The V8 Owners Forum -

Judging by the username, it's a hotwire system......

I am going to guess that it is running 'closed loop', i.e. using lambda sensors. Can you change the tune resistor to run open loop? I think it was an option.

Is there a manual for hotwire?

Chris.

PM me with e-mail address as I have an LR Hotwire test manual and some other useful stuff when I stripped down my EFI system.

does it have a crank trigger? Trigger wheel may have come loose or crank sensor faulty?

Thanks everyone.

Yes, it's Hotwire, sorry, should have said that.

The plugs are soaked. I took them out, cleaned them, regapped them. Think I will pop up the road and get a new set, always handy anyway.

I don't have lambda sensors.

The fuel pump is certain running, and getting 38psi.

I bet it is going to be really simple. It's just so odd that there is spark, air and fuel!

Reset the ecu it always ticks that off the list and is easy
Disconnect the battery for 30 secs then reconnect no more retained error codes

Ian

Thanks Ian.

Done that. I have a battery cut off switch, so I'm always disconnecting the battery. Plus, I have run the battery down a couple of times now.

I have a feeling it is fuelling. Any tips on how I can check the injectors are firing as they should?

Here's a summary of everything,

It's an MGB with EFI hotwire, on 3.5l, turns over but does not fire.

It has previously run trouble free for three years, really really well.

No jobs were done prior to this problem. It was being drivig in dry weather at the time, started running lumpy, then stopped.

- no crank sensor or lambdor sensors
- new coil, just in case
- new dizzy cap
- negative lead is attached to coil
- EFI has a good earth
- spark is good; well, I can see a spark at each plug. Is they a way of knowing it is good enough?
- plugs smell of petrol
- exhaust smells of petrol
- fuel pump kicks in at startup, and gives 38psi
- fuel pump kicks in again after turning over the engine

Something is niggling me about the fuel. The plugs are not dripping wet. Is there a way of testing for coorect fueling?

Another question, I got sent a new rotor arm, but it is tool tall for my dizzy cap. Are there lots of variants?

Regards,
Jim

Welcome aboard mate, you got here at last

I know the square root of bugger all about EFI. But the guys on here haqve a wealth of knowledge to help sort you out.

Having read the above, maybe you could dump some petrol or easy start downs its neck while cranking?? If it tries to fire them maybe that will confirm lack of fuel?

Thats it!! I dont know anymore

Pel

Spark plug leads going to the correct plug

I have a spare but modified ecu you can try if you want no doubt Perrry will be over my neck of the woods sometime soon

Injectors fire in batches of 4 each side so if plugs are smelly on both sides then injectors are working

Do one other check pull the dip stick and feel the oil is it normal or thin it may be that the injectors are stickingopen

Other than that it is out ith the multi meter

Ian

Did you try unplugging the CTS as I said? That has the major effect on the fuelling. Unplugging it will make the ECU think the engine is cold and deliver maximum fuelling for a cold start.

Or simply unplug it and measure the resistance between the two terminals. Should be approx 2500 ohms at 20C. A faulty one will be miles out.

Spark may be there but it needs to be full 12 volts for starting. Try hot wiring the coil straight from the battery positive. And yes, rotor buttons are not created equal and there's a lot of dodgy aftermarket ones around

Right, I'm back on this again. I am certain fuel is not the problem now.

Robrover wrote:Spark may be there but it needs to be full 12 volts for starting. Try hot wiring the coil straight from the battery positive. And yes, rotor buttons are not created equal and there's a lot of dodgy aftermarket ones around

Like it. I'll try that.

DaveEFI wrote:Did you try unplugging the CTS as I said? That has the major effect on the fuelling. Unplugging it will make the ECU think the engine is cold and deliver maximum fuelling for a cold start.

Or simply unplug it and measure the resistance between the two terminals. Should be approx 2500 ohms at 20C. A faulty one will be miles out.

Sorry, yes, tried that too. Thanks mate.

Sorted.

Not sure what it was exactly. But I cleaned up all the terminals at the starter motor, and at the fuse boxes, and it now runs lovely!

The end.