P0401 Defeated - with pics (3 Viewers)

[kayaked56]

call me dumb but can some one who has done this post pictures and step by step? or email?

thanks mat

Give me a call I can walk you thru it. Greg 602-478-8810

 

[Flank]

Its tough to break the camera out every 15 seconds when your hands are full of grease and dirt, bro. The step by step with pics is the factory service manual, or FSM for short. You do not want to attempt this unless you have one. Sorry to be so blunt.

 

[FloridaFJ80]

Flank, I used your instructions and I was able to do this without an FSM.

Thanks for the writeup, been 6 months and no P0401 codes

 

[LCHardriver_02]

Started working on this this weekend, along with replacing my valve cover. I had not read through this thread until tonight. I guess I will go pick up a fuel filter, since "I am already in there"...LOL! Looking forward to completing this little task.

 

[LCHardriver_02]

OK, so I just want to confirm that you do indeed have to remove the EGR valve to remove the top air manifold, correct? I see no way around this.

 

[LCHardriver_02]

Can someone confirm whether I have to remove the EGR to remove the upper air manifold, or am I missing something? I will need to purchase a new wrench to do this as I do not have anything that big in my combos and want to pick it up on my way home from work.
Thanks!

 

[Flank]

Can someone confirm whether I have to remove the EGR to remove the upper air manifold, or am I missing something? I will need to purchase a new wrench to do this as I do not have anything that big in my combos and want to pick it up on my way home from work.
Thanks!

The EGR valve is attached to the upper intake plenum. I did not use any special tools in the process. Ratcheting box ends, standard socket ratchets, screwdrivers, etc. Make sure you have roughly three 12" socket extensions to get to the plenum bolts from underneath.

 

[LCHardriver_02]

I have all of the bolts and nuts loose, but it seems trapped by the two studs for the EGR valve and the two studs below. I have not loosened up the EGR (32mm open end wrench) to allow movement on the EGR because i dont have that size wrench. I was hoping that I did not have to go out and buy that wrench just for this job, but if I have to then so be it. Can the air manifold be removed without loosening up that 32mm connection?
Thanks.

 

[Kevin Rutherford]

Thanks Flank

Great write-up.
Now I'm going to do it also...

 

[Splangy]

I have all of the bolts and nuts loose, but it seems trapped by the two studs for the EGR valve and the two studs below. I have not loosened up the EGR (32mm open end wrench) to allow movement on the EGR because i dont have that size wrench. I was hoping that I did not have to go out and buy that wrench just for this job, but if I have to then so be it. Can the air manifold be removed without loosening up that 32mm connection?
Thanks.

You can loosen the 32mm nut with an adjustable wrench and pull out the two studs with a small socket (I forget the size) and 1/4" ratchet.

 

[LCHardriver_02]

Thanks for the reply. I had to order a 32mm because all of my adjustables were too small and no one in town had either the 32mm or the 1.25" in a combo wrench. Will be here on Christmas Eve, so I am planning on removing the air manifold that evening! Hope the wife doesn't get too upset. LOL!

 

[dontblink]

I've been trying to defeat this code for a while now.

Screw it, I'm removing the whole damn EGR system this weekend.

Stick that in your pipe and smoke it, Mr. Emissions Testing Man.

 

[raynyc]

http://www.jcwhitney.com/weiand-universal-egr-valve-plate/p3073906.jcwx?filterid=c23785d1389u0j1

will that work?>

 

[dontblink]

http://www.jcwhitney.com/weiand-universal-egr-valve-plate/p3073906.jcwx?filterid=c23785d1389u0j1

will that work?>

If that'll work, I'm buying one today.

 

[Biaggi]

...just run a new piece of hose from the EGR straight to the EGR VSV and bypass the passage hole through the upper manifold at least until you have figured out how to unclog the passage. I just did this and will probably never bother to unclog the passage hole. I used constant tension clamps on both ends of the new hose as well.

Do you have a pic of this? I'm tired of the cel and need to pass emissions before I spend more $$ on parts....

 

[UZJ40]

Do you have a pic of this? I'm tired of the cel and need to pass emissions before I spend more $$ on parts....

It would be very difficult to take a picture of this routing because the hose snakes in and out of the manifold. Really, it is quite simple if you pull off the top of the manifold and look. All you are doing is bypassing little metal pipes.

 

[SierraMtns]

Great write up. I sent you a PM with a couple questions.

 

[jdeitch]

Great write up! Thanks for sharing. I NEED to do this repair myself. I have been ignoring this same fault in my cruiser for too long.

 

[medicbob]

I just bought a 94 with the EGR Valve and modulator missing. Has the block off plate installed. The P.O. left the pipe open in the engine compartment that connects to the EGR. Obviously this is just blowing exhaust into my engine compartment. Until I decide whether to replace the egr and modulater or desmog is there or has anybody plugged this pipe without block off plates at the exhaust manifold? Thread size?

 

[450LXMark]

I started to throw a dreaded P0401 code that was constant, and recurring immediately after clearing.

I have the FSM, and read God knows how many EGR and P0401 threads - More than enough burn my eyeballs and confuse the hell out of me, so I decided to dive in.

Preparation -
I had decided to take the upper intake off - the better to see what I was doing and learn what is under there - as well as replace the vacuum hoses under there. I also decided to pre-order the apparently most common failure parts - The VSV for EGR and the Vacuum Modulator (right off of the EGR valve, had previously tried to clean - it looked rough).

First: I will list the parts I ordered and or used:
-Throttle Body Gasket 22271-66010
-Upper to lower intake gaskets (2) 17179-66010, 17171-66010
-VSV for EGR - 90910-12079
-VacuumModulator for EGR - 25870-66011
-EGR Valve Gasket - 25627-66010
-Water Hose Clips for hoses into TB - 96135-51300
-5/32 ID Vacuum hose - 'bout 9 feet total
-1/4" ID Gas line hose (for gas and water lines replacing)
-5/16 ID vacuum hose - Bout 2 feet-ish
-Fuel Filter - 23300-69045 - It was right there - might as well...
(edit to Add cleaners)
-new bottle of Simple Green for general cleaning and de-greasing without harshness
-two cans of Throttle body cleaner
-Spray bottle of water to wash Simple Green off of engine
-Cleaning brushes - Tooth brush, nylon brushes, etc for cleaning
-Lots of the Blue paper shop towels.
(I was doing this in my garage, did not want too harsh of chemicals hitting the floor)
-I cleaned parts requiring Throttle Body Cleaner on an oil drain pan - the kind that has a hole in the top keep the oil until you can dump it - so solvents drained into it and did not have risk of spilling in garage.

I had a very dirty engine to start with, thanks to recent rain and big Vegas desert mud puddles. I took pictures of all assemblies prior to removal, in case i had trouble remembering how it went together again.

-I removed the Air cleaner and MAF sensor, intake hose, and per the FSM, removed the throttle body. It was very dirty, doubt it has been cleaned in the engine's 15 years.

-Removed the EGR Valve.

Here is what the intake and throttle body looked like:

Quick question did you get all ur hoses at your local auto store? Or do i have to get it as oem part? Thanks