4l80e questions

[Burning oil]

I was asking because you can change the shape of the wave with some resistor/s. My brother is the real expert though, he has a scope to look at the wave and he experimented til he made enough change to make the PCM happy. (this was on a cummins swap)
It seems to me you could use a 6.5 timing cover one with CPS. Then machine a new or modify the ring on the crank (having a brain fart now, I think its called a reluctor ring???). A CPS signal might be reconized by the PCM easier??

 

[billyg38120]

Sweet! A trip to Tn, and convincing you to school me could be in my future.:joke: I think I see light at the end of the tunnel for real.

I tried the tech 2, when I was the Mac Tool guy- i took my truck to every gm dealer at the valley auto mall (9 gm dealers) and 6 others in town, along with about a dozen regular shops just trying everyone I could with no luck (its amazing how many techs will help when your the guy with all the chrome they want!) I knew about the p truck thing and also tried as a g van. I took it to the hummer dealer while it was still here, and they already had my vin on file from the p.o. As one of the problem children. They did say a $7500.00 upgrade was available if I was interested in seeing if would help.:yeah: maybe the wrong aldl adapter but even the 2 hd truck shops couldn't get it. Everybody could read just no control. Do you know the adapter id by chance?

If I get the usb adapter I don't follow you on where to go from there.

I spoke to vetronics about it (had to deal with them as a tool guy already) guess how that went.

I really wish i knew trans better- It gets over my head too quick and I just don't have the patience for it. All hummers are automatics, but I sure thought about altering that when I was in limp mode over bad tiss & toss that went out at the same time.

Will,
The Tech-1 WILL communicate with your TRUCK. It has to have a 12 PIN ALDL under the dash. (That is where we @ GM Proving GRounds always found them with the H1 military and commercial hummers. By the steering column. If I remember right I saw a few inside the water tight TCM box which was under the drivers rear seat. If you can't find it, it's easy to make on work. From the TCM pins you need a Ground, the Pin B, and Pin L or M which is the communication wire. Pin b is the ALDL wire you ground to ALDL Pin A and flash thte codes. (You can elect to NOT use this as I have). The TECH-! End has letters so you can connect it to them. ALDL Pin M or L connects to B-10 and the Ground can be found on TCM pin C-1, C-2 or C-3. The Pin B to flash the codes is TCM Pin A-8.

The Tech-2 cable END is interchangeable. The 1996-present is a 16 PIN DCL Oor DLC they term it. The TEch-2 KIT has the 12 PIN ALDL and comes off easy. I've used this for many years when I looked ot Hummers @ work that didn't have Instrumentation to display data. There is a G-Van with the TCM but the Engine select as Diesel is the easiy way I used and what I remember from 5 yrs ago.

The USB is this. http://www.moates.net/aldu1-and-cabl1-p-127.html?cPath=64
Moates.net has a calbe that connects to your LAPTOP USB port and the other end connects to your 12 PIN ALDL. You use a program called Tuner Pro with the correct files to view Data and you can recalibrate the PROM or chip. BUT you HAVE to have a few more items to calibrate it. The Tuner Pro program, the ADLD from Mr Moates, and files. You need to be able to burn PROMS which Moates has @ 328 or less. I use this one at 328 each.
But to VIEW your DATA you need the TP program and the ALDL cable and a few files I have.

 

[billyg38120]

I was asking because you can change the shape of the wave with some resistor/s. My brother is the real expert though, he has a scope to look at the wave and he experimented til he made enough change to make the PCM happy. (this was on a cummins swap)
It seems to me you could use a 6.5 timing cover one with CPS. Then machine a new or modify the ring on the crank (having a brain fart now, I think its called a reluctor ring???). A CPS signal might be reconized by the PCM easier??

BURNING OIL,

The TCM can understand either a sign or square wave. The Square wave that works well is an old Ignition module. I used the TCM at first with a carb on my 77 crew cab. I tapped off the Pick up coil (It ran the HEI and my extra HEI MODULE). The EXTRA module was from a aprox 1990 GM pick-up or Camaro. (I wanted all parts to be able to be purchased at any parts store if It failed) It was a 7 pin module. The module was powered up with the sealed 2 pin, and the pick up coil was connected and protected. The other 4 pin connector has ports for Ign By-pass, Electronic Spark Timing, REFERENCE PULSE and a Reference pulse low or ground plane.. It was mounted to a alum plate with silicone grease for heat. I used only the REFERENCE PULSE AND REF LOW/GRD to hook up to the Engine Speed port on the TCM Pin D-6. It DID require a calibration change. The old TCM interpreted the pulses as TWICE the RPM so I had to double the pulses to 8 instead of 4. Works really well. When I switched to EFI with a 89 MAF box I still had the same connections but was able to just use the REF pulse from the ECM/HEI.
The TCM understands sigh and square. I do not know the voltage limits.

 

[Burning oil]

BURNING OIL,

The TCM can understand either a sign or square wave. The Square wave that works well is an old Ignition module. I used the TCM at first with a carb on my 77 crew cab. I tapped off the Pick up coil (It ran the HEI and my extra HEI MODULE). The EXTRA module was from a aprox 1990 GM pick-up or Camaro. (I wanted all parts to be able to be purchased at any parts store if It failed) It was a 7 pin module. The module was powered up with the sealed 2 pin, and the pick up coil was connected and protected. The other 4 pin connector has ports for Ign By-pass, Electronic Spark Timing, REFERENCE PULSE and a Reference pulse low or ground plane.. It was mounted to a alum plate with silicone grease for heat. I used only the REFERENCE PULSE AND REF LOW/GRD to hook up to the Engine Speed port on the TCM Pin D-6. It DID require a calibration change. The old TCM interpreted the pulses as TWICE the RPM so I had to double the pulses to 8 instead of 4. Works really well. When I switched to EFI with a 89 MAF box I still had the same connections but was able to just use the REF pulse from the ECM/HEI.
The TCM understands sigh and square. I do not know the voltage limits.

We tried both the Cummins crank sensor and a speed sensor from a 4L80E trans, neither would let the TCM do its job until the sensors signal to TCM was modified. Maybe both had the same wave pattern (dont remember) and we just needed to try the other type (at time did not know there were two). We went with the 4L80E sensor.
So, Will maybe you just need different sensor?

 

[billyg38120]

We tried both the Cummins crank sensor and a speed sensor from a 4L80E trans, neither would let the TCM do its job until the sensors signal to TCM was modified. Maybe both had the same wave pattern (dont remember) and we just needed to try the other type (at time did not know there were two). We went with the 4L80E sensor.
So, Will maybe you just need different sensor?

The TCM Eng Spd will function with a ISS/OSS for Engine RPM input to the right pin on the TCM. You may have to change the calibration to correct for the engine speed. (Yes you can make up a wheel or sloted wheel and place an ISS or an OSS close and it will serve as your ENgine Spd sensor. Two slots on the crak will work well. Or you can have 4 if you like. Only this spd will function for the Engine RPM on the TCM. (I hope this is clearer than the muddy water round here)

Back in 96 I took a Tech-1 and temporally powered up and connected sensors to a TCM with a prom installed.

I used a Engine Pick-up coil plugged into the wall socket (110v A/c) that was TAPED to another pick-up coil that was connected to a Ignition module from aprox 1990 4.3, 5.0, 5.7, 7.4L truck engine. (ead of the Pick-up coil plugged into 110v you can use a Weller trigger soldering gun held close to the sensor/Pick-up. It inducted the signal into these sensors ISS/OSS to test and see what Tech-1 would output. These ISS, OSS, and Engine Spd ALL read correctly with the pick-up coil plugged into the wall and the soldering gun. I did the math (pulses per rev for each sensor 31 for the ISS 40 for OSS and 4 for Eng Spd) and all read correctly. I was verifying other items as well but they worked.
I then tried the Ignition module with a pick-up coil taped to another that was plugged into the wall. I powered the module up to 12 v and grd. I used the Reference Pulse out and ref low or grd plane and fed it into the TCM for Engine Speed. It read double engine speed. (The TCM interrupts each drop or rise as a pulse.) I cut the calibration and it read correct RPM for the 110v 60hz signal I was inducing into the module pick-up coil.

(A trick I use to do for hard to start or Intermittent stall or stall no start was to get a Weller soldering gun close to the ignition pick-up coil (HEI or DIS) and test it. UNPLUG THE INJECTORS AND PLUG IN A NOID LITE. IT WILL FLOOD THE ENGINE and LOCK IT UP. I used Delco ST-125 Spark tester on the Secondary COIL WIRE. (On DIS I used a ST-125 on each plug wire)

THEN pull the trigger on the soldering gun and it will set the system off. I then would slowly move each connector or wire and watch/Listen for cut outs on the coil or injectors. TBI and Port Fuel work well for this test. IT was a trick I used when I worked on GM Buy-back vehicles in the late 80's. I didn't like walking in the MI 20 below winter. I did walk a few times before that.

Hope this will help all to improve things.

 

[Will L.]

I was looking for a different transmission thread I ran across this one, thought I should "bookend" it.

I still have not bought anything for communication with computer yet that's worked, but found the trans problem when doing a filter drop on it.

I pinched a inside wire with the trans pan. I moved it out of the way this time and a little experimental oil proof sealant on the pinched wire then crossed my fingers. So far 5,000 miles and no crazy shifts, no 2nd gear limp. The sealant is not available on the market so if you find this is a problem you have, swap the harness. Hope this helps someone in the future...

 

[Will L.]

The reason I looked up this thread today was to add info i just learned of from a guy on a different forum.

2 wire crankshaft sensor available!
Part # 5714531
Or NSN # 01-455-8424

Credit due: DaveH aka nant2

 

[Emmett]

Hi BillyG38120

Hi there. I see i where you offered up help to a guy with programming his pre-1994 GM transmission controller. Are you willing/interested in helping me with a similar problem? I'm happy to pay you for it.

I have a 1991 V30 that I recently put a Duramax 2006 into. I'd like to continue to use the stock GM transmission controller but have no idea where to start. I can easily tap the ESS signal from the Duramax and the APPS (accelerator pedal position sensor) is effectively the TPS, just located down at the pedal, and of course, the VSS is already in place. I have no idea how to burn a new chip and until I read your post, I was just going to buy a standalone transmission controller.

So, if you're interested I'd make it worth your while.

thanks

 

[THEFERMANATOR]

If you have a 2006 duramax, repin the harness, swap in a t42 tcm, and set it up that way. Tapping into the lbz 2 sided apps is a BAD idea. You would need to get your tps info via class 2 data bus or high speed GM lan to get an accurate signal. Trying to integrate the old controller to the newer engine would be a nightmare.

 

[Emmett]

Thank you.

After reading several posts between you and BillyG38120, it sounds like a standalone controller like US Shift is damn near impossible for my trans, correct? Because all the current controllers require a Holley force motor, does this mean I need to swap out the entire valve body with a newer 94+ valve body to make it work? BillyG sure seems to think that swapping a Holley force motor into my 91-93 valve body is a bad idea. Would you agree? (BTW, I've tried to read out to BillyG)

thanks for the help. Your swap was my inspiration to do this swap. Almost there...jus need to iron out the trans.

also, I idon'thave the complete lbz harness...its a modified standalone harness. Or can I still swap in a T42?

 

[Emmett]

If you have a 2006 duramax, repin the harness, swap in a t42 tcm, and set it up that way. Tapping into the lbz 2 sided apps is a BAD idea. You would need to get your tps info via class 2 data bus or high speed GM lan to get an accurate signal. Trying to integrate the old controller to the newer engine would be a nightmare.

So what about using the LBZ apps signal with a modern standalone controller? The install instructions on US Shift and Compu shift both say to tap into the apps signal. Do you agree that would work? Isn't the apps just a potentiometer with 0-5V signal?

 

[Will L.]

I don't think Billy G has been around for over a year.

 

[THEFERMANATOR]

I prefer tapping into the class 2 data bus or the high speed lan as it is a corrected throttle amount. Yopu can tap into the APPS, but do NOT use the factory cruise control if you do. It would show 0% throttle as the apps would be idling while the ECM would be fueling. For an LBZ I would use stock controllers since the E35A BOSCH ECM can talk just fine to the T42 GM TCM. As to the PCS, replacement force motors are now the 94+ style from most suppliers. You can swap to the newer force motor, swap in a newer internal harness, and plug the line pressure damper circuit, and you would essentially have a 94 trans(but if it's a 4X4, you would have both an input and an output speed sensor in the trans). For a stand alone controller with the BOSCH ECM, I would REALLY stick with a controller capable of reading high speed LAN. Also keep in mind without defuel, a 4L80E will NOT last for long behind an LBZ. Even with defuel and the 4L85E they weren't known to hold up to much more than stock power output with many tearing them up running stock power.

 

[Emmett]

Okay, that sounds reasonable. I've studied the diagrams and I'm not confident I have identified just exactly how the ECM and TCM communicate? Is it simply via two wires (GMLAN + and GMLAN -)?

I've looked around for a van harness to no avail...

 

[THEFERMANATOR]

Yes, the bosch ecm and the t42 tcm would be linked via the high speed GM lan(can bus), the same wires the ecm and glow plug controller currently are linked with. You have to flash in a van operating system to make it talk to the t42 tcm, but to me it's so much better to have defuel on shifts as well as to allow the tcm to control peak torque in each gear. You could also use a pcs trans controller as they can work with GM lan, and I believe the megasquirt Jr also works with GM lan and is a fairly low cost trans controller(since it gets most all of it's data via can bus, it requires minimal inputs to operate). Theres stand alone options out there for the 4l80e, but I would strongly reccomend spending some money on a 4l80e before you go throwing even the detuned van power levels at one. You'll also find many who have stuck with there 4l80e regret it, and wished they would have gone with an allison.

 

[Emmett]

So I have a ECM from a 2006 Silverado HD but haven't located a T42 yet. Do I need to hunt down a T42 from a van, or can I simply buy a new, unflashed T42 and flash it using EFI Live or can I get away with a used T42? My overall plan is to put the stock van tune on the ECM and then put the stock trans tune on the T42. Is that all feasible using EFI Live? FYI...I do not possess any existing van tunes...do they exist in a EFI Live repository?

All the local GM dealers around here require that the T42 be installed in the vehicle for them to flash it. I really want to avoid this...

 

[THEFERMANATOR]

Theres some van files over at mcrats site. As to the t42 tcm, it can be flashed with a V2, but there was rumors of new blank ones not taking flashes until flashed by GM. I just seen a van engine for sale on facebook earlier today. Your truck ecm will work, but you'll need the van harness or repin the ecm plugs as GM made some pinout changes so a truck ecm couldn't go in a van and vice versa(the ecm's are the same, it's just the tune that's different). You may also want to check with Russ at rpm motorsports as he sometimes has some extra harness's laying around.

 

[Emmett]

I think I have a dilemna...

Again, my trans is a 1991 and was rebuilt 12 months ago by a reputable local shop. I'm assuming they didn't swap valve bodies, but do you think they most likely updated the force motor, harness, and plugged the line pressure damper circuit? I ask because I wonder if a T42 will correctly control a 1991-1993 4l80. Or will a T42 control it if all those updates were performed? The current stock TCM work fine, BTW.

 

[THEFERMANATOR]

The mods are only done if you use an early trans in a later truck. You don't have to plug the damper circuit, it will just lag behind in line pressure changes like they did stock. You can use a later controller, you just have to use the correct internal harness. If your 91 trans is a 4x4, then they're worth a little money as 91-93 4x4's are unique.

 

[Emmett]

The mods are only done if you use an early trans in a later truck. You don't have to plug the damper circuit, it will just lag behind in line pressure changes like they did stock. You can use a later controller, you just have to use the correct internal harness. If your 91 trans is a 4x4, then they're worth a little money as 91-93 4x4's are unique.

First, thanks for all the help.

So to be clear, to make my 1991 rebuilt 4L80e (has updated internal harness but old Bosch force motor) operate correctly with a T42, I most likely need to swap to the newer force motor, correct?