Low idle at start up
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Junior User
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From: west central illinois
Low idle at start up
My wife's Ranger is idling really low at start up. She says 500 rpm and after a few seconds it idles up and runs ok. I have noticed the sound of the fuel pump coming on lately would it be going out and causing this?
Post Fiend
Joined: Jul 2005
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From: Durant, OK (SOSU)
Depends...what kinda sound is it making? Does it run for two seconds when the key is turned to run but the engine not started?
Sounds like you're losing pressure in the fuel system somewhere...so I could imagine either the pump or relay going out. Is it a random event or does it happen every single time?
What year and engine?
Sounds like you're losing pressure in the fuel system somewhere...so I could imagine either the pump or relay going out. Is it a random event or does it happen every single time?
What year and engine?
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Junior User
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From: west central illinois
2000 3.0 I don't know if it makes the noise everytime or not I don't drive it but I will ask her when I get home from work. She did say it idles a little rough when sitting at stop signs also.
Post Fiend
Joined: Jul 2005
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From: Durant, OK (SOSU)
Well...if the fuel pump is making normal noise when turned to Run, try cleaning the MAF (mass air flow sensor in the intake tube), the procedure is outlined quite nicely in the sticky tech thread up top of the main Ranger board. And have the codes pulled at an auto store, and bring the numbers back here, not the descriptions. That'll definetly narrow it down some.
Elder User
Joined: Apr 2004
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From: North US Border, Canada
Originally Posted by Bob Ayers
Low, or rough idle is normally caused by the IAC valve, located on the throttle body:
http://bob-ayers.smugmug.com/photos/124318532-L.jpg
You can try removing, and cleaning it to see if helps.
http://bob-ayers.smugmug.com/photos/124318532-L.jpg
You can try removing, and cleaning it to see if helps.
Madmike33
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From: Durham, NC
Originally Posted by Madmike33
This would also possibly cause the idle to fluctuate also, correct? What I mean is you could have a low idle for a minute (500 RPM) and then bump up to normal for a minute and then back down... etc.
Madmike33
Madmike33
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From: Durham, NC
Originally Posted by big_daddy_bigfoot
Is it a pain to get off? What do I clean it with?
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My 90 Ranger also idled slow when cold. I had to keep the rpm up until it warmed up a little. But I noticed my gas mileage increased almost another two miles a gallon. So I lived with problem. I think what happened was a temperature sensor was defective and let the computer think the engine was already warmed up and didn't increase the idle speed.
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From: west central illinois
Idle Air Control Valve And The Mass Air Flow Sensor Can Be Cleaned? Whats The Mass Air Flow Sensor Look Like And Where Is It? After I Posted This I Took It To The Shop (chevy Shop Because It's A Block Away) Because It Would Not Start At All. They Checked The Fuel System And Spark System And It Started Without Doing Anything To It, So We Just Let It Alone. Now Its Sitting At The Walmart Parking Lot And It Wont Start But It's Cold Outside. Its Going To Be In The Upper 40's Tomorrow Do You Think It Will Start? I Know I Need To Take It To The Shop But Want To Take It To A Ford Dealer Not Just Some Shop. But My Ins Will Only Tow It To The Nearest Shop No Matter What It Is....anyway Does Anyone Think It Will Start With A Warmer Air Temp????
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Junior User
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From: west central illinois
Ok so I had it towed to a shop, and again they ran some tests on it, did not replace anything, and it started right up. What's the deal??? They are leaning towards the fuel pump, why would it be the fuel pump???
Post Fiend
Joined: Jul 2005
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From: Durant, OK (SOSU)
The fuel pump relay can go bad (I know...mine did) and produce a low and very rough idle at startup, then eventually it works and voila, you have a nice idle and full power. Mine used to regularly cut out after filling up...worked fine otherwise, but would die every time after filling up.
The IAC can cause a low idle, but once the engine is warmed up typically won't get rough due to the bypass in the throttle plate.
The MAF is just after the air filter box...held on by a couple of security screws, once you get it out justa little spray of throttle body cleaner and letting it air dry is good. The battery should be disconnected to reset the system.
Does the fuel pump run when the key is turned to run? Does it sound solid and strong? It can be a truly intermittent problem as mine was, it works perfectly, then just stops working completely, then comes back to perfect operation again sporadically.
The IAC can cause a low idle, but once the engine is warmed up typically won't get rough due to the bypass in the throttle plate.
The MAF is just after the air filter box...held on by a couple of security screws, once you get it out justa little spray of throttle body cleaner and letting it air dry is good. The battery should be disconnected to reset the system.
Does the fuel pump run when the key is turned to run? Does it sound solid and strong? It can be a truly intermittent problem as mine was, it works perfectly, then just stops working completely, then comes back to perfect operation again sporadically.