97 Dakota 3.9 issue UPDATE
#1830280
05/19/15 08:11 PM
05/19/15 08:11 PM
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Joined: Jan 2003
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79powerwagon
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Truck worked fine going in to work this morning. I came out this afternoon, started it up (fired up easily as always), but was idling at 2000 rpms. It wouldn't "kick down". I had to get going to take my wife to the doctors, threw it into drive and it drove fine, though straining against the brakes a bit at stop signs and lights.
I did notice the trans not shifting like it should, but it did go through all the gears and lock-up, just far touchier.
I made it home, did the doctor thing, and just started it back up. Now it's idling at between 1200 and 1500 rpms, not steady.
The engine sounds fine, there are no dash lights on (and yes, they all work), the tune up is about 6 months old, and the only thing odd about the truck is the defective air control motor (or whatever it's called, on the TB) which makes the truck a hard start if it sits for days. If I run it daily (and in any temp) it shows no symptoms at all. It has 165000 miles on it, no work has been done beyond maintenance, bone stock, complete new exhaust with new cat.
Any idea what to look for?
Last edited by 79powerwagon; 05/26/15 10:14 PM.
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Re: 97 Dakota 3.9 issue
[Re: 79powerwagon]
#1830349
05/19/15 09:45 PM
05/19/15 09:45 PM
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Joined: Apr 2010
Posts: 10,570 Sunny South Florida
Golden-Arm
I Live Here
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I Live Here
Joined: Apr 2010
Posts: 10,570
Sunny South Florida
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put the key in your ignition and turn it to the "on" position three times. (insert key, on, off, on, off, on). leave it in the on position. the first trouble code will be displayed on your digital LED odometer. quickly cycle the key again (off, on) to display the next code, and just keep cycling the key to get the remainder of the codes.
"When Tyranny Becomes Law, Rebellion Becomes Duty"
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Re: 97 Dakota 3.9 issue
[Re: moretoys]
#1830781
05/20/15 01:57 PM
05/20/15 01:57 PM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
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Marysville, O-H-I-O
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If you've been having a known problem with the iac solenoid/motor on the back side of the throttle body, then I'd start there.
Next time it's idling high, take the air hat off the top of the throttle body and put your thumb over the hole behind the 2 butterflies. If idle drops and you can stall it out, that rules out a vacuum leak elsewhere.
**Photobucket sucks**
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Re: 97 Dakota 3.9 issue
[Re: DaytonaTurbo]
#1831888
05/22/15 12:23 AM
05/22/15 12:23 AM
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Joined: Jan 2003
Posts: 16,823 Between Houston & Galveston TX
SattyNoCar
Smarter than no class Flappergass by a mile
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Smarter than no class Flappergass by a mile
Joined: Jan 2003
Posts: 16,823
Between Houston & Galveston TX
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Sometimes the IAC's still "work" internally, but are so gummed up with crud the plunger gets stuck. And if the IAC is gummed up, the throttle body itself is probably long overdue for a good cleaning. On my '93, I didn't have the idle extremes you are but, the idle was never consistent. I pulled the TB, pulled all the electrical parts off it, and gave it multiple hits of oven cleaner to clean it out (it was cheap). Idle is nice and steady now.
John
The dream is dead, long live the dream.......😥
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Re: 97 Dakota 3.9 issue UPDATE
[Re: 79powerwagon]
#1834827
05/26/15 08:57 PM
05/26/15 08:57 PM
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Joined: Jan 2003
Posts: 27,728 places
79powerwagon
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Part arrived today, so I installed it. No troubles with install, and the TB was surprisingly clean. I shot out the opening for the IAC anyway, for good measure.
Truck started right up (which is a good beginning since it hasn't been run since this problem started), and idled at 3000rpms. The instructions said that it would do that, and to drive it up to temp, then drive it 40mph or faster for five minutes for the computer to reset.
I drove it quite a bit, and it is still running at 3000 rpms. If the rain stops, I'll disconnect the battery overnight and try it again (unless you all have another trick that is more affective?)
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Re: 97 Dakota 3.9 issue UPDATE
[Re: 79powerwagon]
#1835520
05/27/15 08:38 PM
05/27/15 08:38 PM
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Joined: Jan 2003
Posts: 27,728 places
79powerwagon
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Turned on the headlights for a good 5 minutes after leaving the battery disconnected all night, just to clear ANY residual voltage. Hooked it back up, and gave it a start. She started hard, but then caught and idled as normal! I took it for a long drive (so teh computer can start to relearn me) and all was perfect! I'll drive her to work in the morning, see if there remains any hard start condition, then attack that problem (if it exists). Thanks all! I LOVE this old truck!!!
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