The MGF Register Forums

Hi all,

After a bit of guidance if I may? I have a new to me 1996 MGF VVC, engine turns over but does not start. On further investigation there is no power to the fuel pump. There is power across the inertia switch, indeed, I have tested this on another MGF and it works fine. Brought a new fuel pump relay and took the cover off the old one, the relays seem to work inside when they should ie at turn of the key to pressurise the fuel system and then when you crank it. Stuck a multimeter in the purple/white wire in the connector and no voltage goes to it under any condition.

Is there anything obvious I am missing?

Happy to elaborate more if I haven't explained myself very well.

Thanks in advance

Matty

Have you checked the cut out switch on the nearside of the engine bar, just inside from the boot? It should be down.

start at the beginning, have you checked the fuse?

Yes Sirs, all fuses are fine, the inertia cut out switch is fine as I removed it and tested it in a working MGF. Curiously, the fuel gauge doesn't work now either. It did when I first go it.

Many thanks for taking the time to reply.

Matty

Is the fuel old? Is there a spark?

Fuel is fine, no idea about spark as I am troubleshooting the non energising fuel pump at the minute. Once that works I will check for spark.

Update.

The fuel pump runs if you give it 12v via the connector that is first inline after the fuel pump relay. So the fuel pump is fine. Question is, why won't the relay energise the fuel pump like it should? Tried two relays, one of which is brand new. Is it possible that just the fuel part of the ECU has failed?

Matty

Further update.

I believe the ECU to be at fault. After much probing with a multimeter and a continuity tester and consulting Dr Google, there is a purple/black wire from the ECU to the Fuel Relay. This is grounded when the fuel pump is energised and for some reason it isn't happening. If I ground it with a continuity tester then it works.

Next step is to cost out having the ECU tested/repaired vs a ebay one and see it that works. Is it usual for just one aspect of the ECU to fail?

Thanks in advance

Matty

Further, further update.

Matched ECU, 5AS unit and key fob swap. Car started and fired first time, ran for 30 mins plus. So, quite happy now. Got a few issues to fix, a water leak on the underfloor coolant pipes for a start, but progress non the less.

Thanks for everyone who took the time to reply and I will keep an update of my progress as and when if anyone is interested?

Matty

Matty,
There seems to be a common problem with the 5AS not releasing correctly and the MEMS unit then cuts of the fuel causing the problems you saw. Maybe you can get in touch with the guy that makes the PSCAN unit and see if he would like to use your ECUs to see what is going on and create a diagnosis for us.
Nigel

Countax wrote:Matty,
There seems to be a common problem with the 5AS not releasing correctly and the MEMS unit then cuts of the fuel causing the problems you saw. Maybe you can get in touch with the guy that makes the PSCAN unit and see if he would like to use your ECUs to see what is going on and create a diagnosis for us.
Nigel

Do you mean donate my old faulty ECU and 5AS to him? I am happy to do so if he would find it useful.

Matty

Matty,
I have posted a thread on the PSCAN forum on rovertech.net asking Philip if he is interested in your kind offer.
Nigel

Matty,

Engine you had problem with is the engine you got and you could not start it at all, or this is problem that occured after some time of sucesfull engine runing?
This behaviour to be able to spin motor for second or two and then it dies is common when you do not have matched 5AS and engine ECU, or when immobilzer is still active and not removed by pressing fob.
I read this on RoverTech.net and came here to ask.

Hi and welcome to the forum Roverlike

James

Thanks, James!

Roverlike wrote:Matty,

Engine you had problem with is the engine you got and you could not start it at all, or this is problem that occured after some time of sucesfull engine runing?
This behaviour to be able to spin motor for second or two and then it dies is common when you do not have matched 5AS and engine ECU, or when immobilzer is still active and not removed by pressing fob.
I read this on RoverTech.net and came here to ask.

Roverlike,

To give you some background, I got the car off my Uncle who brought it in 2014 as a 'project' car. It's previous owner stored it in a shed after it failed its last MOT in 2010 on a heavily corroded brake line in the offside rear wheel well. My uncle drove it on to a trailer and off the trailer on to his drive and it hasn't moved since 2014. Sadly, a bout of ill health and his own MGF to keep roadworthy has seen this one pushed out. So he offered the car to me and we are working on both F's together. It's symptoms were as follows; engine would turnover but not fire.

1st thing we did was check all fuses and earth points went to ground, confirmed 12v at the battery and the inertia switch was functional.
Next was call out a specialist Alarm tech and he confirmed the immob was functioning and not inhibiting the start procedure.
Next was a new fuel pump relay.
After all this we gave 12v to the fuel pump to see if it was functional which it was.
We discovered that the fuel pump should run for 2-3 seconds with the first turn of ignition to prime the fuel system, it did not.
After much prodding and poking with a continuity tester and multimeter, taking the housing off the fuel pump relay and doing the functions manually we deduced the ECU was at fault. Apparently it controls the fuel pump by sending to ground a black wire with a purple trace that goes from the ECU to the fuel pump relay.

So, I got a price for having the ECU sent away for testing and it was the same as buying a known working unit complete with matched 5AS and fob from an MG breakers.

New ECU, 5AS unit fitted, she fired first turn of the key. Turned her off and checked for leaks, belt and hose integrity and then fired her up and let her run for around 30 minutes, rad fan kicked in when it should.

So that is currently where I am. She has a leak on the flow side of the under body coolant pipe and the temperature gauge doesn't work.

Next steps are to fix the coolant leak, full brake system check and replace as required, new seatbelt reels sourced, bulbs checked and then it's off to the MOT station. When she returns I will work through the fails and advisories, as soon as she passes and MOT I will know she is a keeper and then it's getting her to how I want her.

'She' is a 1996 jap import 1.8 VVC ABS model in metallic green.

Any other questions, just ask.

Matty.

PS: I am more than happy to donate my old ECU, 5AS and fob to the Pscan chap if he can use it to help others.

Matty,

Thanks for background. I checked the diagrams and now I can see where problem was and solution you took to resolve it. Really seems like ECU has problem and not providing ground when needed.

Roverlike wrote:Matty,

Thanks for background. I checked the diagrams and now I can see where problem was and solution you took to resolve it. Really seems like ECU has problem and not providing ground when needed.

Glad it helped.

Been at the F again this afternoon, seems it has suffered the usual fate of the K-Series, the dreaded HGF. Got some thinking to do now.
If I can help you with the non start problem, shout out, I am more than happy to help.

Matty

Mattyboy2154 wrote:[I am more than happy to donate my old ECU, 5AS and fob to the Pscan chap if he can use it to help others.

Thanks. I should be able to figure out which ECU has the fault if I can have your old 5AS, MEMS and key fobs. I have sent a PM with a postal address.

pscan.eu wrote:

Mattyboy2154 wrote:[I am more than happy to donate my old ECU, 5AS and fob to the Pscan chap if he can use it to help others.

Thanks. I should be able to figure out which ECU has the fault if I can have your old 5AS, MEMS and key fobs. I have sent a PM with a postal address.

Hermes picked it up this morning, it is on it's way to the address you supplied,

Matty