96 explorer has trouble starting cold p0455 and seems to be diffent if the tank is full

[410explorer]

So my 96 explorer has new MAF IAC new plugs new wires fuel injectors and ect I recently have been getting p0455 code evap system major leak and rich bank 2 I have had a ongoing issue with the rich bank 2 but the problem recently started when I got the p0455 code now if the truck is cold and I go to start it it will fire up run for a second then bog out like it's flooding it does this over and over until the motor gets a little warm then it will run but if I let the gage get to the quarter tank mark it won't start at all if it's cold and the issue seems to go away if the tank is full but starts again about half tank it has a new fuel pump from. This past summer not even 6 months old and another thing to note when I bought this truck the fuel neck had been replaced with so e after market **** the cap won't fit right and I can't seem to find a cap to fit but that's been that way and the problem started recently another odd thing is it seems like the truck uses gas while it's parked call me crazy but I can park it at half a tank and come back 2 or 3 days later start it and somehow it's a 8th of a tank less then when I parked it I was able to drive all the way too e until recently I got this evap code and cold start issue I guess I should also mention. If you keep the truck running you can go down to e but if you cut it off and let it cool it won't start if there's less then a quarter n a half tank any ideas ?

 

[wollimann]

p0455: Purge Valve maybe stuck open, hoses leaking or canister is leaking (valve o-ring).
bank2 rich: replace upper and lower air intake seals.
Check fuel pressure.

 

[410explorer]

Intake seals have been replaced and the pressure tested. About 29 psi at idle and spikes up normally when the motor is reved

 

[BTR]

Check the fuel vapor return line where it connects to the left and right sides of the upper intake manifold. It connects to the manifold using special “hairpin” clips. Once the hoses get old, they become stiff. Thus, sometimes making these 2 connections leaky.

 

[410Fortune]

Okay 96 4.0 ohv

The fuel vapor lines do not connect to the intake on a 96 4.0’pushrod, the vapor line actually goes through the canister vent solenoid (above spare tire) and then to the canister purge solenoid (below the battery) and then over to the bottom of the throttle body

Your truck won’t start easily with 29 psi fuel pressure spec is 36-42 psi
Sounds like you need a new strainer, fuel pump and filter

With 29 psi it makes perfect sense that it will only run a little bit. The injectors need 36 psi behind them to spray fuel

Then check the evap hose especially the plastic fittings under the battery where they connect to the tank vent lines… the plastic fittings like to break down there leaving you with the 0455 code

 

[BTR]

Ignore my previous post (post #4). It's for a 4.0 SOHC, not a 4.0 OHV.

 

[410explorer]

Okay 96 4.0 ohv

The fuel vapor lines do not connect to the intake on a 96 4.0’pushrod, the vapor line actually goes through the canister vent solenoid (above spare tire) and then to the canister purge solenoid (below the battery) and then over to the bottom of the throttle body

Your truck won’t start easily with 29 psi fuel pressure spec is 36-42 psi
Sounds like you need a new strainer, fuel pump and filter

With 29 psi it makes perfect sense that it will only run a little bit. The injectors need 36 psi behind them to spray fuel

Then check the evap hose especially the plastic fittings under the battery where they connect to the tank vent lines… the plastic fittings like to break down there leaving you with the 0455 code

Ya the line that runs from the throttle body to to the the valve under the battery then run to right behind the tank where the purge solenoid correct?the seem ok I'm starting to think the p0455 has nothing to do with the hard starting I going to re check the fuel pressure but a weak pump should give me a problem all the time correct? This only happens from a cold start when the tank is under halfway full I have heard alot of horror stories about these fuel pumps

 

[wollimann]

going to re check the fuel pressure but a weak pump should give me a problem all the time correct?

The fuel pump makes her own thing, sometimes more or less pressure, sometimes no pressure.
Craket fuel pump connection hose and clogged intank filter could cause issues too.

heard alot of horror stories about these fuel pumps

The "horror" is to get them out.

 

[wollimann]

going to re check the fuel pressure

After ignition on the fuel pressure must stay for a while.
If it drops rapidely there is a internal leak, mostly inside the tank, maybe the fuel pressure regulator.

 

[allmyEXes]

1995-2001 Explorer fuel pump access.

 

[amj441]

1995-2001 Explorer fuel pump access.
View attachment 460460
View attachment 460461

My 2000 does not have this access hole. mine was solid steel. I had to drop the tank which honestly wasn't that bad.

 

[410Fortune]

These guys are cutting access holes so they don’t have to drop their tanks

The info about where to cut and how is on this forum. He is just showing you his latest access panel

If there is a problem
With the relay or fuse it can cause intermittant fuel pressure issues
But it sounds to me like your pump is weak

Back in the day a fuel pump worked or didn’t
The way these new ones are designed they run forever but with time they lose the ability to
Build pressure… usually pressure drops off as the pump warms up. More fuel on top of the pump keeps it cooler longer. Also more atmospheric pressure on top of it helps it make flow… but 29 psi… that’s well below spec

 

[96eb96]

So my 96 explorer has new MAF IAC new plugs new wires fuel injectors and ect I recently have been getting p0455 code evap system major leak and rich bank 2 I have had a ongoing issue with the rich bank 2 but the problem recently started when I got the p0455 code now if the truck is cold and I go to start it it will fire up run for a second then bog out like it's flooding it does this over and over until the motor gets a little warm then it will run but if I let the gage get to the quarter tank mark it won't start at all if it's cold and the issue seems to go away if the tank is full but starts again about half tank it has a new fuel pump from. This past summer not even 6 months old and another thing to note when I bought this truck the fuel neck had been replaced with so e after market **** the cap won't fit right and I can't seem to find a cap to fit but that's been that way and the problem started recently another odd thing is it seems like the truck uses gas while it's parked call me crazy but I can park it at half a tank and come back 2 or 3 days later start it and somehow it's a 8th of a tank less then when I parked it I was able to drive all the way too e until recently I got this evap code and cold start issue I guess I should also mention. If you keep the truck running you can go down to e but if you cut it off and let it cool it won't start if there's less then a quarter n a half tank any ideas ?

Get a gas cap for a 97 or 98.

There is a thick steel vapor hose that runs from the engine to the rear of the truck (canister). Mine was rusted out and broken. I replaced with 20'? (I bought 25, had some left over, best to measure) of appropriate rubber sized fuel line ( 7/16?) from Oriely. Put wire loom on it and ziptied. I had lots of gas fumes around the truck. The fuel lines are stainless steel and indestructible.
Also check that the hoses on the purge valve are good (the pv can be bad too, it is down by the left fender I think,, there is a tube from the throttle)
Good idea to smoke test the evap system for leaks. There is actually a special service port for that on the truck!

You could have a rotted out fuel tank, there are replacements available too.

 

[C420sailor]

Your fuel is evaporating off. Get a proper filler neck and cap on it.

And yeah that psi is way too low.