DPFE or EGR?

[fordwheelinman]

pull a vacuum on the egr, the engine should run rough or die. if it does not the egr valve is no good

not always

A Key On Engine Off code could also represent a hard code, or one that has stored in memory.

 

[FL_forlife33]

had this same problem, replaced the egr valve for no reason, ended up being the dpfe sensor... no more "egr flow insufficient" code anymore

 

[MA Ranger]

I'm experiencing a similar problem on a '94 Ranger - check engine light is on and code scanner shows 337 during the "KOEO" test. So far I have replaced the EGR Vacuum Regulator solenoid and the DPFE sensor - no luck, check engine light still comes on. I have tested the referrence voltage on the DPFE sensor with a multimeter and it showed 5.0 volts, which I believe is within the normal range. From reading the replies above, it seems the problem is most likely electrical in nature (I ran a vacuum test on the EGR valve itself a while back and it responded normally - engine began to stall). The hoses all look normal - I replaced the two coming out of the DPFE sensor when I replaced the sensor. The engine is running good otherwise - no signs of overheating, idle is normal and gas mileage is the same as it was before the check engine light came on (18 - 20 city/25 highway). The connector on the DPFE sensor looks o.k. on the inside - no broken or bent pins. The wiring on the outside of the sensor looks normal too - nothing broken or bent, no damaged insulation.

I'd like to give the circuit a complete electrical check, but I don't know where to begin and I don't have a wiring diagram or instructions to follow (the aftermarket repair manual I have doesn't go into that level of detail). Can I obtain a wiring diagram with instructions on what/how to test (and repair)without buying a Ford repair manual? Is there a "better code reader" on the market that can narrow the problem down more? Also, could the problem be in the power distribution box?

 

[MA Ranger]

Were you ever able to fix the problem? I'm experiencing a similar problem on a '94 Ranger with a 3.0 engine. The only difference is it's not overheating.

 

[MA Ranger]

I'm having a similar problem with a '94 3.0L. The KOEO test is showing trouble code 337 and the check engine light is on. The engine is not overheating or even running warmer than normal. It idles normal and operates normally under all driving conditions. Gas mileage is the same as it was before the problem stated. I have checked the hoses to the DPFE sensor, run a vacuum test on the EGR valve, replaced the EVR solenoid and DPFE sensor - no luck, trouble code 337 still shows during a KOEO test and check engine light is still on. I checked the reference voltage on the harness connector to the DPFE sensor with a multimeter with the ignition on and engine not running and it showed 5.0 volts (normal range for this truck according to the Haynes manual is 4.0 - 6.0 volts).

The only other "clues" I have are (1) it takes a few seconds longer for the check engine light to come on in the morning than it does when the engine is warm or hot and (2) the check engine light goes out momentarily when the DFE sensor is unplugged (the KOEO test shows trouble code 327 - DPFE sensor reference voltage is below minimum range when it's unplugged; not surprising, but thought I'd mention it).

I'm interested to know if and how you were able to solve your problem and any suggestions you might have. Thanks.

 

[Cacher]

working in the parts business, i see this all the time. 80% of the time its the DPFE. On my ranger i replaced the DPFE and the solenoid and that fixed my light problem and gave me about 2 more mpg (not kidding!). The parts were cheap for me so i just replaced both atthe same time.

Solenoid for the sensor? Where is this located at if I may ask. I just replaced the DPFE.
2.3L by the way.

 

[AllanD]

The FIRST ground to check is the one between the wiper motor and the cylinder head.

That was what was causing my (False) high temp indication.
Yes there are half a dozen other grounds on the engine all of
them making perfect contact, but that one being dirty/loose
cause a whole host of computer error codes and that was the
clue that made me go looking for a bad ground.

Before replacing expensive components always look for a "Stupid"
solution, a loose wire, corrosion, etc... FIRST, it'll save you a lot
of money that you would otherwise have spent on parts you didn't need...



AD

 

[Purerock Racing]

sorry for bring up this old one, it's happened to me. Just bought a 94 Ranger 4.0L, with both these 332/337 codes. The vacuum lines to the DPFE were not even connected, and I need to see a digram of where the hoses are suppose to be correctly hooked up? Anyone have a diagram?