Thread: LPG Causes D2 V8 to tick

Had reports of similar problems before. The pressure of the gas rises with the heat and causes the converter to knock. I now mount all injection converters on rubber mounts to isolate them from the cab.

Find where the gas injection hoses come from, there will also be water hoses, and it will be hot to touch: that is your converter. This will knock, usually under acceleration when hot.

Originally Posted by bee utey

Had reports of similar problems before. The pressure of the gas rises with the heat and causes the converter to knock. I now mount all injection converters on rubber mounts to isolate them from the cab.

Find where the gas injection hoses come from, there will also be water hoses, and it will be hot to touch: that is your converter. This will knock, usually under acceleration when hot.

Dont want to hijack the thread, but its partly on topic.

Hi Bee utey - you might recall that my D2 has a mixer and lambda controlled converter idle and main gas tap. I saw your recent post about a particular brand of injection causing problems and now this (which doesnt sound anything more than annoying though). My mixer works well and gives me smooth economy. I was always hesitant about all the extra parts in injected systems (for fault diagnosis later on) versus single mixer. I was also concerned about the black gunk with the injectors and injector pipes etc. What is your view on the injection systems now, a few years down the track versus a well set up lambda controlled mixer system.

Cheers

Originally Posted by mrapocalypse

My beloved D2 has always had a slight engine tick..... but lately after some big trips where speed limits were not really strictly followed and there was lots of rough tracks.... the LPG injection System seems to make an even louder tick in the engine (Not sure if it's the same tick made louder, can't hear old tick over new tick and old tick cannot be heard with bonnet open .... i know cool huh???)

It sounds very much like tappets, but goes away when you turn the LPG off....

I have stared at the engine while it's ticking and it seems to come from that strange sensor attached to the intake hoses, but it could be coming from anywhere! Usually only does it when warm too.... I have heard that it could be the catalytic converters (Thanks Mike 90 RR).... so i am looking into that. Any other suggestions.

Thanks in advance.

Ian.

the gas injectors are a little noisy, maybe with age they are getting noisier.
Perhap the rubber mounts insulating the injector brakets are gone and the brackets are sitting hard against whatever they are mounted on.

Originally Posted by mrapocalypse

..... but lately after some big trips where speed limits were not really strictly followed
Ian.

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just a thought and i am not familar with a d2 but i have seen on a county 85 . The fuel pump was still running and only using a solenoid for petrol isolation thus giving the ticking sound (pump is pumping against a shut supply and wearing )

Originally Posted by Pedro_The_Swift

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Ah. You know. Chatting while driving on the open road. Few tunes playing. You look down and see you're doing 140!

I would say it was not coming from the gas system itself. So far the cats are the most likely cause. Aside from replacing them I can't really work out how to test them. It's a really hard place to get your ear next to with engine running!

These things love the teens--

On idle I hear one gas sol tick,,(idle with bonnet open)

with this motor I have no tappet noise!(idle)
(the green one had one noisey tappet, idle)

can you hear the tick in the cab?(idle)
while driving?

Originally Posted by ozscott

Dont want to hijack the thread, but its partly on topic.

Hi Bee utey - you might recall that my D2 has a mixer and lambda controlled converter idle and main gas tap. I saw your recent post about a particular brand of injection causing problems and now this (which doesnt sound anything more than annoying though). My mixer works well and gives me smooth economy. I was always hesitant about all the extra parts in injected systems (for fault diagnosis later on) versus single mixer. I was also concerned about the black gunk with the injectors and injector pipes etc. What is your view on the injection systems now, a few years down the track versus a well set up lambda controlled mixer system.

Cheers

Well your gas injection is mandatory to prevent backfires ruining all those plastic inlet manifolds being fitted to cars these days, and cars with coil packs or individual cylinder coils are really hard to prevent backfiring on. As far as the black gunk is concerned, the best gas injectors are serviceable and the vapour filters have got better. Having said that a well set up mixer system loses little to injection on something as simple as a RRC/D1 engine. They are usually best controlled to the lambda sensor voltage in any case. I don't recommend fitting injected gas to any car that doesn't run lambda sensors to the ECU and generally group firing is a pain for pulsing gas flow noises.

Back to this injection system, get the vehicle hot so the noise occurs, pull over and open the bonnet. Rev the engine via the throttle cable and listen for the noise. Switch to petrol and check again. If it's the gas converter you will hear it from under the bonnet.