Hello all,
I have a 94 aerostar that suddenly started to start fine, run great for a half minute, then surge and eventually die before I can get it into gear.
Once it's in gear it will idle great till I start it up again. Just getting it in gear solves the problem
Thanks in advance!
Ed
You did not say whether this is a 3.0L or 4.0L engine we are dealing with, but as a starting point, two components cause most idle/surge problems on either engine.
The Mass Air Flow(MAF) sensor is a small, rectangular affair that sits just downstream of the air cleaner box. It is a very delicate sensor that uses tiny, heated wires to measure air flow volume. That information is sent to the Engine Control Unit (ECU) or computer brain which in turn uses it to determine how much fuel to inject at any given time. The tiny wires can become contaminated with minute amounts of dirt/debris that get past the air filter. Often just cleaning the MAF with electronics cleaner will restore function. There are many posts on this forum on how to do this. It will take a "security Torex" bit to remove the screws.
The most likely culprit is the Idle Air Control (IAC) valve. This is an electromagnetically operated valve that kicks up the idle whenever a load is put on the engine - such as putting the car in gear or when the A/C compressor kicks on. The IAC can get gummed up with deposits and stick open,closed or somewhere in between. The IAC is found in different locations depending on what engine you have, but is generally a silver colored, small canister looking affair mounted just past the throttle body, secured by two bolts and has a two wire electrical connector. You can easily (relative term around here) remove the IAC and try cleaning it with an aerosol carb/choke cleaner. Just don't lose the gasket when you pull the IAC off.
These two items are a good starting point. If cleaning does not help, post back and you will find lots of excellent advice on this forum.
My money is also in the IAC. You should hear it up the idle a fraction as soon as you put it in gear. Also 1/2-1 min is about how long it takes for the o2 sensor to start giving voltage feedback, it sounds like it is this transition period from cold start to warm up which is giving you grief. At this point IAC should take over to bring idle RPM's under control. If IAC is a bit sticky idle control will be sluggish & this sounds like whats happening during warm up.
Whats it like when fully warmed up?
Aeroman
__________________
Green-96, XLT 2wd, 3L Vulcan, from Ontario, Canada
All original powertrain except alternator & starter motor. 292,000 kms & going strong !
Hello, and thanks for your help. Sorry about the lack of detail, it is the 3.0L. 158000mi.
This only happens when It gets started, hot or cold, and dissapears completely when put in gear. Drives perfectly at all speeds from idle to 80mph. only happens at startup.
Like what others have said, that sounds like your IAC valve, try cleaning it out with some Berrymans B12 or Seafoam. If that does not work, you will need to replace it.
__________________ '96 Ford Contour 2.0 I4 MTX 77k mi- Rear Ended 12/22/07 '97 Ford Aerostar AWD 4.0L v6 AT 81kmi '97 Chevy Lumina 3.1 v6 ATX 135k mi Parents old beater, temp vehicle
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