My truck tends to go from 3 to 4 fairly quick, but my other shifts are what I would call "normal." Your situation sounds slightly unusual but I have no idea if it indicates a problem or not... could just be the way it is for some reason. Typical AZ scanner won't read any PSD codes.

 

Soft codes will not set the check engine light, but will show up on a scan. I expected to see some soft codes, but didn't and haven't.

BTW Chase, don't worry about putting your other pcm back in cause I don't think it will work. I finally found someone to let me try it using their computer in my truck. It was out of an 02 with the only difference from mine being it was a single rear wheel. I drove it prior to trying and that truck ran like mine was with the correct rpm at the right speed.

With a completely different pcm in mine, it DID NOT make any difference!!

This tells me a couple things:
1. I'm glad I didn't spend more money to buy one or have Ford reflash the pcm as it wouldn't have done any good.
2. The issue is coming from whatever the pcm is getting its signal from - i.e. speed sensor, abs module, cps, etc. If everyone that I've talked to is correct in that the digital ford AIC gets its data directly from the pcm and not from the dash cluster, then the issue is definitely pre-computer.

Still searching

 

Sorry I didn't get to it sooner Ryan. I'm still wondering about an up-pipe leak, but I can build good boost so I don't know.

 

No worries. It took me a while to track someone I knew down that for sure had a truck with the same pcm code.

Truthfully I don't think the up-pipe leak has anything to do with it. If it did, you'd think that others on this forum with massive up-pipe leaks would have experienced the same thing. From what I've found so far in searches, nothing has been mentioned of it. I'm not completely ruling it out, but don't think it's our culprit. I've been wrong before though!!

 

I have a solution... pull motor and trans, rob bank for funding and do a full build on both. That would eliminate any "what ifs" and give us a good baseline to judge things from. I nominate you to go first

 

Sounds like a hellofa plan!! If only I could get away with it!!

 

Didn't read page 1 or 2 since the thread was started, but are you both running oversized tires? Or undersized?

 

Don't know about Chase, but I'm running slightly larger tires. Maybe an inch taller. I've had them on for a year before this deal started, under 10,000 miles so wear is minimal.

The tire size has not changed during this deal. The speedometer is accurate. Checked it with a gps over Thanksgiving weekend.

 

I'm running 285/75/16's. They've been on there since I bought the truck in March, have around 11k on them now.

 

So, it's been a month or so since I last tried anything. Had family up for the holidays so didn't do much with the truck while they were here.

Here's my long winded update:

I ran buy a shop in town last week that I've gotten to know really well. They do alot of cummins conversion and the owner races drag and funny cars. Super smart when it comes to gas/alcohol and diesel machines. He has a digital revolution reader that can be used on virtually anything. Very similar to a timing strobe for a carborated gasser, only it uses a laser and a piece of reflective tape for a reference.

Put a strip of tape on the crank pulley and have a guy laying under the truck to get the reading. Checked at idle and at 2100 rpm. The readings were nearly exactly as my dash and digital AIC were reading. I think there was only 3 rpm variance!!!

So I know for a fact now that my speedo and tach are both accurate! I'm thinking more and more that my gauge on the dash was just not reading right before and somehow corrected itself. I've heard of it but never seen it.

I'm going to be installing a van turbo in the next month. Unfortunately, I'm not going to have the cash to get the bellowed up-pipes at the same time. So I'm going to just replace the donuts for now. The van turbo has been on the shelf for a while now, but am going to do it sooner than planned because I think my turbo is starting to give me some fits.

I've noticed that it's leaking oil and it's making some different noises that I recall it doing in the past. I've also been running lower boost and power seems to be down (at least by the SOTP) anyway. So I think it's a good time for the turbo swap.

I'll update again when the turbo is replaced.

 

Ryan, any ideas as to a possible solution yet? It seems like my RPM is climbing slightly per speed still, at 68mph on the freeway over Christmas I was dang near 2k rpm on the tach. I'm only going on the factory tach, no AIC or other way to measure RPM.

 

Nothing yet. It might not be anything more than the factory tach reading different. I didn't have my AIC originally and bought it after this all started. With the manual check we did last week, it told me there was no interferance due to electrical sensors or connections and what rpm it's doing is what it's reading. I'm still searching, but so far have nothing concrete.

My boost has been lower throughout this as well and it seems that the power is getting less and less. I've had the chip off it it since Sept. and it still feels like the power is deminishing. That's why I'm going to get the other turbo installed sooner than later to see if that fixes my issues there. Don't know if it'll do a thing for the rpm's, but we'll see.

 

Ryan- I'm almost convinced I have no boost leaks anywhere... I can pull some good boost #'s (25 lbs coming up the White Bird grade coming home from Christmas) so I think I'm sealed up tighter than a gnat's butt. Power seems on par for me, prolly a little better with the cold weather (and dense air). But... I still don't like how the rpm's seem to be climbing... I'm at a loss as well.

 

Last time I came up White Bird pulling a load we were coming back from a rodeo in Ontario, OR. One of my buddies left quite a while before we did with their Dodge and trailer. We were pulling vertually the same weight with our rigs. They were already half way up the hill when I hit the bottom and had them passed before we crested the top!!! They didn't think my '95 psd could run with their new Cummins, but they were sadly mistaken!! Started wanting to pull with me to the ropin's after that!!


Well, like I said, I really don't see swapping the turbo making any difference on the rpm's and think my boost thing is coincidentally happening at the same time.

I know my system is tighter than a gnat's a$$ as well because when I changed my torque converter, I pulled the intercooler and had it checked for leaks, put all new DieselSite boots on, cleaned everything thuroughly, and did the CCV mod so my new boots would get all nasty again. Since the turbo is what builds boost and if it's going out or getting weak, then in my mind would result in low boost and low performance.

"IF" I can ever figure out why the rpm changed or the gauge changed, or whatever is beyond me. I'm still searching for a reason, I guess because I'm too dang ****!! Hopefully I'll figure it out. Maybe it was just the dash not reading right and it somehow corrected itself. I just want to know WHY it corrected at 103,000 miles!

 

Mine waited until 170K... you should be grateful