1993 F250 4x4
351w E4OD trans
88000 miles

I have one code in the KOER: Code 632-
Overdrive cancel switch not changing state (E4OD) . It may be because i didnt hit the button on the shifter.

111 in KOEO and
Code 172- HEGO sensor circuit indicates system lean (right side)
Code 327- DPFE or EVP circuit below minimum voltage of 0.2 volts.
Code 328- EVP circuit below minimum voltage of 0.24 volts.

Would the EVP need to be replaced in order to clear the 327 and 328? What could cause the code 172, does that mean this truck needs a new O2?

I was looking around under the truck and the line going back to the gas tank from the canister looking thing by the radiator is rusted through. Is that hurting anything being like that?

 

Yes replace the EVP.. that's the postion sensor on top of the EGR valve btw.. just in case you don't know.

 

Being in the continuous memory section, 327 and 328 could be an intermittent problem or a poor connection rather than the EVP itself. You can do some checking with a voltmeter to find out for sure. I would recommend checking first before unknowingly replacing a good part.

The line from the charcoal canister near the radiator to the fuel tanks might cause a small issue with air/fuel ratio, but I don't know how big of an effect it would be. The evaporative emissions from the fuel tank would also be vented to atmosphere instead of being stored in the carbon canister.

 

May also check the AIR injection system steel lines, one way valves and diverter valve(s). If the one way valve at the heads/manifolds isnt one way anymore, the steel lines are bad, or the diverter valve isnt operating correctly; air could get in ahead of the HEGO but after the exhaust valves causing the HEGO to mistake a lean condition when the motor is not running lean. If all is good and the HEGO is the factory original, you may consider replacing the HEGO.

 

Thanks for the replies. Much appreciated.

Would this year motor have the tube connectiing the heads? I know the pass. side collector is rigged up my the p.o. and is leaking, so tht may be the problem.