I've got some issues with my mum's 5.0 LPG LTD. it has various intermittant problems including
-lack of power on petrol, but idles ok
-power with LPG but idles rough
-strange gearbox behaviour, going into neutral suddenly when cruising (i do not believe this to be a mechanical gearbox issue, but something else - as it is usually flawless)
-hesitating or stalling when taking off after idling for a while (eg traffic light), seems to be only on lpg though.
I have just done a self-test (engine off) on the ECU and it came back with codes 87, 44 & 95. one is a smartlock fault, which i have no idea about... but the other two are telling me the fuel pump relay is not operating correctly. I have noticed that when the ignition is turned on (not cranking), the fuel pump will operate continously, not just prime the lines like my LTD does. I have located the fuel pump relay and have swapped it with the high beam unit but the problem remains. it does look like it has been altered for the LPG installation however.
what should the fuel pump be doing when the LPG is being used? Im a bit baffled as to what to do next as the fuel pump relay circuit has obviously been changed to suit the LPG, so i cant refer to the workshop manual. does anyone have any ideas?
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1992 DC LTD 5.0
Duel exhaust, Genie extractors, Ported E7 heads, ported lower HO inlet, 70mm maf, Underdrive Pullies
I was under the impression that the fuel pump power was cut when you switched to LPG. If it ran that wouldn't be too much of a problem but it would be a waste of power. The fuel pump coming on and staying on is a sign that the fuel system failed it's test as showen by the fault codes.
I would have thought that with LPG, they would have cut and inserted a relay in the main power run to the fuel pump. This shouldn't really effect anything if you are switched to petrol.
BTW, the gearbox going into neutral while cruising sounds like a faulty neutral safety switch. Mine went and did exactly the same thing, cruising or accelerating it would drop into neutral and rev the hell out of the engine and then sometimes slam back into gear which is not fun at all. When I taked to the mechanics at ford they said it was fairly common for them to go.
Like Grant said, having the pump running while on gas shouldn't cause the car to run bad. Is there a fuel shut-off solenoid? Check that its working, I remember on my parents old XD this stuffed up, so it would run on petrol and gas when switched to gas.
If the gearbox is playing up as well, it could be TPS-related. Have you checked the voltages across the black and green wire on wither TPS?
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95 EF Fairmont 5.0 - Heritage Green - 4 Speed auto with AU S5 - 3.23LSD - 17x8" LWT Wheels - King Superlows - 76mm Cobra MAF - 65mm throttle - BPT Underdrive Pulley Kit - 3" Mandrel-bent Lukey exhaust - Tinted Windows - MP3 CD player - White faced dials.
I have swapped the TPS sensor with mine and the problem persists, so it may be the neutral safety switch like grant said.
the most frustrating thing is that i cant replicate the engine problems consistantly. i know it does it, but its very hard to see if you've fixed the problem when it wont do it again.
one train of thought was that the injectors were leaking because of the constant fuel pressure when on lpg, causing it to run a mix of both petrol and lpg.
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1992 DC LTD 5.0
Duel exhaust, Genie extractors, Ported E7 heads, ported lower HO inlet, 70mm maf, Underdrive Pullies
so could you give me some details on this NSS grant? what part is it, the big white thing bolted to the side of the trans on the passanger side? how much is it worth from ford/aftermarket/wreaker? whats involved in replacing it?
cheers buddy.
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1992 DC LTD 5.0
Duel exhaust, Genie extractors, Ported E7 heads, ported lower HO inlet, 70mm maf, Underdrive Pullies
Yeah its the white electrical connector on the passenger side of the trans. Worth about $50 from ford (I may have a spare one laying around though if you want to test it first). All you need to do to replace it is remove the wiring loom, undo two small bolts and then replace, 20-30min job.
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