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Insufficient EGR

My '98 Camry 4-Cyl has turned on the "Check Engine" light. My scanner says it is "Insufficient EGR." I see there is an EGR Valve and an EGR Vacuum Modulator, and a small pipe connecting the exhaust to the EGR Valve. What is the best way to check what component is causing the "Insufficient EGR?" The EGR Valve is butt up against the firewall. -- Any tips on ease of removal? Any help is much appreciated.

Dick

Reply to
Dick Byrd
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You can easily check if the EGR valve is working by pulling a vacuum on its port. This is really the first thing you should check.

If the engine idles rough or quits, then you know it's working and the problem is with other components in the system: the modulator, the vacuum switch that operates the valve.

One guy in this group had a problem where the throttle ports for the EGR were plugged while cleaning and caused the insufficient condition. Here were some excerpts:

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In addition to Haynes repair manuals, the following web site has many good technical articles check it out:

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read the following: 61 Emission#7 - Exhause Gas Recirculation.pdf

I assume you have one vacuum pump with a gauge on it and maybe a short vacuum hose if needed to bypass the EGR VSV between the EGR valve and the modulator.

I would do the following:

  1. Warm up the engine to operating temperature
  2. Connect the TE1 and E1 connectors on the DLC connector (passenger side of the engine compartment behind the strut. page 6)
  3. Connect the vacuum gauge to the hose that goes to the EGR valve
  4. Start and run the engine at 2500 rpm

Q1: Do you see low vacuum of 3 in/Hg? This is what the modulator should pull on the EGR valve. (page 7)

  1. Reconnect the hose to the EGR valve
  2. Now disconnect port R hose on the EGR Modulator. You may need to plug the port R on the throttle body to avoid air leak.
  3. Run the engine at 2500 rpm
  4. Pull vacuum on port R of the EGR Modulator, say to 15" or whatever your saw on the Evap port (use an engine vacuum source, tee into the MAP hose for example)

Q2: Does the engine run rough? (page 7)

You should answer yes to both questions. If not you can repeat the above with a direct hose connection between the EGR valve and the modulator's port Q this bypasses the VSV. If this works, then the two hoses going down to the EGR VSV and/or the VSV may be suspect. Make sure the vacuum hoses are connect to the right ports on the VSV behind the manifold (You said you had this VSV changed out?)

  1. Restore your engine to the original state. Make sure you disconnect the TE and E1 jumper.

  1. Pull the EFI fuse for a couple of minutes to clear the computer.

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To rule out VSV as the problem:

1A. Disconnect hoses from Port Q at the modulator and at the EGR valve. This leaves VSV with two long hoses to test. Mark them so you can put them back in the right places.

1B. With the engine cold, stopped and ignition ON, Port Q hose leading to the VSV should hold vacuum, use about 15". And blowing through the EGR valve end of the hose you will hear air coming out of the VSV filter, which will help you locate it as well.

1C. With the engine warm and at 2500 rpm, Port Q end of the hose should loose its vacuum automatically as VSV is opened. This means the Port Q hose now opens all the way to the EGR valve end of the hose.

This confirms VSV and its control circuit is working; otherwise the VSV or the vacuum hoses leading VSV to are leaking or VSV is not energized. Verify proper electrical connection to VSV. Clean or change the VSV and hoses.

Dick Byrd wrote:

Reply to
johngdole

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