Susspect glow plugs

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dingdangdoo
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Susspect glow plugs

Post by dingdangdoo »

Hi i have just got my 1.6 diesel up and running but with a small problem.It is a pain to start taking up to a few min turning over.I have put a volt meter across the 2nd glow plug from the rear and it only reads 10.8 volts when the yellow light is on.I thought it would of been the full 12volts.I am just gled the bleeders running.

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ewenmaclean
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Re: Susspect glow plugs

Post by ewenmaclean »

Hello,

you will get a bit of voltage drop from the wires across the relay from the battery so check the big thick red wires and see if maybe they are getting hot which they shouldn't really. I would be more inclined to check the actual glow plugs - if you are getting infinite resistance then they are burnt out - check that with a multimeter between the tip and a good earth. Are you using the ignition advance and is that working and connected to the pump?

Ewen

dingdangdoo
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Re: Susspect glow plugs

Post by dingdangdoo »

Cheers Ewen i have just had another look and have found that the voltage is from the rear forward the voltage is roughly 10.9v at all the glow plugs.I would of thought the rear one that has the main feed would be 13+volts.The battery has a full charge and is spinning over well.Also the cold start pull has been broken off cab side for a long while but always has started after one or two cranks.Would it not be worth disconnecting the feed and using a jump lead on the rear feed just to see if it is any better baring in mind i have a few spare plugs of my old engine?Or is a big no no?

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ewenmaclean
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Re: Susspect glow plugs

Post by ewenmaclean »

Hello,

where is your battery located? Usually I think the diesel batteries are in the engine bay (I may be wrong) so the voltage drop to things like the starter and glow plugs isn't so bad. Is yours under the seat at the front? Cleaning up and sorting your earths is a good idea too - gearbox nose in particular.

I suspect that you might want to check the connections from the battery to the relay itself. If the cable is old or the ends are corroded and introducing extra resistance you will get hot cables and lose voltage. What you want is a big fat cable to the relay - I'm sorry but I don't have any diagrams handy, but I seem to remember the glow plug relay gets its feed from the starter motor connection - so not far.

Is it possible you've changed the timing of your pump recently? If it is slightly retarded this really won't help in starting and it's not that cold at the moment so I'd be surprised if the glow plugs were the real problem. An engine with decent compression shouldn't really need them if it's not cold out.

Hope you manage to find the problem

Ewen

dingdangdoo
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Re: Susspect glow plugs

Post by dingdangdoo »

Cheers mate will have another look tomorrow.The battery is in the engine bay so will have a look in the relay box while i am there.Hope fully its nothing more.

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Oldiebut goodie
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Re: Susspect glow plugs

Post by Oldiebut goodie »

dingdangdoo wrote:Cheers Ewen i have just had another look and have found that the voltage is from the rear forward the voltage is roughly 10.9v at all the glow plugs.I would of thought the rear one that has the main feed would be 13+volts.The battery has a full charge and is spinning over well.Also the cold start pull has been broken off cab side for a long while but always has started after one or two cranks.Would it not be worth disconnecting the feed and using a jump lead on the rear feed just to see if it is any better baring in mind i have a few spare plugs of my old engine?Or is a big no no?

I am not sure what you have measured to get the 10.9v at all the glow plugs - did you run a wire to each plug in turn to get that reading because if you didn't all you have done is check the voltage of the busbar.
Either check the resistance of each glow plug with the busbar disconnected or check the total amperage drawn:

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Oldiebut goodie
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Re: Susspect glow plugs

Post by Oldiebut goodie »

ewenmaclean wrote: If it is slightly retarded this really won't help in starting and it's not that cold at the moment so I'd be surprised if the glow plugs were the real problem. An engine with decent compression shouldn't really need them if it's not cold out.
Ewen

Mine wouldn't start in the full heat of summer with no glow plugs - these engines aren't as good as something like a tranny engine with high compression that will start all year round with no glow plugs.
1.6D 2019 VW T-Cross
200hp VW T6
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ewenmaclean
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Re: Susspect glow plugs

Post by ewenmaclean »

ok - apologies - I stand corrected. Still worth checking the timing though I reckon.

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Re: Susspect glow plugs

Post by kit »

Fit a non return valve between the filter and the pump just in case it is not the glow plugs.
1y Tin top rust collector.

dingdangdoo
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Re: Susspect glow plugs

Post by dingdangdoo »

Many thanks,i went over every electrical connection and also noticed a the blanking grommet missing on the return and it was weeping a little.I tightened up all the pipes and fitted a new grommet and it fired up first time.I think it could of been puling in air to the fuel pipes.Any way thanks again.

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