Glow plug fuse.

[wookie]

I'm thinking the busbar is touching something it shouldn't.
95 VW T4 1.9

I'm not familiar with that engine but how hard is it to whip off the busbar ? Then you can measure the resistance of each glow plug (to earth) in turn to work out which if any are faulty. I've been stung with dead brand new glow plugs in the past so now I always test them on a battery before fitting.

Another quick test is to disconnect the feed wire to the glow plug busbar and use a test lamp from there to earth, after replacing the fuse that has blown when you turn on the ignition the lamp should light up for a bit might be 1 second or longer, if it's not lighting up then the supply is the problem (the cable might be chaffed after the fuse, or a burnt out relay that's shorting out) The fuse shouldn't blow whilst doing this, if it does then there defiantly is a problem with the supply.

If the test lamp works as expected then I'd measure the resistance of each glow plug if you have a meter, otherwise a quick and dirty method is to run a thickish wire from the battery positive and touch it on each glow plug in turn, if there is no spark then that glow plug is probably dead (open circuit) if there is a big spark then that glow plug is probably dead (short circuit).

The best way to test glow plugs is out of the engine, just connect them to a battery (polarity doesn't matter) and the non-threaded bit at the bottom should glow red after a couple of seconds.

 

[puffernutter]

Good luck - I have broken more glow plugs trying to get them out of the engine and at times they are not the easiest of things to get at! Sometime better trying to remove after the engine is hot.

Last time I tried, I had to get the head off to fish out what was left.....

 

[wookie]

Good luck - I have broken more glow plugs trying to get them out of the engine and at times they are not the easiest of things to get at! Sometime better trying to remove after the engine is hot.

Shouldn't be a problem as he said he has already changed the plugs, but I totally agree with you that they can be a sod to remove, if they are being awkward then try again with a hot engine, the same with stubborn sparkplugs.

 

[p0689109]

AS they have not run long they should come out easy but for ones that have been in some time it is always best to use plenty of wd40 and turn a bit anti then clockwise a bit at a time so that any build up of carbon can be cleaned off the plug which is sometimes the cause of them snapping. Slow and laborious but better than the alternative of snapping them.

 

[Rig Pig]

I posted on here a few years ago about the 'fun' I had with glowplugs in a Toyota Yaris.
But if you have had them out recently there shouldn't be a problem.

 

[Bryan Williams]

I was going to ask some of advice given above ,cheers .
I'm a black belt at getting these out.
The 1.9 is quite easy really, you can lift the rad into the service position which helps, but I just undo the bottom hose ,fan and rad sensor, the power steering cooler pipe then the rad hinges away to the right and you can get your head right in.
A dedicated 12mm and 8mm ratchet plug spanner cracks them off ,then because there is not much room to turn said spanner I flick the ratchet round with a thin screwdriver. I was chuffed when I realized I could do that until I figured that is what they are probably designed for anyway and I had done the job twice without realising..
Two off them I reach easily with an old box spanner.
The best bit is when putting the fiddly 8mm nuts that hold the busbar ,a telescopic magnet fits through a box spanner ,holds the nut in place and screws on really quickly.
The thing I reckon I did wrong was this time instead of taking the busbar out and tidying it up I pushed it down out of the way then pulled it back up and on
I think its shorting out.
I always screw the new plug in a couple of threads then wind out then in a bit more like in tapping them.
They always seem to come out easy.

 

[Bryan Williams]

Finally got chance to have a look tonight , I had twisted the end of the busbar over and then connected the power wire to it so it was shorting against the block..
Easy fix.New fuse didn't blow.
Thanks for all the advice.

 

[carbon]

Have had two five cylinder t4’s lots easier with the front in service position but found two glow plugs easier to get at from underneath, two from the top and the least said about the one behind the injection pump the better