Are these two problems related?

[Donald360]

A strange tale of two, possibly related, problems.

(problem 1)
Took the van up to the Western Isles for a week. While tootling around Lewis and Harris (on lpg) we started to hear a strange 'knocking' noise from the back of the van . We thought at first that it was coming from the rear n/s wheel. I suspected the cv joint. We got a mechanic in Stornoway to check things out as we were concerned about the long drive home. He couldn't find anything obvious wrong with bearings, brakes, driveshafts and suspected it might be the gearbox. The knocking noise starts slow and seems to increase with road speed and sounds like a wee hammer tapping away under the engine.

Gently drove back south, with this knocking noise driving us mad and concerned that something was going to fail catastrophically in the gearbox. At Fort William we filled up with lpg, but decided to use up most of our tank of petrol on the remaining journey home. Would you believe it, as soon as we switched to petrol, the knocking went quiet and the van drove all the way home to Fife, sweet as a nut!

(problem 2)
Still running on petrol, we drove to Glasgow. Went into the city centre and parked for a bit. Time to go home and the van started up, it drove for about 20 yards and then conked out! No fuel was getting to the carb, by the sound of things. Tried to switch back to lpg, but couldn't get it to start on that either. Of course we were stuck in the middle of the busiest spot in the city (George Square/Queen St). We got the AA out and the wee mechanic eventually diagnosed a problem with the fuel pump and we had to get towed all the way home.

What I'm wondering is if the knocking noise we heard earlier was the fuel pump wearing out (running dry so to speak) while we drove on lpg. It then went quieter when it had some petrol in it, but was still on the way out. Or has anyone got any other ideas?

I still can't figure why it won't start on lpg now though.

Cheers,
Donald.

PS - I also have a problem with my left hip which has been very sore recently, could this be related as well?

[jaylo264]

Sounds vaguely possible to me -- tho not having LPG , i don't even know if lpg uses a fuel pump or whatever -- have you replaced the thing , and does it now start ?
jaylo

[Donald360]

Haven't had a chance to do any tinkering yet (hip is still too sore). Lpg doesn't use the petrol fuel pump at all as far as I know, but I suspect it is still 'pumping' away even though the petrlo supply is isolated during lpg use.

Cheers,
Donald.

[Donald360]

BTW the engine is a 1.9 water cooled - with an lpg conversion.

[Ian Hulley]

Hi Donald, who's gas conversion is it ? If it's a Gasure I'd ring Steve and have a chat.

I can't think it's to do with the petrol pump itself because it runs happily on petrol ... unless it's cavitating when it's on gas ??

Ian.

[Donald360]

When we tested the petrol pump in Glasgow, It pumped a couple of pathetic squirts and then next to nothing. So i reckon it, or the push-rod thingy, is goosed. What I'm not sure of, is whether this could be related to our lpg 'knocking' problem.

Cheers,
Donald.

[AngeloEvs]

Did the chap check the solenoids? One for the petrol and three for the LPG (you may only have two IIRC). If the fuse blows then you wont be able to start on either fuel. Petrol Solenoid should have a manual over ride control on the solenoid itself, either a lever or a rotary control in the event of total system failure. Can't help with the noise though but could be worth checking for the starting problem.

[Ian Hulley]

When we tested the petrol pump in Glasgow, It pumped a couple of pathetic squirts and then next to nothing.

Sorry but I thought you said it ran fine on petrol ?

Ian.

[ermie571]

It did, then conked out after being parked up!

Donald, no idea if the two are related....first thing is to get a known good pump an see if you can get it to start on petrol. Or fill the float bowl in carb with petrol, and see if it will start.

If its once again happy on petrol...next stop is LPG. Check fuse...mine went on the fuse that was controling thd gas system...so it no startie.

Good luck,

Em
x

[Donald360]

Thanks for the replies. The AA man got the engine to fire up when he squirted some magic spray can into the carburetor throat - that was when he was certain that the pump was at fault, so I think a new petrol pump is needed. I will also try to locate and check the fuse(s) for the lpg solenoids and will let you know how I get on.

Thanks,
Donald.

[Donald360]

Seems the two problems aren't connected at all! Been out and had a tinker with the lpg electrics and found a loose connection that was stopping one of the solenoids from working. Van now working on lpg again! Funnily enough, the knocking noise seems to have stopped as well. However it did this before and then the noise came back, so I'll keep my ears open for now. Just have to sort out the fuel pump issue now.

[ermie571]

Hi Donald!

Well done on getting it going again.

IS the knocking the solenoid or wiring moving which is allowing the wiring to come adrift?

Em
x

[Donald360]

No the wire came off at the back of the lpg guage at the dash, this prevented one of the relays from working I think. i'll keep you posted on my progress with the petrol pump.

Thanks for your interest,
Donald.

[Donald360]

Have now replaced the petrol pump (courtesy of JK) and it all seems fine now. Went for a short run and tried out both LPG and petrol systems. So far so good, so I'm hoping that is the problem sorted.

Cheers,
Donald.

[Donald360]

Eventually tracked down the cause. Turns out it was the CV joints all along. Although not actually worn, they were very dry with almost no grease left. So we packed the boots with grease and sealed them better. So far, so good - thank goodness. Just thought I would wrap this thread up.

Cheers,
Donald.

PS - The latest problem seems to be an extreme reluctance to run on petrol after a long time on lpg. Trying to switch to petrol for a short time more often and, so far so good - seems a bit better behaved.