Idle problems
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Idle problems
I got my 87 b2 recently and when i would start it up, it would almost stall then go back up to 500-600 rpm, and it would go back and forth and some times going to low and stalling. If I drive it right after it would run alright but somtimes it felt like it would cut out for a second then go back to normal. after bout 3-5 minutes of driving it, it fixes itself. I went to an autowrecker and replaced the AIS motor or more commonly known as the idle motor and now the problem has changed. I know longer almost stall when i start up the vehicle, instead it will idle at around 1800 rpm and will slowly go down but again if i drive it for 3-5 minutes, it fixes itself. someone please help, thnx
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Joined: Dec 2001
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From: UT
I find that the most important first step in diagnosing these engines is to start with the trouble codes. This is especially true on an '87 which doesn't have a functional check engine light so the computer can tell you when it has seen a problem. If you aren't familiar with the self-tests, check out the tech info post where our moderator has posted a link to performing the EEC-IV self-tests. Only tools required are a jumper wire/paper clip and a voltmeter/test light.
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From: Nanticoke, PA
My '89 Bronco II does that same thing your '87 was initially doing. It seemes to be worse on cooler or cold days. I have checked the trouble codes and am getting a code for the AIS. I haven't changed it yet but plan to ASAP.
I would recommend that you retrieve your codes if you have a scanner or you can go to your local Auto Zone and they will do it for you free of charge. If it is the AIS, replace it with a new one. Never install a used one since most chances are that it might not be any better than your original. I found that out the hard way on an '85 Tempo that my wife had many years ago. I had to end up with a new part in the end.
I would recommend that you retrieve your codes if you have a scanner or you can go to your local Auto Zone and they will do it for you free of charge. If it is the AIS, replace it with a new one. Never install a used one since most chances are that it might not be any better than your original. I found that out the hard way on an '85 Tempo that my wife had many years ago. I had to end up with a new part in the end.
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I know it was the AIS, but someone told me i can just clean it out cause it supposedly gets gummed up. so i opened it but it looked fairly clean but I went and got a used one and now it idles alot higher but apparently the older vehicles AIS's make the vehicle idle higher when the engine is cold cause then it wont stall and will warm up the vehicle faster so i think my high idle problems are normal. someone tell me if its normal. if its not normal then ill go and get a new one.
thnx
thnx
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Joined: Aug 2004
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From: Nanticoke, PA
How long does it take until the idle starts to drop down? It should take less than a minute.
It also seems like the high idle is a little too high. Mine never exceeds 1500 RPM's. It's usually around 1300-1400 for me.
Also try to clean the throttle plate (hinges, etc.) thoroughly. Sometimes if it's gummed up it will cause the idle to stick a little higher for a short period. It has worked for me in the past.
If that fails, try disconnecting the battery for a few minutes to clear the "learned" idle from the computer. After reconnecting the battery, start the engine and wait about a minute. Next, drive the vehicle, not exceeding 35 MPH for the first mile. Drive several more miles at various speeds (a highway is ideal). This process will cause the computer to "re-learn" the idle.
If none of that works, I would replace the AIS with a brand new part.
It also seems like the high idle is a little too high. Mine never exceeds 1500 RPM's. It's usually around 1300-1400 for me.
Also try to clean the throttle plate (hinges, etc.) thoroughly. Sometimes if it's gummed up it will cause the idle to stick a little higher for a short period. It has worked for me in the past.
If that fails, try disconnecting the battery for a few minutes to clear the "learned" idle from the computer. After reconnecting the battery, start the engine and wait about a minute. Next, drive the vehicle, not exceeding 35 MPH for the first mile. Drive several more miles at various speeds (a highway is ideal). This process will cause the computer to "re-learn" the idle.
If none of that works, I would replace the AIS with a brand new part.
Last edited by KawiG5; Aug 28, 2004 at 03:28 PM. Reason: adding
Senior User
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From: Nanticoke, PA
Give it a few days to re-learn the idle. Unfortunately it's not a quick process. Let me know how you make out.
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From: new braunfels ,tx
similar idle problems
i have an 89 BII 4x4 2.9 with similar problems sounds like its the throttle plate . Is that the plate inside the breather tube? the tube coming from the air box?
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From: Bixby, OK
my 90 BII does about the same thing, when i start up for about 5 seconds it idles about 600 RPM then goes up to about 1200 but i let it sit for a second and it stays about there but then when i put it into reverse to get out of the driveway it goes to about 700 or so, without hitting gas, but then when i have my foot on the brake and sitting at a light or something it idles at about 800, but as soon as its in neutral or park it idles at like 1200-1300, is that normal? i used to have one of those cheap little performance modules that made me run super rich on fuel, and it idled at about 3000 then so i took it off