icenutt
New Member
So in other words what you are telling me is that it will take a miracle to find the shorted signal or the piece of electrical that is causing my issue with the gear selector?
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6.5TD turbo issues
- Thread starter icenutt
- Start date
buddy
Active Member
I looked at some stuff last night, I have been reviewing how the tranny responds when you actually put it in OD and its in first, vs how it responds when its manually selected in 1, 2, or D. I think that one of the "range mode" signals, A, B or C could be the issue, but havent studied it enough to say.
You should probably go look under the truck to see if any wiring is around the shift linkage, like rubbing against something. If only it was easy like that.
You should probably go look under the truck to see if any wiring is around the shift linkage, like rubbing against something. If only it was easy like that.
icenutt
New Member
Ok, throw everything out that we have talked about and lets start over. I just took the truck out on the highway to see if I can figure a few things out. Here is what I found.
Just to note, it's 3 degrees above zero with a wind chill of -25 below.
Anyway, I took off and the turbo was not working in OD so just before I got on the highway I shifted to D and turbo started working. I got on the highway and the turbo stayed working till I hit about 40 mph and then it went dead. Truck was running at about 3000 rpms. I shifted into OD and it shifted into 4th and sped up to 65 mph. No turbo. I tried several different things to see if I could really tell if the TCC was locked. I don't think it locked once. I ran at 65 mph and the rpms were at 2400. I came back into town, still no turbo. I shifted to D and still no turbo. Then all of a sudden it started working again then shutoff and I was in D at the time. I stepped on the gas and the turbo jumped to 10 lbs of pressure and then went right down to zero. Could not get it work after that in either D or OD. Shifted into 2 and it started working again. Shifted to D and OD and nothing. Got back to the garage and pulled the error codes. Same three from previous DTC 74, 78 and 85. I am sick of this. And to top it off, my studder at idle is getting worse. It never dies but the motor will studder at idle speed. Never when I am on the gas or when I switch on the high idle switch. Only on low idle and more often with its in gear. Do I have a PMD box going out or maybe a ground issue? Any ideas?
Just to note, it's 3 degrees above zero with a wind chill of -25 below.
Anyway, I took off and the turbo was not working in OD so just before I got on the highway I shifted to D and turbo started working. I got on the highway and the turbo stayed working till I hit about 40 mph and then it went dead. Truck was running at about 3000 rpms. I shifted into OD and it shifted into 4th and sped up to 65 mph. No turbo. I tried several different things to see if I could really tell if the TCC was locked. I don't think it locked once. I ran at 65 mph and the rpms were at 2400. I came back into town, still no turbo. I shifted to D and still no turbo. Then all of a sudden it started working again then shutoff and I was in D at the time. I stepped on the gas and the turbo jumped to 10 lbs of pressure and then went right down to zero. Could not get it work after that in either D or OD. Shifted into 2 and it started working again. Shifted to D and OD and nothing. Got back to the garage and pulled the error codes. Same three from previous DTC 74, 78 and 85. I am sick of this. And to top it off, my studder at idle is getting worse. It never dies but the motor will studder at idle speed. Never when I am on the gas or when I switch on the high idle switch. Only on low idle and more often with its in gear. Do I have a PMD box going out or maybe a ground issue? Any ideas?
ak diesel driver
6.5 driver
You do realize the tcc won't lock until 170* temp. Always a good idea to check grounds. My self I see a TM in your future
buddy
Active Member
When the turbo "isn't working" do you lose much performance?
icenutt
New Member
ak diesel driver, whats a TM?
Buddy, I don't loose alot of performance other than it has a little more snap and giddy up when the turbo is working. I tested the mileage last summer two separate road rips of over 100 miles and I got 26 mpg both times. And that was with the turbo acting up at times.
Buddy, I don't loose alot of performance other than it has a little more snap and giddy up when the turbo is working. I tested the mileage last summer two separate road rips of over 100 miles and I got 26 mpg both times. And that was with the turbo acting up at times.
ak diesel driver
6.5 driver
tm= turbo master= mechanical wastegate
- Staff
- #28
I think a TM might be a good idea, but I'm still concerned that the TCC is sporadic ... a soft code causes that, and is likely causing the WG problems, too.
Of course, some people will tell you that you have air in your fuel ... but that ain't it. It ain't your ECM, either, so you can ignore that advice, too.
Check your grounds - strange things happen to people whose grounds get flaky - and all of your wiring and connectors. This baby is electrical.
Of course, some people will tell you that you have air in your fuel ... but that ain't it. It ain't your ECM, either, so you can ignore that advice, too.
Check your grounds - strange things happen to people whose grounds get flaky - and all of your wiring and connectors. This baby is electrical.
icenutt
New Member
I totally agree now that this is an electrical issue....of course. I have been hestitant to put the TM on my truck because since I have the "S" motor I have to change the entire intake or atleast modify it. Then flash the computer to eliminate the EGR settings. I wanted to try and keep this old beast as original as possible but if that is my only option, then so be it. I read one guy put a manual TM on his turbo and then just unplugged the wastegate solenoid. Is that recommended or will that cause other issues? The intake switch is what has me on the fence. It doesn't seem like a huge job but finding the right intake up here might be fun. I have asked around a while back when I first got the truck and everyone was telling me to switch the intake but outside of ordering a new one there wasn't any around. Does anyone have a good place to look for these intakes? Money of course is an issue so I don't want to spend a ton of money on this truck if I don't have to.
I am going to check all the grounds and connections first before I proceed any further. Let me know if anyone has some places a guy can find those intakes. Thanks.
I am going to check all the grounds and connections first before I proceed any further. Let me know if anyone has some places a guy can find those intakes. Thanks.
buddy
Active Member
You do not have to change the intake, it is recommended, but you can modify yours or leave it as is. You will not set any codes for a non-functioning EGR valve itself. So if you want to disable the EGR, just unplug the vacuum line going to it, and plug the line coming from the solenoid with a golf tee or something. I would recommend taking the upper intake plenum off and cutting out the restrictive plating, and plugging the EGR channel in the lower with a frost plug, the opening is like 45mm. Then your non-functional EGR valve can stay there or just put a blockoff plate on it. Those steps will get you the 80% solution.
