Evaporative Emissions...important or not?

[ldittman]

I just bought a new car (05 Focus ZX3) with a colored history. It was wrecked by the previous owner and repaired by them as well. It has been throwing up a P0171...
The car is missing parts, we have learned this after looking up parts on the ford parts site. It does not have a vacuum line coming off of the intake manifold and attaching to the air check valve, auto hub lock vacuum control solenoid, I'm not even sure if it has an air pump...or at least I haven't found it yet. We're assuming all of these parts were broke after the wreck and never replaced.

It's kind of hard to replace these parts that seem to be pretty useless without knowing what parts are missing. Useless, because the engine runs fine without it, but it will keep throwing up that code as long as it remains unfixed. I'm wondering if someone out there has removed the evaporative emissions crap and found a way around this, or anything that helps point us in the right direction.

[arlenn]

you will not clear the code by removing components.

pictures would help, air check valve? PCV? Auto hub lock? these cars do not have an air pump, do any after about 1990?

[sailor]

arlenn - our US Duratec PZEV ones do have an air pump at least... A version you possibly won't see up there.

Auto hub lock lost me as well...

[sleepyboy]

P0171 is a lean code. You might have a vacuum leak some where. Is that hole plugged up that went to the manifold to the other part? You shouldn't look up a parts list. You should compare it to another focus like yours. You could have a PZEV or a non PZEV that would make a difference on what emission controls you have.

[whynotthinkwhynot]

If you have an air pump, then you'll see AIR lines going to the exhaust manifold. That's what the air pump is for- to force clean air into the exhaust and maximize the effect of the catalytic converters. That is not evaporative emissions.

Evap emissions is how our fuel tanks are vented, and although it's considered emissions- it's not a bad thing as far as engine power until you lose the vacuum line. Back in the day, fuel tanks were vented to the atmosphere. To reduce hydrocarbon emissions from escaping fuel vapor, that vent line was sent up to a charcoal canister up front where collected fuel vapor is allowed to liquify. Then when the canister is full, the purge valve opens and collected fuel is sucked into the intake manifold via a vacuum line.

I'll have to read up on evap emissions again, but that's how I remember it working.

On a Dtec, the purge valve is on the firewall, you'll see a device with an electrical connector in the center of the firewall horizontally, and up near the cowl vertically. There will be some green caps on the test ports. The vacuum line should run off that valve, tie in beside the fuel line, and travel to the throttle body- or just behind the throttle body on the intake manifold. I can provide some better pics once my wife comes home from shopping, or if the baby goes to sleep.

Auto-hub? There are no 4WD US Focis that I know of. We've seen a few outrageous claims of those on Ebay. That would most likely end up being one of those guys who swore that his car had floating axles which is why there was no rear differential in his 4WD setup.

[ldittman]

I used the part names off of the ford parts site, hoping that it would make sense to someone.

There isn't any hoses that could connect to the exhaust manifold, but what started all of this is that we found a leak coming off of the intake manifold out of where it looks like there should be a hose. Of course the hose is missing and that's why I was trying guessing at what is missing. We plugged the leak off of the intake manifold with a chunk of vacuum line that was blocked off. And it started running smoother while at idle. It is still throwing the same code.

I agree I need to see a motor that is identical to mine.

[ldittman]

I know it is not a 4WD, although that would come in handy in ID!
It makes sense that it is non PZEV, since there isn't an air pump and nothing on the exhaust manifold. So what did they do on the non PZEV's to the intake manifold where that leak is? Did they just block it off or is there suppose to be a vacuum line running somewhere?

[whynotthinkwhynot]

Here's a pic showing the engine from the top, but it doesn't show the location of the vacuum line that I think you're missing. You'll see 2 lines on the right side (of the pic, left side of engine) of the valve cover that are clipped together. One is the fuel line that goes down to the fuel rail, the other looks like it heads off away from the engine, but really it turns down and comes under the throttle body to a vacuum port there. That's the vacuum feed for the evap purge valve located in the middle of the firewall up high- the fuel line goes underneath that valve.

[ldittman]

Uh...Maybe I'm blind, but where's the pic?

[whynotthinkwhynot]

Sorry, I forgot to link it, been busy.

[sailor]

FWIW - required emission control info. sticker under hood gives vacuum hose routing info., it's just a bit difficult to decipher - may help a bit in knowing what is supposed to be there and where things hook up.

[ldittman]

Sticker under the hood is MIA, I think it was removed after repairing the front end damage.