E-Check Misery

A few weeks ago I had to renew our license plates and the girl at the license bureau there told us that first we needed to get the car e-checked for emissions. At this point in time the car ran great with no issues. It's a 2004 Taurus SEL W/Duratec engine. So we get to the e-check place and they take our gas cap off and hook up some machine to it (presumably to pressure check the system). The test they ran only took around 15 seconds. The car passes all of the tests but on the way home I noticed that our check engine light had come on. I didn't worry about it because in the cars owners manual it says that this light could go off by itself in a few days, which has been our experience with the light too (it came on when we first bought the car and then went off a few days later).

Well its been a few weeks and the light still won't shut off, so we removed the negative battery cable to 'reset' everything. It worked great - for about an hour :p Now the lights back on again. It would be fruitless to go back to the e-check place and yell at them as they would probably be clueless about what was wrong, so I'm just going to try to focus on doing whatever is necessary to fix the problem, but where do we start? What could have happened? :frown:

First make sure the fuel cap is tight and they didn't overtighten it and crack it or something like that.

Next, stop by a auto parts store and ask them to read the codes in your car. See what they come up with. Try to get the exact codes which will be in the form P0123 and post them here.

-Rod

I took it to an auto parts store but when they tested it the only reading they could get said that the tester couldn't 'communicate' with the car. While I was there I bought a can of Seafoam and put it in the tank. At least it will clean the system out. Every now and then under load (like getting on the freeway) it sounds like a muffled backfire noise (towards the header area) and it did stall out today when I was parking it at the store, but other than that the car runs incredible, and I can't imagine what could be wrong with it. I'll drive it to the other side of town tomorrow where there's an Advanced Auto store. Hopefully they will have better luck with the codes :frown:

Well yesterday I took it to Auto Zone and the guy there was really nice. He used the scan tool and pressed a button on it to clear the code. The engine light immediately went off and the car started running better.

That lasted for around a day, and now today the light came back on. So I took it back up there and another guy (also really nice) was able to get the code for me. It is P0443. He printed out something which I will try to post later tonight.

One thing I've noticed is that when you start up from a red light, or are getting on the freeway, it sounds like the car is backfiring (at the manifold, not the exhaust in the rear). The car also pulses when this happens. I can't imagine what they could have done to the car when they pressure tested the gas cap.

Quick Update: I was just pulling the car in the garage and heard that noise by the manifold again. It doesn't have to be the car backfiring. I remember when I was at Auto Zone the guy mentioned something about a 'canister' and come to think of it, that could be the sound we're hearing too. It sounds like someone is thumping on a long tube. I just don't know where to look for this canister so I can't verify.

According to the factory service manual for a 2002 Taurus (which is probably similar enough to your 2004), P0443 - EVAP Control System Canister Purge Valve Circuit Malfunction. The manual describes this code as, "The PCM monitors the EVAP canister purge valve circuit for an electrical failure. The test fails when the signal moves outside the minimum or maximum allowable calibrated parameters for a specified purge duty cycle by PCM command." As for possible causes of this code, the manual states:

VPWR circuit open
EVAP canister purge valve circuit shorted to GND
Damaged EVAP canister purge valve
EVAP canister purge valve circuit open
EVAP canister purge valve circuit shorted to VPWR
Damaged PCM-Rod

Where would I find the EVAP canister purge valve?

Is the PCM the cars computer? If so I'll rule that out temporarily too. I'm looking for things that 'too much pressure' would damage, like the valve.

For the time being I don't think it could be an electrical issue because they weren't playing around with any wires. They simply 'pressurized' the system where the gas cap is. I could see them damaging a valve this way if they used too much pressure.

I just found this (http://www.automotiveforums.com/vbulletin/t889243.html) thread with a similar problem. In it you mentioned that "the EVAP canister purge valve is located in the right rear of the engine compartment, but the EVAP canister is located near the fuel tank." If I get under the car and look around the gas tank will I be able to see the EVAP canister? What does it look like, and how big (approximately) is it?

Yay! Someone who uses the Search feature!!!

From the diagrams in the factory service manual, it looks like the EVAP canister will be mounted to the underside of the spare tire well, underneath the car. It appears to take up most of that area.

The PCM is the Powertrain Control Module which is the engine computer as you suspected.

The code pertains more to the valve than a leak in the system, such as the canister. Therefore it won't hurt to look in the area of the canister, but your effort may be better spent on the valve. The canister vent solenoid is in this area as well with an electrical connector plugged in to it. That is different from the purge valve though.

The purge valve and solenoid is located at the firewall below and a bit to the outside of the upper heater hose. From the diagram it would appear to be about the diameter of a pop/soda can but only about 1/4 as tall.

-Rod

Yay! Someone who uses the Search feature!!!
LOL :tongue: Being the admin of several other forums I can appreciate the humor in that :)

What I originally thought was backfiring at the manifold appears to be the purge valve making noise. It does appear to be coming from the firewall area.

I thought this was going to be easy to fix but it appears that it's starting to get involving. I called the e-check place that damaged the car and asked them about filing a claim. He said that nothing was attached to the car, but to the gas cap itself. So, on that assumption I went out and bought a new gas cap, but so far the check engine light is still on.

Is it possible that a bad gas cap could be causing this problem?

It's actually possible that it just happens to be coincidence that this occured just after the e-check. It would be interesting to connect a scan tool with datastream capabilities and monitor the Fuel Tank Pressure (FTP) sensor readings.

According to the factory service manual (still for 2002):
The fuel tank filler cap:
relieves system pressure above 14 kPa (56.21 inches H 2 O).
relieves system vacuum below 3.8 kPa (15.26 inches H 2 O).-Rod

Well here's an update: The e-check place told me to take the car to one of their mechanics, which I did. Apparently the mechanic doesn't think this is related to when I brought my car to e-check so now I've got to try to fix it on my own. The mechanic wrote something like "EVAP purge valve" on the notes that he took when he looked at the car. He wrote something else underneath it but it wasn't legible. So I'm going on a hunch that the purge valve is bad so that seems like the best place to start. I went to the car parts store and they said that the part was around 40.00, but I need to get the number off of my old part before they order it. The problem is that the Ford manual that I have doesn't show what the part is supposed to look like, so I don't know which part is which :frown: Tracing back from the EGR valve I can see 3 parts (shown below) that seem to be emissions related. Can someone please tell me which one is the EVAC purge valve so that I could get the number off of it? I think it's number 2 but I need to be sure. Most of the parts shown on the dealers (http://www.trademotion.com/partlocator/index.cfm?action=getLocator&siteid=213787&chapter=DR2JN00&appSectionid=2496&groupid=2497&subgroupid=2498&componentid=0&make=10&model=Taurus&year=2004&graphicID=JN00215&callout=6&catalogid=2) site don't seem to match from the picture that they supplied.

http://www.angelars.com/pics/car2.jpg

Unfortunately I don't have the service manual for the 2004 model year. The 2002 service manual shows the EVAP purge solenoid as looking like item 8 in the dealer site picture. It should be mounted on the firewall a bit below where the (upper?) heater hose connects at the firewall.

Maybe Way2Old will have some better detail for you, specific to the 2004-2007 model year.

According to Rock Auto (http://www.rockauto.com/catalog/x,carcode,1425057,parttype,4936), the part number should be:
MOTORCRAFT Part # CX2005 {#4F1Z9C915AC}
OHV; F413-9G683AB,AC

-Rod

My Ford manual only goes up to 2003, and it shows the picture below as the canister purge valve. I wouldn't think that there would be a difference between the 2003 models and the 2004. When I went to Auto Zone they said their replacement purge valve looks more like #1 above. So I went to our local Ford dealer and he said that it looks like what the Ford manual shows (below). I ended up going to trademotion.com and ordered the original Ford part (4F1Z-9C915-AC) for 20.00. It's "supposed" to be the purge valve but they call this part by so many different names that it's hard to know what part they'll ship. I didn't see anything that looks like the Ford part below anywhere in the engine compartment. Is it usually mounted on the drivers side or the passenger side of the firewall? :confused:

http://www.angelars.com/pics/CCI00000.jpg

Going strictly off the diagram in the 2002 manual it would appear to be on the passenger side.

-Rod

Thanks Rod. I removed the shroud above the firewall on that side and I'm 99% sure that I've now found it. It's under where the cabin filter is. The cars main electrical connector runs right above it. According to the '03 Ford manual there is a heater hose above it too, but for '04 it looks like that hose is now made out of a metal tube. The main part that's in the way is the main electrical connector which bolts to the firewall. If we unplug that main electrical connector, other than loosing our cars radio station presets and the time, will anything bad happen? I would think disconnecting that electrical connector from the firewall would have the same effect as just removing the battery, right?

I would expect you're correct, it shouldn't be any different than unplugging the battery. Just be sure you don't break any wires, cut wires, etc. You will loose your I/M Readiness data so you will need to complete the drive cycle before you'd be ready for any emissions testing if that's a requirement in your area and the car may run/idle a bit strangely for a few start cycles afterwards.

-Rod

I'm going to try to remove it without disconnecting the main plug from the firewall. I was able to loosen the two nuts holding it on today, so as long as the vacuum lines come off as planned it shouldn't be to hard to replace. The part on the car looks a lot more like the Auto Zone part shown below (which costs 4 times more than the original Ford part) than what the Ford service manual shows as the part, which kind of surprised me. The new part is 'supposed' to arrive here on Friday. In the mean time I'm cleaning all of the other emission parts like the EGR valve. I soaked it in Seafoam and now it looks like new. I love that stuff, it's great for removing carbon off of parts.


http://www.autozone.com/images/products/wl2/wl2pv236003.jpg

I installed the new part last Friday. All of the cars symptoms have gone away and the car runs great, however, the cars engine light is still on. I think I read somewhere that it takes a few days to recycle and go off, but it's been over 4 days now. Is this normal? How long should we wait before we take it back up to the mechanic to have everything rescanned? :eek7:

If the mechanic charges you to scan it, stop by your local auto parts store and see if they scan codes at no charge. I would expect that your light would have gone out by now.

-Rod

This weekend I will try to get the code cleared. Assuming that the engine light comes back on (and is the same code as before) what should we test next?

Let's wait and see what the code is.

-Rod