Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Complex EFi issue

K, I can see where you are coming from, however it seems unlikely that the MMC would have produced numerous auto boxed +8`s.. With that in mind the assumption would seem to be that part of the LR wiring harness was utilised and adapted to suit a manual box installation..? Whether the MMC used a LR advised method of "conversion" to part of the LR wiring harness or not... who knows..! Add to that as many variables as digital programming might involve, then throw in a speed sensor and,and,and... Yeah rather pleased to have a pair of carbs on my old +8.

Hope your investigations with the speed sensor prove successful Grumpy2...

To the best of my knowledge MMC produced only one automatic plus 8 with the Rover V8, it was used by Mrs Morgan.
Most of the BMW engined Plus 8s are automatic.

I once had similar intermittent problems, I think if it was a duff resistor then once broke you would have the problem constantly . The problem I was having eventually ended up being a cable fault -I’m not saying this is what your issue is, but it might be worth cleaning the ECU multi pin plug & checking the 4 stepper plug cables - might also be worth checking base idle. If the stepper shuts off totally , the engine should still tickover at base idle revs . It may be the ignition amplifier starting to fail.

I don’t know about modern electronic auto boxes but many moons ago when things went up & down and round & round the neutral/park switch simply allowed the engine to start , positions 1-2- Drive inhibited a start
Good Luck

My 94 +8 is a manual gearbox but I once had an issue with the engine stalling when coming to a stop at junctions or traffic lights. The faulty code shown was 48 the Stepper Motor, tried a few new ones but could not resolve the issue. Finally I got to the Road Speed Sensor, cleaned the screws attaching it to the bodywork making sure the earth was good and the issue was solved. For good measure I also checked and reset the Base Idle along with the timing which made a considerable difference to improved performance.

Thats very odd as theres no connection between the circuitry inside and the body of the speed sensor. The two wires simply connect to a reed switch and resistor in series. The rotating magnetic pickup opens and closes the reed switch. Theres no connection to earth via the casing. Still worth a go as its easy to accomplish. Thanks

[/quote]Thats very odd as theres no connection between the circuitry inside and the body of the speed sensor. The two wires simply connect to a reed switch and resistor in series. The rotating magnetic pickup opens and closes the reed switch. Theres no connection to earth via the casing. Still worth a go as its easy to accomplish. Thanks
[/quote]

Maybe I just jiggled something inside the sensor that resolved it, I didn't take the sensor apart.

Maybe I just jiggled something inside the sensor that resolved it, I didn't take the sensor apart.
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What did you set the timing arm idle to ? Mines at 4 degrees advance with an idle of 600 (plus 100 by stepper)

Perhaps a further clarification might help

The engine cuts out in two ways

1. When coming to a standstill I can see the revs drop as I dip the clutch to around 1100rpm then to around 900 and once at a standstill 2-3 seconds later down to around 700rpm. It’s at this point that the engine may or may not cut out.

2. When idling perfectly well for some time, say at traffic lights, in neutral with the clutch disengaged (foot off the clutch pedal) the engine will go lumpy for a second or two and then cut out.

In both cases the engine will restart with no problem (so far) and run fine until it decides to cut out again in one of the two circumstances outlined above.

The only other feature that may or may not be present is a slight weakness pulling away from standstill. But that could be me as my ‘normal’ car is an auto

The engine runs well, smooth and powerful and with decent economy too. Plugs are correct colour although getting the Exhaust gasses through an MOT is always a bit hit and miss but we get there.

I have no experience with digital fault finding on vehicles.... It would seem that your thinking on unfortunate experiences may be related to coming to a stop, and I can well understand why. However there may be some advantage in looking closely at idle settings both when hot and cold, to be sure the engine is running as close to perfectly as possible, as that would seem to be the foundation on which the rest of the programming settings are built upon...?

My guess is that maybe the connection from the MAF sensor into the loom is maybe not as clean as it could be.

Why do I think this?

1. Because a few years back we called out the AA to sort out a friend's +8 that kept cutting out. He immediately said "99% certain it's the MAF. It always is." He traced the connection to the plug which was right under the seam in the bonnet, unplugged it, gave it a good blast with contact cleaner, and hey presto no more issues.

2. Because a couple of years later I had a similar problem, the engine revs didn't seem able to cleanly hit the target idle as they came down and sometimes it would cut out. So remembering the AA guy's words I removed the MAF from my car (1.8 VVTi Ecotec) and gave it a good spray of MAF cleaner. Also cleaned the contacts in the main loom connector. Same result - no more problem.

So my experience of ECU stalling has been 100% MAF related. Make of that what you will! :-)