audi 80 tdi starting issue

[sjp001]

Hi all, Just wondering whether anyone might have any advice at all. Basically my b4 audi 80 1.9 tdi has always started first turn of the key as soon as the starter cranks. Recently it cranked over ever so slightly longer then started and did this for a few days, and by the end of the week it would need repeated prolonged cranking say 8 times or so with smoke coming out of the exhaust before it would eventually start. Once started it will run fine and can be restarted like normal, but if left for a few hours it's back to the same story. The garage don't think air is getting into the fuel lines and have changed a couple of sensors and no change, and have now told me they are going to wire in a manual glow plug control and say it starts fine like this (I normally never see the auto glow plug light come on at all until it starts getting much colder).

Other things potentially to note (or not haha) is a couple of weeks before this I started hearing more turbo/exhaust noise and it has snapped an exhaust manifold stud but apparently this shouldn't affect starting. 2 years ago I did also have a fuel leak from the fuel pump and the rubber gasket was replaced and the pump pulses a bit on idle, which I was told by a pump expert is just how it is. In case any of this is relevant.

[struikie]

Was the fuel shut off valve at the back op the pump checked?

JW

[sjp001]

Thank you very much JW that's a brilliant suggestion. They didn't mention that so I'll ring them and suggest it tomorrow. Thank you so much for the help!

[RedV6]

Well if it starts fine when the glow plugs are powered directly, then you have your answer! Or at least its not the glow plugs themselves or anything else not directly related to the pre-heat system. Most likely the glow plug relay..!

[John.]

Hi all, Just wondering whether anyone might have any advice at all. Basically my b4 audi 80 1.9 tdi has always started first turn of the key as soon as the starter cranks. Recently it cranked over ever so slightly longer then started and did this for a few days, and by the end of the week it would need repeated prolonged cranking say 8 times or so with smoke coming out of the exhaust before it would eventually start. Once started it will run fine and can be restarted like normal, but if left for a few hours it's back to the same story. The garage don't think air is getting into the fuel lines and have changed a couple of sensors and no change, and have now told me they are going to wire in a manual glow plug control and say it starts fine like this (I normally never see the auto glow plug light come on at all until it starts getting much colder).

Other things potentially to note (or not haha) is a couple of weeks before this I started hearing more turbo/exhaust noise and it has snapped an exhaust manifold stud but apparently this shouldn't affect starting. 2 years ago I did also have a fuel leak from the fuel pump and the rubber gasket was replaced and the pump pulses a bit on idle, which I was told by a pump expert is just how it is. In case any of this is relevant.

If it cranks with smoke coming out the exhaust then that suggests it's getting fuel (so cut-off switch on pump ok) which might point at glow plugs, but if it's been run and then wont restart after sitting 2 hours would point to something other than glow plugs as there'll be heat in the engine?..... but then your garage says it starts fine if the glow plugs are powered directly ?

Check the turbo impellor is free to turn.....also check inlet manifold, these become choked up but it'd be really bad to effect starting....it can be checked if you take the EGR pipe off.

[sjp001]

Well if it starts fine when the glow plugs are powered directly, then you have your answer! Or at least its not the glow plugs themselves or anything else not directly related to the pre-heat system. Most likely the glow plug relay..!

Thanks very much for this Red, will pass it on and fingers crossed

[sjp001]

If it cranks with smoke coming out the exhaust then that suggests it's getting fuel (so cut-off switch on pump ok) which might point at glow plugs, but if it's been run and then wont restart after sitting 2 hours would point to something other than glow plugs as there'll be heat in the engine?..... but then your garage says it starts fine if the glow plugs are powered directly ?

Check the turbo impellor is free to turn.....also check inlet manifold, these become choked up but it'd be really bad to effect starting....it can be checked if you take the EGR pipe off.

John thank you so much for giving this some thought and sharing your wisdom. You know I'm slightly suspicious of the turbo as I started hearing a load of bearing noise for a few weeks prior to the starting issue, but figured maybe that was just because of the snapped stud/exhaust leak. Will pop down to the garage on Monday and pass this great suggestion on.