96 ext 2wd about 130,000 miles
Got a lean bank code 41. Traced it to cracked broken tubing near the charcoal cannister. Changed the tubing, but also found that the purge valve would not seal off tight. Looked closely and found a couple particles of charcoal in the valve seat. Cleaned it out real good and got it to seat off tight. Char particles had to come from the cannister. Didn't have a spare cannister and didn't feel like getting one. I bought a $3 fuel filter and placed it upstream of the solenoid valve. You have to kind of make it fit in, but there is just enough room, at least in a 4.0. The fuel filter is large enough not to restrict air flow.Any carbon breakthru will get caught in the filter, not the valve. About 200 miles later I am CEL clear. Just an FYI in case anyone has this problem.

 

That's a great tip. Thanks.

Has anyone found a flexible replacement for the stock stiff tube? The cracking is such a common problem that something like a flexible fuel line must be better.

 

Thats a really good idea, thanks for the tip.

 

Here's a handy pic of the purge canister. I just happened to have the air filter box out to replace it due to a (typical!) missing captive nut, so dust was bypassing the filter's seal. I also took some time to do the bowed air filter box mod while it was out.

Which gizmo is the purge valve that you found debris in? The black gizmo or the yellow gizmo lower in the pic? I've never touched them in any of my Aeros (yet).

(click on image for larger)

 

The yellow gizmo is the solenoid valve, although I thought on mine it was located around the intake manifold. I'm not sure what the black gizmo is.

 

In that pic, there's definitely wires into the black gizmo. I can't tell if there are wires to the yellow one.

The yellow gizmo can be taken apart?

I've owned several Aeros, but this '97 is my first with the 4.0l, and of course the emissions system has evolved over the years, so I haven't delved into it -- no problems yet!

 

Thanks for that picture, none of the diagrams I have seen showed a good view of the hose routing. Mine were rotten. I guess it should be easy to figure out, but sometimes a picture helps make sure.

 

If the black gizmo has a line going to the tank, it must control the venting of the tank.

 

yellow "gizmo" is the PCM controlled solenoid purge valve that opens and allows gas vapors to be removed from carbon filter and gas tank and sucked into the throttle body.. it can plug from carbon particles from purge tank

black "gizmo" is purge vapors sensor that senses vapor buildup in gas tank and carbon filter. sends signal to PCM to suck the vapors out. PCM waits until closed loop and rpm above certain point with tranny in gear and above set speed. can't be flooding a cold engine at idle with overload of gas vapors.

the thin wall molded rt. angle hose coming out of the carbon tank into the purge valve fails early because of flex and heavy exposure to fumes.

I wire tie the whole assembly in several places to support the hose and reduce flex after hose replacement.
the hoses fail from the inside.

 

If you pull out the purge valve, you can look into the inlet or outlet and see the plunger/valve seat. It is very small, and is easy to stick open if anything gets in it. I cleaned mine with carb cleaner and WD40. And you may still have trouble getting it to seat. They are supposed to be leak free if you pull vacuum on the outlet. After I cleaned it, I checked it with a mighty vac and it did seat off. Someone correct me but I believe if the valve sticks open, allowing flow all the time, the black plastic sensor will show flow when there is not supposed to be any and it will throw a code.

You can sort of check the valve operation ont the workbench with a 12 v battery. You will see that the plunger has a very small amt of travel.

 

Thanks for the clarification.

I once had a ('75?) Vega with a leaking vapor canister. The Weber carb kept getting carbon into it! I put an inline fuel filter on the vapor line to fix that, about the third time I had to open the carb up and clean out the carbon!

 

The P1443 has been haunting me again for a while, and for the past four years I've been campaigning this rig hard, commuting 54 miles per day plus trips to LA.

I had cleaned the purge valve and got relief for a while, then I replaced it with new and again had relief for months, but eventually the P1443 was triggering every drive and lighting the CEL every other drive cycle (so, once per day).

I'm using a bluetooth OBDII adapter and the Forscan iOS app to clear the code and read data, but neither it nor my old Snap-On MTG-2500 will access freeze-frame data -- 1996/97 Fords are notorious for non-standard OBDII handling -- and I've been mostly ignoring the CEL for a few months.

I've nibbled around the problem here and there for a while. One issue I had was the rotting proprietary-size/shape flexible tubing.

My picture from 2012, the OEM setup:

(click on image for larger)



The elbow hose cannister-to-purge-valve is about 3/8" on the cannister end and 1/4" on the purge valve end, and it's a short radius 90° elbow. It breaks and cracks and is apparently NLA.

I bought some random Gates 352106 power steering return hose (1990-91 Toyota Corolla) that has a short-radius 90° with 3/8" ID, and then used some brass fittings to do a 38/"-to-1/4" 90° transition. That seemed the best way, because all other solutions I'd tried made the line on the cannister bend too sharply once the air filter box was bolted in place, restricting flow. The air filter box no longer mashes the line from the cannister.

I also removed the "do-nothing" OEM fitting and the two associated rotted lines (see markup below), connecting the purge flow sensor directly the the intake manifold line.

There are NO leaks from the cannister to the fuel tank, and NO leaks from the flow sensor to the intake manifold. I have double- and triple-checked.

There was a defunct website, TomsHints.com, where he had done a nice job of troubleshooting the purge flow sensor, including both "bad" and "good" resistance readings from the flow sensor (archive.org link, saved copy on my own server). Armed with that info, I backprobed the flow sensor and found low signal output at full flow.

"Backprobe" is misleading, since I could not access the back of the connector well, so I pierced the black/green signal wire with a hatpin, connected positive lead of voltmeter to it and grounded the meter's negative lead. With MAF connected, start engine, disconnect flow sensor to purge valve hose and with air hissing heavily into the flow sensor, watch the voltmeter. It takes several seconds to stabilize, because the sensor is apparently a thermistor and is measuring temperature. Record highest reading, then put thumb over sensor line to stop air ingress, let voltage reading stabilize, the record the low reading.

My results:

Bad flow sensor = 1.2v no flow, 2.7v full flow
New flow sensor = 1.7v no flow, 3.8v full flow

I will put another 250 miles on this in the next week and report back.

Marked-up OEM & modified pictures with notes:



Good practice is to seal the wire harness pierce point after testing. I used a dab of RTV on the entrance & exit holes.

 

Nice write up Al. Rebuilt my purge system 5 years ago with all new parts then except the NLA hoses which are now DIYer upgrades.
Can't work on mine much anymore, age.
She still sets out of the street and fires within 2 seconds of hitting key. Drives like a dream, smooth and powerful.
Just old tired and forlorn like me. Been hit twice by road rage drivers.
Makes her trips to the PO and Home Depot, still a good driver.
Seldom see an Aero in this area anymore.

 

Update: P1443 continued to plague. Testing the Echlin purge soleoid, it seemed fine but I swapped the original Motorcraft unit back in, and it's been six days of commuting and 300 miles and no repeat of P1443, pending or CEL.

I don't know what is up with the Echlin unit, it seems to work OK. [shrug].

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The ONLY Aerostars I see in these parts nowadays are AWD ones.

 

The carbon particle fume entrapment in the purge filter box breaks down after years of use. Particles migrate out with sucked off fumes, plug valves hoses etc.
I had to replace the box (tank).