99 Ranger High Idle Problem
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99 Ranger High Idle Problem
I have a 99 Ranger, 3.0, automatic with a well maintained 53,000 miles that developed a high idle about 6 months ago. (1,000-1,100rpm in drive).
Tried resetting computer by removing battery cables, touching them together, etc. Dealer installed a new IAC valve, mass air flow sensor, cleaned the throttle body and checked for vacuum leaks. No change. Truck runs perfectly otherwise. Dealer agrees it's a problem, but is stumped as no codes show up. Any ideas?
Thanks. (Seems to have started with a new battery installation, but not sure.)
Tried resetting computer by removing battery cables, touching them together, etc. Dealer installed a new IAC valve, mass air flow sensor, cleaned the throttle body and checked for vacuum leaks. No change. Truck runs perfectly otherwise. Dealer agrees it's a problem, but is stumped as no codes show up. Any ideas?
Thanks. (Seems to have started with a new battery installation, but not sure.)
Logistics Pro
Joined: Jan 2002
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From: suburban atlanta
I'd check the alternator output. If you get spikes on the output, it can send weird signals through, that may confuse the ECM. I had a bad regulator (someone washed the engine compartment...) that caused the engine to die when shifted from D to N. The IAC couldn't handle the signal change quickly enough to prevent the engine stalling. I *THINK* that there was garbage on the "dc" current (hash..) that confused the ECM or was enough to mess with the signal the IAC was getting. From what I know, the IAC gets a 'buzz' that energizes the solenoid at quick enough rate to position the spool valve. It does not move to position "X" and sit there, it must be coerced by continuously sending pulses of juice. More pulses, more solenoid movement against the spring-load. Add some hash to the mix and you get a confused solenoid...or bad feedback to the ECM.
tom
tom
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From: sunny fla sometimes windy
Take off the intake hose at the TB and see if your butterflys are open anything more than a C-hair. If so somebody tweaked the throttle hard stop or your throttle linkage is hooked on something and not getting to the idle position!!
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Joined: Aug 2007
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From: NC
I just had the same problem with my 02 xlt 2.3l. There are 2 IAC valves and mine are vacume operated. drove me nuts for several weeks until I was changing my shocks, looked up at the engine through the splsh guard in the drivers side wheel well and saw a small crack on the underside in the bend of a vacume hose. just so happens that it was a hose that went to my #1 IAC. bought a foot of hose for .68 cents and replaced in about a minute. The problem was solved by pure luck and the truck runs great again.
Good Luck
Good Luck
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From: St. Peter
I would suspect a vacuum leak. do you hear any whistling at all? Check your fuel pressure regulator, they will cause a high idle. I seem to remember my 88 idling around 1k until I replaced it
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Joe Kucinski
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Joined: Nov 2004
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From: Salt Lake City, Utah
A quick simple test for an electrical IAC valve is to unplug it. If the idle drops the problem is with the valve and/or its controls. At that point spray it with some throttle body cleaner (do not scrub it). If it improves further, the valve is sticking. Cleaning it may fix it, but if the problem did improve, but did not go away, the problem is beyond a simple cleaning. The valve will need to be replaced.
I am not familiar with vacuum actuated idle controls, but I would assume if you uses a clamp of some sort to pinch of the vacuum source and then disconnect the vaccum line from the valve, the idle should rise since deep vacuum would trigger the valve to open.
I am not familiar with vacuum actuated idle controls, but I would assume if you uses a clamp of some sort to pinch of the vacuum source and then disconnect the vaccum line from the valve, the idle should rise since deep vacuum would trigger the valve to open.
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Joined: Jan 2003
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From: Connecticut
Originally Posted by JPFergy
I just had the same problem with my 02 xlt 2.3l. There are 2 IAC valves and mine are vacume operated. drove me nuts for several weeks until I was changing my shocks, looked up at the engine through the splsh guard in the drivers side wheel well and saw a small crack on the underside in the bend of a vacume hose. just so happens that it was a hose that went to my #1 IAC. bought a foot of hose for .68 cents and replaced in about a minute. The problem was solved by pure luck and the truck runs great again.
Good Luck
Good Luck
However, there is only one Idle Air Control (IAC) valve used on your engine, and it does not have any vacuum hoses running to it. So I suspect you are talking about something else, like maybe the DPFE sensor or an EVAP system component, something along those lines.
Last edited by Rockledge; Sep 25, 2007 at 11:04 AM.
