swapping out MGF engine management ECU gotcha's

1997 MGF VVC :

Can I use PSCAN to re-code a replacement engine management ECU and alarm or is that beyond its feature set?

I suspect my Engine Management ECU has a fault. The PSCAN software shows no obvious alarms.

Once the engine warms up I get momentarily engine fuel starvation it seems and the engine almost stalls for a split second then all is well for a while then it dips again. The engine will very occasionally stall.

My classic MG garage has changed sensors, fuel valves and tried all sorts etc. All except a new wiring loom. (Note: This fault started immediately they installed a new clutch, could be a coincidence)

If I swap out the Engine management ECU for a replacement the garage says it won't work due to mismatch with the alarm system?

I'm in Sydney Australia so having to physically send an ECU & alarm back to UK to be re-configured is a very expensive option especially as I'm not sure its the cause of the problem yet.

thanks for any help.

Fuel pumps on these things can be intermittent.
I don’t think it will be the ECU.

OK , would the ECU and PSCAN detect a fuel pump problem ? If its a maybe, what sort of PSCAN error should i look for?
thankyou.

If it is the ECU then the simplest solution might be to buy a remapped ECU from KMaps , not only will you get an increase in power and better fuel economy but the immobiliser is removed so no incompatibility issues.

I checked with KMaps and unfortunately they only deal with post 2000 ecus's not 1997 versions, which is a shame.

Palmplex wrote:

1997 MGF VVC :

If I swap out the Engine management ECU for a replacement the garage says it won't work due to mismatch with the alarm system?

Your garage is correct. The alarm transmits a code (called an EMS code) to the engine ECU. If the ECU receives a different EMS code to the one it expects, the engine will not run. In this way the engine ECU and the alarm are "matched".

The good news is that pscan can "rematch" ECUs. So, you can buy a used engine ECU and install it into the car, and then use pscan to "relearn" the EMS code and then the replacement ECU will now be happy with the alarm.

There is a video showing the process here

The video shows "relearning" the EMS code from a Simtek emulator, but the principle and process is the same.

Palmplex wrote:

OK , would the ECU and PSCAN detect a fuel pump problem ? If its a maybe, what sort of PSCAN error should i look for?
thankyou.

I guess you could monitor oxygen sensor voltage in live data. My understanding is that it should fluctuate between a low and high voltage indicating that the ECU is able to control the fuel mixture. I would guess that if the engine is not receiving enough fuel then instead of fluctuating it will be nailed to the "lean" voltage.

The ECU doesn't monitor fuel pressure so apart from the fuel mixture it won't have any visibility of fuel pump problems.