever can be moved by hand when the engine is running or not... is that supposed to happen?
I've read a bit about a Manual Wastegate controller, but haven't seen any examples... I'll continue my search for answers, and if I think of anything else, I'll add it here.
I bought a 94 Yukon 6.5 Turbo from a guy in September of 2006... From day 1, it blew black smoke when I got on the throttle, and never really had much in the way of "balls"... it would still go anywhere, but it would go there slowly, and with not much power to spare. In December, I took the truck to the shop I used to work at, and they sent it off to Diesel Injection Service for diagnostics. DIS returned a quote for $2200 for an Injection Pump, Wastegate Solenoid, Intake Cleaning, and new HD Gasket to remove the EGR Valve.
After the work was done, I was still blowing soot, but not as much, so I thought everything was great... It had more power, got better mileage, and felt like a "new" truck... or so I thought.
A couple months ago, I hooked up a trailer to tow some (2-tons) of Lannon stone, which is basically big flat rocks taken out of the Lannon Quarry near here. The first 45 miles of the drive produced billowing clouds of black smoke, and my mileage dropped to probably 14mpg from 18mpg average. I was constantly on the throttle, and not gaining any speed. I think my top speed was about 60mph, on the freeway, with my friend calling me every few minutes and telling me to speed up, with me replying "I can't"...
We stopped at a farm store on the way back to my house, and while we were there, left the truck running to cool everything down, as I had been running hot almost the whole trip. When I got back to the truck after about 45 minutes in the store, the engine sounded different, and I couldn't put my finger on what it was.... until I got in and hit the skinny pedal... If I thought my truck felt "new" after the repairs, this was like getting an entirely different new truck.
Suddenly, after idling for 45 minutes in a parking lot, my turbo began to audibly spool and make a ****load of power. It no longer blew black smoke, and if it blew smoke at all, it was white and clean looking. I had hill-climbing power that I didn't realize I could have, and my mileage went back to about 18mpg for the remainder of the 45 minutes home. I unloaded the rocks, took the trailer back to its home, and thought my truck had somehow fixed itself permanently...
Then a couple weeks passed, and the spooling was intermittent... if I stopped and punched it, the spool and loud whistle would come back for a while, then slowly fade out again. This effect was noticeable in the harmonic vibrations of the truck, sounds of the engine when the turbo was spooling and whistling, as well as sounds and vibrations from the engine when the turbo was not spooling. Now, the turbo only spools in the first 10 minutes after I start the truck, and then goes away leaving a rattly, noisy, smoke blowing non-turbo'd engine. Nothing I do can get it to come back anymore, except letting it sit overnight, and having a small amount of boost - though enough to stop the smoke and give me a bit more power feel - when I start it up again in the morning.
The codes it had in the history were related to too much MAP volume, Accelerator Positioning Sensor #1, and the Wastegate Solenoid inoperable. I am looking now at taking the truck back to DIS and saying the WG Solenoid is broken again, less than 9 months after you replaced it... what are you going to charge me for this time?
My mechanic thinks I need a whole new turbo, but I'm very hesitant to believe that the WG doesn't separate from the turbo and that I can't just replace that part, and not spend $1000 on a turbo.
Any advice would be appreciated, and yes... if I am capable, I do plan to do the work myself this time.
***EDIT***
I forgot to mention - that's a big forgot - that I attempted to wire the wastegate actuator towards the firewall... Not all the way, but enough so that the solenoid wouldn't have to push as hard to get it to open all the way... I think this is when the WG Solenoid and MAP sensor codes were thrown, as there were no current codes when I plugged it into the tester. While the thing was wired that way, I got no better performance, and in fact blew more smoke - in my opinion - than when it wasn't wired. Also, the lever can be moved by hand when the engine is running or not... is that supposed to happen?
I've read a bit about a Manual Wastegate controller, but haven't seen any examples... I'll continue my search for answers, and if I think of anything else, I'll add it here.