2004 explorer 4.0L V6 SOHC 12V FFV

[JESSCIA]

i am having issues with codes saying MASSIVE EMISSIONS LEAK. you can smell gas when you start it and my gas mileage has gone down. have had a mechanic tell me that i have "2 dead cylinders" but when we did a compression check i am getting 150, 150, 160 145, 125, 125. called a ford dealership and spoke with a service manager he stated you take the highest reading and then the lowest should be within 75%, which it is.
it runs rough at idle but when put into drive it evens out fine, has some issues once in awhile at stoplights but still goes, its my daily driver. we have replaced so many parts due to codes that we are at a complete loss.
can someone offer any advice? i love my vehicle and do not want a car payment. i am at 204, 681 miles at this point...ANY ADVICE OR SUGGESTIONS WELCOME!!!!!! thanks

 

[Tech By Trade]

Exactly what codes is it throwing?

 

[JESSCIA]

i will have to run the code machine on it again and let you know, but prior it was P0103, replaced the part, code came back. p0455 evap system large leak, p2106 throttle actuator cntrl system forced , limited power, p0113 IAT sensor 1 ckt high, p0102 MAF or VAF A ckt low input.
oh and CHECK GAS CAP, have replaced it, still have code.

 

[Tech By Trade]

Is the wire sheathing still good on the wires MAF sensor and the IAC? When you changed the MAF sensor did you install the correct one, and is it sealed properly?

 

[JESSCIA]

Is the wire sheathing still good on the wires MAF sensor and the IAC? When you changed the MAF sensor did you install the correct one, and is it sealed properly?

as far as i know, yes on the part and yes on the wiring. how can we tell if the seal is done correctly?

 

[Tech By Trade]

If it was installed correctly it should be sealed. Have a real close look at the wiring though. For had a few bad years when the insulation gets brittle and breaks causing shorts that reek all kinds of havoc. 2004 is right in the middle of that. Bare wire can usually be seen at places the wires bend. Some times it can be hidden under the wire loom as well.

 

[JESSCIA]

If it was installed correctly it should be sealed. Have a real close look at the wiring though. For had a few bad years when the insulation gets brittle and breaks causing shorts that reek all kinds of havoc. 2004 is right in the middle of that. Bare wire can usually be seen at places the wires bend.

ok great, i will check this evening, thanks

 

[koda2000]

"150, 150, 160 145, 125, 125"

Your compression test does not sound good. You should be seeing around 160-165 PSI in all cylinders with no more than a 10% difference between cylinders.

Spurious compression readings can result if the test wasn't performed correctly (warm engine with throttle wide open).

Your fuel tank is connected to an evaporation canister. This canister sits over the spare tire and can rust away and fall off into the spare tire. This can explain the emission issues. Also the evap canister has valves that are electronically controlled. Then there's a line that connects it to a purge solenoid located under the battery box, which opens when when the engine is started allowing fuel fumes to be sucked into the engine and be burned. There is a rubber hose that connects the purge solenoid to your intake manifold. This hose has been know to disintegrate, then it causes evap system leaks. As you smell gas, I'd start by checking the hose under the battery box to see if it's rotted.

A "massive evaporation leak" can cause your poor fuel economy because un-monitored air is getting sucked into the engine. I'm surprised your not also getting P0171/0174 codes too.

Your poor compression will also mess with your fuel economy.

 

[JESSCIA]

"150, 150, 160 145, 125, 125"

Your compression test does not sound good. You should be seeing around 160-165 PSI in all cylinders with no more than a 10% difference between cylinders.

Spurious compression readings can result if the test wasn't performed correctly (warm engine with throttle wide open).

so the engine should be cold?

 

[JESSCIA]

"150, 150, 160 145, 125, 125"

Your compression test does not sound good. You should be seeing around 160-165 PSI in all cylinders with no more than a 10% difference between cylinders.

Spurious compression readings can result if the test wasn't performed correctly (warm engine with throttle wide open).

Your fuel tank is connected to an evaporation canister. This canister sits over the spare tire and can rust away and fall off into the spare tire. This can explain the emission issues. Also the evap canister has valves that are electronically controlled. Then there's a line that connects it to a purge solenoid located under the battery box, which opens when when the engine is started allowing fuel fumes to be sucked into the engine and be burned. There is a rubber hose that connects the purge solenoid to your intake manifold. This hose has been know to disintegrate, then it causes evap system leaks. As you smell gas, I'd start by checking the hose under the battery box to see if it's rotted.

Often when you see multiple TDC's they get generated from a single problem.

we have replaced both evap canisters, and the purge solenoid. we will check the hose this evening though. thanks!

 

[koda2000]

so the engine should be cold?

No, warm with throttle body wide open. If low compression is detected, you can also squirt some oil in the cylinder through the spark plug hole and retest. If the compression comes up you have a ring problem. If it stays the same you a valve problem. I don't know what the hell the Ford dealer is talking about. Never heard of that.

 

[JESSCIA]

No, warm. If low compression is detected, you can also squirt some oil in the cylinder through the spark plug hole and retest. If the compression comes up you have a ring problem. If it stays the same you a valve problem. I don't know what the hell the Ford dealer is talking about. Never heard of that.

ok great, we will retest. thanks!

 

[koda2000]

ok great, we will retest. thanks!

Please reread my last post. I added that the throttle must be held wide open while testing too.

 

[JESSCIA]

Please reread my last post. I added that the throttle must be held wide open while testing too.

got it, thanks