Engine running issues 3.5 EFi

Before I go in to complete melt down about a running issue with my 1986 RC 3.5 efi I thought I would seek the help from the experts.

I did a very silly thing when welding the inner wing on my RRC, I connected the welder earth lead to the water pump. The battery was disconnected, I now have an engine that runs rough and does not tick over (if I disconnect the Air flow meter, sometimes it will, but HUNTS badly). I have changed the coil and distributor amplifier with no difference. If I disconnect the 2AM air flow meter it does run a better, there is also a bad smell of un-burnt fuel. When I do manage to get the revs up it does run on all cylinders.

I have also changed the three temperature sensors.

ANY advice will be much appreciated as I have cancelled the MOT I had booked for the 9th.

Not the best place for an earth but regardless of where you would have put it, the earth path would still go round the engine anyway....

That being said, it could be your MAF as you say it runs margainly better with it disconnected!

opps...for future reference unplug the ecu too..

now before replacing everything check your engine earth lead is still good...just in case..

As Zen said but i guess its a new ECU where are you as I have one to confirm failure if you are close

Thanks to all for you replies and comments. Zen I am near St Albans Hertfordshire. A little distance from you, but many thanks fror the offer.

Ooops, sorry Pete1987RRC, thanks for the offer.

Yep, I second ECU failure.

I blew a few of them up in my early days, & the age of them now would mean they would be naturally failing.
Is the fuel consumption about 5 miles to the gallon?

Rick the Pick

It does about 10 mpg around town and 12ish on a run. But I know it needs a new cam & followers ect and it does have BIG tires on. Have you ever had experience of having an ECU repaired? New AFM arriving today-fingers crossed.