ECU Questions

[FEF]

As a few know, my '88 Burb is a donor for a conversion. I'm to a point now where I'm starting to get the engine ready for the conversion. To this end, I find a lot of wires not needed. This leads to a few questions, in no particular order.

1) Is it true that the OBD ECU really only controlling the TC lockup and the EGR circuit?

2) As I'll probably install a gas engine in the Burb when I'm done, is there a place (or book) I can get information that has the values the ECU is looking for? I'd like to put imulators (usually resisters), in all the connectors and tidy them up.

For example, if I'm not using the water temp sensor for the Glow Plug controller, It's a good idea to clean it up and put a plug in it's place.



So far, it's been a nice project.

[john8662]

For conversions, this is what you'll end up doing, modifying electrical.

For the glow, yes remove the relay and temp sensor that resides on the water crossover. The controller is the same as the previous year 85+ years used, so just simplify it to that wiring type.

ECM for the diesel, yep TCC lockup an EGR & EPR & Cruise control. Lockup can be accomplished manually, or reverting to the previous 6.2L switch not sensor (TPs) setup (simple) and simplying the switch & harness in the transmission to reflect only one wire (hot wire) verses the Two it has now (always hot wire, and a switched ground).

As for the ECM, I have no earthly idea what it'll take to make any of that stuff work with the gasoline engine. I don't know whether the speedo and other things will still work, they likely will but with some work arounds.

You'll likely forget the ECM completly with the gas engine, I'm sure it's carbureted.

J

[FEF]

For conversions, this is what you'll end up doing, modifying electrical.

For the glow, yes remove the relay and temp sensor that resides on the water crossover. The controller is the same as the previous year 85+ years used, so just simplify it to that wiring type.

ECM for the diesel, yep TCC lockup an EGR & EPR & Cruise control. Lockup can be accomplished manually, or reverting to the previous 6.2L switch not sensor (TPs) setup (simple) and simplying the switch & harness in the transmission to reflect only one wire (hot wire) verses the Two it has now (always hot wire, and a switched ground).

You'll likely forget the ECM completly with the gas engine, I'm sure it's carbureted.

J
I'm haveing some hard starts on cold mornings, so I'm going to have to go through the glow system anyway. I may as well simplify it while I'm there.

I was hoping to take the cruse with me, though. On the older units, the speed cable goes into the unit, and another speed cable comes out and goes to the speedo. I guess this means I'm going to use the '73 speedo system, with the vacuum diaphram on the 6.2 engine. That should work.

I'll be using the TH425 tranny. I'll need an intake vacuum imulator. The early 6.2's must have had it for the TH400.

HUmmmmmm... This is looking like it should be in the conversion area. Sorry about that Mods.

With regard to the gas side, it should be pretty easy to get the cruse working again. That and the TCC lockup are all I want to work from the diesel ECU.