Toyota 2AZ-FE 2.4 L rough idle help

[LeakySeals]

I have a 2AZ-FE 2.4L engine in a 2002 Camry XLE (172k) with a really rough idle. After warm up, when the AC is on or in drive at a light, real rough. Idle seems too low, exhaust pipe shaking, a hand over the exhaust feels almost like a skip.

Tasks performed that worked with other cars:

- Changed plugs, pvc, air cleaner.
- Tested all coils with a new coil rotated through.
- Cleaned MAF sensor.
- Cleaned the 02 sensors with the MAF cleaner.
- Cleaned throttle body, but wonder if it requires removal to do it right. There is a hole in the throttle body like an IAC which I put TB cleaner in, but this throttle body has a plastic cover so if there's an IAC or a TPS, its not visible.
- Has no EGR valve, direct to canister.

A google search shows this problem is common on this engine, but very few resolutions. Some people say its mounts. Others say its the AC compressor. Others say Toyota tells people that's the way these engines are. Only problem with it is blue smoke at startup, not bad, very common also. Burns a quart every 5k, using M1 HMO 5w-30 so I'm not worried about the valve seals for now.

If anyone has resolved this please let me know, thanks!

 

[brandini]

Try the spark plug wires/boots. My friend's girlfriend has a yota 2.2 in her 91 mr2 and we found that you could arc the spark plug wires through the boot to another wire. It ran like a turtle and $50 later was fixed.

 

[Quest]

Originally Posted By: brandini
Try the spark plug wires/boots. My friend's girlfriend has a yota 2.2 in her 91 mr2 and we found that you could arc the spark plug wires through the boot to another wire. It ran like a turtle and $50 later was fixed.


LOL! 2AZ-FE has coil packs above spark plug holes, no boots nor wires (yes, my wifey currently owns/operates a 04 2AZ-FE).


@ OP: aside from checking for CEL codes (to see if there's any intermittent codes or so), also perform a compression check on all 4 cyl to see if you have fairly even compression across the board (uneven compression on a 4-cyl will cause rough idle, power loss and poor fuel economy also).

-Throttle body cleaning is a good thing. I do mine (wifey's) every 2 yrs, with CRC throttle body spray and that typically restores the smoothness in terms of idling/acceleration responsiveness of the engine.

are you using the right/correct type of spark plugs? Iridium and/or platinum is a must to ensure good performance/responsiveness and reliability.

have you try running a bottle of PEA based FI cleaner such as Shell V-power or Chevron TEchron? If not, try it.

Have you check for EGR valve leaks?

LAstly: when was the last time you check/replace your thermostat?

Q.

 

[The Critic]

Check if the head bolts have stripped out or if the head gasket is leaking. Probably won't cause the blue smoke issue, but some people have mentioned the head bolts being an issue on the early 2AZ-FE.

http://toyotanation.com/forum/showthread.php?t=325124

 

[OVERKILL]

It needs a 2JZ swap with NAS!

 

[LeakySeals]

Originally Posted By: Quest

-Throttle body cleaning is a good thing. I do mine (wifey's) every 2 yrs, with CRC throttle body spray and that typically restores the smoothness in terms of idling/acceleration responsiveness of the engine.

I did that, but I don't think its thorough enough. Whats behind that plastic cover with the torx screws? IAC valve? TPS? There's nothing visible like most cars.
Originally Posted By: Quest

are you using the right/correct type of spark plugs? Iridium and/or platinum is a must to ensure good performance/responsiveness and reliability.

Yes NGK OE Laser Iridium 4589
Originally Posted By: Quest

have you try running a bottle of PEA based FI cleaner such as Shell V-power or Chevron TEchron? If not, try it.

Used Redline S1 once so far. not much better.
Originally Posted By: Quest

Have you check for EGR valve leaks?

Doesn't have one. Has a couple of plastic valves on the way down to the charcoal canister. doesn't appear to have any leaks, would think idle would be rough under all conditions, not just idle?
Originally Posted By: Quest

LAstly: when was the last time you check/replace your thermostat?

Q.

Never. Been purging Toyota red from the radiator couple of times. analog dash gauge reads normal. Could it read normal at the dash but send something else to the ECU?

 

[LeakySeals]

Originally Posted By: The Critic
Check if the head bolts have stripped out or if the head gasket is leaking. Probably won't cause the blue smoke issue, but some people have mentioned the head bolts being an issue on the early 2AZ-FE.

http://toyotanation.com/forum/showthread.php?t=325124


Yeah, that ones scary. some guy makes a head bolt kit because Toyota wants to replace the engine. its why I'm not bothering with the valve seals

Coolant level is stable never have to add any.

 

[Quest]

If I understand you correct RE: TB plastic housing, it's where the stepper motor resides as part of the throttle body(plate) actuator and also responsible for turning the throttle plate (drive by wire, electrical wires, that is). No IAC involved in this design for when the motor closes the throttle plate, it leaves a small gap behind for air for idling.

Try spray cleaning the throttle plate and the plate shaft part so as to restore the smooth motion (no binding) of the throttle shaft. Only use TB cleaner and not carb cleaner of any sort (some throttle shaft is coated with PTFE/teflon and certain carb cleaner will eat the coating).

Also: never attempt to adjust the motor by yourself (we do not have the factory spec on how to calibrate/adjust the motor, so I wouldn't bother).

Also worthy of consideration: given it's age (engine mileage), consider running a couple of rounds of PEA based FI cleaner again. Check all the gaskets (intake manifold, exhaust manifold, certain vacuum-related rubber hoses, etc.) for leaks. A can of starting fluid spray works wonders in this case.

LAstly: if there's a means of acquiring a used throttle body assembly for a song, I wouldn't hesitate to give it a try. Drive-by-wire throttle body can be a bit of a pain as they get older, for there is no one universal/standardised design and diagnostic procedures differ from one manufacturer to another....

Q.

 

[LeakySeals]

Originally Posted By: Quest
If I understand you correct RE: TB plastic housing, it's where the stepper motor resides as part of the throttle body(plate) actuator and also responsible for turning the throttle plate (drive by wire, electrical wires, that is). No IAC involved in this design for when the motor closes the throttle plate, it leaves a small gap behind for air for idling.

Yes thats right No mention of IAC, TPS on the parts list. Just a complete motorized throttle body. No EGR hose snaking in Toyota Fuel Injection Parts Diagram.

Originally Posted By: Quest
Try spray cleaning the throttle plate and the plate shaft part so as to restore the smooth motion (no binding) of the throttle shaft. Only use TB cleaner and not carb cleaner of any sort (some throttle shaft is coated with PTFE/teflon and certain carb cleaner will eat the coating).

Also: never attempt to adjust the motor by yourself (we do not have the factory spec on how to calibrate/adjust the motor, so I wouldn't bother).

Ok will try again. Your right about the electronic motorized throttle plate. In order to clean it need to have somebody step on the gas to keep it open. There is an "IAC like" hole in the side of the throttle body, will hit that again too

Originally Posted By: Quest
Also worthy of consideration: given it's age (engine mileage), consider running a couple of rounds of PEA based FI cleaner again. Check all the gaskets (intake manifold, exhaust manifold, certain vacuum-related rubber hoses, etc.) for leaks. A can of starting fluid spray works wonders in this case.

have another bottle of Redline S1 will try it.
Originally Posted By: Quest

LAstly: if there's a means of acquiring a used throttle body assembly for a song, I wouldn't hesitate to give it a try. Drive-by-wire throttle body can be a bit of a pain as they get older, for there is no one universal/standardised design and diagnostic procedures differ from one manufacturer to another....

Q.

Tons of them from junk yards on ebay. May look into that if none of this works. Just seems like the AC compressor is dragging it down. Works good, no noises, so I havent bothered with a recharge. I don't want to use one of those recharge kits, cause I dont want to overfill the oil. It has had a CEL for catalyst efficiency P0420, but it went away after I cleaned the downstream 02 sensor.

 

[Quest]

try isolating it by mean of disabling the AC (stop it from dragging down the engine, thus cranking up the throttle plate while idling) and then go from there...

Normally, when these DBW (drive by wire) TB on 2AZ-FE gets old, A/C cycling when warm tends to give a very mild "bump" (drop of rpm when A/C kicks in and the throttle motor tries to catch up)...this is normal in our 2AZ-FE. I don't experience any rough idling and the engine is still idling steady @ 750rpm.

If it's not too expensive, try a junk yard throttle body assembly and see how it goes (make sure you get a tb gasket when experimenting, no use when testing with a used gasket that may complicate things when it has a leak)

Q.

 

[Hokiefyd]

Wasn't there an issue with the earlier 2AZ-FE engines where they would develop a vacuum leak in the intake manifold gasket? I seem to recall something like that with this engine.

 

[brianl703]

If you have a scanner capable of getting the long term fuel trim, it would usually be high if there's a vacuum leak, if this engine has a MAF.

 

[mechtech2]

TB cleaning, for sure. but not 1/2 way - do it right, even if it is tedious.
But the idle air control motor should be cleaned also, since your idle is stated as being too low. The IAC motor may be actually faulty, as well.
Vacuum leaks can be from lines, connections, and the intake system. Double check the whole PCv system. Another manual and tedious inspection.

 

[LeakySeals]

OK I just went and let the car warm up. Stopped at 750rpm which is perfect, then it started what seems to me skipping, some say rough idle. turn on AC it maintains 750, shakes more. No idle fluctuation whatsoever except the recovery idle when the AC goes on or off stated above. Clean under hood, detailed it over the summer. Has 3k on oil, consumed none, that's a first. That little rubber seal on the top of dipstick has been missing, assume it doesn't matter. Only noise is a fairly loud rattle from a replacement NAPA PCV valve installed 6 months ago. Coolant down a tad below the mark I made when last added 6 months ago, could be cause it was cold.

 

[Quest]

OK...here's what I'd recommend you to do:

(1) w/o hesitation, order a replacement PCV valve from Toyota and get rid of that aftermarket Napa one.

(2) replace the O-ring on that dipstick end. Nothing worse than having an unintentional vacuum leak into the crankcase (assuming that you still have negative crankcase pressure(normal) with that Napa PCV valve.

Cheers.

Q.

 

[LeakySeals]

Originally Posted By: Quest
OK...here's what I'd recommend you to do:

(1) w/o hesitation, order a replacement PCV valve from Toyota and get rid of that aftermarket Napa one.

(2) replace the O-ring on that dipstick end. Nothing worse than having an unintentional vacuum leak into the crankcase (assuming that you still have negative crankcase pressure(normal) with that Napa PCV valve.

Cheers.

Q.

The idle problem was there prior to the PCV swap, but your right, makes sense to get the right part. Not sure if I took factory PCV out, but the inlet hole was tiny compared to the NAPA one. I tested to see if the dipstick hole requires an airtight seal by removing it and plugging it with my finger, didnt seem to matter. May as well buy a new dipstick, never thought that would happen.