Dies in gear when throttle applied

[1990Z71Swede]

The TPS & CTS ECU grounds (5v return) are tied together, could a sh1tty ground at the ECU pin be the cause of all this?

I have issues with both sensors.

Thats very likely, what happens if you unplugg BOTH sensors?
I would not be at all surprised if the CTS Voltage comes back up to 5V.

If so, it means that you have high resistance somewhere in the Return B circuit, downstream from wherever the TPS and CTS is joined together. The ECU connector or the splice is where I would look first. (Maybe the splice is right at the connector? IDK)

Edit: Don't get your hopes up to much though. There is a good chance that there is more to this, (and from what you write it seems that you are somewhat aware of this already) and as @Schurkey said a scanner is the fastest way forward.

 

[92GMCK2500]

Wiring, fun times.

It's scanner day.

Not sure how successful my old scanner will be. Can anyone recommend a goyod ALDL cable? Preferably i would amazon prime this to my doorstep if my scanner is no good.

Tunerpro is the software you say? Maybe @PlayingWithTBI can chime in?

 

[someotherguy]

Did I miss at some point confirming the grounds are good at and near the thermostat housing? (as well as braided strap from rear of passenger side head to firewall, then firewall to frame)

Richard

 

[92GMCK2500]

@someotherguy
Grounds are.good and clean. The CTS and ECU currently share a ground point, at the front of intake manifold on a dedicated bolt behind the belt tensioner.

I see the FSM shows the ECU ground on the thermostat stud. I can move it to there for what it's worth.

 

[1990Z71Swede]

The CTS and ECU currently share a ground point, at the front of intake manifold on a dedicated bolt behind the belt tensioner...

If I interpret the wiring diagram correct, that is not how GM intended the CTS return to be routed.

 

[PlayingWithTBI]

Tunerpro is the software you say? Maybe @PlayingWithTBI can chime in?

Here's the 12 pin one I use.
www.aldlcable.com/

OBD Diagnostics

aldlcable.com

Yes, TunerPro RT the straight TunerPro doesn't allow for data logging.
www.tunerpro.net/downloadApp.htm

TunerPro and TunerPro RT - Professional Automobile Tuning Software

 

[PlayingWithTBI]

What Service Number is your ECM?

 

[92GMCK2500]

Thanks for the links.

Not sure on the service number, guessing this will be on the ECM? I will be digging in there over the weekend, can report back.

 

[PlayingWithTBI]

Not sure on the service number, guessing this will be on the ECM?

Yep, here's a 1227747 ECM with the cover plate removed and a ZIF (Zero Insertion Force) socket soldered in so I can flash the SST 27SF512 EEPROM. In this case, the original BCC (Binary Coded Chip) was ANLW. You may wanna record that too for future reference.

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FYI: your ECM is sitting on a shelf behind the glove box. You may have to pull it out to see the labels. It's held in place with spring clips. Just slide it to your left, disconnect the 2 wire connectors, and pull it out. HTH

 

[92GMCK2500]

Great info, thanks.