New ignition trouble code

[stev0n]

alright a new mass air flow sensor today, and NO check engine light!

I'm getting a 111 all systems pass, but i'm still getting 112 and 336 from the CM.

so i'm gonna reset the computer and see if these come back.

NOW, for some reason i still have a rough idle, really jumpy, and it idles between 600-750 rpms. I turn the idle adjustment screw 2 full turns and the idle didn't change. I know the 4.0 doesn't have a smooth idle, but is it supposed to be this bad?!?!

MrShorty or anyone else, if ya'll can help me with the idle issue, Thanks!

 

[cjones101812]

alright a new mass air flow sensor today, and NO check engine light!

I'm getting a 111 all systems pass, but i'm still getting 112 and 336 from the CM.

so i'm gonna reset the computer and see if these come back.

NOW, for some reason i still have a rough idle, really jumpy, and it idles between 600-750 rpms. I turn the idle adjustment screw 2 full turns and the idle didn't change. I know the 4.0 doesn't have a smooth idle, but is it supposed to be this bad?!?!

MrShorty or anyone else, if ya'll can help me with the idle issue, Thanks!

return the idle screw back to where it was. (sounds like the IAC is working properly)

disconnect the battery for atleast 15 min. (that will clear the CM codes and will delete the KAM.) drive truck for a couple of days so the computer can relearn. the truck may run a little funny until the computer relearns.

if you still have idle problems or codes after above, let us know and we'll tackle those.

 

[stev0n]

alright, will do, thanks

 

[stev0n]

alright, i've put right at 40 miles on the truck since reseting the computer the other day. and i still have a rough idle to the point it stutters somewhat and acts like it wants to die sitting at stoplights, but doesn't.

 

[stev0n]

ttt

 

[MrShorty]

Are there new codes in the computer after clearing codes? Same codes come back? What's fuel pressure now?

 

[stev0n]

no codes... not sure of the fuel pressure.

once i'm in motion it runs fun it just idles rough when its parked or stopped in gear. gas mileage has gone up 3-4 mpg since the new maf

 

[stev0n]

alright i've got the cel again today, but it's only on sometimes at idle it's 112 & 114.

so i'm guessing it's from the rough/low idle.

 

[MrShorty]

KOEO, KOER, or CM? My code list shows KOEO/CM 112 and KOEO/KOER 114 apply to the IAT (Intake Air Temperature) sensor. KOEO IAT codes (esp KOEO 114) could potentially be because you performed the KOEO test without getting the engine/sensor warm enough. IAT is a simple thermistor and can easily be tested with an ohmmeter/voltmeter. 1st make sure the engine is fully warmed up and then repeat the KOEO test and see if that resolves any KOEO IAT codes. If not, then figure out what is wrong with the IAT circuit.

 

[stev0n]

it was KOEO test, i checked it after the truck had been running for about 45 minutes. the CEL didn't come on until it had been idling for about the last 15 minutes. i turned the truck off and checked it.

the 112 was from CM.

Both 114 & 112 led me to think the voltage was low because of the low idle. it's so low to the point the interior lights get dim, then bright, then dim, etc. from being only 500 rpms from stalling.

 

[MrShorty]

The "voltage" source for the IAT is a 5V computer grade power supply that is supposed to be 5 V no matter how the vehicle's 12V power supply varies. I would be inclined to believe it is the other way around. Whatever is wrong in the IAT circuit is causing the engine to idle low/rough, which causes the alternator output to be low. One would also note that a KOEO 114 wouldn't be effected by variations in the alternator output, because the engine isn't running (or stumbling or whatever) when this code is set.

1st thing I'd do would be to put an ohmmeter on the IAT and see what it is reading. Compare that reading to one of the many tables (BrooklynBay's posted it here a couple of times or in many repair manuals) that show resistance as a function of temperature. If the IAT reading looks reasonable, then check the wiring between the IAT and the PCM.

 

[stev0n]

alright...will do.

but what i was trying to say was i didn't get the code 114 until the truck had been running for a long time, the CEL only came on at idle and went away as soon it the truck was in motion again.

i haven't got the light at all so far today, tho.