Sandy Johnson
Harry Member
Disclaimer: This is a story I'm providing purely for entertainment on irate. If you don't care about the trials and tribulations of some random yahoo wrangling his RV home across 320 miles of California countryside, then this thread is probably not worth your time.
I may have mentioned it in a few other threads, but I've got an old 30' 1980 Avco Class A motorhome with a 5.9 12v and Allison 2200HD transmission. It's got a few other cool bits on it like a Dana 80 with disc brakes out back. I love it, the wife loves it, our kids love it.
It is 40 years old, and has that breaking bad vibe, so we had to add this to clear a few things up:
So yeah, this thing is awesome, but over veteran's day weekend, it let me down.
We were coming back from Supersition OHV towing our jeep on a flatbed, kids and all. The trip had been good. It was the first time I had got to live out my plan of towing our 5,300 lb jeep on a flatbed trailer to camp in the desert and four wheel with the kids. The 500+ mile drive down (with a stop at the grandparent's house in san diego) had been good, and the motorhome kicked ass over the two big mountain passes we had to drive to get there, fully loaded. I was pretty stoked.
Cue the problem. We had just come up out of the desert on I-10 when my transmission threw a code and the problem light came on my dash. I have had throttle position sensors go out in the past on this thing, and I could tell from the way it was shifting that was the issue. As soon as the TPS dies on this thing, the Allison computer basically decides it doesn't know what's going on and decides that it's no longer safe to lock up my torque converter. When you're weighing in around 23,000 lbs rolling down the road, no lockup means no more freeway speeds and tranny temps soaring to the moon. No big deal, I had a spare, so I pull over at a local gas station, the wife takes the kids to get some lunch, and I swap the TPS. We load back up, go to get on the freeway, and boom. Tranny error light comes back on. This is not good.
Long story short, I end up extending my trip by a day, paying a pile of money to get the whole the towed to my in-laws house in Torrance, Ca. and going through the whole setup with a multi-meter the next morning.
I also bought two more sensors from the local auto parts store. I found one hot wire that was arcing out on a metal relay plate the previous owner had installed, so I cleaned that up and added a rubber ring to make sure that didn't happen again. I traced everything else and it looked good... the arcing wire had nothing to do with the TPS or the TCU, but I had seen stranger things cause the problem so I figured I'd swap in a new TPS and flogged it on a 30 minute test drive. Everything seemed to be good to go, so I headed back, hitched up the trailer with our jeep, loaded up the wife and kids, and headed out. It looked like we'd be home by dinner time. I got about 5 miles down the road from their house when BOOM, error light comes on and trans starts shifting weird.
Wife and I decide we don't want to deal with this right now or pay out the nose for more towing, so we put the damn thing in storage. Wife drove the kids home in her mom's little honda, and I took some drastic measures to make sure my jeep and trailer made it home(it was the biggest drop hitch I could find on short notice):
So there it sits, in storage in Redondo Beach:
Now, before I started carrying spare throttle position sensors, I have had to limp this thing home with no lockup up highway 101 from Ventura. So I know it can make it without towing anything. Extra bonus this time is it's fairly unloaded with none of our crap for the kids, no water in the tank, and freshly dumped grey and black water.
I have ONE spare TPS that I haven't burnt up in it, and I think I'm going to take one last final crack at tracking down my TPS gremlin before I give up and limp it home.
So here's the plan: I'm driving my mother-in-law's little honda down to southern California on Thanksgiving day. I THINK I'm going to make a detour to San Diego, see the parents for thanksgiving and grab a bag of tools I forgot there on our last trip down. After that I'm going to give the honda back the day after thanksgiving, hop in this motorhome and drive it to the nearest county park parking lot to begin my sketchy troubleshooting. At this point, I'm driving back north no matter what.
As far as trouble shooting goes. I'm first going to test the "bad" TPS with my multimeter. I don't know why I didn't think to do this last time, but it could be that all of the sensors are fine, it's my TCU that has crapped out.
I also plan on checking the adjustment of the TPS. It should be reading 0 volts at no throttle and about 5 volts at WOT. I have heard you can adjust this with a 10mm crescent behind the TPS bracket. We shall see how that goes:
If all of those are good, my final guess is that maybe the TPS is getting too hot right there on the block and the plastic is deforming, thereby not allowing everything to work right in there. I do have a length of AC duct that I might try running from the grill to the TPS somehow. I'm also thinking I'll try not to crank down too hard on the two bolts holding the TPS in place.
Lastly, I bought a sketchy license and version of the Allison diagnostic software for $40 (MSRP $3,000) and a $20 USB to OBD dongle to plug everything in. I know you can monitor the TPS output with that IF everything works. I actually don't expect it to, but you know what they say: "You miss 100% of the shots you don't take".
Other than that, I just might be driving ridiculously slow back home and taking breaks at the top of every big hill to let the tranny cool off. Depending on how well my phone posts pictures to irate, I'll try to update this thread.
Ok, I now open the floor to the irate peanut gallery to tell me what I'm doing wrong.
I may have mentioned it in a few other threads, but I've got an old 30' 1980 Avco Class A motorhome with a 5.9 12v and Allison 2200HD transmission. It's got a few other cool bits on it like a Dana 80 with disc brakes out back. I love it, the wife loves it, our kids love it.
It is 40 years old, and has that breaking bad vibe, so we had to add this to clear a few things up:
So yeah, this thing is awesome, but over veteran's day weekend, it let me down.
We were coming back from Supersition OHV towing our jeep on a flatbed, kids and all. The trip had been good. It was the first time I had got to live out my plan of towing our 5,300 lb jeep on a flatbed trailer to camp in the desert and four wheel with the kids. The 500+ mile drive down (with a stop at the grandparent's house in san diego) had been good, and the motorhome kicked ass over the two big mountain passes we had to drive to get there, fully loaded. I was pretty stoked.
Cue the problem. We had just come up out of the desert on I-10 when my transmission threw a code and the problem light came on my dash. I have had throttle position sensors go out in the past on this thing, and I could tell from the way it was shifting that was the issue. As soon as the TPS dies on this thing, the Allison computer basically decides it doesn't know what's going on and decides that it's no longer safe to lock up my torque converter. When you're weighing in around 23,000 lbs rolling down the road, no lockup means no more freeway speeds and tranny temps soaring to the moon. No big deal, I had a spare, so I pull over at a local gas station, the wife takes the kids to get some lunch, and I swap the TPS. We load back up, go to get on the freeway, and boom. Tranny error light comes back on. This is not good.
Long story short, I end up extending my trip by a day, paying a pile of money to get the whole the towed to my in-laws house in Torrance, Ca. and going through the whole setup with a multi-meter the next morning.
I also bought two more sensors from the local auto parts store. I found one hot wire that was arcing out on a metal relay plate the previous owner had installed, so I cleaned that up and added a rubber ring to make sure that didn't happen again. I traced everything else and it looked good... the arcing wire had nothing to do with the TPS or the TCU, but I had seen stranger things cause the problem so I figured I'd swap in a new TPS and flogged it on a 30 minute test drive. Everything seemed to be good to go, so I headed back, hitched up the trailer with our jeep, loaded up the wife and kids, and headed out. It looked like we'd be home by dinner time. I got about 5 miles down the road from their house when BOOM, error light comes on and trans starts shifting weird.
Wife and I decide we don't want to deal with this right now or pay out the nose for more towing, so we put the damn thing in storage. Wife drove the kids home in her mom's little honda, and I took some drastic measures to make sure my jeep and trailer made it home(it was the biggest drop hitch I could find on short notice):
So there it sits, in storage in Redondo Beach:
Now, before I started carrying spare throttle position sensors, I have had to limp this thing home with no lockup up highway 101 from Ventura. So I know it can make it without towing anything. Extra bonus this time is it's fairly unloaded with none of our crap for the kids, no water in the tank, and freshly dumped grey and black water.
I have ONE spare TPS that I haven't burnt up in it, and I think I'm going to take one last final crack at tracking down my TPS gremlin before I give up and limp it home.
So here's the plan: I'm driving my mother-in-law's little honda down to southern California on Thanksgiving day. I THINK I'm going to make a detour to San Diego, see the parents for thanksgiving and grab a bag of tools I forgot there on our last trip down. After that I'm going to give the honda back the day after thanksgiving, hop in this motorhome and drive it to the nearest county park parking lot to begin my sketchy troubleshooting. At this point, I'm driving back north no matter what.
As far as trouble shooting goes. I'm first going to test the "bad" TPS with my multimeter. I don't know why I didn't think to do this last time, but it could be that all of the sensors are fine, it's my TCU that has crapped out.
I also plan on checking the adjustment of the TPS. It should be reading 0 volts at no throttle and about 5 volts at WOT. I have heard you can adjust this with a 10mm crescent behind the TPS bracket. We shall see how that goes:
If all of those are good, my final guess is that maybe the TPS is getting too hot right there on the block and the plastic is deforming, thereby not allowing everything to work right in there. I do have a length of AC duct that I might try running from the grill to the TPS somehow. I'm also thinking I'll try not to crank down too hard on the two bolts holding the TPS in place.
Lastly, I bought a sketchy license and version of the Allison diagnostic software for $40 (MSRP $3,000) and a $20 USB to OBD dongle to plug everything in. I know you can monitor the TPS output with that IF everything works. I actually don't expect it to, but you know what they say: "You miss 100% of the shots you don't take".
Other than that, I just might be driving ridiculously slow back home and taking breaks at the top of every big hill to let the tranny cool off. Depending on how well my phone posts pictures to irate, I'll try to update this thread.
Ok, I now open the floor to the irate peanut gallery to tell me what I'm doing wrong.
