Mechanics

EXTENDED CRANK. STALLS OUT AT IDLE OR LOW SPEEDS.

1996 Plymouth Voyager • 218,000 miles

There is an extended crank and I have to. Push the gas to get it started. It stalls out at low speeds or idle. Replaced IAC and that didn't help. It happens more when hot
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Gtomuscle26@gmail.com
August 2, 2012.




Sounds like the battery might have been disconnected or run dead recently. If so, the Engine Computer lost its memory and has to relearn "minimum throttle" before it will know when it must be in control of idle speed. It also might not give you the normal "idle flare-up" to 1500 rpm when you start the engine. To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals.


Caradiodoc
Aug 2, 2012.
I've had the van for 2 months and I haven't had the battery disconnected or
run dead


What about before you bought it? You didn't include any history of what led up to this problem. When and how did this problem start?


Caradiodoc
Aug 2, 2012.
I'm an assistant at an auto shop. It was a shop car. We have never had much trouble with it until now. I replaced the iac valve and reset the computer but its still doing the same thing


What do you mean by "reset the computer"?


Caradiodoc
Aug 2, 2012.
Reset or to relearn it


Did you remove the battery cable to rest it? If not, how did you clear the adaptive memories?

Roy
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I cleared it with a Chrysler. Scan tool


By erasing the adaptive memories, it has to learn to idle all over again. Should not do that.

As the previous answer said about the re learn, you must do this procedure now that you wiped out the memory.

Roy


Sorry to be gone so long but I'm baaaack. ASEMaster6371 is right. There's nothing to "clear". That used to be more of a GM thing. Disconnecting the battery will cause the idle problem, not solve it. While it sounds like you didn't do that, there isn't anything you can do with the scanner to make it NEED to relearn minimum throttle. Erasing the adaptive memory, (fuel trim numbers), will just make it start over from preprogrammed values and it will immediately start to rebuild those tables when you start driving.

Given the history and details, do the coasting procedure first. If that doesn't result in a nice idle flare-up at start-up and solve the low idle problem, use a scanner to view the idle "steps". They range from 0 to 256. "32" is about typical for a properly running engine. If you find it at "0", minimum throttle hasn't been relearned. Try holding the brake pedal up with your toes while doing the coasting procedure. If you find a relatively high step such as 45 to 50, the Engine Computer sees that idle speed is too low and is trying to raise it but without success. It's rare but if you find a really low step, say 10 to 15, the computer thinks idle speed is too high and is trying to bring it down. Look for something causing a double signal from the crankshaft position sensor or camshaft position sensor. I've read about a cracked core in the crank sensor causing something like that.

Most scanners will allow you to run the idle speed up and down by pressing a couple of buttons. Look for a listing for "automatic idle speed test" or something like that. I use the Chrysler DRB2 and DRB3. They allow you to raise engine speed to 2000 rpm in 200 rpm increments. If that works, you know the AIS motor is working and the air passage is not plugged. As I recall, that test with the scanner does not work if minimum throttle hasn't been relearned yet but that might not pertain to all models.


Caradiodoc
Aug 3, 2012.

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