PO401 and EGR/air intake manifold with pictures

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This is an awesome thread! Thanks Cahill!

I just took out my EGR valve and TB. EGR to upper intake was all plugged. I tried to clear it with some carb cleaner. Is it okay that I don't take off my Upper Manifold?

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Anyone ever repaint the intake? I am going to do this removal and cleaning when it warms up and want to paint the intake. What paint you use with success.
 
P0401 Cleared

Fantastic thread - helped me a bunch! Cleared my P0401, (finally) changed my fuel filter for the first time at 220,000 miles, installed the Kobalt catch can, and pulled the fuel injectors and had them serviced.

BTW, part #5 in post #1 is a "gas filter", p/n 90917-11022. You might think I know this because I snapped the plastic nipple off of mine and had to figure out what the heck it was so I could replace it. But really, I just happen to know the part number off the top of my head, like Dan, or Beno...
 
cahill said:
At this point you can then take off the upper air intake manifold. There are 6 bolts and 2 nuts holding it to the lower intake. Some can be taken off from above in the engine compartment and some you have to crawl under the vehicle to access via long extensions on your wrench. I didn't get too many pictures of this phase. Using different combinations of extensions and different wrench handles you can get it done.

The location of the bolts is pretty predictable. In the first picture the circles are where the bolts are and the squares are wher the nuts are - all of which are under the lower air intake manifold.

I found having the intake manifold stay loosened as well as the oil and tranmision dipsticks and power steering resivour tank unbolted helps free up some room.

Once the bolts are taken off the upper manifold can be taken off. There are 2 gaskets here as well that need to be replaced.
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cahill said:
At this point you can then take off the upper air intake manifold. There are 6 bolts and 2 nuts holding it to the lower intake. Some can be taken off from above in the engine compartment and some you have to crawl under the vehicle to access via long extensions on your wrench. I didn't get too many pictures of this phase. Using different combinations of extensions and different wrench handles you can get it done.

The location of the bolts is pretty predictable. In the first picture the circles are where the bolts are and the squares are wher the nuts are - all of which are under the lower air intake manifold.

I found having the intake manifold stay loosened as well as the oil and tranmision dipsticks and power steering resivour tank unbolted helps free up some room.

Once the bolts are taken off the upper manifold can be taken off. There are 2 gaskets here as well that need to be replaced.
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THANK YOU SO MUCH.

Your article encouraged me to do the job. I found a broken VCV - and after I started the engine the P0401 was gone immediately, YES!

One tip: In order to save time for the adjustment of the actuator cables, I put some nail polish on the thread and nut on the side where the nut should stay put. So I had no adjustments to do later.
 
Harald said:
put some nail polish on the thread and nut on the side where the nut should stay put. So I had no adjustments to do later.
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Come on, you can tell us...what color nail polish do you like to use on your toes?...........
 
alia176 said:
Come on, you can tell us...what color nail polish do you like to use on your toes?...........
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Funny, I didn't expect any reply to this. I used the nail polish method 40 years ago when I repaired reel to reel tape machines to lock the screws for the recording and playback heads.
 
Harald said:
Funny, I didn't expect any reply to this. I used the nail polish method 40 years ago when I repaired reel to reel tape machines to lock the screws for the recording and playback heads.
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Good advice one the nail polish. I tried marking them with a sharpie and it didn't work so well. Re-adjusting after the fact can be a pain.
 
Just started this yesterday. Great thread.

One piece of advice: Put something soft under the vehicle when you're putting in the injectors. I had one fall out and land on the tip on the concrete floor. It looks fine, but I'm sending it back for flow testing just to make sure. I don't want to take the risk of immediately doing this again.

Also, one of the bolts on the underside of the intake manifold is easily accessed from the wheel well. So when you're tearing your hair out with trying to get to one of them, remember that.
 
cahill said:
While I had things this far apart, I decided to pulle the fuel injectors as well and have them cleaned by RC engineering. I was able to drive them down to them and pick them up the same day. They did a great job.

To get the fuel rail off, it isn't much more work at all.

1. Simply unbolt the banjo bolt/union bolt holding the fuel inlet pipe to the fuel rail (the bolt is seen in picture 2 and circled/labled #1 in picture 1). There are 2 gaskets here that aren't re:usable. They look like aluminum washers.

2. Disconnect the electrical connections from the fuel injetors being careful not to damage the wiring or connectors. Some of them are highlighted with red squares in picture 1.

3. Unbolt the 3 bolts that hold the fuel rail to the injectors and lower air intake manifold. They pass through 3 plastic spacers that can fall out if you don't realized they are removable. They are seen in the last picture. The little black gaskets are the old lower insulators for the fuel injector that sit in the lower intake manifold. The other 2 grommets/insulators are on the injector/fuel rail.
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Any idea part number for those 2 aluminum non reusable washers!!?
 
No, I don't know the part numbers off the top of my head. Beno or Cdan would likely know. I realize Cdan is out of the business but I bet he still has those numbers in his head :)
 
cahill said:
For dissassembly of the EGR vacuum modulator and EGR valve.

The EGR vaccuum modulator is held in by the vacuum hoses and a metal clip. Disconnect and lable the vaccum hoses and remove the modulator from the clip.

Next unscrew the the 2 nuts holding the EGR valve to the upper air intake manifold.

Loosen the EGR Pipe nut being careful not to damage the wire harness with the handle of the wrench as you unscrew the nut.

In order to remove the EGR valve, the 2 EGR bolts need to be unscrewed from the air intake manifold. I tried the "2 nut technique" but messed up the bolts and nuts. I recommend just getting a star shaped socket to unscrew the bolts. I found a set at Harbor Freight for 9 bucks. A 5mm socket also sort of works.

There is a gasket between the EGR valve and intake manifold that is supposedly not re-usable. It has a tendancy to want to fall into the engine bay (especially when putting things back together).
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What direction do you turn to loosen the nut on the egr pipe?
 
NJD96LC said:
What direction do you turn to loosen the nut on the egr pipe?
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Lefty loosey, righty tighty. It's normal, right-hand threads. The nut stays with the pipe, so you are needing to remove it from the valve itself.
 
cahill said:
So a few months ago I got a P0401 and did a lot of reading on mud and the FSM in an attempt to get things lined up for taking care of the problem. I am a poor mechanic but want to learn so figured I'd give tackling this problem a try.
I had a week to get it done (it shouldn't take that long) and didn't have time to do as much diagnosis/trouble shooting as I would have liked but was pretty certain my EGR regulator and valve were ok. I wasn't sure about the VSV and decided to replace it as well as the other components as they weren't looking great. I just didn't want to have to come back and do things over.
I'm posting this thread, not as a way to diagnose what is wrong, but more as a thread to show what I did with lots of pictures in the attempt that anyone else running into this problem will have some pictures as references. If I describe anything wrong or lable anything wrong please PM me so that I can fix it for other people's sake. I am just hoping to contribute back a little for all that you guys have done for me. So here goes....

Heres a list of links I found helpful in doing this project.

Throttle Body Baseline
Code: P0401
P0401 Defeated - with pics
Replacement of the VSV (in Spanish)
9 times out of 10 a PO401 Code is fixed by . . . . .

Here is a link that seems like an easy way to test the VSV for EGR and moving it from under the manifold. I hadn't seen this post when I had started working on mine. I may move it later if I ever have to go back in there.

Checking VSV for EGR easy way P0401

Here's a list of the parts I ordered from Cdan (I did the PHH and a coolant flush per e9999 thread as well during this project):

EGR system:
EGR Vacuum Modulator (Blue top)
VSV for EGR
EGR valve
EGR valve stud bolts and nuts that go into the air intake chamber x2 (mine were slightly stripped from a previous dissasembly with the wrong tools)
Vacuum hose
EGR gasket
Air intake gasket x2

PHH:
Gates greenstripe

Fuel injector cleaning:
Upper O ring and rubber grommet x6 (comes with cleaning service)
Lower seal on intake manifold side (fuel injector insulator) x6 (came with cleaning service from RC engineering but not others that I spoke with).
Gaskets for banjo bolt (union bolt) on Fuel Rail x2

Other maintnence:
Gas Cap
Air filter
Gas filter with 4 gaskets for the union bolts (came with filter)
PCV valve and grommet and hoses

First a little overview of car anatomy. In the first picture.

1. EGR Vacuum modulator
2. EGR valve
3. EGR gas temperature sensor
4. Brake booster vacuum hose
5. ?
6. Throttle body position sensor
7. Fuel pressure regulator
8. PCV valve and PCV hose #1
9. PCV hose #2


In picture #2.

1. Throttle body
2. Upper air intake manifold.
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Did you ever figure out what #5 is? I can't seem to find this part anywhere in the FSM... Mine broke while doing all of this work. Long story. I know it sucks in air as part of the Emissions system but don't know what it is. Any leads?
 
BrooklynFJ80 said:
Did you ever figure out what #5 is? I can't seem to find this part anywhere in the FSM... Mine broke while doing all of this work. Long story. I know it sucks in air as part of the Emissions system but don't know what it is. Any leads?
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It's up in the thread a little bit... 90917-11022 Gas Filter... I also may or may not have snapped the plastic nipple off...
 
I want to personally thank you cahill for this thread. Especially the vacuum hose pictures that helped me alot since the previous owner made a mess with mine. On a seperate note my p0401 code is gone but now I have a P0330 coming on, any ideas? Engine runs great so im not sure why its on but any help would be appreciated, thanks again!
 
ZRTALPHA1 said:
I want to personally thank you cahill for this thread. Especially the vacuum hose pictures that helped me alot since the previous owner made a mess with mine. On a seperate note my p0401 code is gone but now I have a P0330 coming on, any ideas? Engine runs great so im not sure why its on but any help would be appreciated, thanks again!
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I'd suggest either starting a new thread on P0330 or piggy back on existing threads on this particular CEL code. This way, the current EGR thread doesn't get too diluted with other codes/diagnostic steps!
 
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