| From | Message |
jDoug
Dodge Dakota
JOIN HERE
9/13/2002
14:50:52
|
 Subject: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
Hi.
I recently removed my tb for some machine work (removing a broken stud from a K&N kit, not anything performance related), and now that I have the thing back together it idles at 1500 rpm and deisels when I shut it off. Whats going on? Is this a function of taking off the neg battery terminal for an extended time, and something that will go away once the pcm figures out what its doing? Is it a bad sensor? Did I not reconnect something correctly? Whats going on?
|
alex
Dodge Dakota
JOIN HERE
9/13/2002
15:02:04
|  RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
Probably because you put the gasket back on backwards. Or you tore the first gasket and there's a leak at the base of the TB or else you just forgot the gasket.....
If it's not that, then the throttle position sensor is bad....
Or the idle air control motor is bad in some way...
|
jdoug
Dodge Dakota
JOIN HERE
9/13/2002
15:05:34
| RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
Thanks for the quick response, alex.
iac motor? What exactly does it do, and where is it located? And how can I test it?
|
alex
Dodge Dakota
JOIN HERE
9/13/2002
15:23:35
| RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
Well, if your truck is indeed a V-6, then it's the mechanism that's on the side of the TB that faces the firewall.
When the blades close on the TB bores (when you let off the gas), air has to get into the engine somehow. This allows the engine to idle. In addition to the two big round bores, looking at the TB from the top, there is also an odd looking opening with a tube protruding into it. That is the passage that allows the air into the motor and allows it to idle.
If it were just an open passage, the motor would idle at about 1500-2000 rpm. But that's no good, so the Idle Air Control motor is a small servo motor that pushes a plunger in & out of that little tube to open & close the air flow and attempt to maintain an idle of about 600-650 rpm. If the motor begins to stall, the plunger is retracted and more air is allowed in, if it begins to rev, then the plunger is pushed in and the air flow is controlled.
If the plunger is jammed in the open position (unlikely unless you dropped the TB or put that part of the TB in a vice, etc), then the air would flow in uncontrolled enough to make for a 1500 rpm idle.
I don't know how to test it unless you go to the dealer and hook it up to the scanner. I would suggest you take the TB back off, scrape the gasket off the TB and the intake manifold (dont' drop any down in there). Then install a new gasket (make sure it's oriented correctly) between the TB and the intake manifold and bolt it all down. The gasket cost like $5 at the dealer.
If that doesn't fix it, then I'd have to say you ought to go get the truck scanned at the dealer (or a mechanic) and figure out what the IAC is doing.....
|
RACERDY
GenIII
9/13/2002
15:51:58
| RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
This has happened to me, it was the TB gasket.
RACERDY
|
jDoug
Dodge Dakota
JOIN HERE
9/13/2002
23:47:03
| RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
Yeah, simple things first. I'll monkey with it tomorrow morning.
After I stopped panicing, a thought occured to me. If it were either a bad TPS or IAC motor, the truck would display a MIL light, correct?
Oh, and alex, I sure hope its a V6, 'cause otherwise my V8 is SERIOUSLY down on power. j/k :p
|
Melinda
Dodge Dakota
JOIN HERE
9/16/2002
16:52:23
| RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
Having the same problem in reverse. I haven't gotten any codes at all from the computer, so don't put all your trust in it. The IAC is a common problem according to posts I've seen on this site. Do a search on Stalls, dies or quits and you'll see what I mean.
|
jDoug
Dodge Dakota
JOIN HERE
9/16/2002
18:46:14
| RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
D'oh! Forgot to post the resolution for you guys...
Man, this is embarassing... I put the gasket on backwards. The truck runs just fine now.
The moral of the story? Don't rush!!
|
alex
Dodge Dakota
JOIN HERE
9/16/2002
18:50:46
| RE: Why is my truck idling at 1500 rpm?
IP: Logged
Message:
That's how I knew what you had done.....
D'OH!!
At least it only cost $5!
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
