Lack of power

Tiny
MANZOLARRY24
  • MEMBER
  • 1994 CHEVROLET 1500
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
I’ve put a 1993 4l80e transmission in it that runs on toggle switches to bypass the computer for the shifting of the transmission. But my question is, does the transmission shift speeds have anything to do with the spark advance? Because I can’t get any power out of the engine. I’ve replaced the distributor cap, rotor, plugs wires, and set timing to the book, but the engine still bogs down on acceleration. But it runs fine at idle. Fuel pressure is at 9-13 pounds, compression is 120 psi on all cylinders.
Wednesday, May 22nd, 2019 AT 10:08 AM

16 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

Yes, it does. Are you sure the torque converter is not locked up causing low power?

Fuel pressure is good. Are you sure the catalytic converter is not clogged?

Roy
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Wednesday, May 22nd, 2019 AT 1:14 PM
Tiny
MANZOLARRY24
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Car not clogged torque is also ran on a toggle switch. It’s showing a lean code but smells like its way too rich. I can rev the engine up while in park but as soon as you put it in gear and give it gas it is sluggish and if you let off when at full throttle just a little it revs up a little bit. Sometimes you can feather the throttle and it picks up some speed, but forget about going up hill with any power. Have also put new TPS and IAC in truck.
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Wednesday, May 22nd, 2019 AT 4:53 PM
Tiny
MANZOLARRY24
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Also the ECM is the one with the 2 32 pin connectors red and blue. I’ve got the switches wired to ground the solenoids and use only one positive wire to the solenoids. So when I flip the switch on it grounds the solenoid A grounded solenoid B not is 1 gear solenoid A not solenoid B not is 2 gear solenoid A not solenoid B grounded 3 gear solenoid A grounded solenoid B grounded 4 gear. The TCC solenoid grounded is OD that’s all with the gear selector in the OD position or I can put solenoids in 4 gear and shift with gear shifter. But it won’t go into 1 gear so it starts in 2 gear.
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Wednesday, May 22nd, 2019 AT 5:13 PM
Tiny
ASEMASTER6371
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Your transmission is causing the issue. You need to put it back to having the ECM control it.

Roy
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Wednesday, May 22nd, 2019 AT 5:26 PM
Tiny
ASEMASTER6371
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Did you respond? I got a notice you responded but nothing came up.

Roy
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Thursday, May 23rd, 2019 AT 2:50 AM
Tiny
MANZOLARRY24
  • MEMBER
  • 28 POSTS
Yes I did. I will try to resend.
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Thursday, May 23rd, 2019 AT 11:53 AM
Tiny
ASEMASTER6371
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Okay.
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Thursday, May 23rd, 2019 AT 12:00 PM
Tiny
MANZOLARRY24
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  • 28 POSTS
Car not clogged torque is also ran on a toggle switch. It is showing a lean code but smells like its way too rich. I can rev the engine up while in park but as soon as you put it in gear and give it gas it is sluggish and if you let off when at full throttle just a little it revs up a little bit. Sometimes you can feather the throttle and it picks up some speed, but forget about going up hill with any power. Have also put new TPS and IAC in truck.
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Thursday, May 23rd, 2019 AT 12:04 PM
Tiny
MANZOLARRY24
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Also the ECM is the one with the two 32 pin connectors red and blue. I have got the switches wired to ground the solenoids and use only one positive wire to the solenoids. So when I flip the switch on it grounds the solenoid A grounded solenoid B not is 1 gear solenoid A not solenoid B not is 2 gear solenoid A not solenoid B grounded 3 gear solenoid A grounded solenoid B grounded 4 gear. The TCC solenoid grounded is OD that s all with the gear selector in the OD position or I can put solenoids in 4 gear and shift with gear shifter. But it won t go into 1 gear so it starts in 2 gear.
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Thursday, May 23rd, 2019 AT 12:05 PM
Tiny
ASEMASTER6371
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Got it.

The transmission is the issue. You may not be in first gear when you pull out. The torque converter can still be locked in as well.

Again, you need to repair the harness to work with the ECM and let the ECM control the shifting.

Roy
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Thursday, May 23rd, 2019 AT 12:13 PM
Tiny
MANZOLARRY24
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Could a bad ECT effect the timing and with not having a 3-2 shift solenoid? I am still running the ECM off of the 4l60e and it has not been re-flashed, but I do have the calpac and prom from the suburban the 4l80e came out of could that make a difference on how the engine would run. I’ve put it in a couple of times before but didn’t mess with the timing while it was in. Thank you for the help you guys here are great help when needed.
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Thursday, May 23rd, 2019 AT 10:57 PM
Tiny
ASEMASTER6371
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No, it will not affect it at all.

You need to put all the wiring back together and let the engine control the transmission as it should.

Roy
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Friday, May 24th, 2019 AT 5:14 AM
Tiny
MANZOLARRY24
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Put the wiring back and now transmission is stuck in limp mode no shifting what so ever. Can’t even shift with selector and doesn’t run any better acts like it’s flooding out. Will the ECM from a 4l60e control a 4l80e? With the added VSS and the 3-2 shift disconnected.
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Friday, May 24th, 2019 AT 7:21 PM
Tiny
ASEMASTER6371
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No, it will not. You need the correct ECM with the prom for the 4L80.

Added VSS?

Roy
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Saturday, May 25th, 2019 AT 4:18 AM
Tiny
MANZOLARRY24
  • MEMBER
  • 28 POSTS
The 4l60e only runs the VSS off the transfer case tail shaft where the 4l80e runs 2 VSS one one the tranny case and one on the transfer case. I got some power out of the engine by advancing the timing to about 8 degrees at idle with the tan and black wire disconnected and when connected its about 28 degrees it now picks up speed faster and doesn’t bog down as bad going up hill but still have to drop to second gear to make it up the hill but I’m talking like steep 1/2 mile plus stretches up hill and it will run 80 plus on the hi way. Thanks for the help I will look for another ECM that was connected to a 4l80e with a 350 engine I just don’t want to have to change the connectors to the ECM or the wiring harness I think I’ve spliced wires enough
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Sunday, May 26th, 2019 AT 1:25 PM
Tiny
ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
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Sunday, May 26th, 2019 AT 2:31 PM

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