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steve mezzle

Vacuum leak in 1998 Toyota avensis?

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Hi

 

Im struggling with an issue with my car and cant pinpoint what the cause may be. Perhaps someone here can help on my 1.8 toyota avensis 1998

Im having no driveabilty issues with my car which is causing me some confusion, but have conducted a vacuum test after a after a mechanic suggested i had a vacuum leak. some events leading to issue:

April 2018 . Rusted exhaust system - replaced whole exhaust and cat

June 2018 . Passed emission test

Nov 2019 . Engine warning light comes on. Fault code 21 Oxygen sensor. Replaced oxygen sensor and light went out

June 2019. Failed emission test with 1 year old cat and six month old 02 sensor. Replaced cat under warranty. Failed emission test  again. Taken to engine diagnostic mechanic who found Fault  code 21 Oxygen sensor even though no engine warning light was present and said had vacuum leek (not able to stall the car with hand over throttle body opening). O2 sensor replaced under warranty and code cleared. Found nipple broken off of Bimetalic Vacuum Switching valve and its hose disconnected. VSV replaced. Vacuum test conducted and results indicate from a gauge chart "worn rings or diluted Oil" ie starts about 20hg and the drops to zero as i press the accelerator and the when releasing quickly goes back up to 20 again. Fault code 21 Oxygen sensor returns

 

spark plugs look good, no smoke from exhaust, no engine issues, Oil looks clean and not overfilled as check every 2 weeks

changed Oil, oil filter, spark plugs, air filter 6 months ago, changed fuel filter 1 week ago, inspected all vacuum hoses and look good, no egr valve on this vehicle

Car drives fine to me with no issues but considering the vacuum gauge readings but im concerned as i dont want to damage another cat. Any suggestions with any thing else to try would be appreciated or is it time to scrap the car

 

Thanks

 

 

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Not being an expert, but did own a 1998 leanburn Avensis, it sounds like the vacuum system has a leak or not set properly. Read the following :- 

 

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Hi Konrad

 

Thanks for the reply and the info. Ive had a look at this and the lever of the inlet actuator does not move at all when accelerating and neither can i force it to stay against the stop having followed your instructions, so now im more sure that this confirms the vacuum test i carried out was accurate and maybe its the piston rings that are worn. Just seems strange that the car is running so well with no issues. Have booked it in at the mechanics on Tuesday just to take a quick look but im not expecting a good outcome.

 

Thanks for the advice again. Ill update when i come back from the mechanics

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Hi Stephen.

I assume you followed the instructions by pulling the pipe off the vacuum actuator, then move the rod to push the actuator in, then connect the pipe. Then when you start the engine it moves. Make sure you show the mechanic my post, so they can try the setup and see if it works. 
Also the rod of the actuator detached a few before, so I had to reconnect and secure it. I noticed something was wrong, because the power and torque were hit and miss. When I went to Toyota to see if the part could be obtained separately, I was told no! That is when I thought outside the hat and made my own solution.
Your best bet is to find parts from a scrap car or Ebay.

I look forward to and hope you get a good result. 

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Thanks Konrad , yes i followed your instructions by detaching and reattaching the vacuum pipe but there is no way of making the rod stay in position it kept falling away from the stop. I did notice that there is vacuum in the pipe and it didnt go away when i put my foot on the accelerator. The actuator rod seems is good condition too. Ill do a write up for the mechanic that will include the details from your post regarding this actuator.

 

Thanks again

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An update to this topic and a question for Konrad and anyone else who may be able to help

I took my car into the garage and they said that it is likely that the inlet actuator is faulty (cheers Konrad as i dont think the mechanic would have noticed if i hadnt mentioned you previous post on this subject)and would need to get a new one. As you cant buy it alone a new inlet manifold was needed. (£730 new needless to say i went the refurb route for £50).

Ive just finished fitting this and the actuator now opens and closes , however not as Konrads post suggests it should i believe.

When i start the car the actuator arm hits the stop (opens),but does not close when i switch off the engine.

When i start the car again the arm closes and the opens again quickly and stays on the stop.

The only way i can move the arm from the stop when running is to disconnect the vacuum pipe

Any suggestion as the issue for this please?

 

 

 

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23 hours ago, steve mezzle said:

An update to this topic and a question for Konrad and anyone else who may be able to help

I took my car into the garage and they said that it is likely that the inlet actuator is faulty (cheers Konrad as i dont think the mechanic would have noticed if i hadnt mentioned you previous post on this subject)and would need to get a new one. As you cant buy it alone a new inlet manifold was needed. (£730 new needless to say i went the refurb route for £50).

Ive just finished fitting this and the actuator now opens and closes , however not as Konrads post suggests it should i believe.

When i start the car the actuator arm hits the stop (opens),but does not close when i switch off the engine.

When i start the car again the arm closes and the opens again quickly and stays on the stop.

The only way i can move the arm from the stop when running is to disconnect the vacuum pipe

Any suggestion as the issue for this please?

 

 

 

When you rev the engine, does the actuator move? The position of the The vacuum will hold position position when the engine has switched off for a while. I cannot remember which way to shut off one of the inlet in lean position, but under load it opens. I found a link to explain it better - https://toyota-club.net/files/faq/04-11-20_faq_lb_eng.htm
What about pulling the pipe off the vacuum actuator, the move the lever to another position, then see what happens. It could be reverse of what I originally said. Also well done in sourcing a refurb actuator.

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Yes you are right thanks. After lots of searching the internet this afternoon i now think that the actuator is working correctly. I probobly mis-read your write up. I initially thought it gradually opened and closed rather than either fully open or fully closed .What i gather is that the arm is meant to be against the stop all the time until approx 3000 rpm is reached when the arm then moves away from the stop. when the rev counter drops below 3000rpm the the arm hits the stop again. This is happened so hopefully im now sorted. Need to get an emission test done as the replacement actuator appears to be working fine with no vacuum leak.

 

I use two websites called 24/7 spares and  breakeryard.com to source second hand parts for scrapyards. Took me about 6 hours to do this job. 2 hours to clean old bits of gasket of the mating faces of the manifold to engine block and the same with the throttle housing and clean up the inside of the manifold with manifold cleaner, and then 4 hours to change manifolds, quite easy just access is difficult.

£50 for a second hand manifold with actuator and £17 new gasket.

Cheers for your help again with this Konrad, much appreciated.

 

  • Thanks 1

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Hi Stephen, just saw this recent post from fixitphil - 

I linked your post to his.

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