02-14-2010, 12:21 AM
Join Date: Jan 2010
Location: Boganville, Kweenzlairnd, Ustrailya
Can't maintain idle speed... any guess to what's wrong?
The beast is suffering it's first real dilemma in my hands.
Out of the blue (well, kinda), I can't keep a steady idle - i'm having to try pump the throttle to maintain an RPM above 2000 or it's doomed to stall. The car won't even kick over unless I step on the throttle. Take your foot off and you can just see the RPM diving to zero. Even at 2000RPM, in neutral it's impossible to maintain a relatively steady idle until 2000+ RPM. This is kinda scary in the stop/start traffic of suburbia, more so it's a pain the you-know-where - having to reach for the keys at every set of traffic lights. Kinda unsafe on a major level too.
My first suspicion was that a vacuum line (on the stock Hitachi carb) had come loose, or maybe the carb idle speed screw was whacked somehow. But the idle speed screw was correct, and the vacuum lines seemed to be in order... maybe the idle jet got blocked somehow? If not, that's my detective work dead and buried.
The only thing on the carb that gets my attention is a corroded spring on a carb adjustment screw - it's the lowest screw on the carb - side facing the radiatior - it doesn't seem to be holding full tension... infact most of these little tension springs and coils look a little perished.
Other than that i can't see any clues to what might be wrong.
I did replace the throttle cable last week, and that did bump up the idle speed a little to 1300 - 1400 RPM (i assumed the replacement cable was a fraction shorter, but hadn't got around to adjust the idle speed).
I also noticed after a decent highway run when the car was fully up to temperature, the car the idle speed RPM would drop to 1000 - but not in stop/start driving.
This weekend I clocked around 600km (375 mlies) of mainly highway driving - not much, but the car's biggest run yet. I drove back three hours from a fishing mission - and now time to run my weekly errands the car has begun to stall.... badly.
It just seems the hotter the engine the worse this gets - but at the hottest i've seen the temp gauge barely registering a 1/4 on the temp gauge.
Any ideas as to what's going on here?
Last edited by che_guitarra; 02-14-2010 at 02:02 AM.