One week after 120k, here are my codes, help please?

[Deaks2]

Hi everyone.

Was getting Check Engine lihts this past week following my 120k. Also in stop and go traffic and at stops sometimes the idle fluctuates so bad that it stalls. From what I have researched on the forum that would be the Idle Air Control Bypass Valve, although no codes appeared to indicate that.

Anyways, here are my KOEO codes (did not have time to run KOER):

114 - ACT out of self-test range
116 - ???!!! I confirmed this twice
176 - HEGO sensor indicates system lean (LH) I changed the O2 sensors last summer
542 - Fuel pump secondary circuit failure - I have no idea what this means

I have noticed i have been gettig terrible fuel economy for the past 2 months, so during my 120k I replaced the thermostat, but that has yet to solve anything... Same operating temp, low but ok (A-L in Normal).

Any help would be greatly appreciated!

 

[BlackOnBlackATX]

Hey man, heres what i got for you:

114 ACT out of range, your incoming air temp sensor, this could explain a few other things perhaps. I think this could cause a lean mode where its trying to take in more air but dont quote me on that, im not sure.

116 Engine Coolant (ECT) sensor out of range, this can also cause running rich or maybe lean depending on which way its out.

176 Oxygen sensor not switching - system is or was lean Left or Front HO2S, emm well if you just replaced em i dunno what to say, but i think this would be caused by the fuel pump perhaps if its not sending enough go-juice.

542 Fuel pump open, bad ground or always on. Well im not too sure here, maybe needs replacement or maybe its something you can visually check.

OK well the temp sensor on the thermostat and airbox are easy fixes so maybe you should change those first and then run your codes again to see if they change (theyre also cheap to get a hold of), you may even want to throw some injector cleaner in your gas to see if maybe your front injectors are clogged. hope this helps a tiny bit, keep us informed.

<small>[ December 07, 2002, 03:45 PM: Message edited by: BlackOnBlackATX ]</small>

 

[93MTXSHO]

The 116 means you should replace the ECT. A fairly easy job, and not too expensive either. The 542; I think I remember that it would be thrown if the car stalled. I'm not 100% sure, but fuel pumps generally work or they don't. If it was going, you'd notice a stutter and have no acceleration at higher RPMs

 

[Deaks2]

OK, I cleared the codes, drove her for a while and got the good old Check Engine Light'O Love.

114 - ACT out of Self Test Range - it is winter here, also could that explain bad mileage?

176 - HEGO sensor indicates system lean (LH) - o2 sensors again. I changed them in July. WTF?!?!

542/543 - Fuel pump secondary circuit failure - Damn car stalls, as if it was a sticky IAC, but it only stalls after prolonged running, ie: today 20 mins on the highway and then as I ease up to a stop sign, stall...

What do you guys recommend? I have looked up the proceedure for the IAC but I need pictures I have no idea where the part is! As for ACT out of range (114) how hard is it to replace that sensor?

 

[luigisho]

The ACT just screws out of the air box. The IAC is a long tubular sensor/valve on the opposite side of the throttle body. It has an electric plug on one end and is capped at the end of the tube on the other end. It is held on by 2 screws (hex?) one on top one on bottom.

 

[sdpatt]

You've got one O2 sensor that is probably dying of old age and the other can't be far behind. The 114 and 116 codes would require that you replace the air charge temperature sensor and engine coolant temperature sensor. These are not high dollar parts and you can get them at AutoZone along with the Bosch 13942 ($38.99) O2 sensors.

 

[Deaks2]

THX Scott,

My only question is what would **** my O2 sensors so quickly? I just got them in June.

 

[BlackOnBlackATX]

i dont think you killed the O2 sensors, i think thats just a domino from something else. i used to drive a chevy and one summer the engine began misfiring and the O2 sensors threw a code, but not because they were bad, but since the engine wasnt running properly, the exhaust had an improper mix. i would imagine if you fix your ACT and IAC then you may see everything fall into place. i am not too knowledgable on fuel pumps though so i dont know what the deal is with that but im curious to see.

 

[Deaks2]

OK, replaced ACT sensor, no more Check Engine Light. The idle also seems a little more stable. Sometimes the idle still stumbles, I am reseting the idle right now (via battery). I will see if that help. Also tanked up on a fresh batch of 91 octane, so I can see if my abysmal 15 mpg record can be increased to what i was getting just weeks ago...

 

[BlackOnBlackATX]

ok good, no more check engine light is thumbs up thumbs_u but make sure you clean the IAB valve if your idle still isnt good when you reset it. it may be the best 20-30 minutes you ever spent. hope your troubles are this easily solved!

 

[sdpatt]

What brand of O2 sensors did you install? I recommend the Bosch 15716 for the 3.2L.

 

[Deaks2]

Scott,

O2's were replaced last summer, and since the ECU is not giving me codes anymore I think as suggested it may have been a cascade effect, too rich of a mixture leading to temporary voltage aberations in the O2's signal. I will definately watch then though.

Even if my IAB is not deamed to be at fault I wanna know the proceedure to clean and or replace it. Anyone wanna step me thorugh it or point me to a link? Prob is its mighty cold up here, today was warm with it getting upto 0 deg celcius.

THX

 

[luigisho]

Check out http://www.shotimes.com look under the 'Care and Feeding' section. Bookmark it-> lots of good info.

 

[Deaks2]

OK, I think I am either gonna **** myself or this car

I cleaned out the IAC/IAB today, took less than 30 mins (that bottom hex bolt is a bitch!) Car ran fine for about 15 mins after reseting the idle, then as I am sitting int eh car reprogramming my aftermarket radio it just stalls. I start it up and its ok, take it for a good 30 km test drive, only to saddened to find that any release of the throttle from a steady rpm = a stall, no matter what the speed. Having the engine die @ 100 k/h is fun, no power brakes nor steering

I am thinking replace the IAB and or the IAC. Can these parts be found? I think the IAB would be easy to find, after all its a simple electronic servo-motor, but the IAC scares me. Tomorrow I am gonna rip it apart again and see if I can fix thsi once and for all...

 

[luigisho]

The IAB and IAC are the same part.

 

[Deaks2]

Ok, well I took it all apart again. The IAB looks clean and moves freely, no deposites down south. I cleaned it with some liquid wrench, no carb cleaner around... The IAC's actuator looks good. But I have no idea how the electronics are inside...

Here are some pix:

 

[sdpatt]

The idle air control (IAC, AIB) valve behavior you describe would be due to problems with the servo position feedback rather than the valve portion of the assembly. This is not user-repairable. You can get these at AutoZone for about $50-$60. The part includes the servo and the valve and the toughest portion of the installation is getting to that lower bolt so you know the drill.

 

[BlackOnBlackATX]

glad to hear things are getting better though thumbs_u keep us posted as time goes by!

 

[Bizzy]

542 gets thrown into the computer anytime you stall the car. Clear the codes, drive around a day or so without stalling and you won't see it again. Scared me when I first got my MTX cause I stalled it a few times then I ended up reading the codes.

114 I've been getting that code for a wile now and I'm wondering if it is just cause I'm pulling the codes off the car when it is 20-25 F outside. I'm thinking that it is looking for a different value. it can't be an expensive part to replace though, right?

 

[Deaks2]

Ok, got a new IAC, looks kinda different (you can see in the pix) but it works! Still egt O2 sensor codes, maybe runnign rich for a month or so destroyed them? I got them new in June/July...