2.3L ('83-'97) 2.3 EGR insufficient flow

[Dioderon]

Hi all!
Like most I’m banging my head over this issue. Have replaced egr valve, DPFE, EGR tube and the dpfe hoses with all motocraft parts, as well as the EVR (vac solenoid) on my 97 ranger.

p1401 insufficient egr flow still pops up! I run forscan and the dpfe voltage hovers at .98 or .99 volts at idle. I cycle the egr to 100% and I get vacuum on the line going to egr valve, when plugged into the egr valve and when activated, idle gets noticably rougher but not to the point where the engine feels like its going to stall. When running and driving normally dpfe voltage goes between 1.26 and 1.5 volts.

the ONLY thing I havent thoroughly checked out is the egr port on the engine for carbon. The old egr valve was not totally clogged up and the tube seemed clear so I dodnt give much thought to it.

Does anyone have any suggestions on what else to check to make this CEL go away permanently. Its driving me bonkers!

thanks,

Ron

 

[RonD]

Welcome to TRS

Actually the code is P1401 Diff Pressure Feedback EGR Circuit High Input

Computer could have used these and didn't
P0400 Exhaust Gas Recirculation Flow Malfunction
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
P0402 Exhaust Gas Recirculation Flow Excessive Detected
P0403 Exhaust Gas Recirculation Circuit Malfunction
P0404 Exhaust Gas Recirculation Circuit Range/Performance

P1400 Diff Pressure Feedback EGR Circuit Low Input
P1402 Exhaust Gas Recirculation Metering Orifice Restricted

If possible you should always look up codes on a full list because the codes the computer did NOT use are as important as the one it did use, computer doesn't "think" it just reacts to the "1's" and "0's", lol

It ultimately could be a Computer issue, bad circuit internally
Its interpreting the voltage incorrectly

Good article to read here on Feedback voltages(DPFE sensor) which is what the code references: http://www.tomco-inc.com/Tech_Tips/ttt36.pdf
1997 should use the 1volt type sensor

It could be your EGR Valve intake passage is partially clogged up
P1401 Diff Pressure Feedback EGR Circuit High Input
With key on engine off your .98v would be correct, same for at idle, equal pressure at both ports of DPFE

EGR system is not used when engine is cold, its only used once engine temp is above 140degF, closed loop and O2 sensors are on line
And EGR is then only used when accelerating or cruising above say 40mph, when there is a load on the engine, adding exhaust gases lowers the temp in the cylinders by slowing the burn rate, and this reduces NOx production, a toxic gas

If you see above 1volt when EGR is not in use then that would trigger P1401 code
3rd party DPFE sensors are NOT tested, you are the tester so just because "its new" doesn't mean "its good"

 

[RobbieD]

computer doesn't "think" it just reacts to the "1's" and "0's", lol

That's a mean thing to say. Computers have feelings, too.

 

[Curious Hound]

Thanks Ron. His complaint sounds identical to what I’ve been fighting on my 97 F150 4.6l. (I mentioned it yesterday in that O2 sensor thread)

 

[RonD]

That's a mean thing to say. Computers have feelings, too.

Yes, I am mean, as an adjective not a verb, but I am also mean as a noun, average person

Computers can't have feelings, listen to Spock, feelings are human emotions and can be mimicked by computers but that is also just the "1's" and "0's", a reaction programmed into it, not actual feelings

The AI overlords are a fiction that is very cool, or frightening, to contemplate, but it just couldn't happen
A computer doesn't "die" when you turn it off, no time passes at all as far as computer is concerned, and when its turned on again its just on, not "alive"
AI overlords would "feel" the same way, on or off is the same for a computer, doesn't "care"