IAC, TPS, Vacuum Leak?

[gavin]

:bsnicker:

I was gonna wait 'til I got home to take post 100.

no CEL yet after trip to/from home and work for lunch.
Idle is good. Probably right around 750 in N and P, just a touch higher when stopped in D.

 

[SkyJumper]

 

[gavin]

P0401 is back.
So, I disconnected the small hose to the top of the EGR valve, found another small hose and hooked it up.
I "plugged" the small hose with my finger, and applied vacuum to the hose hooked up to the EGR valve... no change. Although the hose probably wasn't small enough to get a good seal.

Also, I believe I may be hearing a slight hiss from behind the manifold. Will need to see if I popped one of the hoses to the DPFE loose when I was moving 'em around yesterday.

 

[SkyJumper]

Gavin, look at this diagram, it points out all the reference points that have to deal with P0401

 

[gavin]

I need to let the fan sit on the engine a bit longer, still too warm to do much with.

So for testing the EGR valve; disconnect the vacuum line, plug it, connect another line to the EGR valve and apply vacuum. If the vehicle struggles to run when vacuum is applied, the EGR valve should be good.
Correct?

I got a small hose clamp and clamped the hose onto the EGR valve. Applied vacuum and it tried to stall.
This means the EGR valve is good, correct?

edit: check the green hose from the EGR valve to the EGR vacuum regulator; connected good. From the vacuum regulator there's a white line that goes to a hard line underneath the dri side intake manifold? Then there's a red line that goes to.. dunno? shaped kinda similar to the EGR valve with a nipple on top. This red line also goes to the same spot as the white line. They're connected good.
Although, the red line wasn't pressed all the way onto the valve or whatever that is.

hoses to the DPFE are still connected good.

 

[SkyJumper]

Gavin any updates?

 

[gavin]

nope... haven't had time attempt to test the DPFE.
and if I have to end up ordering one it'll take it almost a week to get here, anyway.

 

[gavin]

so I've (obviously) just been dealing with the CEL for the past couple weeks.
got a scan tool from scantool.net

it doesn't appear the DPFE voltage can be read from the ECM, at least without the enhanced codes (although it shows it as being a supported sensor)

which wires do I need to probe?

 

[gavin]

ok, so I'm a bit confused.
got an OBD2 app with enhanced codes so I can read the DPFE voltage from the ECM.
At KOEO it's at 0.884v

reading the EGR System O&T thread by 2000StreetRod, he mentions a reading of 4.0v to 6.0v at the electrical connector, with KOEO.

I take it these are, essentially, different readings, no?

So I'm confused.. the thread says to test DPFE sensor, to disconnect the electrical connection and probe 2 wires/pins. But this would be probing the wiring not the DPFE, no?

 

[BIGTREAD]

Please tell me there is an ending to this story! I can not believe all the hard work that goes into solving these issues where the finale is missing.

Did Gavin ever get his truck running right?

Did the sannner ever reveal the secrets to the mysterious 401 code?

Did Skyjumper ever go to Alaska and black two eyeballs?

There needs to be a 1$ deposit on starting a thread. Finish the thread you start and get your deposit back!

Awesome finish!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[gavin]

lol, I thought I posted my findings and fix, but apparently I didn't.

turns out the small hose that goes between the EVR and EGR, to supply vacuum to the EGR, wasn't connected to the EVR.

I could not, for the life of me, see that until I removed the bracket the EVR is mounted on to, which was a PITA in and of itself.

After seeing that hose disconnected, I reconnected and put it back together.
No CEL's since.

 

[SkyJumper]

No CEL's since.

OMG, this thread still lives. It is about damn time Gavin, 3 months and 111 replies later. AMEN to the CEL GODS.

:mattmoon:

 

[gavin]

OMG, this thread still lives. It is about damn time Gavin, 3 months and 111 replies later. AMEN to the CEL GODS.

:mattmoon:

what can I say, I'm not much of an engine guy.
in my defense, it's been fixed since probably Sept 23rd or so.

now I get to spend time chasing down a wiring gremlin in my Bronco2 since I finally got the junk here