Surging Idle (video)
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Senior Member
Joined: Mar 2005
Posts: 992
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From: Sacramento, California
Car: 92 RS
Engine: a slow one
Transmission: a crunchy one
Axle/Gears: a whiny one
Surging Idle (video)
Video below.
http://www.youtube.com/watch?v=RKAtx...ature=youtu.be
Yet ANOTHER surging idle issue. I've searched and searched, but can find no culprit. Most people seem to have it worse than I do, with a load of other symptoms. Mine only surges, at all RPM's below 2000-2500 or so (hard to tell with the stock tach, it's off by a good amount) unless it's under load or accelerating.
It does it hot, cold, whatever.
It already had a slightly rough idle and some valvetrain noise (160k on the clock, it needs a timing chain I'm sure)
I've cleaned and reset the IAC, unplugged it while running, no change
Fuel pressure at the rail is 42 lbs on startup, levels off at 40 even
Unplugged the MAP, no change
Unplugged the Set Timing Connector, no change
Changed the TPS, no change
Cleaned up the cap and rotor, checked all my plug wires and plugs, all looks good
Held the RPM's up to get it steady, and swamped that thing with starting fluid all over the place... Couldn't get it to surge anywhere, I think the vac hoses and intake manifold (changed 7 or 8 years ago) are good (hoses were ALL replaced about 5 years ago, except the EVAP can stuff).
I've smacked the MAP around, taken the air filter stuff off
...
Just remembered I haven't checked the timing yet (it got dark on me).
Wanted to follow that vacuum hose going to the tank but couldn't get to it today. Seemed impossible to follow without lifting the car.
Going to pump up a few things and see if they hold vacuum just to double check, and check timing tomorrow, but based on what I've done so far I don't expect to find anything... Any suggestions?
http://www.youtube.com/watch?v=RKAtx...ature=youtu.be
Yet ANOTHER surging idle issue. I've searched and searched, but can find no culprit. Most people seem to have it worse than I do, with a load of other symptoms. Mine only surges, at all RPM's below 2000-2500 or so (hard to tell with the stock tach, it's off by a good amount) unless it's under load or accelerating.
It does it hot, cold, whatever.
It already had a slightly rough idle and some valvetrain noise (160k on the clock, it needs a timing chain I'm sure)
I've cleaned and reset the IAC, unplugged it while running, no change
Fuel pressure at the rail is 42 lbs on startup, levels off at 40 even
Unplugged the MAP, no change
Unplugged the Set Timing Connector, no change
Changed the TPS, no change
Cleaned up the cap and rotor, checked all my plug wires and plugs, all looks good
Held the RPM's up to get it steady, and swamped that thing with starting fluid all over the place... Couldn't get it to surge anywhere, I think the vac hoses and intake manifold (changed 7 or 8 years ago) are good (hoses were ALL replaced about 5 years ago, except the EVAP can stuff).
I've smacked the MAP around, taken the air filter stuff off
...
Just remembered I haven't checked the timing yet (it got dark on me).
Wanted to follow that vacuum hose going to the tank but couldn't get to it today. Seemed impossible to follow without lifting the car.
Going to pump up a few things and see if they hold vacuum just to double check, and check timing tomorrow, but based on what I've done so far I don't expect to find anything... Any suggestions?
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