tick over up and down

[Tourettes Tony]

my tickover has started to go up and down even when hot, then it settles down, before i start getting the hump :evil: , is this usually down to vacuum leak? thanks TT Tony

[TheJoyofSix]

It depends...

Often a vac leak will be the cause, but it could be the PCV system (Positive Crankcase Ventilation).

I don't know how the DeLoreans are plumbed, but if it's anything like the Volvo way of doing things then the crankcase gasses are redirected into the air intake. This leads to 'gummy' deposits on the idle control valve and the throttle body as the oil deposits in the fumes are condensed and then dried all over the inlet tract. A good clean up of the intake side of things with carb cleaner every 6 months or so tends to avoid all the problems (or be extremely 'green' and just vent the gases to atmosphere!!).
Us Volvo folks are used to doing this periodically (the cleaning that is, not the dolphin killing....!)

[steve.s]

hi

yes probably vacuum leak...but tracking down is tricky.

mine runs after 12 years of the road but does 'hunt' at idle, and i have stripped the inlet manifold, and replace the vac hoses.

have not checked the ones to the heater control as this is also part of the system.

[Chris Williams]

It could well be a vacume leak. When I replaced all my vacume hoses with Special/T's replacement silicone hose set a few months ago the idle smothed itself out and incresed to about 1400 rpm all the time. So I am guessing there was a leak somewhere.
Chris

[Tourettes Tony]

thanks for reply's , a hose was off :oops: im getting a dab hand at taking my inlets off now TT

[bozzzydmc]

:wink:

Tell me about it :roll: I remember the first time it did it ....scary ! now could do it with my eyes shut .....

[ChrisS]

bozzzydmc Wrote::wink:

Tell me about it :roll: I remember the first time it did it ....scary ! now could do it with my eyes shut .....

I feel a competition coming on..slowest time gets the Magners in ....now who will lend me their car :lol:

[Guinney1971]

bozzzydmc Wrote:Tell me about it :roll: I remember the first time it did it ....scary ! now could do it with my eyes shut .....

ooo errr misssus!!!

:lol: :lol: :lol: :lol: :lol:

[bozzzydmc]

Claire Usher Wrote:

bozzzydmc Wrote:Tell me about it :roll: I remember the first time it did it ....scary ! now could do it with my eyes shut .....

ooo errr misssus!!!

:lol: :lol: :lol: :lol: :lol:

TUT! ...trust you to take it the wrong way .... oops I cant really say that either

[Guinney1971]

ROTFLMAO!!!!!!!

:lol: :lol: :lol: :lol: :lol: :lol: :lol: