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3.9 stalling

Posted: Thu Jan 03, 2013 11:59 am
by noexitroad
hi team,
i recently installed a 3.9 into my old army stage 1
so far i am pretty happy except for an annoying problem.
it idles ok but when pulling up to a stop it often (but not always) stalls.
i have downloaded a disco1 manual off the net which talks about the vehicle speed sensor which disengages the idle air control valve when the vehicle is moving
as mine has no speed sensor as it was mated up to the original gearbox (lt95) could this be the problem??
could the ecu be getting screwed up with no input from the speed sensor?

i have cleaned the iac valve, put in new plugs, checked and adjusted timing, checked maf sensor for any buildup of dirt etc, checked for air leaks around intake, cleaned rocker breather, checked compression is ok

Re: 3.9 stalling

Posted: Sun Jan 06, 2013 3:06 pm
by Pedro
noexitroad wrote:hi team,
i recently installed a 3.9 into my old army stage 1
so far i am pretty happy except for an annoying problem.
it idles ok but when pulling up to a stop it often (but not always) stalls.
i have downloaded a disco1 manual off the net which talks about the vehicle speed sensor which disengages the idle air control valve when the vehicle is moving
as mine has no speed sensor as it was mated up to the original gearbox (lt95) could this be the problem??
could the ecu be getting screwed up with no input from the speed sensor?

i have cleaned the iac valve, put in new plugs, checked and adjusted timing, checked maf sensor for any buildup of dirt etc, checked for air leaks around intake, cleaned rocker breather, checked compression is ok


there is the idle control screw that lives on the intake butterfly, remove pipe between the throttle bottle and idle control valve and block off both ends, then start motor may need a bit of pedal to do so, then when settled see if the idle is about 700 ish rpm, if not wind screw till you achieve the idle, i ended up tweaking mine a few times to get to a point it would not stall or idle to high, use imperial allen key. it is under a seal cap which you remove by piercing it and levering it out

cheers

pedro

Re: 3.9 stalling

Posted: Sun Jan 13, 2013 7:43 am
by noexitroad
thanks, did that and fixed prob.
i figured that would be it as somebody had already fiddled with idle adjustment before me