The MGF Register Forums

Not sure if anyone else has had the same issue I have..

I have had our MGF Tropy 160 for 18 years, and I have spent a lot on it over the years, it has a Quaife ATB LSD, polybushed, Bilstein shocks. It even had a brand new VVC head fitted around 300 miles ago. Car has 65k miles on the clock and is rust free, body-wise.

However, over the past few weeks, it has developed this strange issue of it not running as it should, the revs will be erratic, going high and so low it almost cuts out at idle. Yet no lights on the dash.

Today, I had Russell Walsh of MG Rover Solutions to come down and take a look, in the hope of diagnosing the issue. It seems there is no issue, the engine run perfect for the 90+ minutes it was running while he tried to diagnose. One worrying thing is the fact the software on his laptop said that there is no link misfire information (which is clearly the reason there is no light on the dash). He has never come accross this before, and suggested it may be the ECU at fault.

If the ECU is at fault, what would my options be for trying to fix the issue?

I must admit that I am near the end of my tether with the car, I was hoping today would fix the issue, and the car was then planned for a full body spruce up, followed by a complete overhaul underneath by MGF&TFbits. But now, I do not feel like spending £3+k tarting up the car if it still has a mechanical issue - I feel like driving it to the scrapyard and just getting rid of the problem - but I have had it for 18 years, so hard to stay rational, throwing good money after bad....

Presumably the earth straps have been checked?

Chris Tideswell wrote: ↑

Wed Oct 18, 2023 12:45 pm

Presumably the earth straps have been checked?

No idea! This is why I paid someone who knows a lot more than I do to look for me.

When you say the revs go high and low do you mean whilst driving along or just when idling ? If the latter have you ruled out the Idle Air Control valve & stepper motor ?

Notanumber wrote: ↑

Wed Oct 18, 2023 2:58 pm

When you say the revs go high and low do you mean whilst driving along or just when idling ? If the latter have you ruled out the Idle Air Control valve & stepper motor ?

Both. But was perfect for the 90+ minutes it was running when the mechanic was here, typical.

I think it may be the ECU, as it never threw out an error code, even when one HT lead was pulled from its socket. Not even a warning light on the dash.

If that is the case, what is the procedure for changing the ECU? I know they can be bought from Rimmer Brothers (or B&G)? But they then need to be programmed for the specific car, don't they?

I did give myself a budget of around £3k to get the car looking and running perfectly, so around £300 to change ECU would be OK by me, as I have already bought all the sensors and a lot of other stuff.

It should be possible to use a good 2nd hand ECU so you should be able to do it readily inside that budget .The recommendation I believe is to replace the body control module and fob with them to guarantee a certain and uncomplicated outcome on the turn of the key but others may advise the need for those can be worked around with T4/ Pcan programming.

VVC control is sadly outside my knowledge but I would recommend reading up on whether an ECU from a Mk1 TF VVC 160 would be usable on an F Trophy suitable given they are the same engine and TF ECUs will be more plentiful.

It would be worth giving some of the specialist vendors who know their stuff and stock 2nd hand parts a call. Ive always had very good service from Darren at Mgfntfbitz but others on here will recommend their own favorites of whom they have had positive experiences .

Example, though this one is for a non VVC car https://www.mgfntfbitz.co.uk/shop/nnn10 ... e-ecu-s21/. He would be worth a shout to see what he has as only a fraction of his stock is put on the website.

Notanumber wrote: ↑

Thu Oct 19, 2023 1:16 pm

It should be possible to use a good 2nd hand ECU so you should be able to do it readily inside that budget .The recommendation I believe is to replace the body control module and fob with them to guarantee a certain and uncomplicated outcome on the turn of the key but others may advise the need for those can be worked around with T4/ Pcan programming.

VVC control is sadly outside my knowledge but I would recommend reading up on whether an ECU from a Mk1 TF VVC 160 would be usable on an F Trophy suitable given they are the same engine and TF ECUs will be more plentiful.

It would be worth giving some of the specialist vendors who know their stuff and stock 2nd hand parts a call. Ive always had very good service from Darren at Mgfntfbitz but others on here will recommend their own favorites of whom they have had positive experiences .

Example, though this one is for a non VVC car https://www.mgfntfbitz.co.uk/shop/nnn10 ... e-ecu-s21/. He would be worth a shout to see what he has as only a fraction of his stock is put on the website.

Thank you so much for that.

I actually took a pic of my ECU earlier (NNN000100), and asked Rimmer Bros if they could help - unfortunately not. Still waiting for a reply from B&G.

After the bodyshop, I did plan to take the MG to mgfntfbitz for a complete underside/sub frames restoration - but I need to be sure the car is 100% mechanically sound before spending any more money both of re paints and refurbs.

I must admit, I am on the brink of just taking it to the scrapper, I have never minded spending whatever it takes to keep it perfect, but there has to be a point when I say enough's enough.

.....But I have had this since 2005 (2nd Trophy 160, bought one new in 2001 and part exed it for a TF160 in 2002), and it is very hard to let go...

I know very little about ECU's etc but I believe you can attach a data logger? to the port which I presume would record all the data. Obviously the limit would be according to the loggers memory and I've no idea if it then stops recording or just over writes, perhaps someone up with the tech can advise. In my mind this would mean with an intermittent fault once it appears you could stop the recording and review what changed when the fault appeared, or am I being too simplistic?
Chris don't give up I'm looking forward to your silver!

Deepfat wrote: ↑

Thu Oct 19, 2023 5:55 pm

I know very little about ECU's etc but I believe you can attach a data logger? to the port which I presume would record all the data. Obviously the limit would be according to the loggers memory and I've no idea if it then stops recording or just over writes, perhaps someone up with the tech can advise. In my mind this would mean with an intermittent fault once it appears you could stop the recording and review what changed when the fault appeared, or am I being too simplistic?
Chris don't give up I'm looking forward to your silver!

Cheers I don't want to give up, but it is now testing me. Always loved the original Trophy 160's.

According to Russell Walsh of MG Rover Solutions, the problem with the ECU is that it is not showing any misfire issues, even with the engine running on three cylinders (not even an engine light on the dash), so does this mean the chip in the ECU is faulty? I never got any definitive answer, and because of where I live (Forest of Dean), taking the car anywhere is quite the journey - and I do not trust the MG to get me a mile down the road right now, let alone halfway accross the UK. Which is a shame, as I know the engine itself is very good.

I agree it does rather sound as though the ECU is fritzed if it wont provide a simple diagnostic output. I am sure there is a solution out there and I very much hope that it can be found, affordably, before your patience runs out.

Rather than calling time altogether there would be the option of dropping to MPI parts to get the car back on the road. (I realise many would view that as a bit of a philistine approach )

My ‘96 vvc ran quite well while driving but when stopping in traffic the revs dropped untill the engine died OR ran at a high rate 1,5 - 2k revs per minute. It took a while to trace the issue as all thought about the obvious issues like faulty sensors, broken wires, unset vvc mechanism. In the end we replaced the vvc solenoids and the issue was gone.

Written down in a few lines but it took about 2 years to solve as the problem started quite mild but became more and more irritating during the years. On one of our travels (MGFIM Sweden) it came to a point we decided to find the fault until solved. It took some months before we felt secure the issue was gone, and it still is.

Cheers for the replies, guys, very much appreciated.

As the VVC head was brand new (still in its original Rover box and packaging) 300 miles ago, I am hoping that is fine. I haven't been able to replace the sensors since the mobile mechanic came last Wednesday, as it has rained ever since.

What I shall do is replace the fuel filter and lambda when I can and then give it a good run. Idealling, I would like to take it somewhere where they can actuall take the engine out and check everything, but damn this mid engined layout can be a hindrance, nothing is easy...

So you have had the head replaced 300 miles ago,
and now it's not running perfectly,

logic suggests something has not been plugged back in correctly.

I would go back over all of the electricals that were unplugged to change the head.

I bet this is something simple - like a sticking idle air control valve.

Intermittent misfires have to be very frequent for it to be registered as a "Malfunction Indication Lamp" activation - even with faulty coils (a really common cause for misfires and uneven engine running), it is almost impossible to get the MIL to illuminate or even the MEMS ECU to store the fault.

The best approach is to use a fault code reader, such as the PSCAN, and record the telemetry and hopefully capture one of these events to work out what the fault might be...

PS really love a red Trophy 160! Gorgous cars.