Canister Purge Solenoid?

[DGreatest]

I have been chasing down (part time) lean codes for the last few months. I finally took it to a shop and after 2 days they tell me that I need a new solenoid for the purge canister. Does anybody have any idea if that makes sense for lean codes?

Before anyone asks, yes, I have checked almost everything on the truck. I have changed the intake gaskets, cleaned and tested the MAF and IAC, checked the fuel pump, hoses, spark plugs, changed the fuel filter, tested the DPFE, changed the PCV, etc. My fuel trims are normal when the truck is first started but tend to drop as the truck heats up. No idea why.

Bottom line, can the CANP Solenoid really cause lean codes?

Thanks for reading guys. Any help is greatly appreciated.

 

[2000StreetRod]

Which engine?

Which engine do you have?

What are the voltage swings on your front O2 sensors?

What are all of your current DTCs?

What are your LTFTs for banks 1 & 2?

What is the difference in STFTs for bank 1 vs 2?

Does your ECT rise to your thermostat rating?

Is the intake, engine and exhaust stock?

 

[DGreatest]

I have a 1998 SOHC.

I have both banks lean. P0171 and P0174

Everything on the truck is stock.

I don't have the answers to all the other questions right now. All my data is written down at home but I'm at work.

I got off the phone with the mechanic about an hour ago and thought I would check to see if the CANP solenoid really is a viable option for lean codes. Any idea?

 

[DGreatest]

So am I right in assuming nobody has ever heard of the CANP Solenoid causing a lean code?

 

[2000StreetRod]

Dtc p1450

I suppose that excessive vacuum in the fuel tank could cause a lean condition by restricting fuel flow just as a clogged fuel filter can sometimes cause a lean condition. The first thing I would do is determine if you have a canister purge solenoid, a vapor management valve or a canister vent solenoid. The following is from the 1998 Ford OBD System Operation Summary and applies to the enhanced evaporative system:

"The evap system integrity test is done under conditions that minimize vapor generation and fuel tank pressure
changes due to fuel slosh since these could result in false MIL illumination. The check is run after a 8 hour cold
engine soak (engine-off timer), during steady highway speeds at ambient air temperatures (inferred by IAT)
between 40 and 100 oF.
The evap system integrity test is done in four phases.
(Phase 0 - initial vacuum pulldown):
First, the Canister Vent Solenoid is closed to seal the entire evap system, then the VMV is opened to pull a 7”
H2O vacuum. If the initial vacuum could not be achieved, a large system leak is indicated (P0455). This could be
caused by a fuel cap that was not installed properly, a large hole, an overfilled fuel tank, disconnected/kinked
vapor lines, a Canister Vent Solenoid that is stuck open or a VMV that is stuck closed.
If the initial vacuum is excessive, a vacuum malfunction is indicated (P1450). This could be caused by kinked
vapor lines or a stuck open VMV. If a P0455 or P1450 code is generated, the evap test does not continue with
subsequent phases of the small leak check, phases 1-4."

I would only consider the CVS as a possible lean condition cause if you have DTC P1450.

 

[2000StreetRod]

enhanced evaporative system

According to Rock Auto you have the enhanced evaportive system that uses the canister vent solenoid shown below:

The non-enhanced evaporative system uses the canister purge solenoid shown below:

If you have what's in the first photo and are getting P1450 then I guess the mechanic could be correct.

 

[DGreatest]

Thanks for the input. That's kind of what I figured too. If all I'm getting is
P0171 and P0174 then the CANP Solenoid makes no sense.

 

[budwich]

You could try disconnecting the vacuum line that runs from the solenoid to the engine ... plugging it at the engine with a vacuum cap (and at the solenoid outlet to the stop the "fumes" from polluting the air... ). Run it like that, and see if you problem goes away (i.e. lean / leak issue). It should if there is a leak in the solenoid.

 

[boss 331]

Are these pictures what is found under the battery or under the spare tire?

According to Rock Auto you have the enhanced evaportive system that uses the canister vent solenoid shown below:
View attachment 57626
The non-enhanced evaporative system uses the canister purge solenoid shown below:
View attachment 57627

If you have what's in the first photo and are getting P1450 then I guess the mechanic could be correct.

 

[UKwinsagn]

It is on the rear passenger side of the motor. When I took the cap off of mine i noticed a filter inside and the motor also died.

 

[nssj2]

It's helpful, actually, that both banks are lean. It means one of two things.
A) Engine is getting too much air
B) Engine is not getting enough fuel
If it was electrical, there would be a code for it, including the purge solenoid. So something mechanical, that would cause A or B. If you said you checked for vacuum leaks, I'm assuming with a smoke machine since it was a mechanic, then A is done. B can be caused by 1) clogged fuel filter. 2) clogged strainer in the tank. 3) Fuel pressure regulator gone bad. Have you checked any of those?


edit: yes, a purge solenoid can cause a lean condition, as it is vacuum operated. But it should throw its own code if it is malfunctioning

 

[Lazzman]

What a coincidence I also have both those codes due to a lean bank 1 & 2. I two have done everything to try and fix the problem, including cleaning MAF, Cleaning IAC, just replaced DPFE sensor for a different code and cleaned EGR solenoid.

With the codes you listed I am still getting decent drivabiltiy but the idle is all messed up as if it where a vacuum leak. The engine barely holds idle at cold start up and when the engine warms the idle surges higher, rises all the way up in park until key is turned off or holdes a steady idle that is higher than normal- 950 in D and 1200 in park.

All I have for clues are the engine codes, I suspect it might be the MAF sensor but don't feel like dropping $100 and be incorrect.

I have the exact same engine as you '98 4.0 Sohc, the cannister vent solenoid is the first picture and is located under the battery.

I will let you know if I find anything

 

[boss 331]

thanks for the info