1993 Patrol 4x4 Electrical Engine Power Loss

[Plantagenet]

Hi All,

Hoping someone can provide some advice or recommendations so that I can work out what best to do. I'm no car enthusiast so please be gentle ;)

My father in law has a 1993 Nissan Patrol dual fuel petrol and gas. Sorry I don't know the exact model. If this is important to help diagnose then I will source.

I'll try and detail the problem as best I can. The car drives okay on both petrol and gas. Problem starts when using anything electrical which, what I think, draws a fair bit of amps.

For example at idle it sits at approx 900rpm-1000rpm. Turn the lights on and rev it it cuts out at about 2000rpms. Flooring the pedal and holding it...it revs right up to ~2000rpms drops down and tries again.

Quick presses of the accelerator and the engine struggles, popping and spluttering. Turn the lights off and its fine.

This happens when using the electric windows, pressing the cigarette lighter and using the aircon blower.

Its fine if just using the radio.

We tested with a multi meter. Getting approx 14v at the battery and same at the alternator. When turning on the lights there are no significant volts dropping at the batter or alternator.

Cleaned up the battery terminals but that didn't help.

I have read posts where people have spent big $$$ just to simply diagnose these issues only to find it was a $400 odd sensor switch or something like that. I would rather fork out the money and buy him something else but my father in law is head strong and wants to fix this.

Before taking it to be professionally diagnosed I thought I would try my luck with those who really know these cars.

My basic knowledge doesn't help me wrap around the problem.

Any advice or recommendations would be greatly appreciated.

Thanks

[Mike02Ti]

Have you checked all the earth straps? Eg battery to body, battery to engine

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[Plantagenet]

Yes we found one earth strap disconnected.

Cleaned it up and reconnected but still same problem exists.

How would I go about finding a wiring schematic for the car showing all earth straps so I can co firm they are all connected?

Thanks

[threedogs]

You can never have enough earth straps, even if you run some new ones.
Have you checked all the vacuum hoses they could be brittle and perished
if they are original.
Check all connections

[Plantagenet]

Thanks for all the replies guys.

I think I have worked out that the car is a GU rather than a GQ. I downloaded the manual and thought I would give self-diagnosis a go. But the manual refers to Power lamp whereas on this car we have the O/D lamp.

Is this car a GU? How can I confirm?

Also am I able to run self diagnosis on a GU Y60?

Thanks

[MB]

G'day Plantagenet, sounds like your father in laws truck is a 1993 GQ mate?
https://en.m.wikipedia.org/wiki/Nissan_Patrol
Great thing you're doing to help him out! Sorry I'm an auto elecy nuffy so others can hopefully help or try download here somewhere the GQ manual, Cheers!

[MB]

Just re-reading your post mate and again I'm an elecy nuffy. Can you confirm the coil is getting full power always through all revs? The last petrols with dizzy's I drove many years ago had slightly similar symptoms with dodgy points in the dizzy. If it wasn't the dizzy/points on most occasions it lead back to the coil being faulty and after that the ballast type resistor thingy me bob. I used to isolate the component issue by using a big screwdriver in plug leads or coil lead against/near the block. Bright blue spark was good, red/orange I had an issue to keep working my way back to the battery?