Forum:
Have had an ongoing problem on the CB engine,of my CHARADE G11R (1986),3 cylinder 993cc carbie(non turbo)type.Idle speed on start up is about 500 rpm and rises to about 1300 when hot.Have replaced brake booster recently and various vacuum hoses.Ended up with a smoother idle! Any ideas please?
Idle control valve or MAP
Idle control valve or MAP snesor?
-------------------------------------------------------------------------
'12' Plate Mazda MX-5 2.0 litre NC 3.5 Venture Roadster 160BHP
'15' Plate SEAT LEON 184 FR TDI. 240BHP/500nm Torque.
Past: '53' Plate Yellow YRV Turbo Approx. 150BHP
lol. These are carburettor,
lol. These are carburettor, Not fuel injection. No ECU.
We don't really have any of these in the UK, They only sold a very few and probably only a very few if any still around.
I guess look at the carb settings and any dirt blocking jets
Same here
I had a similar experience with mine. I fiddled with it and it stopped doing it (so far), but I'm afraid I can't now recall exactly what I did.
I can, however recall that trying to understand the pipework surrounding the carb gave me a headache, and that I managed to disable the choke at the same time.
This was an acceptable tradeoff, but further evidence that I really didn't know what I was doing.
IIRC (big IF on that one) there's a vacuum-diaphragm-controlled fast idle pot which I adjusted so its actuating rod didn't make contact with the (throttle? choke?) lever, and that stopped the engine racing.
Around the same time, however, I experimented with injecting water into the running engine via a hypodermic IV line into one of the carb vacuum hoses. This seemed to cure its tendency to sometimes keep going on switching off, as well as an irregular tap/crack noise that I now think might have been pre-ignition. This is suggestive of cylinder coking, and that might have contributed to the over-revving as well.
I described the situation and actions in some detail on an Australian Daihatsu site, but that's now defunct, and I'm permanently banned from its successor (They don't like you disagreeing with established members and they run a tight ship) so I don't have access to the details any more. Sorry.
Bit More Detail on My High Idle Fix
I found a slightly (though not much) more detailed description in the middle of a long, rambling and speculative thread (mostly on water injection) here:
http://www.forumosa.com/taiwan/viewtopic.php?f=75&t=89915&start=10&hilit=water+injection+aftermath
The engine manual referred to is linked in that thread, and the link is, rather surprisingly, still working, though of course you may already have it.
Your problem sounds less severe and may of course, have a different cause, but IIRC my problem was initially intermittant and then got rapidly worse
"Looks like the problem wasn't coke anyway, unsurprisingly.
There's a vacuum diaphragm attached to the carb. Its function isn't described in the manual, but it looks like its supposed to back off a high idle throttle stop once the engine gets going and generates some vacuum, and it'd stopped doing it, so the idle stayed high.
Setting this high idle stop low renders the machine responsive to tuning, and seems to have stopped the racing and overun problem, based on a short test run. Time will tell."