EGR valve replacement

[gathermewool]

Just pulled a CEL code: PO400 (low exhaust recirc flow, or something like that.) I'm still relatively new to cars, so how hard would it be to replace an EGR (Exhaust Gas Recirc) valve, and where might be the best place to find a good, cheap part? Thanks in advance! : )

[Livingtodie]

An EGR is a pretty quick and easy fix, looking at the motor from the front of the car its mounted on the back of your intake manifold on the right side. there are just two 12mm nuts holding it in, its even in a pretty easy spot to reach. so just the nuts and the vaccum hose and you may need a scraper or razorblade to get the old gasket off.

[jokermtb]

How timely! I just got the same code on my Legacy. I was wondering if the faulty EGR valve can be cleaned out/unclogged. Or should I just punt and throw a fresh one on. I found one online for about $135 [good price?].

[gathermewool]

I haven't updated this in a while. I received a lot of help on Nasioc, and kind of forgot about this post after a bit. As an update:

 

All of the components seem to work. At temperature, when I blip the throttle the EGR valve opens. When I manually open the EGR valve while the engine is at idle it bogs down. This proved to me that the solenoid and transducer worked (since the EGR valve opened when I blipped the throttle) and that the EGR valve was ok since the engine bogged down, indicating flow through it. CEL has been steady with the same code for months now, with out change.

 

I cleaned the valve, and it seems to have improved the flow, a lot! Before it bogged when I manually opened the valve. Now, it damn near stalls (which is what the Haynes manual says will happen when you test it.) The CEL actually went out for a full half day, but came back when I left work... Maybe I was kind of on the right track. The code is for "EGR malfunction" not "EGR low flow," however.

 

Oh, I also replaced the MAP sensor and the MAP sensor vacuum line filter, at the suggestion of another. This was a cheap fix (new filter and used sensor) No change at all.

 

I'm at a loss. Any help would be greatly appreciated. The car drives fine, and I've been keeping my eye on cheap part-out EGR parts since I don't want to spend much of anything on this at all! : D

 

I'm kind of at a loss here.

[Osei]

Give www.allforeignautoparts.com a try.

 

Their prices have been very good in the past.

 

O.

[jonklein611]

car-part.com is good for used parts

[gathermewool]

Thanks for not reading the entire thread, guys. haha!

[Osei]

what part did I miss?

 

You stated that the code is for an EGR malfunction.

 

So, it seems to follow that you are still looking for an inexpensive replacement.

 

O.

[jonklein611]

"I'm at a loss. Any help would be greatly appreciated. The car drives fine, and I've been keeping my eye on cheap part-out EGR parts since I don't want to spend much of anything on this at all! : D"

 

 

to me, that reads, help me find places to get an EGR cheap......

 

what part did we miss?

[jokermtb]

I've pretty much given up on my EGR code issue....the car seems to drive just fine, and I'm thinking that a piece of black tape over the check engine text, might be the best fix! Besides, my 1998 GT is gettin pretty raggy, the body is rusting out, etc....so I can't really justify putting any more cash into the car than I really really have to....it's halfway to the glue factory as is!

[gathermewool]

Sorry about that, guys. I guess it sounded different in my head while I was typing it. I meant to say that I've checked everything, and the system is operating properly. I replaced a few cheap parts (MAP sensor, MAP sensor filter, vacuum hoses) and cleaned the EGR valve and am at a loss. I'm keeping an eye on cheap part out parts so that when some one says, "hey, I did EXACTLY what you did, and even though the EGR valve seemed to work just fine, the transducer was just faulty enough to cause the code," or something like that. I think it would be bad practice (especially for a something that is NOT affecting my driveability) to just replace parts willy-nilly.

 

I've read tons and tons and tons of posts where-in the guy replaced EVERYTHING over the course of a year, only to have the code come in and out randomly. I'd rather not spend hundreds of dollars like that guy. : D Sorry for the confusion, guys!

[jonklein611]

It's cool, just trying to figure out what was going on, that's all.

 

 

:-D

[GreenGTWagon]

I went through and am still dealing with the same issue. My last option is to replace the catalytic converter as i feel it is the last possible thing. my headers are rusted pretty good so it's an excuse to get a whole new exhaust system.

[gathermewool]

It's always nice to have an excuse for something like that, but do you think the CAT could really affect this? I'd think you'd have a CAT low efficiency code or something else if the cat were plugged up or depleted. I'll shut up and let you replace the exhaust cuz you wanna and are gonna anyway! haha

[gathermewool]

As an update, and to answer sukaboy's pm:

 

Sukaboy,

 

Firstly, let me say NOT to start buying parts based on what you read on forums! If you notice, there are people who have spent hundreds of dollars only to have the problem come back days to months later. I've spent <$30 on simple things that did not work.

 

Unless you disconected the EGR line from the exhaust manifold to inspect it, the inlet to the EGR valve is in too precarious a position to tell whether it's clogged or not. There are two ways to tell whether your system is operating properly:

 

1. With the car FULLY warmed (the EGR system is not active while the car is cold), reached into the engine compartment and manually operate the throttle to rev the engine. You will NOT have to rev too high, but a a sudden rev and the EGR valve operating should be obvious. If it is, then everything that controls your EGR valve is operating.

 

2. With the car idling (cold or warm), place two fingers inside the operator of the EGR valve (just above the stem) and gently lift the valve open. If the EGR line is not clogged, the engine should bog down heavily, almost to the point of stalling. You need only do this for a second or two to verify. The reason I cleaned my EGR valve was because when I did this, the engine only bogged down slightly. After cleaning, the difference was like night and day. To clean, I poured a small amount of degreaser into the exhaust (inlet) side of the EGR valve so that the degreaser did not come into contact with the rubber diaphragm. I let it sit for ten or so minutes and then cleaned it thoroughly with brake clean (or any other non-residue forming parts cleaner) to remove the degreaser. Remember, the parts cleaner will spray coldly so don't be surprised or alarmed if the valve seems to stick a little when you go to operate it immediately afterward. It'll loosen up and operated tons better when it's hot.

 

If the engine does not bog down ever after the valve is cleaned, then I would check the EGR line. To do this, you can either pull off the EGR valve or remove the inlet fitting. Place a wet cloth (to catch soot, etc) over the opening and start the car. It'll probably be loud, depending on the size of the rag you use, but you should feel a good amount of flow through it, especially when you rev it up a bit. Opening it up and revving it up like this might help clean out any loose debris or soot built up as well.

 

If the flow is still insufficient, remove the EGR line and either replace it or clean it and reinstall.

 

For me, everything was perfect so I had not removed the EGR line until just yesterday. A significant leak that was barely noticeable before has become bad to the point that it can be heard while driving now. I tried to remove the line to replace it and noticed two things. First, the person who owned the car before me must have cleaned/replaced the line because the thread on the inlet to the EGR valve were MAULED and the fitting was not threaded in enough to fully seat the tubing. THIS is the source of my leak and most likely the cause for my check engine light (CEL) code P0400 (exhaust gas recirculation malfunction). Also, the EGR line fitting on the exhaust manifold was IMPOSSIBLE to get off. I ended up rounding the hex on the fitting and will probably have to cut the tubing and remove the fitting with a socket. I tried to fit a set of locking plyers in there, but did not have the room/leverage to get a good bite.

 

If I can't remove the EGR line, my next option, since the tube is not clogged and is leak-free on the exhaust manifold side, is to abrade and clean the upper EGR line fitting surface and JB Weld the hell out of it. I'm open to other suggestions, though. I'm back at it tonight if there's a bay open at the subbase!

[sukaboy]

Thanks Gathermewool, I haven't bought any parts yet. And want to do as much checking before having to replace any parts.

 

What are you referring to as the "operator on the EGR valve"? So I can perform the same check as you did.

 

Can you send me a photo or diagram?

[sukaboy]

Hey Gathermewool,

 

I followed your instructions on the EGR valve.

1) I unbolted it from the engine

2) cleaned it with some brake cleaner

3) checked that the valve was moving freely

4) bolted it back on

 

And when I started up the car and reved the engine I could see the EGR valve opening and closing. So that told me that the vacuum was good and there weren't any leaks in my hoses going to EGR valve. A mechanic friend said that it's unlikely the EGR valve could be a problem, but to check that there was sufficient vacuum going to the valve.

 

One step I forgot to do, was before I took the EGR valve off was to check if it in fact was operating properly when the engine was reved. It should go up and down with the engine revs.

 

But I had been monitoring my fuel consumption before I executed these steps. And I was getting really poor gas mileage.

 

on average about 17L / 100km or worse. (I have a Thule roof rack with a cargo carrier on my 98 Legacy GT which contributes to the increased fuel consumption, but I do know that it should be down to 11L/100km with the roof rack and 9L/100km without it mounted)

 

After I did this I was back down to 11L/100km. This is a mix of highway and city. Just day to day driving.

 

One other thing I did was tire pressure. I think I have been driving with it too low. Although my car recommended pressure (according to the sticker on the door) is 30 & 32 psi (F & R). I put it a little higher. My winter tires have a max 36psi and my summer tires have a max 44psi.

 

So I'm running the winters at about 34psi and the summers at 39.5psi. And my fuel consumption has greatly improved. I just did a 600km roadtrip and my mileage was 10.48L/100km.

 

Didn't change any parts. Just did some cleaning and checking.

 

Thanks Gathermewool for those instructions. Saved me a few hundred bucks in taking it to the garage for servicing.

 

One last thing I need to do is to clear the check engine light. Hopefully I won't get the error code again.

[streetlethal1000]

Oh, I also replaced the MAP sensor and the MAP sensor vacuum line filter, at the suggestion of another. This was a cheap fix (new filter and used sensor) No change at all..

 

Is the vacuum line filter the little white round looking thing in line with the vacuum lines? There is like one or two fo them around the engine compartment right? I was curious if I should replace those little things too.

[gathermewool]

If you look at your passenger-side strut tower you'll see the map sensor and a solenoid valve. The filter is disc-shaped with black foam surrounding it circumferentially. It filters the vacuum to the map sensor. The map sensor, from what I understand, will read the change in vacuum when the EGR opens to send info to the ECU.

 

This didn't turn out to be my cause for the CEL, but the filter was <$10, and I got a used MAP sensor from a buddy for cheap.

 

I think the white, round filters are associated with another portion of the emissions control system. I believe the filter I'm referring to is the only of it's type in the engine compartment.

[sukaboy]

I forgot to post this a while back. What the culprit was on my EGR P0400 problem was a bad solenoid. After I replaced that my CEL never came back. It was causing the EGR valve to remain open.

[gathermewool]

So, that's two solenoids. For any one searching for this, it seems to be a good first check before replacing everything else.

[grokit]

If you look at your passenger-side strut tower you'll see the map sensor and a solenoid valve. The filter is disc-shaped with black foam surrounding it circumferentially. It filters the vacuum to the map sensor. The map sensor, from what I understand, will read the change in vacuum when the EGR opens to send info to the ECU.

 

This didn't turn out to be my cause for the CEL, but the filter was <$10, and I got a used MAP sensor from a buddy for cheap.

 

I think the white, round filters are associated with another portion of the emissions control system. I believe the filter I'm referring to is the only of it's type in the engine compartment.

 

So you still have a check engine light due to a faulty EGR Valve, which you cleaned but did not replace... You have tried a bunch of other fixes as well, but still have the CEL... Did you ever try replacing the EGR valve?

 

I'm just asking because I am having the same issue in my 1997 GT, where I reset the code and it still pops back up. I hit a moose on the highway recently, he landed on the hood and scampered away but broke the "EGR Modulator Switch", which I replaced (I think that it's located above the valve in mine) but the damn light still comes on.

 

I am gathering that I either need a new valve or have a leak elsewhere in the system from reading this thread, as it seems that plugging leaks and cleaning out the valve did not fix the CEL issue?

 

I know that this is an older thread, but I am having this problem currently so any help is welcome!