Thread: 300 TDI Wont Start ??

Did you use a compression tester to test the compression, a diesel only needs fuel and compression to run, you seem to have fuel, that leaves compression.
Sounds like, to me anyway, that because the engine has been sitting for an extended period that the rings may be gummed up and not sealing properly.
How do you know you have compression, check it correctly, with a compression tester. If it is the rings gummed up you could try spraying copius amounts of WD-40 and winding it over on the starter with the glow plugs out, it may free them up, also remove the injectors and test them to see if they are working, something to go on with anyway, Regards Frank.

Thanks Frank,

If I remove the glow plugs how do I test them ?

And if you are correct and I have no Compression and I remove the Glow plugs spray WD40 in ........... Is that likely to be a permanent fix ? or Will that just prove the the rings are gummed up ?? Or once they free up will they be fine again ??

Cheers

Originally Posted by Tank

Did you use a compression tester to test the compression, a diesel only needs fuel and compression to run, you seem to have fuel, that leaves compression.
Sounds like, to me anyway, that because the engine has been sitting for an extended period that the rings may be gummed up and not sealing properly.
How do you know you have compression, check it correctly, with a compression tester. If it is the rings gummed up you could try spraying copius amounts of WD-40 and winding it over on the starter with the glow plugs out, it may free them up, also remove the injectors and test them to see if they are working, something to go on with anyway, Regards Frank.

Is igniton OK, check there is voltage at wire at injector pump. if not run wire from battery to this connection- but you need to use an inline switch to stop
engine running.

its low on compression probabley due to sitting around for ages..

remove all 4 glow pulgs and drop a tea spoon of oil into each pot with the pot at BDC, wind the engine over on the starter for a second then put the glow plugs back in and it should start (especially if your sure that the injectors are ok and youre getting fuel from the pump at pressure)

the other thing it could be is youve burked the pump timing and its injecting too late in which case it might start after extensive glowing but it'll run crook.

I had a similar non staring issues when rebirthing a 300.

- check, as in bench check the injectors, or swapsies with 4 known good ones.

- even though I had fuel at the 4 loosened injector fittings when cranking, my problem ended up being not enough flow through the lift pump, meaning not enough supply to the IP. Once running the IP seems to pull well from the tank but on initial starting the crook lift pump wouldnt adequately prime the IP and it wouldnt start?

Its easy enough to check IP timing as another one to cross off.

its probably running now!
S

The white smoke at cranking sped is unburnt diesel. My bet is it is out of time, even a little bit retarded will cause difficult starting, even more so whenthe engine has been sitting, as the compression pressures will be lower. You are aiming at at least 400Psi, preferrably 450 to 500 as a good cond Tdi, warm at good cranking speed.
Warming the incoming air will help, either by pouring boiling water on the intake manifold, or GENTLY playing an oxy flame over it prior to cranking.
JC

Thanks, will give this ago today !, I presume BDC is piston down ?
The injectors have been rebuilt / serviced along with the pump !
Pump timing was set up at the injection place !

Cheers

Originally Posted by Blknight.aus

its low on compression probabley due to sitting around for ages..

remove all 4 glow pulgs and drop a tea spoon of oil into each pot with the pot at BDC, wind the engine over on the starter for a second then put the glow plugs back in and it should start (especially if your sure that the injectors are ok and youre getting fuel from the pump at pressure)

the other thing it could be is youve burked the pump timing and its injecting too late in which case it might start after extensive glowing but it'll run crook.

yep.. piston down for BDC (bottom Dead Center) although putting the crank at the midstroke position (1/4 a turn before or after BDC/TDC) will also work, the objective being to allow the oil to trickle down the glow plug hole, then dribble out inside the combustion area down the dome of the head onto the cylinder wall onto the side of the piston to be distributed over the top ring giving you a temporary seal and increase in compression ratio.