[let_us_rav(e)]

Hi all, just went to start my Rav4 and it started, but idled around 100-200 rpm before dying. When I press the gas it revs and sounds normal. Earlier today I got the P0136 code, which I believe is the downstream 02 sensor. Are they related and how do I get my car working again?
Thanks in advance

 

[tom1977]

O2 sensor shouldn’t make engine die at idle, code may be picking up on another drivability issue. Start checking fuel air and timing. How’s battery voltage?

 

[Elle_Rav4]

After hitting the gas to bring the RPM up again, and then driving a bit, will the Rav return to the normal idle RPM of about 700 and seem to drive fine?

p0136 should not cause this problem.

Has the battery icon light on the instrument cluster been flickering at all in recent weeks? I too want to know what the battery voltage is with the engine off. If it is under about 12.6 volts, then in my experience, two candidates for the cause of the problem are (1) a dying battery or (2) the alternator brushes need replacement.

Did you have a timing belt job done recently (on your 1998 Rav4), on account of the coolant leak?

 

[let_us_rav(e)]

Timing belt was done 8 days ago (I don’t suspect this because when I rev the engine it works just fine). And I had a local shop check things over afterwards

Battery is at 12.8v and starts the car just fine.
How do you recommend checking the air? (I mean the filter looked fine)
It’s just strange how suddenly this issue emerged
How do I check the alternator brushes? Thanks in advance!

 

[let_us_rav(e)]

Also the battery is only like a month old

 

[tom1977]

Hmm... do you hear the timing belt slap the cover upon deceleration? Anything left unplugged from timing belt job?

 

[let_us_rav(e)]

I haven’t heard any strange noises (besides ones I’ve already identified) and it worked for a few hundred miles just fine so I don’t think it’s the timing belt. I’ll probably just drive it back to the shop because they diagnose and fix things for free if it’s something simple like a plug that came undone

 

[Elle_Rav4]

-- Is the battery icon under the tachometer lighting up briefly (as part of the lamp check) and then going out when you first go to start the Rav? If so, and since the (nearly new) battery appears to be charging just fine, then I would rule out both the battery and the alternator as the cause of the problem.

-- Please clarify: When the Rav is running and it is sitting at a stoplight with the engine idling (foot off the gas pedal), what is the RPM?

-- Is the coolant level in the reservoir in the normal range when cool and also when hot? When the water pump was replaced (as part of the timing belt job), the technician should have burped the cooling system. If air is still in the cooling system, this can result in certain sensors sending an incorrect signal to the engine computer.

-- Do keep checking for pending codes. These will not light the check engine light but they will be stored in the computer.

-- I agree a sensor not plugged in, or not plugged in correctly, could be the cause. Certain sensors when not plugged in do not always cause a code.

-- A fouled idle air control valve (a.k.a. the IAC valve) or fouled mass air flow sensor can cause "air problems." Both of these should be cleaned periodically. Autozone and the like sell a special "mass air flow sensor cleaner."

-- Edit: Thread with description of cleaning the mass air flow sensor:
www.rav4world.com/threads/diy-clean-or-replace-maf-mass-air-flow-sensor-to-cure-rough-idle-p0174-code.268121/

-- Edit: Demoder's excellent video on cleaning the Rav4.1 IAC valve (and other parts):

-- Edit: Two threads whose symptoms seem close to the OP's with responses discussing the IAC Valve:
www.rav4world.com/threads/car-dies-after-i-start-it.65304/#post-672496

www.rav4world.com/threads/low-idle.67854/#post-698530

-- Also, to cover two of the basics: How old are the spark plugs and the spark plug cables?

 

[let_us_rav(e)]

• Battery light does light up briefly when starting
• When the engine is cold and at idle, it stalls and shuts off whenever I’m not pressing the gas pedal. Not sure about when it is warm (will know by tomorrow)
• Coolant seemed normal when cold, not sure about hot (haven’t driven it far since the issue started), but I topped it off (about 3 oz) anyways
• Will definitely research the air valve and MAF sensor!
• Spark plugs and wires are all about a week old
• I’ll update the thread whenever I figure out what’s going on!

 

[let_us_rav(e)]

I think the culprit is the IACV (THANK YOU ELLE!!) because for awhile it’s had an idle that fluctuated between 600-900rpm while in neutral
Going to try this tomorrow:

 

[let_us_rav(e)]

Update: I definitely think it’s the IACV or something near it, because the buildup on the air intake valve is IMMENSE.

On another note, does anybody know the size of the rubber hoses that carry coolant to this valve? One of them disintegrated and I don’t want to have to order it, so I’d like to find a hose in store.

 

[Elle_Rav4]

Your Rav4's throttle body looks way filthier than any I have seen on several salvage yard Rav4.1s in the last few years and on my own Rav4. Hopefully this filth turns out to be thee problem and the throttle body and IAC valve can clean up nice.

In my throttle body adventures, I am aware that there is "carburetor cleaner" and also "throttle body cleaner" sold at places like Autozone and Wal-Mart. I have taken to using the cleaner that is more specific to the part. I try to be mindful of not spraying any electrical contacts or rubber parts with the cleaner.

I think the video by Aussie50 (cool guy) you linked is great, but I would take a look at demoder's video as well. I think demoder's video focuses more on carbon buildup (as opposed to coolant sludge yada) in the IAC valve. See about 16:00 to 17:30 in demoder's video.

Demoder's comment about JIS screws was instructive. I think it explains why Aussie50 (and myself) often find the IAC valve screws stripped. (Okay, I may have stripped a few through ignorance about JIS screws vs. Phillips head screws.)

I am not sure of the hose diameter. I'd likely cut the old hose towards the center of the length and measure it. Or I'd take the old hose with me to Napa or Autozone.

I think this is a good discussion of the IAC valve coolant hoses and some local options:

Gates Extreme 325 Briad Hose for IAC Water Bypass? BMR...

BMR and fellow associates!:grin: Before I post over at the "What did you do to your GEN3 Camry" thread, I am asking some expert opinions on selection of hose material for the Idle Control Valve (IAC) Water bypass application. At first the replacement hoses from Toyota Dealer quoted me a...

www.toyotanation.com

Silicone hoses appear to be worth considering. But I would want the silicone hose manufacturer to be crystal clear that the hose is designed for coolant systems.

I would triple check any substitute hose that Autozone suggests, by googling on the identifying information printed on the hose.

I think I'd go to my local dealer and see how quickly they could get the hoses for me.

For the archives: Long time member Eodgator talks about replacing coolant lines (inclulding the IACV coolant hoses) with "Autobahn88 PTFE Teflon Hose with High Tensile Stainless Steel Braided (Single Layer) fits for Fluids : Fuel, Oil, Water, Coolant, Methanol. Silver" (or whatever is the equivalent in the correct diameter): Photo from Amazon:

For more detail see Eodgator's post at
www.rav4world.com/showcase/%C2%A1ay-caramba-rav4-1-1999-3mz-fe-st205-torsen-differential-4x4-5sp-*******-edition.8241/ . PTFE hose fittings are needed. Youtube has some videos on installing the fittings.

 

[LugNut]

Something other than the OE-like air filter, box, and hose used? And triple check for leaks in those upstream of the valve body.

I'd have to look on mine -- where does the PCV hose connect relative to the throttle plate? I'd change the PCV valve, and do a compression test.

 

[let_us_rav(e)]

SUCCESS!! I cleaned everything up real nice and adjusted the valve so that it looked like the one in Demoder’s video and it worked!! Thank you all a ton!