Will a '90 ECU work in an '89? I have heard some stuff mentioned about the A/C not working, but other than that, any other issues? I am having diagnostic display envy 
Will
Will
Will a '90 ECU work in an '89?
- Thread starter RKORES
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rrrandall
Guest
Will
I think you can use a CUX type computer in the 86 thru 89 RRC. But there would be some rewiring to get the A/C to work as you mentioned. Unfortunately to get the CUX diagnostics you would need to use a CUX wiring harness. The check engine light on the dash may still not work even if you transplanted an entire CUX system into an 89, but it could be tried. Also the 89 probably does not have a VSS. The VSS is normally used on the CUX system as a switch to turn on/off the the idle control mode. The VSS is not required for CUX operation, but your idle will probably slightly unstable if it isn't plugged into the system.
Randall
I think you can use a CUX type computer in the 86 thru 89 RRC. But there would be some rewiring to get the A/C to work as you mentioned. Unfortunately to get the CUX diagnostics you would need to use a CUX wiring harness. The check engine light on the dash may still not work even if you transplanted an entire CUX system into an 89, but it could be tried. Also the 89 probably does not have a VSS. The VSS is normally used on the CUX system as a switch to turn on/off the the idle control mode. The VSS is not required for CUX operation, but your idle will probably slightly unstable if it isn't plugged into the system.
Randall
ok
The ECU will work on the 89 as I put my 89 ECU in my 92. I think I did have to jump the relay at the AC to make it work (compressor I think) but that was it. As far as the diagnostic display, why bother. Get the correct WSM for your vehicle and you can do all the tests with a multimeter with relative easy.
The ECU will work on the 89 as I put my 89 ECU in my 92. I think I did have to jump the relay at the AC to make it work (compressor I think) but that was it. As far as the diagnostic display, why bother. Get the correct WSM for your vehicle and you can do all the tests with a multimeter with relative easy.
Hmmm...This is interesting. I may not do the swap then.
It would be much easier to look at a lit up box that I could get codes off of, instead of doing the whole multi-meter bit.
But, I don't have the time or the $$$ at the moment to pull of a wiring harness swap
My A/C doesn't work anyway, so that's why I don't care about it.
Just out of curiosity though...Were are the lights on the Diagnostic Display? It looks like a black box with no lights???
Thanks,
Will
It would be much easier to look at a lit up box that I could get codes off of, instead of doing the whole multi-meter bit.
But, I don't have the time or the $$$ at the moment to pull of a wiring harness swap
My A/C doesn't work anyway, so that's why I don't care about it.
Just out of curiosity though...Were are the lights on the Diagnostic Display? It looks like a black box with no lights???
Thanks,
Will
ptschram
Well-known member
OK fellas, Shopboy's '88 RRC has an ECU from a '95 Disco. The ECU will work, the diagnostics will work if the vehicle is hooked up to a Rover-specific diagnostic computer, but, the A/C won't work without adding a relay.
The EFI light will work if there is a fault, but the fault light illumination for a non-GEMS engine requires almost complete system shutdown.
The lights on the diagnostic display are seven segment LED digits. They show through the red palstic of the display.
The EFI light will work if there is a fault, but the fault light illumination for a non-GEMS engine requires almost complete system shutdown
.The lights on the diagnostic display are seven segment LED digits. They show through the red palstic of the display.
Thanks PT...I probabley won't do it then. I just wish there was an easier way to check codes beyond the multi-meter. Anyone have any ideas? Supposedly there is some kinda Lucas reader that will work.