View Full Version : Help... no shifts
Hello All,
I have just joined the diesel page to help me find out about my 95 K3500 dually. I found a artical in there saying it will help me in shifting problems for the 4L80E trans when switching to MFI pump. This is what I have:
95 K3500 Crew Dually, 4L80E, 4X4 - Purchased with no engine, previous owner blew up 6.5L turbo engine and removed engine and sold truck.
93 C3500 w/ 6.5L turbo engine, MFI.
I took the 6.5L MFI turbo engine out of my 93 and put it in the 95 K3500. The only wiring I could hook up was the glow plugs, ECT sensor, sensor ground wires, power to fuel shut-off solenoid. This is all i could hook up under the hood. I left the TP module under the dash hooked up with the pedal on it. So the computer would still see a TP signal. I hooked up the mechanical throttle linkage and new pedal to the mechanical pump. The MFI 93 6.5L engine starts up and runs great!!! no problems there. BUT the truck will not shift most of the time now, if I rev out the truck every once and a while it will upshift VERY hard. What imput am I missing??? I figured it is somthing dumb. please help me out as I have racked my brain for some time now tring to figure this out.
I will also add that the 4L80E shifted great before the prevoius owner pulled the engine. all wiring is plugged in on the trans and the T/Case. While I am driving the speedo works aswell. jumping the ALDL pins i get a code 13 and 62, both irrelevant to the no shiftting thing... PLEASE HELP ME!!! any info would be great. thanks for your time!
How did you hook up the throttle?
The pps unit is designed with 3 TPS setups in it. All three have to agree within a certain percentage or the ECM has a fit.
Actually you can set this up to use a smaller TPS unit that mounts on the IP to feed the ecm the signal.
There are some folks here that have done this swap and made it work ok.
Do some digging in the archives and I believe there is an article on this very subject.
The ecm must see a variable signal from the PPS to control throttle pressure (Tranny oil pressure) and shift points.
You may have to fuss with it to get things to work smooth enough to be satisfactory.
Best
Robyn
xtrempickup
02-06-2008, 20:31
Like Robyn says or you may choose to run a controller and lap top to be able to work the 4l80E like ppl are doing in some different vehicles that were not electronically controlled transmissions.
How did you hook up the throttle?
The pps unit is designed with 3 TPS setups in it. All three have to agree within a certain percentage or the ECM has a fit.
Actually you can set this up to use a smaller TPS unit that mounts on the IP to feed the ecm the signal.
There are some folks here that have done this swap and made it work ok.
Do some digging in the archives and I believe there is an article on this very subject.
The ecm must see a variable signal from the PPS to control throttle pressure (Tranny oil pressure) and shift points.
You may have to fuss with it to get things to work smooth enough to be satisfactory.
Best
Robyn
The PPS is plugged in and sitting on the center hump on the floor, I actually have the TPS mounted on the pump and adjusted to show the correct voltage signal for TPS sig #1 that the PPS gives. I ran the three wires in the cab and just havent hooked them up yet to the TPS #1 circuit on the PPS. I figured the truck should shift with just the PPS plugged in like factory. Your saying to hook up the TPS i have on the IP to show TP position and override TPS#1 on the PPS, and it should shift???
Thanks I will try hooking it up.
Also I have searched in the archives and the articles that should help me arnet posted anymore and it says I have to purchase the book. I thought paying the 20 bucks would get me access to all the articles? anyone have some more info on this??
More Power
02-06-2008, 23:28
It was thought at one time (about 8-10 years ago) that just one of the three APP (Accelerator Pedal Position) signals might allow the trans to shift correctly, but it doesn't.
Only a couple of people have been moderately successful when using hybrid APP/MFI cable accelerators, but it is not an ideal way to go if you read about their difficulty in getting the hybrid system to function and shift the trans normally.
In terms of conversion ease and transmission shift quality, an aftermarket Trans Control Module (TCM) & wiring kit is the recommended way to go - though it raises the cost about $800.
Jim
Doesn't the PCM need an engine speed input? Seems to me that most of this was covered in the mechanical pump on an EFI engine articles, but I'm guessing you cut a few corners going to an MFI engine.
If you used the 4911 IP off the '93 you need to search around about converting a '94-later to a mechanical IP - which is pretty much what you did with the 4911. It's been done, but it's not just a bolt in thing. The ECM MUST see a TPS signal, or you'll be saying goodbye to the tranny in very short order. Good luck.
Don
Ok, so it was worth a try hooking up a TPS on the pump. I will see what happens, but still any way I can find the tech artical for the MFI pump conversion??? I think that would help me alittle. I didnt want to purchase a standalone computer right now if at all possible. If it isnt avalible on the diesel page.com then where do I look. The big reason I paid to be a member was to get the info and i cant find it. any help would be great,
Chad
how about this, can i take the computer out of the 93 c3500 I have and plug it into the K3500? The ECU would then match the engine, the only problem would be the 93 computer is for a manual trans, not a auto trans, will it work? Will it plug in? Are the pin-outs the same for the basic sensors I have pluged in, ECT, Oil pressure switch, etc??
road test 95 K3500 with tech 1. with app plugged in. truck keeps setting code 24, vss circuit low voltage. tech 1 shows a very irratic signal, jumping all around, truck bangs into second and stays there. where should i start? i think this is the only reason the truck is not shifting. only transmission related code. wiring to t/case vss looks ok, and is plugged in. where should i start? anyone else run into this code? is it common? thanks for your time, i dont mean to be difficult, just frustrated with truck for right now. keep on replying to my thread!!:)
A '93 with a manual trans didn't have an ECU.
More Power
02-08-2008, 10:58
The following articles are currently online and are available to subscribers, and which discuss specific aspects of an EFI/MFI conversion.
http://www.thedieselpage.com/members/features/1996MFI.htm
http://www.thedieselpage.com/members/features/tps.htm
http://www.thedieselpage.com/members/features/cruise.htm
Some of the articles we've produced in the past dealt with creating a hybrid APP/MFI pedal assembly. This was in the EFI/MFI discovery phase of the learning curve, and we made this info available over time as a way of furthering the learning curve. We now know (or at least I do) that a hybrid pedal is not the best solution - a separate TCM is (either aftermarket or possibly a retrofit GM).
Retrofitting a 1991-93 GM TCM and harness is the least costly, but it is quite a bit more tedious because you're using a TCM & harness that was stripped out of a salvage vehicle. Getting the wiring connected is the tedious part. An aftermarket TCM and harness kit is way easier, because it comes with instructions and the hook-up is straightforward (i.e. much simpler).
As far as bolting on the MFI components, it's easy... It's all covered in the 6.2/6.5 Diesel Troubleshooting & Repair Guide and in many-many posts here in this forum. If you're not equipped to install the DB2-4911 fuel injection pump, injector fuel lines and throttle cable/brackets, you probably shouldn't consider a conversion - this is the easy part. :)
Jim
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