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alex-the-lyon

Engine won't start. Seem to have weak spark - help!

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Got a 4.0 v8 from a p38 in my 90.  Fitted megasquirt back in 2012 which has been working pretty well!  I have got it out of dry storage (3 yeard...)to get it back on the road and it started first time!  It started to run badly then died and I can't get it running again.

We have fuel, 2.7bar on the fuel rail.  We have compression and the plugs are getting soaking wet with fuel.  I checked the spark and the spark is not that powerful and orange.  I am running the stock landrover coils (4 of them) mounted to the rear of the plenum with the edis8 module.  I checked the spark on all 4 coils with the same results.

Megatune shows sensible readings from all the sensors, including a 150ish rpm reading while cranking.

Any ideas would be much appreciated!

 

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It could just be that the plugs are fouled, taken them out, put them in the oven at 150C for 20 mins and reinstall, then try to start again.

Or just replace them ;)

How are you testing spark?

Do you have full low voltage (12V) at the coils?

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I wouldn't put it past there being an earthing fault which has triggered this whole thing off. Check your EDIS and engine grounding carefully, clean and reseat while the plugs are baking. 

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If the plugs are soaking wet, could it be a stuck fuel pressure regulator?

I'd imagine the other suggestions are better though - bad earth or coil supply.

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Thanks all for your suggestions - ill give them a go over the weekend.  I got a nasty feeling this may have started after I replaced the battery...!  will go and check the earthing!

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Hi all, sorted and now running a dream!  Found it was a combination of things...  Old fuel (drained it out and filled it back up with new fuel), took out all the spark plugs, cleaned them and when I checked the crank shaft sensor the cable connector fell apart in my hands 😩.  Replaced and it fired up as if nothing was wrong!

Thanks for all your help!

(sorry for the delay posting this reply - covid has put a damper on things!)

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If you're running the standard 4.0 coils, would you mind taking a photo or two of how you've wired them up? I've got the same setup and translating it from the more normal Ford packs is difficult. As yours is running, it would be a huge help if I can see how it's done.

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