Low idle in reverse?
Chrisvr6
Member Posts: 166 ✭✭
When in reverse (first detent) idles so low it dies after awhile. Bump idle mixture up? Forward is ok.
Comments
if EFI: when it's 'cold', it's trimming fuel and adjusting spark off of hard tables (open loop operation), which are factory drafted and non-adjustable... if it's operating in closed loop (after reaching operational temperature), it's operating off of tables created by environmental variables. If you've reached operation temperature and this happens, I'd recommend you pull the battery cables or the PCM connection, and allow it to rest for a minute or so, to make sure any capacitors are drained and the PCM has an opportunity to drop all the enviro's from it's RAM... which will force it to 'start fresh' and not use and data collected from last season.
if carb'd: if you're not idling properly in gear or out, and it did last season just fine, there is a greater chance you could use a good cleaning of that carb- adjusting linkage to achieve the speed wanted is NOT fixing this issue, but instead putting a band-aid on it. you likely need to clean needle valves and throats with some good carb cleaner, to remove any varnish or gum that's built there over the off season by evaporating fuel... or.. change fuel filters.. the fuel filter will restrict flow and present the evidence of blockage much more clearly at low RPM's... the last thing you wanna do is run that engine lean, and it's pretty easy to do with a carb'd motor.
just my opinion.
if carb'd, check the autochoke by tapping on it.. its a coiled spring in a black housing on the side and are notorious for hanging up or not setting. the best thing to do is to press the button on your controls and go to mid-to-full throttle before turning the key to start... this provides a squirt into the throat of the carb, so, you'll only want to do this once, but it also moves the mechanisms- namely the butterfly valve- which can jostle the auto choke mechanism if it's hung up and allow it to function.
if EFI it's just about got to be your IAC, because the PCM will send a command to move that plunger to achieve the idle speed no matter what.... just because you haven't tripped a code (alarm) doesn't mean the sensor is running correctly- it could be checking out electrically, but not doing what it's 'sposed to do, which is move that plunger back to let more air in... this speaks of a gummy plunger passage, which is cheaper to clean than replace.
I think the stock coil is 35k volts, so, anything north of 40k is good, with 55k being the ceiling before you start seriously cutting into the life of plug wires, caps and rotor buttons. That spark can jump, which makes widening the gaps on plugs from .045 to somewhere around .05 for 40k coil or .057~8 for 55k coil a good idea- as it gives a larger yet just as hot spark/point of ignition....
i'd only do this on a carb'd engine (not ECM/PCM controlled), ~and this is directed at other users here who might read this and think 'hmmmm'...~ because when the computer is advancing/pulling ignition timing it's expecting a precise toolset to work with... if you mess with that toolset, you're playing with fire (literally, too) and inviting predetonation.... but for us carb'd guys, that wider and hotter spark will allow a more uniform burn and a more powerful exhaust stroke, read: more power.