406 98 TD knocking intermittently

[cox377]

Hello guys, following recently having the bosch pump off my 1900cc TD 98 406 to change the seals, I now get an intermittant knocking / clattering when it starts.

I did 250 miles after the seal changes before this problem developed.

If I turn the engine off and back on again it tends to start normally, or bump start it. When I start it and get the clattering, the rev counter flys all over the place then goes to zero. Rev counter works perfectly when not clattering.

I've unplugged the lift needle sensor and all the sensors on the pump and sprayed them with WD40, made no difference.

I've looked for the TDC sensor on top of the bell housing but only saw a connector plugged unto a blank plug. Checked my other 406 and had the same setup..

Can anyone advise

Thanks in advance

James

[Doggy]

You've got to expect it's related to the bits that have been disturbed, but it may help to know that the pump will not be able to control the injection timing accurately if it's starved of fuel - may be worth making sure the filter's OK, the in-tank strainer is clear and you don't have any air leaks.

[cox377]

Thanks for coming back to me. If we look at it the other way, what things can cause the rev counter to act as it does?

[Doggy]

Well, the tacho effectively works of the needle lift sensor, so you've got to think that isn't working consistently. All suggests poor pressurisation to me.