93 3.0 startup problem
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Joined: Aug 2003
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93 3.0 startup problem
When starting my van in the morning wether it be warm or cold outside (colder lately) it has a fluxuation in the idle speed it goes up and down for a few minutes maybe 5 at the most. Then levels out. Any ideas what may cause this? Also anyone have a problem with flux in the battery level? It seems when my rear defogger button gets pushed in everything slows down a litttle. It's like the engine wants to die. New altenator installed and battery tested fine. I sure could use a little help. Thank you all
Shane
Shane
Lead Driver
Joined: Sep 2003
Posts: 7,016
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From: SoCal
When everything is functioning properly, the EEC attempts to set the engine idle with the idle air control IAC valve. This will usually compensate for a very wide range of conditions from cold start to hot idle. If the valve is not functioning properly, your idle could fluctuate as you describe. The first thing you can do is to pull it off and clean it out with something like Gumout or fuel injector cleaner.
The rear defroster takes a lot of current to run, and will present a big load on the alternator, and thus onto the engine. The few minutes right after a cold start is usually the worst, since you will be running your rear defroster as well as the heater at full blast, and the EEC cannot properly control the idle speed of the engine.
So, first see if you can get the engine to idle properly with a cleaning of the IAC valve. It is mounted on the right side of the intake manifold when looking from the front of the engine.
The rear defroster takes a lot of current to run, and will present a big load on the alternator, and thus onto the engine. The few minutes right after a cold start is usually the worst, since you will be running your rear defroster as well as the heater at full blast, and the EEC cannot properly control the idle speed of the engine.
So, first see if you can get the engine to idle properly with a cleaning of the IAC valve. It is mounted on the right side of the intake manifold when looking from the front of the engine.
Junior User
Joined: Feb 2004
Posts: 51
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From: Western New York
My 94 fluctuated also. Check your vacuum lines and see if your trans modulator is leaking fluid. My 3.0 has a 3 way splitter near the distributor. If you crimp the hose that leads to the transmission and the idle improves, you can assume your're leaking vacuum in that line. Usually caused by a bad modulator. Trans fluid in rubber hoses causes hoses to go bad. If yours are bad, replace all. One thing leads to another........ I'm in the process of doing mine up.
Junior User
Joined: Jan 2004
Posts: 58
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From: Ottawa, Ontario
Anytime I ever activate the rear defrost you can tell it's been turned on. if it's night you can literally SEE the current being drawn away from the dash lights for that split second it takes for the alternator to catch up. IT's a BIG window back there. Watch your volt meter the next time you turn it on... or the next time you go from heat on minimum to heat on maximum it jumps a bit each time. simply a power current issue.
