40 replies to this topic

[se7enmvu]

Yeah the injectors had a good strong spray when checked with the syringe and battery but when plugged into the loom nothing.

 

The fuel cut off switch is fine that's the first thing I checked as its caught me out previously.

 

The crank sensor is the last thing I can check without diagnostics? Is there a way of checking it or is it a case of swapping it for a new one?

 

Cheers

Mark

[cian]

Your going to need to get hold of diagnostics as the ecu May not be sending a pulse to the injectors if thats the case then the ecu May be the issue, could also be the crank sensor but again the diagnostics will be able to test that

[Sprocket]

Will the engine show signs of life if you pour a little fuel through the throttle and then try and start it?

[se7enmvu]

This evening I've swapped the crank sensor which made no difference and checked all the wires associated with fuelling for continuity.

All wires checked out ok except the wire from the ecu to the furthest injector.

Tomorrow I'll strip back the loom and see what I find.

Would a break in the wire for one injector stop the ecu from firing the other? I would have thought not but I've no idea how they are controlled.

Cheers
Mark

[cian]

If I recall the two wires on each injector plug are spliced from factory into one and go directly to the ecu ( will double check rover wiring diagram)

The ecu itself may be goosed and not sending a firing signal

[se7enmvu]

If I recall the two wires on each injector plug are spliced from factory into one and go directly to the ecu ( will double check rover wiring diagram)

The ecu itself may be goosed and not sending a firing signal

So there’s only one wire from both injectors that feed back to the ecu? I’m sure I read the diagram as though there were two. There’s definitely two wires of the same colour/trace next to each other on the ecu multi plug.

[cian]

Two injectors at the top of the diagram, two wires for each injector from the ecu but get spliced into one

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[se7enmvu]

Thanks cian,  so if theres a break in the wiring for one injector the other should still fire?

 

If the ECU is goosed can the be repaired or is the only option replacement?

 

Cheers

Mark

[cian]

Yes if you have one injector with good wiring it should still fire, you would need to send it off to a specialist as it may be as simple as resolderinng a track but Im not ecu expert, complete ecu and immobiliser with fobs seem hard to come by

[se7enmvu]

I've had another evening trying to get it started and still no joy.

I've re-checked the wiring and all ok. I didn't realise there's four wires out the ecu to the injectors.


Years ago I bought a mpi engine, loom, fobs and ecu for a project that never got started. So I swapped the ecu and alarm box out and it's still not cured it.

I don't know the history of them and they've been in the attic 10+ years but it must be unlikely that they would both have failed in the same way.

So I checked the fuel lines and they were the wrong way around at the tank. Swapped them over and still nothing.

Really scratching my head over this. Hopefully I have an auto electrician coming over but waiting for home to get back to me with a time he's available.

Could the relay box on the servo be at fault? It's the last thing I can think of changing.

Cheers
Mark

[se7enmvu]

Well the head scratch worked 😀

I'd left the canister plug out tomorrow I'll swap the ecu back as hopefully it was just the crossed fuel lines.

Thanks everyone!

[se7enmvu]

Well it looks like my original ecu is toast. Put it back in and the injectors failed to fire.

Now I have a new problem. The new ecu fires the injectors only once or twice and then nothing.

So the engine starts and then immediately dies.

Any ideas? I'm going himley tomorrow so I'll try and pick up some spare mpi bits.

Cheers Mark

[Wiggy]

Sure the inertia switch hasn't tripped whist you've been in the engine bay? Is the pump still priming? Definitely got fuel in the tank? 

[se7enmvu]

Yeah the inertia is fine and the pump still primes I put 10 litres in the tank so even with the losses I've had changing injectors there should be enough.

They are a right ball ache these mpi's

[Wiggy]

Next guess would be crank sensor. Try taking it out and giving it a clean. 7mm bolts, I believe.

 

Biggest weakness of an Mpi is the fact that you're very limited in options for diagnostics.