Vortec 454/4L80e HD swapped 1999 Tahoe OBS

[Sam Harris]

What's up with your second ride?

I’ve been chasing a misfire for a while. It started very slight, and I started replacing ignition and fuel components, since they all had over 200k on them and were cheap (Honda civic). Replaced coil, cap rotor, plugs, wires, fuel filter, now fuel pump. It’s funny, seemed to be fixed and then before I did the fuel pump, it finally threw the codes for misfire on 2 cylinders, as well as random. So replaced the pump, but it’s still there. Slight again, and only after it’s warmed up. Going to take in for a compression and leak down I guess next. Also the trans is noisy as hell (manual), so it’s going to let go at some point. [emoji107][emoji3525]

 

[bigfootchiro]

I’ve been chasing a misfire for a while. It started very slight, and I started replacing ignition and fuel components, since they all had over 200k on them and were cheap (Honda civic). Replaced coil, cap rotor, plugs, wires, fuel filter, now fuel pump. It’s funny, seemed to be fixed and then before I did the fuel pump, it finally threw the codes for misfire on 2 cylinders, as well as random. So replaced the pump, but it’s still there. Slight again, and only after it’s warmed up. Going to take in for a compression and leak down I guess next. Also the trans is noisy as hell (manual), so it’s going to let go at some point. [emoji107][emoji3525]

I did the same when I noticed the smallest misfire on Cylinder 4. Replaced everything else, only to find that one of the valve seats in the head was cracked. Did a top end rebuild, engine started knocking after a while, and now here are with a 454, billet 4L80e, and 0411PCM swap lol

 

[bigfootchiro]

https://cpt4l60e.com/4l60e-neutral-safety-switch-diagram/

Can someone help explain where the 4 pin NSS wires run to? Looks like they run directly to the PCM. In my 0411PCM swap, I had to run 4 wires from the PCM and tap into the 4 wires at the NSS plug; however I'm tracing a short in one or more of the wires. Can I run them straight from the plug to the PCM and not tap them, or do those wires run up the harness to somewhere like the TPS?

 

[bigfootchiro]

I also pulled up this wiring diagram. Fuse 20 is the one blowing. 2 pink wires (which I have confirmed from looking at back of fuse box), one going to instrument cluster and other going to TCC solenoid? TCC solenoid through what? Am I reading that correctly?

 

[bigfootchiro]

Looks like it might be going to the 7 Pin connector at the transmission. Can anyone confirm that?

 

[randeez]

Looks like it might be going to the 7 Pin connector at the transmission. Can anyone confirm that?

whats going on man?

that fuse 20, looks like it prob goes to the large round connector the E, T, S, B....etc is the position in the connector im guessing? if you drop the pan it should be easy enough to identify it looping to each solenoid.

 

[bigfootchiro]

whats going on man?

that fuse 20, looks like it prob goes to the large round connector the E, T, S, B....etc is the position in the connector im guessing? if you drop the pan it should be easy enough to identify it looping to each solenoid.

Fuse 20 keeps blowing every time it's put into gear, so transmission goes into limp mode. I'm thinking there is a short in that pink wire. The transmission guy said they ohmed out all of the solenoids and they were good.

 

[randeez]

if there was a short in the wire then it would blow as soon as you put the fuse in. looking at the above it energizes 12v to that side of the solenoid always at all times.

you repin'd the 4l60 connector to work with the 4l80?

 

[bigfootchiro]

if there was a short in the wire then it would blow as soon as you put the fuse in. looking at the above it energizes 12v to that side of the solenoid always at all times.

you repin'd the 4l60 connector to work with the 4l80?

Yeah, I had it re-pinned to work with the 4l80e. The brown and white wires (which aren't used on the 4l80e) are just hanging out.

 

[randeez]

Yeah, I had it re-pinned to work with the 4l80e. The brown and white wires (which aren't used on the 4l80e) are just hanging out.

https://sites.google.com/site/sloppywiki/everything-ls/4l80e-info


never done it, but seems pretty straight forward. i would recheck the wiring tbh