1979-1993 & 94 Conv [Subscribe to Daily Digest] |
unless you have replaced a part, unknowingly loosened something, or knocked something out of whack, you should not need to go making adjustments. you didn't specify what year 900, or n/a or turbo. if you have in a previous post, then i missed it. at any rate, it sounds as though your car is going into limp home mode. this is a safety feature as part of the design of the car so that if a component fails, the engine will run well enough to not leave you stranded. that said, there are components that could fail that would leave you stranded anyway. there are two possibilities that i can think of. one, something is causing a condition at idle that your ecu can not compensate for. two, one of your components failed. in the first case, almost all of the high idle problems i have run across have been due to a vacuum leak of some sort. if you have a hand pump, pressurize each of the vacuum lines in the car. they should all hold vacuum and pressure. if you don't have a hand pump, diconnect all the vacuum hoses from the intake manifold. put caps on all the nipples and start the car, see if it idles normally. if it does, than one of the hoses (or the component it is connected to, is not holding a vacuum). replace them one by one to see when the idle rises. when the idles goes up to 12-1300rpm, you've found one of your problems (i say that because there may be more than one). keep checking until you have confirmed all of your leaks. other areas of suspect could be the 't's and nipples for the hoses. they snap into the manifold and are sealed by a rubber grommet. these grommets can get old and shrink. you can replace them, or pull the t's and wrap electrical tape around them to make them fit snug. go through all your fittings and vacuum lines first.
the other cause of my high idle past, was the 30# injectors i added. turns out the mixture at idle was too rich for the ecu to compensate so it tripped to limp home mode. pita...
if that does not work for you, then start checking individual components per bently.
keep this in mind, unless you messed with something, don't go making adjustments until you are definitely sure nothing else is the cause. too many times people jump in a start tinkering only to send their systems further out in space... sorry so long. good luck.
posted by 4.60....
, Tue, 30 Oct 2001 23:09:02
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