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Discussion Starter · #1 ·
I finally have fixed my EGR problem. I figured that an EGR problem meant that the EGR valve needed to be replaced or cleaned, so i took it off last week and tried cleaning it. There was some carbon buildup in there but nothing too excessive. Last night while driving home the CEL came on again...so it was back to the drawing board. After some research i found out where the EGR ports were in the throttle body, and attempted to clean those.
this is what i found...

i could not even fit a small hex key into the port opening. The left port was completely blocked off, and the right one wasn't too much better. After cleaning and taking the carbon out of the ports, it looked alot better.

so if you get a code for the egr valve flow and cleaning your EGR valve itself doesnt do the trick...try this.
 

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What was the code you got that signalled the problem. I got a 1195 dode after checking the check engine light and getting codes read. AutoZone said the code meant that the SCP HVCC failed to initiate whatever that means. When I called Mazda the stated it was a problem with the exhaust recirclating but they would have to search the whole system to find out what it actually was. Where exactly is the EGR valve anyway in plave I need to clean it? Any help is appreciated.

M
 

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Can you take a pic of that area zoomed out a little? I'm having trouble referencing that area on the engine bay.
 

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Discussion Starter · #4 ·
i got a P0400 code...and here are some more pics.

this is where the EGR valve is...


and this is where the EGR ports are...



and yes i know my engine is dirty...and will be getting a full cleaning within the week.
 

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I had the same problem, I took the egr valve off, took the throttle body off, made a tool out of a small flat blade screwdriver and cleaned it right on the car. This was about six months ago and no more problem. I can't remember the code number, but it was EGR flow malfunction when autozone scanned it for me. Cost abou $2.50 for a can of fuel injector throttle body spray cleaner.
 

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Thanks for the new pics. That helped a lot. I have to do the same sometime tomorrow.
 

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No inspection sticker? That's a $43 ticket here... Anyways, I've heard AutoZone reads codes for free. Is this true? because I think I need to get it done. my CEL has been on for like 3 days solid. not flashing tho.
 

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Originally posted by SpecialKnetix@May 29 2005, 05:49 AM
No inspection sticker?  That's a $43 ticket here... Anyways, I've heard AutoZone reads codes for free.  Is this true?  because I think I need to get it done.  my CEL has been on for like 3 days solid. not flashing tho.
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Yeat autozone reads them for free, but so does Cottman Transmission and if you go there you can get a expert opinion on how to fix it also.
 

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This info is great! I have a 97 with about 70K, and the CEL has been on for about 3 months. AutoZone reported P0400 also (ERG Flow Malfunction), finally broke down and took to local Ford dealer, (Mazda dealer too far away) and had them put in new EGR valve. (part $352, test $139, labor $150) $641 total, that was this last Saturday the 4th of June. This morning I get the CEL light again. ($#@*&(&^'s). I plan on looking into the throttle body ports to clean but I don't seem to be able to get to the pics you posted of where they are located. Would it be possible to send them to me @ [email protected]. I would be most greatful.
Thanks,
Jon
 

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Great job by 9milly7 in posting how to clean the EGR ports. My 1995 Millenia 2.5L engine with 140K miles had the same problem. The right port was totally closed with carbon deposit. The left port just has a small <1/8" hole remaining. I took both the input throttle and EGR valve as described and clean them with a scapper and carburator cleaner. I'm pretty sure the blocked EGR ports were the main cause of the followings:
1. OBD code P0400 (EGR system flow)
2. OBD code P1195 (Baro/EGR boost sensor)
3. High Nitrous oxide emission, almost failing California smog inspection

I have all three of these problems. I would have saved $500 in replacing the EGR/Barometric sensor if I had known about cleaning the EGR ports. Replacing the old EGR/Barometric sensor with a newer, more sensitive sensor did remove the P0400 and P1195 codes and did make the check-engine light dissappear. However it did not help in reducing the nitrous oxide emission.

I want to add the following notes to help others to clean the EGR ports and the EGR valve more easily:

I) To remove the input throttle easily, do:
1. Remove the battery.
2. Remove the air cleaner top assembly and the fitting/hose/pipe from the air cleaner assembly to the input throttle.
3. Remove the electrical connectors and gas pedal cable around the input throttle to get access.
4. The hose connected to the bottom rear of the input throttle does not need to be removed before removing the throttle. This hose is hard to remove. Just pull the input throttle out to the front with enough force to take the throttle out of the top two mounting screws.

The EGR valve does not need to be cleaned. My 140K miles EGR valve looks reasonably dry and clean. However, you can remove the EGR valve to check that the air can flow from the EGR ports to the EGR valve easily. You can use compressed air blower to check air passage by blowing into the EGR port. The air will be blown back to the opened mounting holding the EGR valve.

II) To remove the EGR valve easily, do:
1. Remove the electrical wire and mounting bracket on top of the EGR valve to get access.
2. Remove the vacuum hose on top of the EGR valve.
3. Remove the EGR valve mounting bolts.
4. Remove the EGR hose feeding into the EGR valve. This hose is dotted red.
5. Remove the water hose feeding into the EGR valve. This hose is not dotted red.

Now I'm very confident that my car will have low emissions :D . I had replaced the 2 pre-catalytic O2 sensors at 122K miles and noticed a significant reduction in carbon monoxide (CO) and hydrocarbon emissions (HC) (also noticed better fuel efficiency). I think a fully functioning EGR system will definitely reduces the nitrous oxide significantly.
 

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I'm having trouble getting the Throttle body to open i can get it open for about 3 inches but it will not pull further. i've took out the four screws and the screw pointing down into the trottle body but it still seems like something else is holding it for the trottle to fully open... am i missing a screw or something??
 

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I'm having trouble getting the Throttle body to open i can get it open for about 3 inches but it will not pull further. i've took out the four screws and the screw pointing down into the trottle body but it still seems like something else is holding it for the trottle to fully open... am i missing a screw or something??[/b]
Is that an 2.5?
 

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Question...is there a gasket between the air intake and the throttle body (the parts you opened up to get to the egr ports), or are the surfaces just metal and bolted together? I'd like to know prior to opening this thing up. I've got a 2002 w/65k miles, 2.5L with the CEL giving me a PO400 as well as failure readings on both o2 sensors. I'm hoping the fix is as easy as this.
 
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