TDI cold start problem

[eddy_p]

got an A4 2.5 TDI that only just starts when cold after 10+ seconds of trying.

starts first time when warm.

have replaced the glow plugs. 2 and a half of them were covered in black stuff the other 3 and a half were silver.

i guess the black ones are not good?

all the glow plug electric connectors on the top are fitted correctly and stay pushed on.

have changed the battery for one with a higher CCA. the one in there was 580, changed it to 750. new battery that came charged.

still the same!

could it be the starter motor?
loose/bad electrical connection somewhere?

any general advice for troubleshooting cold start problems with diesels would be great. any help would be appreciated! :1zhelp:

[Redzer]

I've seen on some other posts here and elsewhere that the water temp sensor causes a lot of these cold start problems.
seems the faulty sensor makes the ECU think the engine is already hot resulting in difficult starting from cold.

I'm sure some of the guys on here will have some ideas for you though.

[eddy_p]

thanks for the suggestion.

i searched the forums and on google and found the temp sensor can cause problems. i tried replacing the temp sensor and it's the same unfortunately.

i think i'll test the current going to the glow plugs next... should have done that earlier than now i think

[adamss24]

The glow plugs dont get energised unless its bellow 5 degrees celsius, so you wasting your time ! Either you have air in the fuel lines or the pump its on its way out....First problem its easy to rectify with a new fuel filter and new o-ring seals. If its still there, replace the plastic non return valve on top of the filter ! The second(fuel pump) its a bit more expensive though 600+ quid!

[kenney]

I would suggest before you do anything else, and that is, to check the basic timming,

[donnadiablo]

Help!!!

I have exactly the same thing going on with my 1996 Audi A4 TDi. It takes about 20 seconds to start - and that's after having the glow plugs and a coolant sensor replaced by my garage.

It's got to go back in next week as they're going to get an electrician to look at it. Should i be asking them to look at the fuel pump instead. Mind you, if it is the fuel pump then i won't be getting it done if it costs £600!!

Also... had the Cam Belt changed about 2 weeks ago... could that cause this problem to happen? I'm guessing that this could be timings??

Cheers.

Donna x

[kenney]

Hi (Also... had the Cam Belt changed about 2 weeks ago... could that cause this problem to happen? I'm guessing that this could be timing) Yes these engines are very sensitive regarding the basic timming