Fixing a Code 51

[flashlight]

Recently my check engine light has come on quite a bit.It comes on as a code 51. Wich is the EGR Circuit. How do I go about fixing this problem? Is there something that I can clean or replace so that the check engine light will stop coming on? Also could you supply pictures if it is something that requires cleaning? Thank you.

[Johnny Mullet]

One trick I use to see if the EGR port through the head is plugged is to remove the EGR valve and start the engine up! This will make you hear an exhaust leak which is the flow from the exhaust manifold to the valve. No noise = clogged!

This info may help.................. http://geometroforum.com/topic/678529/

Ok, so this is the EGR system of a Geo Metro. This example comes to us from a Gen 2 with a 1.0L engine and a 5-speed transmission.




**Make sure you have the data plate under your hood with the hose routing. That way you do not have to remember or mark hoses.**

Part A: EGR valve This is held to the engine with two 10mm long bolts. There is also a gasket. This is the last part of the system you will remove.

Part B: EGR Pressure Transducer (say that 5 times fast). This part contains a pad that looks like a filter. It may need cleaned. It is also easily replaced. It is the first part, along with it's bracket that you will take off.

Parts C and D: EGR Solenoid Vacuum Valves There are two of these. One is red and one is blue. You can tell the difference on your data plate mentioned above because the red one has and extra piece on it. The wires for these come from your main wire bundle that runs through your engine. My wires are red from where I re-taped them during the rebuild. Yours will be black. You will have to remove these to get to the EGR Valve.


Here is my data plate. Yous should most likely be the same if you have the same powertrain as mentioned above.



This plate will give you where your vacuum lines go. Take it slow when pulling these apart as most of the nipples they go on are plastic.

Here is the removed EGR



The two larger holes on the left go in and out of the engine. This is where your clogging problem is. This carbon also works it's way into the diaphragm on top All of this carbon must be removed. I used carb and choke cleaner from the auto parts store. When you are spraying it give it hell and don't let up until everything comes out clear.

Next make sure by pushing on the inside that the diaphragm moves smooth and there is no binds at all. After doing this spray it out with cleaner even more. Do this to all the pieces of the system.

Next, put it all back together. Take it slow and use the data plate when putting it back together, afterall they could have been hooked up wrong to begin with.

The last step is to test the system. First start the car and let it warm up until the cooling fan comes on (try not to think about waisted gas).

There is a metal ring around the inside of the diaphragm. Place your finger on this ring and race the engine. You should feel the diaphragm moving slightly when you do so.

[Woodie83]

When you get all those parts off, you can start in on where the problem usually is: The passages leading to and from the EGR valve are usually clogged up solid with soot. To get them truly clean you need to remove the intake and exhaust manifolds.

[flashlight]

Thanks for the quick replies. I'll try and get this cleaned and done before I head out to work later.

[flashlight]

If I'm unable to get everything completely cleaned will it cause problems for me? I mean does it hurt the engine to be plugged up like it is? I'm only asking because at the moment it less than nice outside to be out working on the car.

[flashlight]

Does anyone know of any tool that will make cleaning the passages of the intake and exhaust easier to get the carbon and soot build up out? I tried blasting the passages with carb and choke cleaner and that worked a little but the check engine light is still on. Also where does all that crap go when it's getting blasted? And when yoou try and start the car up after blasting those areas it doesn't like it very much. I mean it has an extremely difficult time even turning over. And when it does get going it runs pretty rough until all the cleaner has been burned off.

[RossT]

Read this thread

http://www.automotiveforums.com/vbul...ight=RossT+egr

[DOCTORBILL]

I ran into this problem two years ago when I rebuilt The Phoenix.

http://www.automotiveforums.com/vbul...d.php?t=619189

http://www.automotiveforums.com/vbulletin/t622536.html

Came up with a tool I used to clean those passageways out.

As always - took some pictures.

DoctorBill

Does anyone use the SEARCH function on this forum anymore ?

Do we have to reinvent the wheel every single time ?

[Woodie83]

Originally Posted by flashlight

Does anyone know of any tool that will make cleaning the passages of the intake and exhaust easier to get the carbon and soot build up out? I tried blasting the passages with carb and choke cleaner and that worked a little but the check engine light is still on. Also where does all that crap go when it's getting blasted? And when yoou try and start the car up after blasting those areas it doesn't like it very much. I mean it has an extremely difficult time even turning over. And when it does get going it runs pretty rough until all the cleaner has been burned off.

That's why you should have disassembled the manifolds to clean them out, you absolutely do not want all of that crap going into your engine. The air cleaner is there to keep dust out, you just flushed great chunks of carbon in there.

The check engine light doesn't go off instantly, might take a couple of complete warm up cycles.