fallon

Anyone ever used a fog machine to locate a leak in the EVAP system? Dealer wants about $400 to smoke my EVAP system. Just sounded a little expensive.

johndeerebones

Yes, and they work to find leaks specifically. Sometimes you can check solenoids and such too. Yes, 400 is high IMO. I realize part of the cost is paying for the expensive machine, but around here that is also 4 hours give or take... Shop around.

ezone

A smoke machine is a great tool and quite useful for finding some hard to figure out problems. It has its limitations though, it is not always the miracle tool it's touted to be.

It is extremely rare for me to actually need one on these cars, and it seems like whenever I get frustrated enough to actually try to use it, 90% of the time it doesn't help at all.



$400 for a checkout sounds pretty dang high unless you are in a wealthy or metro area. Then it might be more average.......
Nobody would pay that much where I am.


My dealer only has a 1 hour labor charge for a checkout, no matter what tooling gets pulled out of the arsenal.

A problem has to be pretty serious to need more than time than that.



Shop around at other dealers, to start with. Then any Honda/Acura specialty shops.

Tackle it yourself?

johndeerebones

Pretty standard here too. Ya agreed, years ago it was way more useable. Still has it's uses, but more often than not only frustrates the mechanic.... The new on board computers and a scan tool aids diagnosis, that and the evap systems are more streamlined and better made now too.

fallon

Thanks for the feedback guys. The dealer was saying they'd have to drop the tank to look for the small leak in the evap system that was preventing the self test from clearing. They changed a "two-way" valve but that didn't solve the problem. I know they have equipment that can cycle the valves involved independently during troubleshooting so I thought they would have better luck getting the engine light out on the dash. They did clear the code so the light is out on the dash but their equipment still detected a system leak which the mechanic said would eventually trip the light again. Still can't go thru emission test as is. I was wondering if using a spray bottle with soapy solution under the car might indicate where the leak is. I know the shops like the smoke machines. I've read of pressure being released when you take the gas cap off if the system is operating normally. What actually pressurizes the system? If the system is slightly pressurized when operating, I was thinking the soapy solution approach would be the shotgun version of leak detection. That way, if it's not one of the components but actually a line or fitting, it would foam up. Am I out in left field on this or what? Let me know. Thanks again for the quick replies.

ezone

That's old school. It's not always true now.

Yes, absolutely. I use this at times too. But it only works if you can seal and pressurize the system.

Reid Vapor Pressure and evaporation of the gasoline creates pressure naturally in a sealed container. Same thing that happens with a gas can in your garage, it builds a little pressure naturally.

But:
When the computer performs a self-test, the system is put under a vacuum.

Gotta run....

fallon

ezone - I'm looking at picking up a Stant Fuel System pressure tester. It's literally a gas cap with an air pump hooked up to it. My question is if I pump up the tank pressure in a power off scenario, is the pressure suppose to remain or is there something in the system that normally vents pressure to the atmosphere? Based on what you said in your last post I'm looking pressurize the fuel system so I can check with the soap solution. Are there certain parts of the EVAP system that would be isolated from the tank pressure and would need to be pressurized separately to check for leaks? Any info on the EVAP system's operation would be helpful. Thanks.

ezone

You would have to be extremely careful. The system cannot withstand a lot of pressure or vacuum. The self test is run at only a couple in.hg., it's not anything like applying a full 20" of manifold vacuum to the tank.

If you are going to try to pressurize the tank, I'd say 1 PSI MAX. Stay under that, like I would try 0.5 PSI first.
No more than what your lungs can push LOL.



Study the construction of the system.
Study how it all works, design-wise. Study enough to understand it.
Once you understand it, then the answers of how to test should become more apparent.

The vapor side of the 7th gen tank/canister system has 3 more places to seal up:
(The gas cap you already took care of)
FTP sensor hose to atmosphere (shown in a diagram)
The purge solenoid in the engine compartment
The canister vent tube under the car
Ideally, one would turn the appropriate solenoids ON or OFF as needed to seal the system, this way all the valves can be smoke checked along with the rest of the tank and canister. (If I didn't use a scanner, I'd use a battery and jumper wires for each solenoid as needed.)


You never did say what the actual code is either. Maybe a smoke check or bubble check isn't the first thing really needed? Most of the EVAP issues I see are valve/solenoid/gas cap related.

Quick google gave me this link: http://www.scribd.com/doc/106038727/...Service-Manual

fallon

ezone - sorry, the code was P1457 system leak detected control canister system. The tester I was looking at maxed out at 60 in H2O (about 2 psi) so controlling it to 0.5 psi shouldn't be a problem. I'll try to find an EVAP system map before testing the various components. Do you know of any TSB's for the EVAP system leakage problems? Thanks for your feedback.

ezone

Wow. You're gonna be WAY off base.
P1457 is related to the canister side of the system, not the gas tank side. The PCM splits the 2 areas and tests each one. Leakage in the gas tank area would give a P1456 instead.


Step 1
Manually (apply power and ground) operate each of the 3 solenoids PCS, CVS, BPS. Each one should make an audible CLICK. If one doesn't click, then replace it.

If they all click, then
(Step 2) each one should be leak checked to make sure each valve actually seals.

CVS valve is probably the more common culprit here for both no click, and for poor sealing.
It is also subject to contamination ---you may find water has entered the large diameter rubber hose attached to that valve.
IF you find that CVS valve is bad, then pull the canister down and try to get the screws out that hold that valve in. They corrode and seize, causing a need for the charcoal canister to be replaced along with the valve and screws.

The BPS valve has a bulletin, but there is a VIN range affected on this so it might not apply to your car.
http://www.tegger.com/hondafaq/misc/...ag/A02-026.pdf

Different bulletin related to the BPS valve, should apply to your car:
http://ww2.justanswer.com/uploads/ac...t_solenoid.pdf


Aaaaaaaaand I have seen the PCS restricted too, causes the code due to being unable to pull the tank into a vacuum within the allotted time frame during the self test.
(Paraphrasing from the service info)
During a self test with a half tank of fuel, the time to reach 1.7v (FTP sensor) is usually around 2 seconds...If it takes longer than 5 seconds, the valve could be restricted. IF it is restricted, it should be checked for carbon by tapping the inlet onto a sheet of white paper. If any carbon particles come out, that would indicate the charcoal canister is bad and passing chunks of charcoal into the valve. Blow out the line and replace both.

ezone

Use a service manual (Did the link earlier work?) and go through the diagnostics for the P1457 and you should be able to figure it out.

fallon

I don't know what te deal is with the service manual link but everytime you click on the service manual download button, you end up on a page which wants you to upload your material. ??? How do you get to the service manuals? Is that link a scam? I don't trust the "bait and switch" links. At the risk of sounding ignorant, what is the PCS, CVS, and BPS. I haven't worked around these long enough to decipher the acronyms. Thanks.

ezone

Ah sorry. I didn't actually try the link. Just found it on a google search so no clue here.
PCS=Purge Control Solenoid
CVS=Canister Vent Shut solenoid
BPS=Bypass solenoid

ezone

You got the links for the bulletins OK though?

Matt_75

01-05 civic service manual link below.

http://downloads.hondatech.info/Auto...Civic01-05.zip

fallon

ezone - yes, the TBS links worked. Thanks also for the clarification on the acronyms and the troubleshooting steps.

Matt 75 - Thanks for the manual link. It's in the process of downloading now. Maybe now I can gain a little clearer picture of what you folks are talking about. From what I've read so far, it looks like the canister removal is quite an undertaking. I'd like to confirm as much as possible before diving into that repair. Thanks again guys for all your help.

fallon

The dealer said they changed a "two way valve" the last time it was in there but didn't fix the problem. What is the "two way valve"? PCV? CVS? BPS? The service advisor also said all three solenoids were tested for the audible click and worked. It didn't sound like the solenoids were tested for sealing ability. The next step for them is to drop the tank to smoke check the system.

ezone

Read the linked bulletins.

Sounds like you are right. They can click but still not seal properly.

Kinda like shutting off a faucet but it still drips.
Dropping the tank would be pointless right now.
The tank itself isn't included in that code. The code deals with the canister areas only.

I said this before: I'd sure want to prove it needs dropped before wasting a crapload of time and energy doing a dangerous job for no reason.

fallon

ezone - I understand what you said about the different zones calling out different codes. This is what the service advisor at the dealership is stating is the next step. Should I be looking for another dealership? I asked specifically what was tested so far on my car and was told the solenoids were checked for the audible clicking. They changed the Bypass solenoid/two way valve and still have a leak. The service advisor said the only way to smoke test the car is to drop the tank and test the whole system. The whole reason I started with them is I don't have a place to work on it myself at the moment and the dealership is next to where I work.

ezone

He's a phone jockey, not a tech. He knows next to nothing about cars. He parrots what he hears, and uses sound bytes to construct a conversation. Has no clue about accurate info.

What he said told you may have absolutely nothing to do with what is really going on.

Trust me on this, I hear it every day.

You get told whatever info they think will get you to buy.
The phone jockey is on commission pay too.



Of course, the tech could be just as wrong too. So many can only replace parts and are clueless when that doesn't solve a problem.
I'd want to hear what the tech has to say first. (I'd want to evaluate if the tech is even the right person to be doing the job anyway.)
I'd want to hear it from the tech, not the phone jockey.

Ever play the game, "telephone"?
It's like that.
Here:

Chinese whispersn (functioning as singular)1. (Group Games / Games, other than specified) a game in which a message is passed on, in a whisper, by each of a number of people, so that the final version of the message is often radically changed from the original
2. any situation where information is passed on in turn by a number of people, often becoming distorted in the process






Every dealership needs at least one rocket scientist that can truly solve problems.
Seek out that one wherever you go.

The rest of the shop can be just flunky parts changers and oil change kids.
Can't diagnose their way out of a wet paper bag.
Guess what it sounds like you got?






I offer you a quote, copied from elsewhere:

"Almost everyone, except those of us who have worked at
dealerships, thinks that they hire, train and retain only
the best technicians. This is just more evidence to the
contrary. They are no better or worse than independent
shops. If the manager and owner hire a bunch of clowns then
you end up with a three ring circus. Sounds like Bozo was
hard at work..."

fallon

Thanks for putting that in perspective. The only problem with trying to check the components properly is the lack of specialized equipment. As you said earlier, you're looking at pressures/vacuum less than 1 or 2 psi. I have a hand vacuum pump but one pull on the handle will give about a 5 psi draw. Is there some way of testing the individual components for vacuum sealing ability without spending an arm and a leg on test equipment? If not, one is stuck with a dealership. Or just buying all the components and replacing everything in the EVAP system. (which actually might be a cheaper option than what the dealership is proposing) That tank pressure pump I spoke of earlier will pressurize to 2 psi but no vacuum option. Is there an equivalent vacuum pump that is low psi? Have you tested these components on your own?

ezone

I don't have anything different. That's what I use.

It's fine for checking if the valves seal, if you know what you are doing....

I also use vise-grips to clamp off lines, and a variety of hose adapters to connect to the large tubes. Improvise as needed to do a task.


EDIT: And jumper wires. Manually operate solenoids, no need for a scanner sometimes.


When I said low vacuum (or pressure, whatever), I meant that the system is self tested at very low vacuum. You try to pump the gas tank down with a bunch of vacuum and it will collapse like you stepped on a beer can. Ditto for pressure, blow it round like a balloon. Use common sense.

cb450sc

Thanks for the link matt

fallon

ezone - I got a question concerning the canister purge valve in the engine compartment. When I first got under the car to check for vacuum leaks I disconnected the rubber hose from the metal line which goes to the canister purge valve. I hooked up my vacuum pump to the metal line going to the canister purge valve and pumped about 2 mmHg of vacuum to see if it held. It did so I then started the car to see if any vacuum was present with the engine running. There was none that I could read on the gauge. While the engine was running I again pumped about 2 mmHg and it held as before. The ECT was around 120 degrees when I performed this check. When does the canister purge valve open? Should there have been vacuum present when the engine was running? What would be a typical vacuum reading at that end? You mentioned the system self tests at very low vacuum. I'm just wondering if my vacuum gauge on the pump is not graduated for the level of vacuum in that canister purge line.

ezone

Purge valve operates on a duty cycle.
Connected to manifold vacuum.
Modulated to control the amount of vacuum on the tank and canister systems.
Operates when the PCM commands it.
At least at operating temperature, but not sure exactly what temp it starts operating prior to op temp. Could be 160*F ECT?

Purge valve has to be activated (powered and grounded) before manifold vacuum will pass. Valve is sealed when not activated (at rest).

However, there must also be sufficient flow when the valve is activated. The purge valve is known to get restricted so it can't pull a sufficient vacuum on the tank in the allotted time during the self tests. (Did I mention this already?) It might show good vacuum on a gauge with a short hose, but can it suck a good vacuum on a 10 gallon tank?



Did that answer it?