The V8 Owners Forum -

The 'flapper' type EFI system had a diode pack, but that was never fitted to the 4.2 litre engine as far as I know.

It sits next to the main relay and fuel pump relays next to the ECU, which I think is under the drivers seat.

Chris.

I can't tell unfortunately. My copy of RAVE is 1995, and there is no mention of a diode pack in the fuel pump / inertia switch circuit.

Chris.

Any idea what it's for. I've been looking at the Land Rover electrical manual which gives component locations, but there are a lot of diodes!

Chris.

Good news!

Chris.

I think you have two problems:
1. Bad ECU
2. Bad AFM

Can you get one more of each??

Chris.

Does the tachometer appear to work correctly?, i.e. stable, and an accurate representation of engine speed?

The AFM does not need to be calibrated to the ECU.

Chris.

If you have not got this already, here is the factory manual for diagnosis: www.cowdery.org.uk/downloads/FlapperManual.zip Are you taking all of your readings from the ECU connector? (that eliminates any wiring problems). The system is 'open loop', so if the sensors are correct, it will run OK. It d...

One comment I can make about 4.2's is that they can break the crankshaft! I can't remember the details, but there was a guy on this forum who had worked for Land Rover 'back in the day'. In fact, the post was probably 10 years ago at least! The gist was that you could snap the 4.2 crank fairly easil...

Are you sure that 3.9 and 4.2 rods are the same? If they are, then I guess the pistons must be different?

Chris.

I suppose it depends what problem(s) they are having. I would go for the later block with crossbolted main caps, but have it top-hat linered.

Chris.

Also note that the biggest nuisance is getting clearance of oil filter and cooler pipes around the front diff.

On the P38, the diff is on the other side...

Chris.

Just be aware that Thor uses a 60-1 trigger pattern, rather than 36-1 like GEMS. This one is a Thor flywheel (although for reasons that escape me, the trigger feature is at the wrong radius, so I had to move the crank position sensor to detect it. It was also rotationally offset!) DSC08839.JPG And t...

Just a note on using a flywheel as the trigger wheel - the GEMS engines had a 36-1 configuration, and Thor uses 60-1 (I think). So you have to make sure the flywheel you use is compatible with the ignition system you use. Also, as far as I know, the flywheels are all the same size, but drilled diffe...

Sounds like a great project! I've done some similar things over the years in my Landie. You seem to be well on top of your research, top marks there! My comments: - I went distributorless with a P38 front cover. First go was with MegaJolt + EDIS8 + Thor coilpacks + flywheel trigger (and carbs). That...

There should be a lot of slack - it's the motion used to alter the timing with engine speed - the centrifugal advance.

But it does indicate a timing issue for sure...

Chris.