Yea my first CEL in the 5.0 and i havent had the motor in the truck more than a month lol..... Its not too much of a big deal but id kinda like to know where to start looking for this problem. Any Suggestions?

 

Check your gas cap, or have your evap system smoked to see where the leak is

 

smoked? who does that?

 

Ford dealer or anyone with a smoke generator. Oil smoke is introduced into the evap system under pressure to locate any place where gasoline vapors can escape. A smoke machine is often the only way to find a really small leak.

Before you resort to that, notice that your trouble code is for a large leak. Check that your fuel cap is tight and the seal is in good condition. Then you could check your filler neck/vent connections and any vapor hoses going to the top of the tank or to the charcoal canister above the spare. Check the condition of the wiring to the canister.

There is also a long vapor line that comes forward from the canister to the Evap Purge Valve in the engine compartment, just to the rear of the battery under the ABS pump. You did connect the purge line and electrical connector when you swapped to the 5.0L, right??

 

Ill go ahead and try this... I probably disconnected something when i was installing the motor.. lol

 

There's a plastic vac line that runs between the VMV/canister purge valve and the intake manifold just like it was with the 3.0. Leave it off and you'll get the code.

 

found it.. Ive had problems with this hose before. I looked at the canister in the rear of the truck and there was a hose disconnected. I never threw the code before because ive had problems with this hose in the past. My exhaust burned right through the hose before when i had the problem. Now im having a problem keeping the hose attached to the plastic fittings on there now lol Ill keep an eye out on it though. thanks for the help

 

its cause your tires are low...oh you figured it out nevermind


haha

 

bahahaha yea i should check that out.. For some reason I lost a center cap, maybe thats it :(

 

Well, glad Im not the only one that gets this code... I smoked mine and found no leaks at all, the machine was building quite a bit of pressure, but no smoke coming out anywhere... Bob, could the pressure sensor in the fuel tank cause this code? or would it have a code of its own?

 

The pressure transducer has its own set of codes (P0452 and P0453) but they check for gross electrical problems like a short or open in the sensor or wiring. I guess that a transducer that was within the electrical limits but also bad some other way could conceivably cause the P0455. I've never heard of it happening though.

Ford says that a P0455 could be caused by a missing or leaking fuel cap, 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.

OBDII Summary:

http://www.motorcraftservice.com/vdi...tsid=diagsheet

 

yeah he said he found it in the canister. Figures since that thing has always got my attention like, "someday somthings gona go wrong with that and IDK wtf it does,but its in a bad spot"

 

I replaced the VMV solenoid (the one in the engine compartment) 2 times. The first time I replaced it, there were no codes for a month or two, but from what I understand, if it is below 40 degrees outside, this system is inactive. Well, when I replaced it, it was usually below 40 degrees while driving... After spring started coming on, the code came back. I replaced it again, and it didn't help this time, so Im pretty sure that's not my problem. I also checked the CVS (canister vent solenoid) by putting 12 volts to it, it closes and I can't blow through it so it must be fine too. The gas cap is also new. And like I said, I put a smoke machine on it and found no leaks... Im stumped. I need to get it fixed though. It is the one and only problem I haven't been able to resolve.

I guess my next question is about the electrical part of it... If there was a wiring issue somewhere in the system, such as the wiring for the CVS was damaged and not working, would that throw a code other than the P0455? If I can eliminate a wiring issue, then I might be able to get somewhere with this.

 

"P1451 (Canister Vent Solenoid Circuit): open/shorted."

That quote is from the link I gave you before. It explains OBDII Theory and Operation including the Evap Leak Check and the codes associated with it. The answer to your problem is probably in there. Be sure to look at the year of the Explorer donor since you are (presumably) using that PCM.

 

Thanks for that link, I followed it to the 1996 model year section (both the truck and explorer parts are 1996) and printed it off. I will look into it more. I have been fooling around with the EVAP system on this truck for almost a year, and I am getting fed up with it. Thats why I was asking you questions. Sorry if I bothered you, but hey, I cant help it that you know these things like the back of your hand!

Thanks for the help Bob!

 

No problem. Just wanted to make sure that you checked out that link. It should point you to the solution of your problem.