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Torque » Torque OBD ECU Scanner » Torque Discussion / Ideas » EVAP SYSTEM

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Author Topic: EVAP SYSTEM
Carlgrizzly
Member
Posts: 6
Post EVAP SYSTEM
on: February 11, 2021 (GMT)

Hi there,
My Purge Valve Solenoid , the one close to the throttle housing, remains closed even when it receives 8-9 volts from the ECU. But when I unplug it and connect it directly to the battery, it opens and closes when I disconnect. Engine coolant temp makes no difference plus there is no fault code but the car is jerking and idling roughly, plus with new battery it turns over once…twice and then starts, fuel consumption is quite bad. I checked the vacuum hoses from the charcoal canister and there are no leaks.
Any ideas?

Love Cars and Gadgets and the Ocean. Live in South Africa

F-150Torqued
Member
Posts: 437
Post Re: EVAP SYSTEM
on: February 17, 2021 (GMT)

You didn’t mention Mfg/Model of vehicle you’re working on. And I have WELL LEARNED there are dramatic differences in OBDII PIDs and Sensors between models – even on like Mfgs. But I have done exhaustive research and hacking the EVAP system on my 2004 Ford F150 5.4L 3v. And find it to be far more complex logic (though simple in practice) system. I suspect your vehicle might be very similar in operation – though likely NOT same PIDs. The Dashboard and a CSV type file with the custom PIDs is posted here: https://www.f150forum.com/f4/how-use-torque-pro-diagnose-evap-system-p0451-others-446165/

First the Purge Valve Solenoid (Actually called the ‘Electronic Vapor Management Valve’) is opperated by ‘duty cycle’ pulses from zero to 100 percent. That’s why you are reading lower voltage on it (~ 60%)- and why you see it open/close when connected direct to 12v sorce (100% duty cycle). The ECU learns MUCH by gradually modulating this valve open and ‘noting’ JUST when the pressure in the tank begins to decline. It plays with the voltage at that point, to determine if the EVMV leaks or seals properly. If it can’t change Tank pressure at all = gas cap off, etc. It increases to 100% (with Canister vent valve closed) and monitors time for tank pressure to decay. Determines gross leak, or small leak by time for decay. When it opens Canister Vent Valve, with EVMV open, it can determine how much fresh air passes through the Canister or if Canister Valve isn’t working right – OR other trouble codes.

I suspect some of this would apply to non-Ford vehicles also, although it is doubtful many of my PIDs would match other vehicles. Hope this gives some direction.

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54371019

Carlgrizzly
Member
Posts: 6
Post Re: EVAP SYSTEM
on: March 4, 2021 (GMT)

F-150 Torqued: Sincere apologies for the delay in responding to your totally
Informative response to my measly, confusing (no mfg even noted) post. But
you still provided info that literally explained certain issues I had suspected but others I hadn’t even considered! BTW, my vehicle is a Hyundai i10(not even sold
in most countries) But, as you said, the principle and way the EVAP System operates is almost identical. I read all of your previous posts and your responses just remain so inspiring and enthusiastic. The egg on the face ? had no place in any way (as your numerous fans have stated) Now it’s my turn for an entire omelette plus a Bakers Dozen of Eggs on the noggin.
I am so guilty of overfilling my tank…. wait for it…. my tank is tiny 35 litre but Mr
Smart*** not only overfill using the nozzle but my mate would shake the car and eventually 42 litres would be our record. Cringing, right. Or wondering why someone would do that. Keep those eggs coming.
Removed the Carbon Canister and it was literally soaked in moisture(fuel obviously) since around 2011 when we here in South Africa had serious fuel shortages. And to add one last thing: During the Lockdown Periods I “decided ” to destroy the system just a wee bit more by only putting in, in US Imperial Gallons (adds to my stupidly admission) literally 1/4 Gallon (Reserve light remained on for 8 months.
Ok, back to the good stuff: I have the new Canister but I am sure I have slowly been destroying other components, one being the camshaft gasket as there is oil leaking slowly and the cooling fan does its own thing.
And to think that I was going to connect the Purge Solenoid aka……….(you know the official name) directly to the battery. Fortunately there matter decided to think about it for long enough to be rescued by you.
Thank You Thank You etc… F -150 Torqued (Don’t even get that beast of a truck here)
If you get a chance please let me know of any other possible issues that my lack of stepping back and looking at problems from a different perspective but my enthusiasm overules my knowledge and these things happen.

Thanks Buddy,
Keep well and chat soon

Regards,
Carl

Love Cars and Gadgets and the Ocean. Live in South Africa

F-150Torqued
Member
Posts: 437
Post Re: EVAP SYSTEM
on: March 7, 2021 (GMT)

Thank YOU Carlgrizzly for a great – much needed uplifting message to bring a smile to my face and chuckle to my tummy. It’s been a very difficult week. As a result of the South Texas 1000 year cold weather/snow/freeze event, pipes froze – and when the thaw came, flooded my home rendering it destroyed and totally un-inhabitable. All insured and I’ll survive – rebuild, but it is terribly dis-heartning. Seriously, your acknowledgement helped more than you could know. And Thankfully, though I’m a member of a high risk category, I’ve dodged the virus so far!

Wish you had a F150. I could (and would) share a lot. But the Manufacturers want to hold us ALL hostage by keeping their secrets for their service departments.

Cheers to you too
F-150Torqued

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54371019

Carlgrizzly
Member
Posts: 6
Post Re: EVAP SYSTEM
on: March 8, 2021 (GMT)

F-150 Torqued
This isn’t a chat room so I hope I can send a short message, without a mention of my trivial EVAP problem, without getting into trouble.
All I can say is that what I saw on the News was, as news goes, the devastating
situation the people of the State of Texas were in, but your words of Thanks, followed by words of grief (and positivity looking forward) were more like a personal flood (for lack of a better word) of emotion and I have never even met you or been to the US and on a Vehicle forum. I am truly glad that I managed to lift your spirits slightly by nothing more than abusing my Emissions System and taking some of the egg that you never deserved in the first place.
Lastly, let me just say that the mere fact that you didn’t continue any discussion of my silly little problem with a steel pipe while you are basically rebuilding from scratch tells me that you speak from the heart and that is why all your reply posts, from way back and from all over the world, all had one thing in common. Appreciation. Respect. Not one post that I read was anything but understanding ( the mistake you beat yourself up about) and gratitude. That, my friend, is almost unheard of on any platform these days.
Oops, my short message has become a shortish novel.
My thoughts are with you and please don’t ever feel obliged to even mention my nano problem until you and of course your family and fellow Texans, are in a better frame of mind. I mean that.
Stay true to yourself and in the not to distant future we will discuss charcoal and fossil fuels again.
All the best and we’ll definitely chat again.
Cheers F-150 Torqued

Love Cars and Gadgets and the Ocean. Live in South Africa

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