Great video at idle manifold vacuum is high so will draw in unmeasured air, open throttle vacuum leak less effect so SHFT falls immediatley. It is great you demonstrating on the scan tool what is happening, need to check my purge valve on my car.
Excellent video. Helped me diagnose a lean condition I couldn't understand. I did a smoke test expecting a leak, but none was found. I cleaned a dirty hot wire on the air mass, but the engine light still came back on. After watching your video, I got the customer to call back in the next day, clamped off the evap line and hey presto, problem diagnosed. Thankyou very much for your help!
Yes, I do find O.E electrical parts are the best way to go but on this occasion opted for the aftermarket alternative to keep the bill as low as possible 🤔👍
I’m glad it helped, I have another one recorded about proving an inlet manifold gasket leak recorded which I’ll be uploading in the next week or so. Thanks Peter 👍
Nice one Peter major failure on that breather valve ( I have changed 5 within 3 months ) myself , the last one I wanted to order the dealer told me it did not had one 😂 sneaky maindealer, after I pulled the part number he said yes we do this part, but yeah great video
@@kennedysgarage3281 I just checked my engine it’s a z14zep it don’t have the pvc valve it has 2 breather pipes that goes into the rocker cover, my problem is exactly the same as your, can’t find any air leaks, changed o2 sensor still reading stft at +25 and stays like that untill I rev it to above 2000rpm it goes back to normal? Any ideas mate Thanks
@@kharali3475 I can’t be specific but I do know that that engine suffers from air being drawn into the crankcase through the rocker cover & then causes a lean condition through the crankcase breather pipe. So wherever the crankcase pipe from the rocker cover or crankcase joins into the air intake pipe from the air box to intake manifold, block it somehow. By crimping it or remove it and block it at the air intake side. Does that make sense? 🤞
@@kennedysgarage3281 yes it makes sense, if I restrict the air a a-bit should then be the correct air/fuel ratio, and then check where the pipe goes to Thanks I will keep u posted tomorrow
Had a dual vvt car in with a failed timing chain tensioner and guides, all inlet valves bent and rear most cam journal ruined. The upper guide runner had cracked reducing oil pressure to the head. Replaced chain and head rebuilt the car only to find out it idled like crap and smoked line a tank, initially MAF sensor fault then o2 sensor voltage fault codes, cleaned and tested resistance etc and was happy to say they were not the issue i cleaned the earth to the coils and the main battery post earth just in case with no change. Replaced the faulty purge valve and reset fuel trim which helped and seemed to get rid of the 02 sensor fault codes but started throwing fuel trim codes. All the manifold gaskets and rocker cover gasket had been renewed but there was a squeeling from the rocker cover, I expected the pcv diaphragm to be faulty but no. It turned out the pattern rocker cover gasket wasn't sealing, I dug the old one out the bin ran some fresh sealer where needed bolted it all back together and it idles perfectly now with no plumes of smoke. Let it cool down completely reset 02 heater learning, fuel trim and idle learning and the car is good to go.
😂😂😂 they can give you the runaround at times. I have been there and bought the t-shirt , then every 20 minutes the customer ringing to see what’s wrong & you pulling your hair not knowing what’s going on 😤 Very well done on getting to the end of this one 💪💪
Purge valve is not venting fuel tank. As the volume of fuel decreases, volume of air needs to increase in the tank. That could only happen by letting atmospheric pressure in the fuel tank not vacuuming it with engine vacuum
The vent solenoid is stuck in the open position, meaning that when the car is not running atmospheric pressure can reach the tank from the intake manifold threw the solenoid. Then on start up the intake pressure drops and draws that air back into the engine giving a lean condition. If the engine is running for an extended period and empties the tank of air the fuel might come back below 10 ( total trim ) but will go lean again if the engine is turned off & restarted. Does that make sense 🤔??? That’s the best I can explain it anyway 😂😂👍
@@johncollins8304 the PCV ( positive crankcase ventilation ) is in the Rocker Cover & they fail quite often too. As qpla said replacing the rocker cover solved his issue. Does that make sense??
@@kennedysgarage3281 Well it doesn't make sense to me YET but it will soon! Thanks, I'll look into it. But I have no sound coming from rocker cover, no hiss, no whistle. I wonder would that rule it out. Thanks again!
Possibly, but watch out for the PCV valve in the rocker cover. The Zafira suffer from drawing air in there causing a lean condition 🤔🤔 Let me know how you get on 🙏
Polo failed emissions in nct .. co was 1.18 . Lambda was 1.08 .. changed bank 1 sensor . full service .. .. got co down and lambda down to pass range ... Then nct 2 weeks later and retest it ..still failed . Co 0.10 pass . Lambda fail 1.38. lambda even higher now .. help
Lambda is the oxygen content, high lambda is high oxygen content. This can be caused even by a small exhaust leak. But get your garage to look at the ‘ long term & short term fuel trims’ this will tell how much fuel the engine ECU has to add or take away & help with the diagnosis. There is also a purge in that model car. Hopefully this will help 🤞🤞
