EGR or PFE? '94 Explorer 4.0 2wd

martinh67 · 12-12-2008, 03:21 PM

Newbie here.

SYMPTOMS
1. Little rough on the idle - sometimes it sways back and forth. At normal driving speed, she purrs like a kitten.
2. CEL comes on after it starts warming up

TROUBLESHOOTING
1. Code 332 KOEO test (EGR Valve opening not detected)
2. Code 335 KOEO test (PFE or DPFE sensor voltage out of Self-Test range)
3. Code 543 KOEO test (When the PCM commanded the fuel pump on, voltage was not detected on FPM) Related?
4. Code 326 KOER test (PFE or DPFE circuit voltage lower than expected with zero EVR duty cycle)

Is it the EGR valve or the PFE? Or both??

KPT · 12-12-2008, 03:56 PM

Almost certainly PFE. I've had the 335 code when I had a bad DPFE.

MrShorty · 12-12-2008, 05:06 PM

KOEO codes have to be electrical in nature, so KOEO EGR codes almost never point to the EGR valve itself. Check the PFE sensor circuit.

KOEO 543 is likely unrelated to the PFE codes. Where it runs, the fuel pump must be working. Check the fuel pump wiring, just in case there's a loose connection that is waiting to leave you stranded.

catdaddy614 · 12-12-2008, 06:04 PM

check DPFE sensor, those are prone to go bad in fords.

martinh67 · 12-12-2008, 08:11 PM

I'll go get one AZ or Adv Auto

martinh67 · 12-14-2008, 01:47 PM

Replaced PFE and after making sure all vacuum lines are connected, CEL went out, however still a little rough on idle. I will go ahead of all the recommended cleaning of the IAC and MAF.

I also found the rubber ends of each vacuum lines to be very loose. Seemed they expanded. Replaced all the ends on the vacuum tree and found an open w/o and end.

martinh67 · 12-15-2008, 01:05 PM

Prior to cleaning the IAC and MAF, The X was running great w/o any roughness. SO I went ahead and inspected the IAC and found some dirt in it. I cleaned it and attached it. Then I went and inspected the MAF, it was clean as a whistle. Then I notice the air filter assembly box was a little open. Fixed that and everything is fine for now.

Gas milage greatly improved based on the miles I driven since last fill-up. I'll find the exact milage on my next trip to the gas station.

12-12-2008, 03:21 PM	#1
martinh67 Wannabe Elite Explorer Virginia '94 XLT Join Date: Dec 2008 Posts: 18 Vehicle Specs (Original Poster)	EGR or PFE? '94 Explorer 4.0 2wd Newbie here. SYMPTOMS 1. Little rough on the idle - sometimes it sways back and forth. At normal driving speed, she purrs like a kitten. 2. CEL comes on after it starts warming up TROUBLESHOOTING 1. Code 332 KOEO test (EGR Valve opening not detected) 2. Code 335 KOEO test (PFE or DPFE sensor voltage out of Self-Test range) 3. Code 543 KOEO test (When the PCM commanded the fuel pump on, voltage was not detected on FPM) Related? 4. Code 326 KOER test (PFE or DPFE circuit voltage lower than expected with zero EVR duty cycle) Is it the EGR valve or the PFE? Or both??

12-12-2008, 05:06 PM	#3
MrShorty Wannabe Elite Explorer Spanish Fork, UT 92 XLT and '87 Bronco II Join Date: Dec 2001 Posts: 4,934 Vehicle Specs	KOEO codes have to be electrical in nature, so KOEO EGR codes almost never point to the EGR valve itself. Check the PFE sensor circuit. KOEO 543 is likely unrelated to the PFE codes. Where it runs, the fuel pump must be working. Check the fuel pump wiring, just in case there's a loose connection that is waiting to leave you stranded. __________________ Mr. Shorty 92 XLT 4x4 87 Bronco II XLT 4x4 '98 Chev K1500 Suburban SLT 4x4

12-12-2008, 08:11 PM	#5
martinh67 Wannabe Elite Explorer Virginia '94 XLT Join Date: Dec 2008 Posts: 18 Vehicle Specs (Original Poster)	Thanks fellas I'll go get one AZ or Adv Auto

12-12-2008, 03:56 PM	#2
KPT Wannabe Elite Explorer NC '95 XL 4x4 Join Date: Feb 2003 Posts: 1,584 Vehicle Specs	Almost certainly PFE. I've had the 335 code when I had a bad DPFE.

12-12-2008, 06:04 PM	#4
catdaddy614 Wannabe Elite Explorer columbus, ohio 97 XLT Join Date: Jul 2008 Posts: 127 Vehicle Specs	check DPFE sensor, those are prone to go bad in fords.

12-14-2008, 01:47 PM	#6
martinh67 Wannabe Elite Explorer Virginia '94 XLT Join Date: Dec 2008 Posts: 18 Vehicle Specs (Original Poster)	Replaced PFE and after making sure all vacuum lines are connected, CEL went out, however still a little rough on idle. I will go ahead of all the recommended cleaning of the IAC and MAF. I also found the rubber ends of each vacuum lines to be very loose. Seemed they expanded. Replaced all the ends on the vacuum tree and found an open w/o and end.

12-15-2008, 01:05 PM	#7
martinh67 Wannabe Elite Explorer Virginia '94 XLT Join Date: Dec 2008 Posts: 18 Vehicle Specs (Original Poster)	Prior to cleaning the IAC and MAF, The X was running great w/o any roughness. SO I went ahead and inspected the IAC and found some dirt in it. I cleaned it and attached it. Then I went and inspected the MAF, it was clean as a whistle. Then I notice the air filter assembly box was a little open. Fixed that and everything is fine for now. Gas milage greatly improved based on the miles I driven since last fill-up. I'll find the exact milage on my next trip to the gas station.