ZX 1.9TD 1993 Engine overreving

Dave Burns · Post by **Dave Burns** » 23 Oct 2003, 03:32

Well the same car with a CAV pump wont have one so its nothing to do with turbo's or whatever, that must mean its Bosch pump specific, my theory is that its just an antistall damper.
On some diesels at cold start if you suddenly close the throttle it can cause the engine to stall, have known it quite a bit on older type diesels but never had it happen with an xud.
Driving lesson time[:D] when you accelerate towards the next gear, instead of slamming the throttle shut and mashing the clutch pedal into the floor at the same time, begin to close the throttle slightly before pressing the clutch pedal, so that the engine is not on load when drive is disengaged, if you have a front seat passenger and he or she lurches forward when you change gear then you aren't a very smooth driver.
Doing this also prevents transmition bounce, as you accelerate, the rubber components of the engine and gearbox mountings become compressed from the engines torque, suddenly de-clutching allows the engine and box to rapidly spring back to its normal position, on rear wheel drive vehicles, particularly light vans you can hear this as the propshaft shudders back and forth often producing a dinging sound.
Dave

Paul Thomas · Post by **Paul Thomas** » 27 Oct 2003, 13:33

Good news.
It's always the simple things.
Removed one end of the damper and the throttle now springs closed. With the damper attached it was taking 15 seconds to return to closed from fully open.
Cheers Guys.

Kowalski · Post by **Kowalski** » 27 Oct 2003, 17:56

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Dave Burns</i>

Well the same car with a CAV pump wont have one so its nothing to do with turbo's or whatever, that must mean its Bosch pump specific, my theory is that its just an antistall damper.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
According to Mr Haynes, the Bosch non-turbo models have no damper where as the turbo ones do.
Mr Haynes may however not be correct about this but all the turbos I've seen had the damper (the orange / white one some had two) and the non-turbos didn't.

Dave Burns · Post by **Dave Burns** » 28 Oct 2003, 00:00

I've got a CAV turbo pump here taken from a 1.9 td ZX and it has no damping device on it what so ever, nor does it have any auxiliary bracketry to fit one, same turbo engine and everything else though.
My Xantia had both the throttle full range damper and the wappy little thing at the back of the pump that damps the last few degrees of travel, as did my sisters Xantia.
R R R RID'EM BOTH[:D] cars drive nicer without the bloody useless things.
Dave

oilyspanner · Post by **oilyspanner** » 28 Oct 2003, 00:08

The Roto pump has dampers but theyre internal! lying horizontally under the top cover.

Dave Burns · Post by **Dave Burns** » 28 Oct 2003, 03:53

I would expect any such internal dampers to be intrinsic to the design of the pump and not have quite the same reason for being there as the Bosch type dampers being discussed (plus being internal they are probably also there on the non turbo pump) these being external add on units acting directly to check the returning external accelerator lever, though I could be wrong of course and stand to be corrected.
Dave