Please help!! 6.5 Td 4l80e issue

[Bigrig594]

Hey guys,
I got my 1993 Chevrolet k2500 Silverado with 6.5l td a couple months back, and it had a bad and leaking transmission (4l80e).

Installed a remanufactured one the day before yesterday and at first when I started it, and put it in drive, the engine would stall.

After that cleared up and the truck run, i had erratic shifting through first and second gear. I could shift it manually and it would work fine. Went to drive it today as b.d it won't come out of 2nd gear no matter what I do. Changed tcm, and both speed sensors and no change.

I did a diagnostic scan a little while ago, and this is what I got...

22,39,59,18,38,58,68,78

DTC 18 - Pump Cam Reference Pulse Error

DTC 22 - Accelerator Pedal Position 1 Circuit Low

DTC 38 - TCC Brake Switch Stuck "OFF"

DTC 39 - TCC Stuck "OFF"

DTC 58 - Transmission Fluid Temp Circuit Low

DTC 59 - Transmission Fluid Temp Circuit High

DTC 68 - Transmission Component Slipping

DTC 78 -Turbo Wastegate Solenoid Fault

Can anyone tell me which of these would cause my issues?

[Bigrig594]

I almost forgot, my speedometer is off. Not by any specific mph, at 35 you're going about 33, and at 85 you're going 75

[JohnC]

Multiple seemingly unrelated codes are often caused by power issues.

First, check all your battery and ground connections. Check the battery leads for corrosion at the connectors under the insulation.

If that doesn't do it, there should be a fuse labeled "instruments". Check the voltage at that fuse. It is fed by a separate set of contacts in the ignition switch and they are problematic. Among other things, it controls the transmission and the speedometer. Also check the voltage on the main circuit coming out of the ignition switch.

Clear all the codes and see which ones come back.

[JohnC]

Wait a minute. Am I getting senile, or should a '93 not have an APP, pump cam or waste gate solenoid? All that stuff came out in 1994. Do you have a mechanical injection pump or an electronic one? Put more basically, does your throttle operate by a cable?

[Robyn]

Yes...
All that electronics on a 93 ?????

Maybe a really early 94 sold as a 93 ?? or the paperwork got messed up.

First thing.

As mentioned....Make sure the power to the main panel is reading 13.5-14.5 V while the engine is running.
Make sure voltage at both batteries is reading the same.
Positive cables
Negative cables
Chassis to engine ground
Body to chassis ground

Clear all those codes and then fire up and see what comes back.

Old codes stored in memory can come out and haunt you.

Very well could be the stored codes are causing a LIMP MODE issue

[ronniejoe]

What's the VIN?

A 93 should have no DTCs associated with engine functions at all.

[Bigrig594]

Ok, after a fun filled day under there hood, I finally traced everything down and got all the codes clear. No more ses light.

It is a mechanical ip. Vin number is 1GCGK24F8PE219191.

It's finally out of limp mode, but I'm still getting a problem in first and second gear, like it's going in and out of gear. I can manually shift it from first on up and it doesn't do it. Also it does the same thing going back into first on the down shift.

They're sending me a new transmission tomorrow, but I'm worried I'll have the same issue.

[Bigrig594]

I'm honestly about ready to put a standard trans in it and call it a day

[JohnC]

Your VIN decodes to a 1993. 1993 should have a mechanical injsction pump, as you say it does. The codes DTC 18 - Pump Cam Reference Pulse Error, DTC 22 - Accelerator Pedal Position 1 Circuit Low, and DTC 78 -Turbo Wastegate Solenoid Fault can only be generated by a 1994 or later PCM. I'm not surprised your trans doesn't work right. You need a '93 TCM (Transmission control module) or, I understand there are aftermarket TCMs available that work, also. Also, if you look into folks that have done mechanical pump conversions on later trucks you might find a workaround, although I recall the solution was a TCM.

[Robyn]

Somebody installed a later control module ?????

Before I swapped out the tranny I would see about scaring up the correct module.

No way can the ECM from a 93 send out the codes pertaining to a 94 or 95 electronic setup...

[Bigrig594]

Just put a new tcm in, same problem with trans. Ses light still isn't on, but it still surges through first and second.

I didn't have these problems with the transmissions I took out.

[DmaxMaverick]

Just put a new tcm in, same problem with trans. Ses light still isn't on, but it still surges through first and second.

I didn't have these problems with the transmissions I took out.

It sounds like you got the wrong or bad transmission. Walk back all the changes you made that either didn't help, or made things worse. You have another transmission on the way, and you won't be able to fix anything until you have the correct or good transmission to work with. These powertrains are generally extremely reliable and trouble-free. Either there is a physical/mechanical or an electronic/communication failure. Start back with your original problem and work forward. While a manual transmission conversion may be desirable for many reasons, this isn't one of them. A conversion will involve many times more headache than getting this right.

[JohnC]

Look at your accelerator pedal. Does it have a round cylindrical gizmo with wires attached? This is the accelerator pedal position sender for a '94 and up electronic pump. If your PCM is generating an APP code then it needs this sensor to get throttle position information. You would also need the mechanical throttle cable from the '93 to operate the mechanical pump.

Does your wastegate have a vacuum actuated wastegate controller? '93 had a "spring in a can. '94 and later have vacuum actuated, computer controlled wastegates. the DTC 78 is generated by this system, which you should not have in the '93.

Until you know where you are, it's hard to plot a course to where you want to be.

[ronniejoe]

I suspect that the "TCM" is actually a "PCM" for a 1994 or 1995 truck...

[JohnC]

Right, with no throttle position input. Not sure how you could expect it to shift the trans properly if it thinks the injection pump and throttle are both FUBAR.

RJ- were you one of the guys who did a writeup on converting to a manual pump?

[ronniejoe]

No. I'm not a fan of those conversions. I think Bobbie Martin wrote that up.

[JohnC]

I think Bobbie Martin wrote that up.

Yes, now that you mention it. That's who I was thinking of.

[Bigrig594]

The accelerator pedal had a cable. No electronics. I do have a tps tho.

I do have a new tcm for this trick tho as of this morning. I'm no longer getting those codes. Now I'm getting 58,59, 81 and 85.

The wastegate doesn't have any vacuum lines or the like going to it. As far as I can tell everything matches up with the year model of the truck aside from the trans.

I think I just got a bad trans, it is a remanufactured one after all. The new one should be here today sometime. I'll install it over the weekend and see what I got from there.

[JohnC]

Those are all trans codes, so you're on the right track. Did you have a PCM from a 94-95 truck in there before? I don't see how that could ever work!

[Bigrig594]

The numbers matched up for the one the parts house looked up. So, I'm assuming it was the right tcm, I may have just looked up the wrong code chart or something. I'm working with a paperclip and Google after all lol.

Just went and got the new transmission, I'll install it Sunday and see what I have after that.

Might my vss on the tcase cause the shift issue and speedo issue? That's the only sensor I haven't changed out yet.

I'm only curious at this point. I'm still gonna put the new one in regardless. There's no telling what may have gotten damaged with all my troubleshooting and what not.

[DmaxMaverick]

....I'm working with a paperclip and Google after all lol.

There was a time, not long ago, we had only the paper clip. Then, along came The Diesel Page....

[ronniejoe]

The numbers matched up for the one the parts house looked up. So, I'm assuming it was the right tcm, I may have just looked up the wrong code chart or something. I'm working with a paperclip and Google after all lol.

The controller chassis part number can be the same for several models and years. However, the programming is different. Did you swap the EPROM from the old controller to the new?

Again, if you are getting engine related codes with your paper clip scanner, you have the wrong program or EPROM.

[Bigrig594]

Yes, I swapped the eprom from the old controller. I'm no longer getting engine codes, just trans codes.

They're all for the internals of the trans from what I could tell. I should have the new one in after this afternoon. So I'll know for sure if it was a build issue.

[Robyn]

The 4L80E is not a one tranny fits all.

There are subtle differences that cause issues.
A sensor that was not replaced could cause issues, as can the pressure regulator.

How old is the TPS on the Injection pump.

A flakey TPS can drive ya nuts and mess up throttle pressure and shift points...

If the TPS is not new REPLACE IT WITH AN AC DELCO

[Bigrig594]

I replaced it with the in and output shaft speed sensors

[Robyn]

What about the TPS on the IP ????

[Bigrig594]

The one I replaced was on the intake... didn't know there was one on my ip

[Bigrig594]

Sorry it was the ip not the intake.

[Robyn]

The TPS fastens to the passenger side of the Injector pump and is coupled to the throttle shaft.
There is a small wire plug that plugs into the TPS.

A faulty TPS will/can cause many issues

[Bigrig594]

Ok, got the new trans in. Still popping through 1st and 2nd gear. Parking brake light comes on now, cruise control no longer works, but I do have all gears now.

Pulled codes 85 trans gear error and 87 transmission gear ratio error.

New parts include input shaft and output shaft speed sensors, tcm, tps, and brake switch.

[Bigrig594]

What is the tps supposed to be set at?

[Bigrig594]

Ok, I have officially replaced every sensor, still having the same issue

[56pan]

My 93 had a similar problem. Turned out to be the ign. switch. Burnt corroded contacts. Not that hard to remove and disassemble and look at. Or you could backprobe the TCM connector C277 at pins C16, wire no. 439, pink/black for battery voltage through the ign. sw. The 2 grounds at that connector are C1, wire no. 450, tan/white and C2, wire no. 551, black/white. At the trans. connector, you should have battery voltage through ign. switch at pin C and pin K. Do_not_remove the connectors and check the voltages/grounds with them disconnected as the circuit will not be loaded and you'll get incorrect readings. I'll try to attach scans of the two connectors from the wiring diagram from my alldatadiy info. Good luck.

[JohnC]

My 93 had a similar problem. Turned out to be the ign. switch.

Refer to post #3. Have you verified the trans and TCM have good power?

[Bigrig594]

Fixed the problem. Turned out to be the connectors and party of the wires for the speed sensors.

[Robyn]

Good deal.
Glad you got it fixed...