Montego ECU help needed

[Maria]

I have an enquiry from a member whose 1989 Montego 2.0EFi is running erratically (misfiring, not staying running, but a little better when warmed up). The garage working on it think the ignition ECU has gone, part number NNN10005. I don't have that part number, but I do have NNN10001, so my questions are:

1) Is the ignition ECU likely to be at fault?
2) If I can't get hold of NNN10005, would any other ECUs be suitable. The ECU is not the original for the car as it was swapped to change to run on unleaded fuel.

[G Force]

Hi Maria

According to my info which I believe to be 99% correct.

NNN 10001 is a 1.6 Maestro Montego unleaded ignition ECU.

NNN 10005 is a Rover 216 SE EFI unleaded ignition ECU.

The correct part for the Montego 2.0 EFI should be for unleaded NNN 10016.

Or for leaded petrol ADU 9336. or ADU 8477.

The ECU could be the culprit but if it turns out not to be we would be able to make a better diagnosis with a bit more info on the car and the fault.

Any known good Ignition ECU will do to test if the original ECU is faulty as the car will be immediately running better with a good wrong type ECU rather than a faulty ECU.

Had lots of problems with the NNN10001 & NNN10005 ECU's when they came out, either No Start, Bad Misfires, and Cutting Out with indicators or brake lamps switched on.

[Jez]

MG Maestro 2.0i unleaded

Do you know the correct one for a 1990 MG Maestro?

Mine has NNN10005

[e692wtt]

Had lots of problems with the NNN10001 & NNN10005 ECU's when they came out, either No Start, Bad Misfires, and Cutting Out with indicators or brake lamps switched on.

Had this problem on Fleagle (see my sig - an F-reg 1.6L Monty) when I got him a few years ago. An interesting drive home...

There is a place in Warrington - Camco Automotive, from memory? - who did me an exchange ignition ECU for £50 + VAT a few years ago. The exchange one was a different model to the one I handed in, they were aware of this and not worried .

[Guest]

my 1990 (G) black 2.0 efi also has the same ecu.

it died after being parked up in all weathers, and had to replace it with one from an earlier car.

mal.

[G Force]

Do you know the correct one for a 1990 MG Maestro?

Mine has NNN10005

According to the data I have the NNN10005 is listed for a 216SE.

I don't seem to have an unleaded ECU listed at all for the MG Maestro just the leaded ECU, which is ADU9336. May be someone with access to the latest parts CD could check on this one for you.

It is conceivable that the NNN10005 is also listed for the Maestro but it would be unusual, although not impossible that it would suit two totally different engines. I have heard of people using the 216EFI ECU on their MG2.0 and claiming better performance but this is purely anecdotal, as I have not tried this scientifically.

The MG Maestro and MG Montego share exactly the same engine and EFI (hotwire Montego’s) and ignition ECU's for leaded fuel so it should follow that the correct unleaded ECU for the Maestro EFI is the one listed for the Montego NNN10016.

It should also be noted that the 2.0 O Series has always been mechanicaly safe to use unleaded petrol, The unleaded ECU was just to eliminate the chance of pinking and satisfy the emmisions regulations of the period.

[Maria]

NNN10005 is listed on EPC under both Maestro and Montego.

[Jez]

ATP electronics and Blue Streak supply and test.

APT claim the NNN 10005 is correct for my late MG Maestro. They can test one for £30 or supply a new one for £75. I don't know if a failed test and a new one is £105, or £75?!

Lucas told me a company called Blue streak do the ECUs tel 01623 886470. don't know anymore.

[mgdavid]

NNN10005 is listed on EPC under both Maestro and Montego.

but only from VIN 503901 to 512465 on Montys, after that they changed it again to NNN 10016

[The Express Valeter]

I have an enquiry from a member whose 1989 Montego 2.0EFi is running erratically (misfiring, not staying running, but a little better when warmed up). The garage working on it think the ignition ECU has gone, part number NNN10005. I don't have that part number, but I do have NNN10001, so my questions are:

1) Is the ignition ECU likely to be at fault?
2) If I can't get hold of NNN10005, would any other ECUs be suitable. The ECU is not the original for the car as it was swapped to change to run on unleaded fuel.

This isn't me but I have the same issue!!