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Help with intake leak code

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mjmallia:
The corrugated plastic hoses also crack and become brittle (age and heat cycles).  I replaced both of mine due to cracks that I could not see......the two from the PCV.

Jons1001:

--- Quote from: mjmallia on November 20, 2024, 09:38:44 am ---The corrugated plastic hoses also crack and become brittle (age and heat cycles).  I replaced both of mine due to cracks that I could not see......the two from the PCV.

--- End quote ---

Thanks for the info will check. Is it possible that a failing PCV wouldn't show anything on a smoke test though? as they reckoned everything was good with no apparent leaks.

mjmallia:
You can take it off and blow into it.  Air should be flowing one way and not the other, via the valve.

ZoliWorks:
Pcv sounds fine to me. Pulling the plug, the engine clearly start going rough but it stabilizes itself and increases the rpm. Thats normal. If the pcv was bad, you'd get misfires, running lean codes and the engine would tend to shake at idle, especially after starting.

On the other hand, if there's a vacuum leak, what will happen is the engine will stabilize itself after 2 minutes or so and then if you pull the dipstick or take the oil cap off, it will make no difference. This means there's a constant air leak in the system.

But yeah, if it hasn't been done, it's worth replacing. Another thing that went bad for me was the brake booster vacuum hose. The plastic hose that goes from the check valve to the vacuum pump cracked and created a constant leak.

Jons1001:

--- Quote from: ZoliWorks on November 20, 2024, 02:35:53 pm ---Pcv sounds fine to me. Pulling the plug, the engine clearly start going rough but it stabilizes itself and increases the rpm. Thats normal. If the pcv was bad, you'd get misfires, running lean codes and the engine would tend to shake at idle, especially after starting.

On the other hand, if there's a vacuum leak, what will happen is the engine will stabilize itself after 2 minutes or so and then if you pull the dipstick or take the oil cap off, it will make no difference. This means there's a constant air leak in the system.

But yeah, if it hasn't been done, it's worth replacing. Another thing that went bad for me was the brake booster vacuum hose. The plastic hose that goes from the check valve to the vacuum pump cracked and created a constant leak.

--- End quote ---

Hi thanks for the reply. Just got back from the garage and they are saying the second code is pointing towards the lambda sensor (post cat). I think the plan is to replace the PCV, and then do a continuity test on the lambda with a view to possibly replacing that if it is showing as bad. Thing is i had the same lambda issue 2 years ago when i went back to the mapping company to get the map tweaked after fitting a sports cat.  They said the lambda was damaged and they replaced it. A week or so later the code was back. However this code only seemed to appear every 500-1000 miles after clearing, which i put down to the map. The code relating to the vacuum leak won't go away. 

They are telling me after the second smoke test there were no leaks showing, so either it is the lambda sensor causing it, or something that wouldn't show in the smoke test (PCV, Diverter valve?) or they have missed something e.g very small leak from a hose - possibly obscured if it was resting on another hose etc.

Very frustrating!

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