I have a 90 F-350 that I put a Cummins diesel into, it had a 5.8L EFI in it. My ABS light has been on and is bugging me. I replaced the sensor on the rear diff. I retained the ford speedo cable/sensor and adapted to the Dodge NP241 Transfer case. All the other connections look good at the master cylinder and the valves that are located on the frame rail.
I removed the computer from the truck as the remaining wire harness was not needed after the conversion. I was under the impression that the ABS system was seperate from the EFI computer. Does anyone know if this is not the case. If it needs the computer I will just pull the bulb and not worry about it. But from what I can tell from the wiring it should be a seperate system from the EFI computer.
If anyone has any ideas I would apprecaite it. I don't post on here that much, I did a search and did not find anything I haven't tried yet.
I also have the EFI computer for sale if anyone needs it, not sure what it is worth, but it is here in Alaska if anyone is interesed, I can ship it in a $8 USPS flat rate box.
Thanks
I removed the computer from the truck as the remaining wire harness was not needed after the conversion. I was under the impression that the ABS system was seperate from the EFI computer. Does anyone know if this is not the case. If it needs the computer I will just pull the bulb and not worry about it. But from what I can tell from the wiring it should be a seperate system from the EFI computer.
The wiring diagram I just looked at from my Mitchell Manual for your year indicates like all of the speed density F-trucks, the RABS system is self-contained and does not require the EEC to be there - in fact the EEC gets it's speed input from the RABS module, not the other way around.
What probably happened is while you unplugged connectors to remove various parts of the wiring harness, you've disconnected either the brake switch or the speed sensor. I'm not familiar enough with the earlier wiring but on my 93 F350 but right outside my firewall where the EEC is there are a couple of connectors that feed the speed sensor and brake pedal switch in and out to the various devices that need it - and disconnecting those connectors results (at least on my 93) RABS problems.
I don't have a diagram as to how the wiring is bundled for your year unfortunately, so this is merely a guess.
What I would do is plug all the EFI harness wiring back in, and drape it over the fender away from the engine and start the truck and see if the RABS is still unhappy. If not, then you know it's related to whatever parts of the harness you've disconnected. If it's still unhappy after this test, that indicates something else is wrong.
I do not know of any connection between them.
Is your amber light flashing a code or is it on steady?
This light comes on when the truck is started, goes out for about 5-10 seconds then comes back on and stay on steady.
Thanks for the replys, I figured it was a stand alone system. Unfortunatly I do not have any of the wireing harness left, it went with the motor when I sold it. I do know that after my conversion was complete and I started and drove the truck the light was off and happy. Only after driving it for awhile after the conversion did it come back on and stay on. That is why I put in a new sensor, I also checked the fuse and it is in good, it fell out on me once and that kept the light on. I will check the connections again this weekend when I can work in they dayllight.
Only after driving it for awhile after the conversion did it come back on and stay on. That is why I put in a new sensor, I also checked the fuse and it is in good, it fell out on me once and that kept the light on. I will check the connections again this weekend when I can work in they dayllight.
If it functioned "fine" after the engine swap then it should still be fine, unless something wiggled loose or maybe something broke coincidentally.
If the wiring you removed was the problem, you would have gotten this problem *instantly*.
Ford's rear ABS was so useless and ineffective that if it were me, I would just pull the bulb and forget about it. Then I would enjoy my Cummins diesel in my Ford.
Ford's rear ABS was so useless and ineffective that if it were me, I would just pull the bulb and forget about it. Then I would enjoy my Cummins diesel in my Ford.
Nice swap. I would love to do the same one day.
I am going to trouble shoot it one more time and if I can't get the system to work the bulb is coming out. The CTD is a joy to drive, gobs of power over the 5.8
I've seen a few that have been run up on racks for testing, when the brakes are applied quickly, and with no load so that it stops the tires immediately, it takes out the rabs valve for some reason. They don't seem to like sudden stops. I don't know if they get stuck, or what happens, but they go bad instantly when they go..
Sounds like an outstanding conversation. For diagnosing RABS faults, pulling fault codes and listing for what each code means go to wwwdotraybestosdotcom/onlinetraining/abs-221.htm and I hope this can help you.
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Help-Rear ABS on 90F-350 W/O a computer
J/K
