General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

I need help ASAP

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Old 03-09-2007
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I need help ASAP

My problem is about my (IAC) Idle Air Control valve. I thought i read that you can figure out if it's bad by disconnecting the plug to it, and see if your idle changes in rpms which it kinda did, but i guess i was wrong what i read. Now my check engine light is on and i disconnected my negative side of the battery, and pluged it back in and put the terminal back on now it is still on. Do you think i hurt anything or i just need to go get a new (IAC) valve.
 
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Old 03-09-2007
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You should be able to reset the codes on any OBDII equipped vechile by unhooking the battery for a couple minutes. Try re connecting your IAC valve unhooking the battery for 5 min or so, Then hook it back up and start the truck. If the check engine light comes back on get a OBDII tester. Either buy one (about 75.00) or free testing at pep boys (or similar). You may get a code (19) loss of PCM power. Dont worry about it. Chect to see if you have a code (12) Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) - ISC or a code (13)O) ISC did not respond properly (extends to touch throttle then retracts for KOEO) - ISC
(R) Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too high)
(M) ISC sticking, open ITS circuit or TP sticking
Good luck.
 
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Old 03-09-2007
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Originally Posted by planefixer
You may get a code (19) loss of PCM power. Dont worry about it. Chect to see if you have a code (12) Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) - ISC or a code (13)O) ISC did not respond properly
FYI - The above codes are completely irrelevant for a 99 EEC-V vehicle using the OBDII standard.
 
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Old 03-09-2007
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the whole reason i unhooked it was becasue of this. But when i unhooked the plug and drove around the block they droped almost emediately. What is normal for my rmps to drop or stay up for 5 or so seconds then go down.

The first problem, is when i shift around 2800-3000 rpms. While im shifting from 1st to 2nd when i push in the clutch to shift to 2nd. My rpms don't drop until like four seconds pass. Is this normal. Because my Dads F-350 diesel 5sp dully and his F-150 5sp his rpms drop almost emedietly when he pushes in the clutch. Which mine i have to wait 5 seconds or else i get a jerk when i let out the cluch out. Just want to know if this is normal.

Second probelm, Iv'e been having a squell in my front end for about a month. What happened was sometimes when i push in the clutch my rpms will drop to like 200. Then rise up to my idle speed which is 900 rpms. That led to me thinking it was my idler pully so i changed that and still same squell and same drop in rpms when i push in my clutch. So I don't know what it could be.

Please help Thanks
 
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Old 03-09-2007
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Ok Check the connector for debris cracks or broken or bent pins. Also check for wire damage.
1st the 2800 shift. Have you checked you pedal? Some times in the cold they will freeze up a little. or your throttle spring {on the throttle} could have gotten caught on somthing or just worn and snapped {although i have never one broken}.
Also it sounds like it could be the IAC or the EGR.

2 the Squeal. Is it when your turning {power steering}, Defrost / A-C, Subs,Head lights{alternator} But the most important thing to check is the Belt. is it worn or SUPER smooth? If it slips it squeals.

The thing about this is.... You may spend over $100 to replace "random parts" When it costs less for a corect Diag from a dealership. Some times they wont charge you. Then you will know Better of what is realy goin on. The WDS {Fords little and VERRY EXPENSIVE "code reader"} can check what it is. And say what to do. Also it cna program certain aspects of the vehicle to fit your needs. And you can controll certain things with it to test them. Not like a Midas "Snap-on" code reader.
In other words IF you want this to be quick and less painfull try the dealership.
 
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Old 03-09-2007
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Originally Posted by htvfd460stx
Ok Check the connector for debris cracks or broken or bent pins. Also check for wire damage.
1st the 2800 shift. Have you checked you pedal? Some times in the cold they will freeze up a little. or your throttle spring {on the throttle} could have gotten caught on somthing or just worn and snapped {although i have never one broken}.
Also it sounds like it could be the IAC or the EGR.

2 the Squeal. Is it when your turning {power steering}, Defrost / A-C, Subs,Head lights{alternator} But the most important thing to check is the Belt. is it worn or SUPER smooth? If it slips it squeals.

The thing about this is.... You may spend over $100 to replace "random parts" When it costs less for a corect Diag from a dealership. Some times they wont charge you. Then you will know Better of what is realy goin on. The WDS {Fords little and VERRY EXPENSIVE "code reader"} can check what it is. And say what to do. Also it cna program certain aspects of the vehicle to fit your needs. And you can controll certain things with it to test them. Not like a Midas "Snap-on" code reader.
In other words IF you want this to be quick and less painfull try the dealership.
ok thanks for the info ill check the EGR also. For the belt I replaced it about 6 months ago when I got the truck. ill check that out. IS THERE ANY VIDEOS OF INSIDE THE CAB WITH THE 3.0L WITH PEOPLE SHIFTING AROUND 2800-3000 PREVARBLY A 99 RANGER.
 
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Old 03-10-2007
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Originally Posted by lilk67
What is normal for my rmps to drop or stay up for 5 or so seconds then go down.
The IAC is commanded to be partially open during part throttle conditions - this is called "pre-position" mode. When you let off the throttle, the IAC continues to bleed air past the throttle plate and this holds the RPM up for awhile. Then the additional RPM should decay over a few seconds and allow the engine to drop slowly down closer to idle speed. Depending on road speed, it may not drop all the way to curb idle (~700 RPM). This RPM decay over time is called the "dashpot function".

Dashpot prevents the engine vacuum from increasing too rapidly during shifting and decels. Sharp vacuum spikes can cause corresponding hydrocarbon spikes on the emission test.

So, yes, it can be "normal" to see your RPM hang up somewhat during shifts and during deceleration with the clutch disengaged. The question really is, "How much is normal?"

How much and how long the RPM is sustained will vary with different years and different engines. If you're seeing something that hangs at 1000~1500, roughly speaking, I wouldn't worry about it. If it is hanging for more than a second at 2000 or higher, then you probably have a malfunction of some kind.

Of course, you will need to be sure that the engine is up to operating temperature (off of high idle) before checking the above.
 

Last edited by V8 Level II; 03-19-2007 at 07:12 AM.
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Old 03-10-2007
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Originally Posted by rwenzing
The IAC is commanded to be partially open during part throttle conditions - this is called "pre-position" mode. When you let off the throttle, the IAC continues to bleed air past the throttle plate and this holds the RPM up for a short time. Then the additional RPM should decay over a few seconds and allow the engine to drop slowly down closer to idle speed. This RPM decay over time is called the "dashpot function".

Dashpot prevents the engine vacuum from increasing too rapidly during shifting and decels. Sharp vacuum spikes can cause corresponding hydrocarbon spikes on the emission test.

So, yes, it can be "normal" to see your RPM hang up somewhat during shifts. The question really is, "How much is normal?"

How much and how long the RPM is sustained will vary with different years and different engines. If you're seeing something that hangs at 1000~1500, roughly speaking, I wouldn't worry about it. If it is hanging for more than a second at 2000 or higher, then you probably have a malfunction of some kind.

Of course, you will need to be sure that the engine is up to operating temperature (off of high idle) before checking the above.
Ok that info helps, My rpms when u shift around 3000 they stay up for about 4 or so seconds. The other day i had a problem when I went to a stop sign and I push in my clutch. The rpms drop down to about 1100 and my idle speed is 900, but it won't go down until i let out the clutch again then push it back in. A video would still be helpful.
 
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Old 03-10-2007
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try to clean your IAC.
I would think that the clutch pedal sensor woud have somthing to do with that. But it could be just for Startup only. I would check it out any way. {Just me}
 

Last edited by htvfd460stx; 03-10-2007 at 05:03 PM.
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Old 03-10-2007
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Well for all my problems my dad just said that were going to take it to the ford dealership. So they can deal with my problems hopefully they can figure them out
 
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Old 03-10-2007
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LOL
"Let them get the headache"
"They are paid to bang their head on the hood dummie! your not!!"
My G/F's Dad's famous lines for when its an inconvience for him to do it. {oil change and wipers}
 
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Old 03-10-2007
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Originally Posted by htvfd460stx
LOL
"Let them get the headache"
"They are paid to bang their head on the hood dummie! your not!!"
My G/F's Dad's famous lines for when its an inconvience for him to do it. {oil change and wipers}
lol
 
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