EGR problem

[pcollins]

Got a 1997 4.0L 5 speed 4x4. its throwing me a P0401 code, EGR flow insufficient. The EGR and DPFE are both brand new as of last year, and working fine as far as i know. i tested the EGR but how do i test the DPFE? My only other 2 thoughts are the Vacuum control solenoid, or plugged exhaust tube (i pray to god its not that, RUST) do the vacuum control solenoids really even go bad? just want to get this fixed and my light off. Thanks guys.

 

[pcollins]

i hate bumping things, but........Bump. Cause i hate throwing parts at my truck.

 

[Yellowsplash]

If your DPFE is a year old, take it back and have them defective exchange it...its most likely the issue.

I am not aware of a way to test them.

 

[BRUTUS_T_HOG]

Got a 1997 4.0L 5 speed 4x4. its throwing me a P0401 code, EGR flow insufficient. The EGR and DPFE are both brand new as of last year, and working fine as far as i know. i tested the EGR but how do i test the DPFE? My only other 2 thoughts are the Vacuum control solenoid, or plugged exhaust tube (i pray to god its not that, RUST) do the vacuum control solenoids really even go bad? just want to get this fixed and my light off. Thanks guys.

you need to activate the EGR valve to test the signal voltage of the DPFE.

at 0% EGR, DPFE voltage should be about 1 volt

at 100% EGR, DPFE voltage should be near 5 volts.

when you activate the egr at 100% the engine should start running bad or die.

i don't know if the egr valve on your truck is electric or vacuum operated

 

[pcollins]

If your DPFE is a year old, take it back and have them defective exchange it...its most likely the issue.

I am not aware of a way to test them.

I still have the reciept i'm pretty sure, hoping they'll take it w/o box though...

you need to activate the EGR valve to test the signal voltage of the DPFE.

at 0% EGR, DPFE voltage should be about 1 volt

at 100% EGR, DPFE voltage should be near 5 volts.

when you activate the egr at 100% the engine should start running bad or die.

i don't know if the egr valve on your truck is electric or vacuum operated

it is vacuum operated. If we have a vacuum tool at the farm, which i think we do, i'll test it today...if not i'll do a faulty DPFE exchange.

 

[BRUTUS_T_HOG]

ok now that i know you have a vacuum EGR.

use a vacuum pump to apply 7" mercury to the diaphragm, this should be 100% egr. if nothing happens then the egr valve is bad or the passages are clogged

 

[pcollins]

ok now that i know you have a vacuum EGR.

use a vacuum pump to apply 7" mercury to the diaphragm, this should be 100% egr. if nothing happens then the egr valve is bad or the passages are clogged

well, i took it into the shop at my vocational school about a week ago, and i'm not sure how many inches of vacuum i put on it, i just plugged the hand pump up and pumped away, the engine definitely bogged down and ran horrible, so i'm assuming the valve is fine? it didn't stall completely.

 

[BRUTUS_T_HOG]

sounds like egr valve performance is acceptable, at that point DPFE sensor signal voltage should have been around 5 volts.

 

[pcollins]

sounds like egr valve performance is acceptable, at that point DPFE sensor signal voltage should have been around 5 volts.

Didn't measure it...i'll have to test again. and at this point i hope its the vacuum control solenoid. because i don't have the receipt for the DPFE and don't want to dish out another $105 for one....

 

[kimcrwbr1]

Go to the bone yard and get a cheap one and see if it fixes it if so you can always get another one later on.

 

[kimcrwbr1]

Get a solenoid too.

 

[pcollins]

Hmm never even thought about the junkyard. normally dont go there. well the solenoid is only like $25, i'll get that new. but yea, i'll be making a phone call today to the JY to see if they have a DPFE in stock for me.

 

[Yellowsplash]

Sometimes the parts store will ask for your phone number when you buy a part with a warranty. Try calling the store you bought it at and give them your phone number and see if they have a customer history of you buying it. You dont need the box, they will just hand you the new part and use the new box to send the old part back to the manufacturer.

 

[pcollins]

Sometimes the parts store will ask for your phone number when you buy a part with a warranty. Try calling the store you bought it at and give them your phone number and see if they have a customer history of you buying it. You dont need the box, they will just hand you the new part and use the new box to send the old part back to the manufacturer.

i know they have record of it. i bought it off of our farm account...he can probably look it up. i have the vacuum control solenoid being delivered to the farm tomorrow, if that doesn't fix it i'll be exchanging the DPFE.

 

[CGordon]

pcollins,

I have the exact same problem on pretty much the exact same truck.

Were you able to fix this? If yes, what was the final solution?

Please help.