I run a 3.9 D1, open loop gas system.

Why cant i just unplug the ECU if it only ever runs on gas? the stepper is the only thing that is doing anything now as the petrol injectors arent being used so control of the injection bursts and so on is defunct, if i can get it to idle well enough with the gas mixture do i still need the stepper butting in and ruining things?

I am asking as todays issue is the fecking thing is refusing to run the fuel pump when the key is turned, now maybe the pump is dead, maybe the relay is dead, maybe the ecu is not getting a signal telling it the engine is powered on at the coil but the relay for the ecu is working, I know this because i have the NAS disco and it comes with the LED fault code display which is telling me the thing is on and yes i have a TPS problem (fault code 17) but it ran fine on petrol with this before and occasionally telling me one of the Lambdas is out or range (codes 44 and 45 respectively right and left) again it ran fine with these issues on the to-do list before but it is point blank refusing to fire the relay for the fuel pump.

If im honest i dont want to get my hands dirty today as I have work in about an hour but i have had a fiddle about and i just cant hear the relay coming in and the pump running.

Now since i did the dizzy et al, it will fire up fine on gas and runs a treat most of the time seeing as the weather is now in the 20s Im not that bothered about warm up times, So what do you think can i just unplug the ECU, what else does it control that Im missing other than the stepper now?

I can't think why not if it's not an auto. But then you can start on gas anyway without unplugging and still have stepper control.

Ah but it is an auto, does it interfere with the autobox too? Pesky sod!

cooltide said:

I can't think why not if it's not an auto. But then you can start on gas anyway without unplugging and still have stepper control.

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Im telling you now this thing will probably end up on carbs at this rate.

Probably end up with a bit of stalling coming to a halt as road speed transducer not being read, low idle in drive with stalling perhaps and resulting lower oil pressure Raise idle will increase clunk through transmission to use techspeak

At least it's working, that's the benefit of dual fuel. When one breaks the other runs, if both break it's ignition. Cheaper than testbook.

cooltide said:

Probably end up with a bit of stalling coming to a halt as road speed transducer not being read, low idle in drive with stalling perhaps and resulting lower oil pressure Raise idle will increase clunk through transmission to use techspeak

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Bugger, right better get myself in the garage tonight then with the multimeter and see which bit needs replacing next then, I reckon the relay is ok as when swapped with the ecu relay it ran the ecu so probably the fuel pump has gone belly up. This was supposed to be a run about whilst I got the tdi rebodied and it's taking all my time to keep this one going. Harrumph I say ha-fecking-rumph, ah well green oval and all that.

Been through it all with them. It's at that age. Pump, dizzy, amp, coil, steel fuel lines will burst a leak next
At least I never had cats and lambda sensors on my RR classics / discoveries. You can remove them and change tune resistor tho if local regs permit

DiscoPol said:

, ah well green oval and all that.

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yeah living the dream
ONE LIFE LIVE UNDER IT

Righto, been out and drilled up the pump access hatch, t'was a bit rotten, i have 5.36 v going to one pin which i presume is the sender and nowt on the others, two of em bell out as neg/earth so i am surmising the last one is supposed to be the feed, it looks white-ish maybe it has a trace on it but sadly im colour blind and its dark out there so i cant really tell.

Anybody know if thats the feed? all the others are either blue, black or dark green i think but definitely dark

The under bonnet fuse is good, the relay is good and clicking over when the ignition is turned to pos 2. If somebody knows then i will cut into that and give it a little jolt of 12v+ up its khyber and see if the pump is goosed or not, I dont really want to disturb the pump if possible if it isnt fubar because as with everything else on this disco the unions are corroded to sh1t and you just know if i pull it out to bench test then i will knacker up the joints and possible snap what looks like very brittle plastic elbows on the send and return pipes.

I might just have a search about for others that have this problem on the net but if you know please pipe up and let me know.

Ta