[Callum Molineux]

Hi all i have a 3sfe rav 4 just changed the head gasket and the engine was running as smooth as. But i started it this morning and it was running really rough and not idling properly, it was probably on quite low fuel but i have filled the tank again. If you could give me any advice on where to look that would be grat

 

[Elle_Rav4]

-- Did you do a good purge of air from the cooling system? Air bubbles can cause the sensors to send the wrong signal to the ECU and cause an erratic idle. Everyone has their own way of doing purges. Here is what I do:
With engine cold, remove the radiator cap and top off. Leave the radiator cap off. Put a pan underneath the radiator to catch run off.
Start engine and rev at 2500 for five minutes.
Add coolant to the radiator to keep it topped off.
Look for air bubbles burping out of the radiator.
With engine still running, top off and put radiator cap back on.
Rev for two more minutes at 2500 RPM.
Fill the reservoir to the high line.
In the next few days, when the the engine is cold like first thing in the morning, top off the radiator.

-- Even if the CEL is off, check for codes and report back. Autozone will check for codes for free.

-- Look for disconnected plugs in the engine bay. A disconnected sensor could cause erratic idle and will not necessarily throw a code.

 

[eodgator]

Squeezing the hoses also helps to break any airlocks in the system.

- As Elle_Rav4 stated start with getting the OBDII read (if you have one) and recheck all of your electrical connections https://www.rav4world.com/forums/83-4-1-general/291247-sensors-their-descriptions-symptoms.html
-- Camshaft sensor
-- Throttle sensor
-- Engine coolant temperature sensor
-- MAP sensor, power and vacuum
-- Oil pressure sensor
-- Knock Sensor
-- Crankshaft position sensor,
-Check your vacuum lines - https://www.rav4world.com/forums/94...-i-y-modifications/255961-vacuum-line-replacement-high-temp-silicone-lines.html
-- EGR system, hopefully you moved the EGR VSV to the firewall. Check that it is plugged in and the vacuum lines are run properly.
-- Evap canister
-- MAP sensor
-- If 4wd many people hook up the transfer actuator vacuum lines wrong
-- Well you really need to check all of them and make sure that they are in good shape, not hard or cracked, if you have never replaced them do so, it's cheap, fairly easy ad will save you countless hours of troubleshooting later.
- Make sure your ignition wires are all hooked up properly and in good condition. Check for signs of deterioration, and any burns no matter how small may be an arc burn through. Check at night to see if you can see any arcs.
- Did you torque the spark plugs right?
- Did you correctly reconnect and install the fuel injectors, fuel rail, and fuel line?
- Did you properly set the timing belt the Toyota way? If you didn't it has likely jumped and your timing is now off. https://www.rav4world.com/forums/94-4-1-d-i-y-modifications/56986-diy-timing-belt.html
- Did you damage the crankshaft pulley pins? If you bent or broke one you will need a new pulley
- Did you clean and reconnect all the engine grounds?

It would be helpful if you would update your profile with where you are in the world, it makes a difference and add a signature block with all of your RAV4's information.

 

[LugNut]

Could be many things, unfortunately. Jumped timing belt comes to mind.


Ditto on reading the OBD codes.

 

[Callum Molineux]

I couldnt find the obd plug where it said
(attachment 1)
I looked for it in the same spot and couldnt find it (attachment 2)
The only diagnostics port i found was in the engine bay (attachment 3)
Pls help
Ps i am in australia so i dont know if the aussie modelsvare different or not

 

[Mick Hatzo]

Unfortunately, first generation Australian (as well as European) Ravs were not required to comply with the OBD2 standard.

You can use the diagnostic port you found to hunt for codes.
Search for "toyota te1 codes" and check this video:

 

[Callum Molineux]

Thanks for the hand mick. I scanned the car and it came up with the 21 code which is oxygen sensor, and seeing as though the car has 357000kms could the sensor be playing up and sending incorrect readings? Thanks in advance :thumbs_up:

 

[Elle_Rav4]

Callum, yes an oxygen sensor that has either failed or is not properly connected will cause rough running. I would first unplug and then re-plug in the oxygen sensor. Then I would probably buy a new Denso oxygen sensor from eBay, triple checking to make sure it really is a Denso sensor. (Denso is the Japanese OEM factory yada manufacturer.) Try densoautoparts.com for the denso part number of the oxygen sensor for your Rav, with the caveat that you should double check that it's right for Aussie Ravs. It is fairly common for oxygen sensors with over 200k miles on them to fail.

Once you think you have solved the problem, remember to clear the codes using the steps at https://www.troublecodes.net/toyota/

 

[Callum Molineux]

The oxygen sensor is a denso brand. I found this one one ebay and i think it should fit but it doesnt come with a plug?
Aswell i ran the car with the sensor plugged in(ran rough) then ran it with the sensor unplugged and was still running rough so id say its not doing its job.

 

[Elle_Rav4]

You want the upstream, OE style sensor. Match the holes in your sensor's end with those in the Denso site's photos. Count the tiny nubs on each side of the electrical connector on yours and match them with what is in the Denso site's photos. It looks like Denso #234-4624 is the one you want.

Your Rav is in Australia, so I ask that someone double check this.

I am seeing 234-4624 for about $40 on eBay, shipped in the U.S.. Triple check that it is a genuine Denso product. I have seen some fraud lately on eBay, with the seller saying it was a Denso part when it was not.

 

[Elle_Rav4]

Callum, first, if one is handy with wiring, then one may buy an oxygen sensor without a plug; save some money; cut off the old plug; and then splice the old plug with the new sensors wires. Try to get the wire length as close as possible to the old plug's. I did this once and all went fine. Second, many say the aftermarket oxygen sensors have worked fine for them. Others say they have not had good experiences with aftermarket. I won't use them since to me, their quality is a roll of the dice. Also shipping from China often takes weeks or even a month+.

If you want the plug-less Denso sensor (to save some money), its part number is 234-4209. Again, check the advertisement carefully to see that it really is a Denso and not a Denso knock-off. When the sensor arrives, "Denso" should be printed on the sensor somewhere, or possibly the "ND" symbol will appear, standing for "Nippon Denso."

 

[Callum Molineux]

Hi all again, my new o2 sensor has arrived and i have fitted it and the cleared all the codes. I then put it back into diagnostics mode and the engine light is flashing 2 times a second which means the system has no fault(according to online sources). I also purged any air from The cooling system. Even afyer all those steps it has not changed the idle one bit, and same as before, if you rev it over 2000rpm its like its gasping for fuel. I dont know what to do anymore and i am sick of chucking parts at this rav..... Plzzz help

 

[gpfleming]

since you have just changed the head gasket... I would recommend re-checking the cam timing ...

Not sure how long ago the head gasket change was ... presumably quite recently?

I know it can be pretty sickening to be going over the things you already did ..but cam timing on these engines is very fickle ...you think you've done it right...the engine runs again ..you're smiling wide..and then BOOM .. runs like a pig cos the tension wasnt set 100% EXACTLY as Toyota says ... and it has jumped a tooth ....

doesnt take too long to recheck timing..I would say do it ...

 

[eodgator]

If the timing belt was not tensioned the Toyota way it WILL jump timing. This is a common occurrence if you read through the threads, see DIY - Timing belt on how to do it the right way.

 

[Callum Molineux]

If the timing belt was not tensioned the Toyota way it WILL jump timing. This is a common occurrence if you read through the threads, see DIY - Timing belt on how to do it the right way.

I have checked the timming an the marks were lined up. And if you are wondering what those white marks are i panedet them on so i didnt have to feel the marks with a allen key through the hole everytime. And yes they were that lined up before

 

[Callum Molineux]

Hi all again, update time.
So I ran the RAV4 again to check it and saw black smoke pouring out of the exhaust manifold when I reved it. I looked at it and noticed some cracks, so I took the manifold off and this is what I found (have a look at the pictures), there were big cracks all through the manifold, could this be causing rough idle?!?
P.S this an Australian RAV4 which do not have egr

 

[LugNut]

Yes, possibly. If the O2 sensors are getting bad signals. Could (also) be many other things. Do a vacuum-side smoke test too.