Cleaning Throttle Body

[BigMo82]

Tried to remove the throttle body myself today. Took the all the hoses off and had some fluid possible water come out of the hose under on the bottom of the throttle body. Undid the 4 bolts but couldn't remove it off the engine. Are there any other bolts that I've missed?

Mo

[BigMo82]

Drove to work this morning (10 mile journey) and it behaved perfectly for 9 miles and then as soon as I went uphill and downhill suddenly it began dropping to below 600 and the car started shaking.

I really dont know what to do here and I dont want to take it to Mr T or I know the first suggestion will be a new trottle body which I am guessing with there labour cost will come in at £300 - £400.

Mo

[Konrad C]

Tried to remove the throttle body myself today. Took the all the hoses off and had some fluid possible water come out of the hose under on the bottom of the throttle body. Undid the 4 bolts but couldn't remove it off the engine. Are there any other bolts that I've missed?

Mo

Mo,

I checked my Haynes manual which covers Avensis from 1998 to 2003, and it described the throttle body removal process. For the post 2000, 2 litre engines one of the hoses is part of the cooling system. That could be the reason for the water. The manual also describes removing the support bracket. I am not sure if it applies to your car.

I know the the manual is for the Mk 1 version of the car, but in Toyota fashion, the engines are carried over. Haynes do not seem to have published manuals for later Avensis. There are other sources like ToyoDIY.

My car is 1762cc which is okay to idle close to 600rpm, whilst your engine is 1998cc, so need to be around 800rpm. It is known that bigger capacity 4 cylinder engines are not as smooth as smaller engines, hence the need of balancer shafts.

[BigMo82]

Thanks for the reply mate, I later thought that the throttle body is probably water cooled.

Mo

[BigMo82]

Called toyota to ask how much a new throttle body would cost and I was told.... £927!

Called a breakers yard and managed to source 1 not from work for £50.

[frankie406]

no mo mines sitting at 650/700 ..was at 600 rpm before i cleaned it but seemed to grumble as in nearly cutting out..there was a support bracket on mine too..is yours a cable throttle or fly by wire?...did you clean out the idle air control and the port in the TB and the throttle position sensor?

[BigMo82]

This is what my throttle body looks like. It doesn't seem to have a idle control valve.

[BigMo82]

Frankie did yours look like this or was it different. I just hope it's an issue with the throttle body and not the ecu.

Mo

[frankie406]

mines is different mo yours is fly by wire type mines is a cable type.did u reset the ecu after u cleaned it? what did u clean the TB with??

[BigMo82]

I did reset the ecu but I didn't clean it I got it cleaned at a garage. I'm guessing it is an issue with the throttle body itself because it got worse after it was cleaned.

Mo

[frankie406]

they must of done something till it! more than likely they moved the butterfly valve and broke something in the motor for the butterfly.does it settle if u blip the acc pedal?? did u try the reset with key on ign off turn key on for 10sec then off do this 3 times may help??

[BigMo82]

Tried the ignition already Frankie, no once it starts dropping to 500-600 if I accelerate it will always rise and then settle back at 500-600. Before I gave it in it would drop down close to 600 and vibrate a little but nothing like what it's doing now.

Mo

[Vlado P.]

this sounds to me like your TB or IAC valve were not cleaned properly. does the car rattle when cold?

those toyota douchebags are always in a hurry to suggest TB replacements!

[frankie406]

can you take off air intake and see if the TB opens and closes get someone to push the pedal and check..i think who ever cleaned it damaged it and push the butterfly valve off its setting?

[frankie406]

mo have you had it on diagnostics? to check the TPS or the operation of the TB?

[BigMo82]

Thanks for the replies gents. I have not had it on any diagnostics other then obd connector and that isn't showing any faults. What it does is that the revs drop to about 550 then it after say 10 seconds they suddenly increase to 1200 and then slowly drop to 550 again. I have picked up another throttle body from a breakers yard along with another part for another vehicle and he gave them both for £75. I think he worked the TB to be about £45 which is worth a risk compared to the £927 toyota want for a new one.

Mo

[BigMo82]

I'm sure it opens and closes as it has no problem starting or when in motion just when it's sat idling or moving very slowly through traffic.

Mo

[frankie406]

yeah cheaper to try that part than a new one..just was wondering does ur old tb open and close right..was the garage toyota that you got it cleaned at?? and was it cleaned both sides?? there anything stuck in b/fly valve. eg cotton/ paper towel?

[BigMo82]

I haven't pulled the whole thing out yet to give it a proper inspection but will do tomorrow. The garage was not Toyota but they looked quite good and even had an Aston Martin in the work shop when I pulled up so I would assume they are quite clued up. I really need to get this sorted. It's made an enjoyable drive a miserable one. Thanks again for all your advise Frank.

Mo

[Konrad C]

Mo, It sounds to me like you have a vacuum leak or there is a gasket missing from the throttle body or associated pipes. For the engine to increase then decrease idle speed, that is the only thing I can think of.

That means that something was not put back correctly, or as Frank has said something could be let inside the throttle body when the garage cleaned it. Maybe the cleaning solution or muck got into part of the throttle body.

Hopefully the other throttle body will be okay, but if it persist then look at the vacuum pipes and connections.

Konrad

[cooper12000]

i dont think its "hunting" as that is quite a rapid change in revs. simple way to check for a vacume leak is spray some wd40 around the throttle hoses and see if the revs increase. other way is whip the plugs out and see what sort of state they are in.

coop

[BigMo82]

Coop are you referring to the spark plugs? They are new and were changed about 1000 miles ago.

Mo

[cooper12000]

i remember u changing them. if there is a vacume leak or too much air getting into the system then the plug electrodes will have a white coating on them.... just like if too much fuel was getting in they would be black. if they are a biscuit brown colour then the mixture is fine. it was just another way you could try and see whats going on.

[Konrad C]

Coop, what I am trying to say to Mo is that there could be a leak is making the engine slow down, then something makes it speed up to compensate.

That is how Mo described how the engine is idling.

You are correct in saying about 'hunting' and that is why I did not actually say the word. I also agree on your remedy.

Mo it should be a nice day today. Hopefully you will try something that solves the idle problem that began with the 'smoking' exhaust.

I look forward to checking the forum tonight after a day out to read the result.

Konrad

[BigMo82]

Thanks again for your help guys. I can't get the sparks out as my spark plug socket has disappeared. I must admit in general the car has been better over the last 24 hours and a part if me thinks I should give it a few more miles to see if it adjusts. The most the rpm fluctuates now is as low as 600 or as high as about 780ish.

Oh and I have found that the smoke situation has got better with the weather and for the last week I can only see it in my mirror for the first few miles of any journey. The smoke never affected the way the car drove and it was just something I was unhappy looking at but a rough idle is a much bigger problem I think.

Mo