hallio

Yup, was the main relay. Nipped out and grabbed another one today and and all is good again 🙂 Thanks for the help. Steve

After more digging it looks like it may be the main ECU relays on the blink - the fuel pump relay is actually OK, however I suspect nothing will work if that main relay isn't working. Certainly an easier (cheaper!) thing to try before the ECU anyway 🙂 Thanks all.

Thanks. I have a spare pump so may just drop that in for the purposes of elimination. My thinking it was the ECU was because both main and pump relay don't switch on when connected to the ECU (but do seem to be working) and in addition my RoverGauge can't read from the ECU when previously it could? I'll go over all the earths though and cleanup all the relay contacts etc though next, seems a sensible move. TBH MegaSquirt probably isn't really worth the effort - I barely do any miles in this vehicle and it's cost me enough to get it this far! I thought all my problems were over when I parked it up a week or to ago after spending most of this year getting it up and running again! (I should know better than that with old Land Rovers). Cheers

Good point, I'll double check the earth tomorrow. It looks like Pin 4 on the diagram above (and mine here) and yes I've been working through the troubleshooting manual. I've been looking on eBay for second hand ECUs and there seems to be a myriad of different part numbers for the 14CUX - does it really matter which I use in this case (mine is PRC9061/80274B) or are they pretty interchangeable? i.e choose a RR / Disco 3.9 from the same year (ish) and it should be OK? Thanks for the help.

Thanks. I'm pretty sure the pump is ok and to my mind the main symptom here is it's not running when I turn the ignition on whereas it always used to. My tests this morning have narrowed it down to what I think is the ECU - it'd be good if you could confirm my diagnosis. With the ignition on I'm not getting 12v on the 87 terminals on either the main relay or fuel pump relay (unlikely both relays failed at the same time). I then confirmed the ECU is getting 12v on the correct connectors when ignition is off and on. With the ECU connector removed I grounded the 'switch' terminal on the main relay and did then get 12v on the 87 terminal. This to my mind means the ECU is not switching on the relays? In addition I hooked up my laptop with RoverGauge to the ECU and it said it couldn't communicate with the ECU (it worked last time I used it). Thanks Steve P.S The 101 came from a guy called Dave in Bristol!

Hi I have a Land Rover 101 with a RR 3.9 EFi in it (not my conversion, it's the way i got it) so I'm posting this question here as it's an engine issue I'm experiencing. The vehicle ran fine a week ago when I parked it up and went out today to use it and it won't start. It spins over nicely so first I checked i'm getting spark by holding the HT coil lead to ground (nice spark) and put a plug tester into one of the plug leads (nice bright light). A squirt of easy start will let it run for a second or two so I assume the ignition is OK and therefore it's a fuel issue. Previously you could hear the pump prime for a few seconds when the ignition was turned on and now I don't hear that. The pump works fine when I hook up a +12v to it, but when the I try to start it with this +12v connected it still won't run, so something is telling the engine that it shouldn't go. Just to confuse matters after a bit of prodding and poking it did run again, so I let it run while I started packing up my tools and then after a minute or two the engine stalled / died and hasn't started since. I'm wondering what simple diagnostic steps I can take to get this sorted, or at least get a little closer to finding the problem. My main issue is that this is a non-standard engine for this vehicle and has been DIY installed and hence any wiring diagrams may not reflect reality! Thanks all Steve H