Thread: Possible computer issue - classic rangie

Hey folks, I've got an intermittent issue with the 3.9v8 in my classic rangie. Its been on and off for a while but seems to have progressed to the next level in the last couple of days.

around the 1800rpm level (its probably than this because its based on the pulley size on the alternator) it seems to drop revs slightly as though its missing, it does it in all situations, highway, low range offroad etc

Yesterday a few times, when I went to accelerate it was just like complete power cut then when I lifted off the accelerator and tried again more gently it seemed to behave.

It has previously been on the dyno but everything was normal and reading correctly. In chatting to the mechanic/tuner yesterday he had a similar one which was fixed by the replacing the computer - anyone else had similar issues/fixes

Does anyone in SE Qld have a computer I could borrow to test - the codes on my computer are:
PRC7081
85007D
14CUX
Date Code 0290 which I assume means Feb 1990.

Suggestions?

Thanks Guy

Hi Guy,
For the sake of elimination/simple, first reset the ECU by either unplugging it for 30secs or disconnecting the battery - that'll clear any fault codes.
If that doesn't work..
I had a similar problem a couple of years back on my 90rrc. In that instance it turned out to be the 6.8 KOhms resistor that's in line between the "-" terminal on the coil and pin 39 on the ECU multipin. It's located under the drivers seat, spliced into the loom - but don't get it confused with the tune resistor! To test whip off the back cover of the multipin and with the ignition on check you have 9.5V (+/- 1v) between pin 39 and ground. If not, the resistor has gone bad or you've lost the engine speed input from the coil to the ECU which will much confuse the ECU.
Other than that it could be one of a multitude of things (of course!) So I'd run through the ECU checks as per service manual - If you need a copy of the fuel injection test procedures just PM me and I'll send them

I'd be really surprised if the ECU is cactus - takes a lot to break one!
cheers
Chris