poor start and dodgey glow plugs

i have had poor start issues lately. I have eliminated fuel problems.

I have to run the glow plugs 3 times in order to get it to start and it does so with no problem but 2 glows is not enough this problem only occurs after it has stood overnight.

Now to day I have changed the cheap plugs for ngk ones. on taking the old ones out they have diiferent colours and one appears to be covered in soot. (see pic)

Does this indicate problem any one had the same problem ??

The dodgy plug is from the cyclinder at the front

Cheapo glowplugs are not reliable, the sooty one may just not be getting hot enough.

a tdi shouldnt need glow plugs if it does its either extremely cold ,cranking speed is low ,air in fuel etc or compressions low

I had same symptoms as you and it got progressively worse until it just refused to go one day, I had changed glow plugs recently and made no difference. Left it for a day and started to fault find, 12v to glow plugs, glow plugs all out and tested individually, checked diesel supply to filter and then to injectors..... Nothing after the pump... After a lot of hammer and chiseling the immobiliser off and 12v to stop solenoid started and first 1/2 turn over and she went, since then I've had perfect starting all through winter haven't bothered using the glow plugs since then

what do you mean with the stop solenoid can you elaborate on exactly what you did to sort it out.

G223 said:

I had same symptoms as you and it got progressively worse until it just refused to go one day, I had changed glow plugs recently and made no difference. Left it for a day and started to fault find, 12v to glow plugs, glow plugs all out and tested individually, checked diesel supply to filter and then to injectors..... Nothing after the pump... After a lot of hammer and chiseling the immobiliser off and 12v to stop solenoid started and first 1/2 turn over and she went, since then I've had perfect starting all through winter haven't bothered using the glow plugs since then

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you can destroy the immoboliser? the black box at back of pump? is there a standard spade under there?

G223 said:

I had same symptoms as you and it got progressively worse until it just refused to go one day, I had changed glow plugs recently and made no difference. Left it for a day and started to fault find, 12v to glow plugs, glow plugs all out and tested individually, checked diesel supply to filter and then to injectors..... Nothing after the pump... After a lot of hammer and chiseling the immobiliser off and 12v to stop solenoid started and first 1/2 turn over and she went, since then I've had perfect starting all through winter haven't bothered using the glow plugs since then

Click to expand...

can you elaborate for me what exactly did you do. In simple terms for me please

g233 cured his non start problem by bypassing the fuel solenoid...I think......depending on your type of pump you could try this, on ssome like mine there is a spade terminal you can simply apply 12v to, tto bypass it, or you can remove the spring inside it, which has same effect, iff you dont have a piece of wire handy, The immobileser can prevent 12v getting to the solenoid if its faulty.

But I dont think that is your problem...as if the solenoid is faulty or not getting 12v it wont fire at all.

In case you dont know, the fuel solenoid job is to cut fuel and stop the engine running, so it is in the pump effectively just before the injectors so it stops the engine straight away, when you turn the ignition off.

If you look at the back of the fuel pump there's a black box, hidden inside it is a solenoid you can put 12v to after you smash off the immobiliser, definitely crack an injector line and see if diesel comes through first before you start smashing incase there's another issue somewhere. I managed to get mine off by smashing the box enough to get a small punch to the security bolt and then once it was loose spin them out with a pair of small vice grips.

Definitely slacken the injector lines off first and crank over a few times and see if diesel comes out it should come out at a steady rate, if not then slack off the bleed screw on the top of the filter housing and pump the lift pump and again a steady stream should come out (you may find you have to turn the engine over a few times to get the lift pump to operate as it may be stopped on the cam lobe) if nothing comes out then I'd assume the immobiliser or stop solenoid is faulty

G223 said:

Definitely slacken the injector lines off first and crank over a few times and see if diesel comes out it should come out at a steady rate, if not then slack off the bleed screw on the top of the filter housing and pump the lift pump and again a steady stream should come out (you may find you have to turn the engine over a few times to get the lift pump to operate as it may be stopped on the cam lobe) if nothing comes out then I'd assume the immobiliser or stop solenoid is faulty

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Stop solenoid or immobiliser will not stop fuel coming out of filter bleed screw-but a duff lift pump will.
Check you have fuel as far as injection pump inlet,before you start smashing stuff off

biolandy said:

Stop solenoid or immobiliser will not stop fuel coming out of filter bleed screw-but a duff lift pump will.
Check you have fuel as far as injection pump inlet,before you start smashing stuff off

Click to expand...

Sorry should have made that clearer ment check and make sure diesel flows to the injector pump clearly first and that it's definitely getting to it and not after it before assuming it's the solenoid