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Low/Rough idle after warm start? 22RE
11-22-2014 | 05:24 PM
#62
Registered User
Joined: Mar 2013
Posts: 49
Likes: 0
Hey guys just resurrecting this thread, I've been chasing this problem for months myself.
It all seemed to start around the time I did the battery/intake swap.
Symptoms:
-starts up fine cold
-runs great on the road
-after engine off and heat soak, engine idles low and rough until you get going
Check to see if your intake air temp (IAT) sensor is getting heat soaked by the AFM housing.
Short version:
Try pouring ice water on the AFM when it's doing the crappy low startup idle and see what happens....
Long version:
I'm also getting CEL lights cruising on the highway, O2 lean. I can clear the CEL by blipping the throttle.. which would make sense because that would un-heatsoak the IAT for a brief moment.
What I want to do now is remove the IAT from the AFM and relocate it somewhere shielded/insulated where it won't get soaked, like right behind the filter in my intake tube before the AFM. Or maybe I could just move the whole AFM itself or shield it really well. Anyone know how hard it would be to find a matching temp sensor that I could mount externally from the AFM? I imagine pretty hard. Luckily I have a spare AFM I can try to rip it out of....
Let me know if you guys have success with this diagnosis procedure. I've been able to reproduce it about 3 times in a row shouting "hallelujah" at the top of my lungs each time as I hear the engine start to run buttery smooth... doing nothing but pouring some dang icewater on the stupid AFM. My IAT is getting super heat soaked, problem solved. I am sure of it. Now I am wondering if y'all are having the exact same issue...
It all seemed to start around the time I did the battery/intake swap.
Symptoms:
-starts up fine cold
-runs great on the road
-after engine off and heat soak, engine idles low and rough until you get going
Check to see if your intake air temp (IAT) sensor is getting heat soaked by the AFM housing.
Short version:
Try pouring ice water on the AFM when it's doing the crappy low startup idle and see what happens....
Long version:
- Stick a multimeter in ECU's THA terminal to read intake air temp voltage at the ECU.
- Go drive around and get the engine nice and hot like normal, write down voltage during throttle open.
- Turn the car off and keep ignition on
- Notice the voltage drop (lower voltage = hotter sensor)
- Turn the ign off & wait 10-20min
- Turn ign on and take note of the voltage, it has probably dropped a ton (heat soaked IAT sensor condition)
- Try starting the car, crap idle like usual.
- Pour icewater on AFM (careful not to get any in your air filter if you have a K&N style) until multimeter reads a similar voltage to the one you recorded earlier
- Start back up... Vroom?
I'm also getting CEL lights cruising on the highway, O2 lean. I can clear the CEL by blipping the throttle.. which would make sense because that would un-heatsoak the IAT for a brief moment.
What I want to do now is remove the IAT from the AFM and relocate it somewhere shielded/insulated where it won't get soaked, like right behind the filter in my intake tube before the AFM. Or maybe I could just move the whole AFM itself or shield it really well. Anyone know how hard it would be to find a matching temp sensor that I could mount externally from the AFM? I imagine pretty hard. Luckily I have a spare AFM I can try to rip it out of....
Let me know if you guys have success with this diagnosis procedure. I've been able to reproduce it about 3 times in a row shouting "hallelujah" at the top of my lungs each time as I hear the engine start to run buttery smooth... doing nothing but pouring some dang icewater on the stupid AFM. My IAT is getting super heat soaked, problem solved. I am sure of it. Now I am wondering if y'all are having the exact same issue...
greetings jennygirl, i really appreciate you sharing your feed back! seems like no one want's to write back these days if they've found the problem and you can tell these people figured out the problem because they don't mention it ever again... any ways, but of course ever since i wrote on this post, i haven't solved the problem yet. i do know its got to be a fuel problem because it feels like it's running rich and you could kind of smell the unburnt fuel... so i will try this when i have a chance and let you know for sure! give me some time though because i hardly drive my truck and next time i'll get a chance to look at it may even be within the week or so...
11-22-2014 | 09:47 PM
#64
Registered User
Joined: Sep 2014
Posts: 507
Likes: 8
From: LA CA
Rabbit did you try it with success?? Iwill be so excited to hear if someone else can reproduce this.
Skebe- firstly I'm happy to hear your appreciation. Thank you kind sir
I'm also looking forward to your results as well as Mudd.
Have any of you done the battery intake swap?
Skebe- firstly I'm happy to hear your appreciation. Thank you kind sir
I'm also looking forward to your results as well as Mudd.Have any of you done the battery intake swap?
11-22-2014 | 10:37 PM
#66
Registered User
Joined: Sep 2014
Posts: 507
Likes: 8
From: LA CA
I hear you. Yeah that stock air tube does get in the way.
If you do, be sure to mount the AFM as far away from the TB and sources of engine heat as possible. It's very likely that doing the battery intake swap ibcreases risk of IAT heatsoak by a large margin
If you do, be sure to mount the AFM as far away from the TB and sources of engine heat as possible. It's very likely that doing the battery intake swap ibcreases risk of IAT heatsoak by a large margin
11-25-2014 | 05:29 PM
#68
Registered User
Joined: Jul 2012
Posts: 1,776
Likes: 110
From: Northern Colorado
Shouldn't be too hard. It's just a thermistor that measures about 2.5K at 25degC. Just go to DigiKey and you can find a bunch that will probably work.
11-25-2014 | 08:15 PM
#69
Registered User
Joined: Sep 2014
Posts: 507
Likes: 8
From: LA CA
Thanks RJR, this one seems like it will work?
http://www.digikey.com/product-detai...014-ND/1014542
I guess it's probably a better option- rather than sacrificing an entire AFM for such a simple component.
http://www.digikey.com/product-detai...014-ND/1014542
I guess it's probably a better option- rather than sacrificing an entire AFM for such a simple component.
11-25-2014 | 08:56 PM
#74
Registered User
Joined: Sep 2014
Posts: 507
Likes: 8
From: LA CA
11-25-2014 | 09:03 PM
#76
Registered User
Joined: Sep 2014
Posts: 507
Likes: 8
From: LA CA
Bummer had to send mine in for the core charge.
11-25-2014 | 10:35 PM
#77
Registered User
Joined: Sep 2014
Posts: 507
Likes: 8
From: LA CA
http://www.bosch-motorsport.de/media...2650379pdf.pdf
Readily available, autozone and oreilly even have it
I just checked cold air routing options, and I guess I didn't realize how little space there is in that area. I'm going to keep the filter and piping as is and try to mount the air temp sensor in the end cap of the filter itself.
Definitely using that bosch unit
Last edited by jennygirl; 11-25-2014 at 11:06 PM.
