1994 C1500 Ext cab swapped Carbureted SBC 350 questions

[GMT400Frank]

I recently purchased a 1994 c1500 ext cab and the previous owner swapped the stock 350 with a carbureted 350 from another truck.

Most of the wiring from the main loom on the passengers side of the block is unconnected but the truck is running pretty good (no strange shifting).

The tach, the speedo, the engine temp and battery voltage gauges are working as they should.

The TPS sensor is not hooked up to the carburetor and I was informed that it should be hooked up in order for the 4L60e to not go into limp mode.

Any suggestions on how to hook up the sensor to the carburetor ?

The carburetor is an edelbrock 1406 and the vehicle has an aftermarket fuel pump that is hard wired separately.

Thanks in advanced for the help!

Pictures of unhooked connectors:

 

[DerekTheGreat]

Oh fawk yeah! Ecklebrock carpitator on top lettin' all 'da extra bald eagles fly for freedom!!

The factory sensor is not compatible with that 1950's technology. My understanding from what I've read on here is that you will need a standalone controller for your 4L60E. That or make even more eagles fly by swapping in a THM350 trans, or better yet, a 400, because who needs overdrive? /s

If it was my truck, I'd figure out if it's another TBI engine (appears to have centerbolt rocker covers), verify it's actually a 350 and then put all the factory TBI stuff back in place to enjoy all the benefits and simplicity of early EFI.

 

[Jerryred94silvy]

I have this same swap done on my truck and I used a kit from US Shift. It hasn’t given me any issues and was super easy to install.

Throttle Position Sensor Kits

A throttle position sensor is needed to use a US Shift transmission controller, like the Quick 4, on a vehicle with a carburetor.

www.usshift.com

 

[GMT400Frank]

I have this same swap done on my truck and I used a kit from US Shift. It hasn’t given me any issues and was super easy to install.

Throttle Position Sensor Kits

A throttle position sensor is needed to use a US Shift transmission controller, like the Quick 4, on a vehicle with a carburetor.

www.usshift.com

Are you still using the factory computer?

 

[Jerryred94silvy]

Are you still using the factory computer?

Yes. My harness is just folded to the side aside from sensors for the gauges. All I did was wire the TPS in and drive it.

 

[GMT400Frank]

Yes. My harness is just folded to the side aside from sensors for the gauges. All I did was wire the TPS in and drive it.

Okay sweet, thank you for your insight. I will be buying that sensor kit and trying to do the same. I would rather not have to opt in to buying an entire new computer but instead just use the factory computer and tie in the TPS.

 

[GMT400Frank]

Yes. My harness is just folded to the side aside from sensors for the gauges. All I did was wire the TPS in and drive it.

So i purchase the tps kit from USShift and wired it in and still no go. Trans is still stuck in 3rd gear and cannot figure out where to go from here in order to get the transmission shifting again.

 

[Jerryred94silvy]

So i purchase the tps kit from USShift and wired it in and still no go. Trans is still stuck in 3rd gear and cannot figure out where to go from here in order to get the transmission shifting again.

That’s interesting. Does the computer have a tach signal from the distributor? It’s a purple/white wire that will need to go to the “tach” port on the distributor. From what I remember, all the tranny needs is the tach and TPS signals to operate properly. Are you sure the transmission isn’t goofed up at all?

 

[GMT400Frank]

That’s interesting. Does the computer have a tach signal from the distributor? It’s a purple/white wire that will need to go to the “tach” port on the distributor. From what I remember, all the tranny needs is the tach and TPS signals to operate properly. Are you sure the transmission isn’t goofed up at all?

Thanks for the reply!

Yes, the computer has tach signal and tach is functioning properly. I can manually shift the trans into 1st but when in Drive it is only in what i presume is 3rd gear. I am not certain the trans is the issue but from what ive been told it is a reman with around 80k miles on it.

Maybe I will try to diag TPS wiring other than that I am a stumped.

 

[Jerryred94silvy]

Thanks for the reply!

Yes, the computer has tach signal and tach is functioning properly. I can manually shift the trans into 1st but when in Drive it is only in what i presume is 3rd gear. I am not certain the trans is the issue but from what ive been told it is a reman with around 80k miles on it.

Maybe I will try to diag TPS wiring other than that I am a stumped.

You bet! It’s an odd problem you’re having and I wish I could be more help. I literally just spliced the wires like the instructions said, watched YouTube videos and prayed and it all has been working for 4 years now. Maybe I got lucky lol.