ZBRA

Vehicle: 1994 Corvette LT1 6-speed

Say you:

1) Removed the engine computer and harness and went DFI
2) Removed the body control computer
3) Removed the ASR

Can the ABS system then be wired and function properly as a stand alone system.

I know the ASR depends on the ABS sytem to function properly, but does the ABS system also depend on the ASR system?

Here is some information from the 1994 FSMs

Since I will still be using a factory PCM/ECM, I can give the EBTCM whatever PCM/ECM signals it needs.

Any help is appreciated.

bogus

wow... I don't think so.

if it was me, I would consider retro-fitting a 1989 ABS computer. That doesn't need any computer.

VenkmanP

Try disconnecting the serial data line between the CCM and EBTCM and see if ABS still activates properly.

ZBRA

Hmmm. Not a bad idea. I wonder if I would only need the 1989 ABS computer or if I would need the 1989 ABS assembly.

ZBRA

Car isn't currently running. Engine is on a stand, and I'm rewiring everything before I put it back in. I'll be pulling the dash out and all of the under dash wiring in a week.

ScaryFast

ZBRA, I've been trying to get my ABS running for two years since i removed the ARS and did the same conversion as you're doing. Funny how I keep popping up in your threads

I've had so little luck that I have put it on hold, but it's frustrating losing a few laps while I wait for tires and brakes to heat up and stop as designed. I got tired of flat-spotting $260 Hoosiers.

I have the EBCTM and the accellerometer that was originally located up under the dash intact, as well as all the ABS sensors (expect the one I cut off tonight to replace the rear knuckle). No dice. Not many here have tried to do this from what I could dig up.

Let's compare notes, here or via PM as I'd very much like to get it working again to brake as late in laps 1 and 2 as the f'ing Z06's I run against.

I started tracing every wire last month but I'm going out of town for two weeks so I won't be able to dig back into it until after Mid-Ohio July 14th. After that I have a month of downtime before the next event.

ScaryFast

This seems like a good idea. Even if the hydraulics and EBTCM are different there are a number of cars being parted out over in the FS section that could supply them.

I have a friend that designs ABS for Bosch, and we've talked about using a Ford GT system as a retrofit. However, same as our cars it's tied into the whole vehicle and tuned specifically to that car's dynamics.

ZBRA

ScaryFast, what year is your car?

I have some interchange information on the early C4 ABS parts:

ABS pump was the same from 1986-1991

ABS computer 14103343 was used from 1986-1989
ABS computer 10223326 was used from 1990-1991

I need to check the cross reference on the hub bearings to see if the ABS wheel sensors from 1989 are the same as 1994.

ASR became standard in 1992, but I don't know what year it was first available.

It looks like 1990 was the first year for a body control computer, so a 1986-1989 system will probably be the way to go if the 1994 system just will not work.

I have the FSMs for 1994. I can scan the wiring diagrams, but that doesn't really help in figuring out what is necessary and what isn't. It would also be helpful to have the diagram for the 1989 ABS computer to compare.

bogus

the thing is, the ABS/ASR computer uses a GM spec data stream... so that is an issue.

ASR was standard in 1992, it's first year of availablity.

ZBRA

The DFI that I plan to use, uses a GM computer (16188051 94-95 F-Body) and could even use stock tuning. I'll also be using the stock wheel speed sensors and vehicle speed sensor. I don't see why I wouldn't be able to give the ABS computer the information that it is looking for.

ScaryFast

Mine's a 1993. I have successfully eliminated all computers except the ECM (Obviously) and the EBTCM, although it's not plugged in to anything right now. The hardest part is removing the CCM as everything is tied to it. Several new PROM attempts were made before the VATS, etc. were gone.

I have the FSM for my year, my guess is that it's the same for '93 and '94. I found that a few of the wires to the EBCTM were cut during my interior gutting, but I've since replaced them, as well as the accel. What I have NOT done yet is plug in a service tool and check what codes are active in the EBCTM. That might give me some additional insight.

ZBRA have you done this yet?

bogus

what I don't know is if the data stream is modified by the CCM. What data does it need? How is it formatted?

another thought would be to retrofit an ABS from an F-body... but I don't know that systems programming, as far as how the vehicle works.

I am doing an LT1/4L60E conversion in bastet44's (my wifes) 87 Vette. The ABS is stand alone in that car, and to kill the serial data line, and eliminate a lot of codes, I had TJ Wong drop an F-body tune on the PCM. Problem solved (I hope, I will let you all know once it is running again).

ZBRA

Please let me know what wiring you have to do to get the ABS working properly with your swap. What harness and ECM are you using with your swap?

VenkmanP

The FSM shows the EBTCM talking to the CCM not the PCM.

ZBRA

I'm removing the CCM along with all of the interior wiring not related to the ABS system.

VenkmanP

Which is why I mentioned it...

-=Jeff=-

Not sure if this will help..

in my 89, I have the 89 EBCM (EBTCM has traction control)

I also have a 91 CCM and ECM in the same car. I get NO codes from the CCM since there is no Serial line from the 89 unit going to the CCM.