None starter

[currymonster]

Hello. I've got a 3.9 Efi motor in my hybrid. Whilest messing about under the bonnet, the coil negative wire(think its the engine RPM input to ECU) touched something. There were a few sparks. Any way engine cut out and now refuses to start. The fuel pump is not priming up and nothing else seems to reset itself.

Have i most likely blown the ECU.

Thanks, Martin

[ramon alban]

Hello. I've got a 3.9 Efi motor in my hybrid. Whilest messing about under the bonnet, the coil negative wire(think its the engine RPM input to ECU) touched something. There were a few sparks. Any way engine cut out and now refuses to start. The fuel pump is not priming up and nothing else seems to reset itself.

Have i most likely blown the ECU.

Thanks, Martin

Martin, Depending upon what touched what, have a look at the temporary image here

http://www.vintagemodelairplane.com/pag ... uit01.html

and note that the resistor (BR) already goes to the ECU, and according to urban myth, the resistor can be left out of the circuit so even 12 volts being touched directly to pin 1 of the ECU will not blow the ECU.

However if somehow the resistor wire came in contact with a spark plug voltage then it would be bye bye ECU. but that unlikely.

So if the WB wire came in touch with ground again no problem. Then maybe it touched 12 volts live and put it across the coil, then the coil would energise and send sparks to the dizzy. should not be a problem, but maybe fried the coil.

However, not sure about the amplifier. If the coil neg wire touched earth this would put 12 volts across the amplifier and if the dissy was in the right (wrong) position it could maybe fry the amplifier.

Then again there is a bit of electronics in the dizzy - a hall effect transistor, usually, and if the coil neg was earthed then that might also fry.

in order of likelyhood i reckon

Amplifier
rotor arm/dissycap
dizzy
coil
ECU

[ramon alban]

The fuel pump is not priming up and nothing else seems to reset itself.

Martin - Whoops, I missed this symptom, if the fuel pump is not priming (running) then its possible that something took out one of the diode(s) in the steering module.

Have a look at this explanation of how it works.

http://www.vintagemodelairplane.com/pag ... ule01.html

Also part of the fuel pump initialising circuit are the contacts in the AFM. check that out too from AFM tests in the efi component index.

Hope this is not getting too vague.

[Coops]

the 3.9 efi dont have a steering module does it?

[sowen]

There is a diode in one of the main relays on the hotwire type wiring loom.

Simon

[Coops]

oh mine never
i just had two relays on mine, fuel pump relay, and main power relay. will go double check though 2mora nite

[Coops]

just double checked the wiring diagram,



and can't find the relay your refere to mate,
iknow the 3.5 flapper system has a steering module relay.

[ramon alban]

Hello. I've got a 3.9 Efi motor in my hybrid. Whilest messing about under the bonnet, the coil negative wire(think its the engine RPM input to ECU) touched something. There were a few sparks. Any way engine cut out and now refuses to start. The fuel pump is not priming up and nothing else seems to reset itself.

Have i most likely blown the ECU.

Thanks, Martin

Sorry Martin, seems I misled you, didn't twig it was hotwire!

Ramon

[ChrisJC]

I would check ignition amplifier (by substitution first), and also the fuses. I would be gobsmacked if the ECU had been damaged.

Chris.

[sowen]

The relays 21 + 22 on the hotwire diagram have diodes in them Tony. They look identical to bog standard relays and I guess will work either way.

On the left is a standard lucas relay and on the right is a bosch relay with the diode inside.



Simon

[currymonster]

Thanks, Simon!

Main relay had packed up. I have put a normal relay in it for now. Every thing seems to set itself now. But- it will try to fire up but won't start. I've got a spark. Theres a strong smell of fuel. Could this be be down to the wrong relay?

Thanks for all your help!!!

Martin

[Coops]

Never knew that.

i had normal relays in my hotwire i ran in the capri was fine for 3yrs until i removed it for the vems ecu,

[sowen]

I read somewhere that you need to fit the correct bosch relay, not the lucas relay or else the efi won't run. I doubt the relay could prevent it from running, as you appear to have a spark and fuel.

Not being an expert (still getting my head round efi myself), I'd start from the top and check everything over carefully, as you have blown a main power relay somehow , there could still be some underlying fault you haven't found yet.

Simon

[ramon alban]

Main relay had packed up. I have put a normal relay in it for now. Every thing seems to set itself now. But- it will try to fire up but won't start. I've got a spark. Theres a strong smell of fuel. Could this be be down to the wrong relay?

Rimmer Brothers website shows that the Main Efi Relay and Fuel Pump Relay have a different part number from the standard relays in the flapper system. Suggest you check out the part numbers for your basic system what ever that is.