EEC IV code help
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EEC IV code help
Okay, be patient: I am a total code NEWBIE............
I pulled codes from my '89 Bronco today, after observing the check engine light flashing sometimes after startup over the last few days. Here's what I got:
With the KOEO test: code 13 = RPM out of specification
KOER test: code 47 = Exhaust Gas Oxygen sensor signal voltage indicates "rich" during "lean" air/fuel conditions OR Vane Airflow Sensor voltage is too low, OR Transaxle problem ; 4X4L switch is closed. (Well, yes, the switch WAS closed; so I guess it's not that one...)
code 75 = BOO switch open (Yes, the e-brake was on, so no worries there.)
code 24 = Air Change Sensor OR Vane Air Temperature signal voltage is out of spec (engine off) or not at normal levels (engine running)
*NOTE* BTW: The truck has a 5.0L & AOD trans. It seems to be running just fine, fuel economy seems normal; (considering the tires & gearing 36's right now w/ 4.10's,) and the tranny shfts just fine. Everything seems okay, I'm just annoyed and want to make sure everything is functionins as its supposed to.
My question is: I guess I should adjust the idle RPM first; but then what? Thanks for your help.
I pulled codes from my '89 Bronco today, after observing the check engine light flashing sometimes after startup over the last few days. Here's what I got:
With the KOEO test: code 13 = RPM out of specification
KOER test: code 47 = Exhaust Gas Oxygen sensor signal voltage indicates "rich" during "lean" air/fuel conditions OR Vane Airflow Sensor voltage is too low, OR Transaxle problem ; 4X4L switch is closed. (Well, yes, the switch WAS closed; so I guess it's not that one...)
code 75 = BOO switch open (Yes, the e-brake was on, so no worries there.)
code 24 = Air Change Sensor OR Vane Air Temperature signal voltage is out of spec (engine off) or not at normal levels (engine running)
*NOTE* BTW: The truck has a 5.0L & AOD trans. It seems to be running just fine, fuel economy seems normal; (considering the tires & gearing 36's right now w/ 4.10's,) and the tranny shfts just fine. Everything seems okay, I'm just annoyed and want to make sure everything is functionins as its supposed to.
My question is: I guess I should adjust the idle RPM first; but then what? Thanks for your help.
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From: Virginia
I looked in my fuel injection book, and it said code 13 is generated when the computer tries to lower the rpm of the motor, and it can't. The guy in the book said this can be caused by the minimum air adjustment being off. He says first make sure none of the throttle cables are binding. Also that the idle air bypass solenoid is not plugged up with carbon, and the throttle body is not gummed up.
After everything is clean, warm up the truck till the engine idle stablizes. Then disconnect the wires on the idle air bypass solenoid. This is up near the throttle body. He said the engine should slowly die. If it dies abruptly, then the idle stop screw on the throttle linkage is back too far. If the engine keeps running, then idle screw is in too far(throttle blade is too far open).
After everything is clean, warm up the truck till the engine idle stablizes. Then disconnect the wires on the idle air bypass solenoid. This is up near the throttle body. He said the engine should slowly die. If it dies abruptly, then the idle stop screw on the throttle linkage is back too far. If the engine keeps running, then idle screw is in too far(throttle blade is too far open).
Last edited by Franklin2; Sep 28, 2003 at 03:16 PM.
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I really appreciate the input; but its still doing it........
Here's what I did;
I inspected and lubricated all the cables, throttle linkage, butterflies, IAC sensor and intake (tubes, air cleaner, ram, airbox.)Even though the IAC and everything looked to be in very good working shape. I performed the test you mentioned, and it was right on. Took about ~3 or 4 seconds for it to cut out, indicating that the idle adj. is fine right? I also checked all the vacuum hoses/ canister and found no leaks.
One thing I noticed is when I drive the truck, when I'm about to come to a stop and am applying the brakes; the engine revs itself up about ~200 RPM, then goes back to normal idle just before I stop. I know this isn't normal, and assume the two are related; I just don't know how. It will rev to just under 1000, then back to about 750 RPM where it's supposed to do. It does it really quickly, (so fast I didn't really even notice before.)
I KNOW there have got to be others who have had this problem, I just need some ideas. Thanks!
Here's what I did;
I inspected and lubricated all the cables, throttle linkage, butterflies, IAC sensor and intake (tubes, air cleaner, ram, airbox.)Even though the IAC and everything looked to be in very good working shape. I performed the test you mentioned, and it was right on. Took about ~3 or 4 seconds for it to cut out, indicating that the idle adj. is fine right? I also checked all the vacuum hoses/ canister and found no leaks.
One thing I noticed is when I drive the truck, when I'm about to come to a stop and am applying the brakes; the engine revs itself up about ~200 RPM, then goes back to normal idle just before I stop. I know this isn't normal, and assume the two are related; I just don't know how. It will rev to just under 1000, then back to about 750 RPM where it's supposed to do. It does it really quickly, (so fast I didn't really even notice before.)
I KNOW there have got to be others who have had this problem, I just need some ideas. Thanks!
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From: peoria, az
I just typed all this yesterday for someone else. Just wish I knew where, it would make it easier.
Franklin is right on.
DTC 13/411 indicates that during Engine Running self-Test, engine rpm could not be controlled within the Self-test lower limit band.
Possible causes:
-Improper idle air flow set.
-Vacuum leaks.
-Throttle linkage binding.
-Throttle plates open.
-Improper ignition timing (distriduter ignition vehicles only )
-IAC solenoid contamination.
-IAC circuit short to ground.
-Damaged Iac solenoid.
You hae already checked most of these. Look at the timing and then for vacuum leaks. I think you may have a booster going bad or maybe a bad check valve.
Franklin is right on.
DTC 13/411 indicates that during Engine Running self-Test, engine rpm could not be controlled within the Self-test lower limit band.
Possible causes:
-Improper idle air flow set.
-Vacuum leaks.
-Throttle linkage binding.
-Throttle plates open.
-Improper ignition timing (distriduter ignition vehicles only )
-IAC solenoid contamination.
-IAC circuit short to ground.
-Damaged Iac solenoid.
You hae already checked most of these. Look at the timing and then for vacuum leaks. I think you may have a booster going bad or maybe a bad check valve.
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From: Virginia
Try pinching the line to the booster and see if it changes the idle. If you did have a vacuum leak, then the engine may be idling on the air from the leak, and not the air going through the IAC valve. This would explain why when the computer closes the IAC, the rpm doesn't lower.
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Thanks guys. I checked the booster and vacuum lines to/from, and found no leaks. I stuck my head up under there, (in Park, and in gear; yes, the e-brake was on) and also found nothing. I'm gonna check the timing 1st thing in the morning, and if that doesn't do it, I guess I'll replace the IAC ??
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Geezer, the code 47 still is a concern. It indicates that the O2 sensor can't enrichen the mixture enough. My first thought is still a vacuum leak somewhere, although it might be a faulty O2 sensor itself.
Try unplugging the O2 sensor and see if the erratic idle continues. If it smooths out, the IAC is OK and the trouble is elsewhere....
Try unplugging the O2 sensor and see if the erratic idle continues. If it smooths out, the IAC is OK and the trouble is elsewhere....
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Geezer, one other thing to check is the BOO switch; (the code 75). When you press on the brake, the ECM senses it through the BOO switch, and changes the timing and fuel delivery accordingly. This might account for the erratic idle when you apply the brakes.
Also check for a blown brake light bulb. This will also affect the idle when braking. I know it's hard to believe......
Also check for a blown brake light bulb. This will also affect the idle when braking. I know it's hard to believe......
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check your vacuum canister for a leak.....It is a reservoir to hold extra vacuum so there is not such a large demand on the engine at one time as when applying the brakes. Could be it is holding some vacuum but not the proper amount for the brakes to work and the engine has to develop extra vacuum by speeding up????? just a thought.
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Okay, this has been driving me nuts, and I still haven't figured it out yet. I've replaced the O2 sensor, checked everything I possibly could as far as vacuum goes, checked the brake circuit, etc.....EVERYTHING seems just as it should!!
HOWEVER: Upon inspection of the exhaust system (installed before I purchased the truck 2 months ago
I have found the catalytic converter to be HOLLOW!! O.
Is this a likely source of my problems? Ie. cat not heating up...sending faulty readings to O2 sensor...trying to compensate for lean/rich mixture that really doesn't exist??? (I'm gonna kill the guy I bought it from...)
If so; is there a module or capacitor or something to "cheat" the O2 sensor without having to buy a new cat to get the right reading?? I know such an animal is popular with the street racing crowd. Does anybody know?? I really don't have a lot of disposable income right now, but I'd like to take care of this before I go nuts!! Thanks fellas.
HOWEVER: Upon inspection of the exhaust system (installed before I purchased the truck 2 months ago
I have found the catalytic converter to be HOLLOW!! O. Is this a likely source of my problems? Ie. cat not heating up...sending faulty readings to O2 sensor...trying to compensate for lean/rich mixture that really doesn't exist??? (I'm gonna kill the guy I bought it from...)
If so; is there a module or capacitor or something to "cheat" the O2 sensor without having to buy a new cat to get the right reading?? I know such an animal is popular with the street racing crowd. Does anybody know?? I really don't have a lot of disposable income right now, but I'd like to take care of this before I go nuts!! Thanks fellas.
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No, the cat shouldn't have anything to do with the code.The O2 is before the cat so it couldn't care less what happens downstream. Can you clear the codes and get it warmed up an check them again?
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From: texas
Okay, Geezer don't feel bad about code knowledge. I would like to know how to pull codes from my 92F250 7.3. Also, I read about the IAC Sensor and / or valve being a possible fast idle problem on a 91 F150 5.8. What is an IAC sensor and or valve and where is it located on the 91F150 5.8?
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From: Virginia
IAC is not a sensor. It stands for Idle Air Control valve. It is mounted on the side of the throttle body near where the throttle cable hooks up. It is a solenoid that is hooked to a metering valve. There is an air passage that goes around the butterfly in the throttle body. The solenoid controls the valve which controls how much air is going around the throttle. This is how the computer controls the idle speed.
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