Engine light on due to erg valve?

Does anyone know where the ERG valve is located and what are most common problems with this?

Also does anyone know where I can get online manual for this car? Which includes all the information about where everything in the engine is located and how you can take apart certain items.

Thanks!

Reply to
td
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Autozone has a free online guide goes up to 1996, but the later 5SFEs and 1MZFEs are similar. Autozone's online manual page is down right now. Just go to

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and click on "Vehicle Repair Guides". Or you can go to Pep Boys and pick up a Haynes repair manual (which I prefer over the Chilton). It gives more helpful hints to the backyard mechanic. It's good to have if you plan to work on your car.

Does your engine knock while accelerating? Does it stall while idle? When warm or cold? You'll have to check the EGR valve itself (which normally doesn't go bad but just gets plugged up with carbon), the hose that comes up to it from the exhaust pipe (might just need a bottle brush cleaning), the EGR modulator (maybe the ports in the throttle body to it are plugged up), and the EGR valve enabling switching valve (solenoid just failed?).

But what led you to believe the EGR valve is the problem?

Reply to
johngdole

BTW, Autozone and probably many other parts stores now will help you read the engine code and tell you exactly what is causing the MIL light. It could be many things, but Toyotas usually can't diagnose EGR problems accurately.

Tell us what the code(s) is/are.

Reply to
johngdole

This I can believe. I put up with my car jerking at 47MPH for almost two years before the problem got bad enough for the light to come on. I thought the transmission was acting up at first (seemed like the TC was locking and unlocking constantly when driving at that speed). Turned out to be the EGR position sensor causing the engine to surge when driven at just the right speed. Unplugged it and the car drove perfectly.

Reply to
Anthony Fremont

This sounds similar to my problem w/1990 V6.

At slow cruise (~15-20,000rpm) with very light pressure on accelerator, the engine cuts in and out. This is not like a miss - the RPM will drop several thousand for several seconds, and then kick back in. If I release the accelerator during this drop, the RPMs go back up again. If I am cruising at idle (but ~15-20Mrpm) down a decline, it does the same thing. Is this an EGR issue?

[Respondents - tell me if you think I should start a new thread for this particular issue].
Reply to
abbottim

I took it to autozone and they told me the code which i have forgotten, but said it was related to this EGR valve, so should I try to disconnect the top or take out the tubes and clean them?

Reply to
td

15-20 million RPM? Tell us what make and model of SR-71 Blackbird you are flying...
Reply to
mrdarrett

Try here

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for a manual.

Reply to
NickySantoro

If you are mechanically inclined you can borrow the MityVac vacuum pump/gauge for free from Autozone to do this. They'll charge you as a deposit and then refund when you return the tools.

I'll post the instructions used to assist an owner to successfully solve an EGR related problem below. It turned out that during his cleaning the throttle body the ports controlling the EGR modulator had gunk plugging in them. This basically disabled the EGR valve causing severe knocks on acceleration (IMO Toyota should have used modern stepper-motor-controlled EGR valve and not the cheap old vacuum stuff).

(Instructions follow)

Reply to
johngdole

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:

-- Make sure your port P of the EGR Modulator connects to the port E on the throttle body and port R to port R (see page 3 of the EGR article).

-- make sure the wire to the engine coolant sensor near the IAC is ok

-- Connect your vacuum gauge to the Evap port on the throttle body to see how much vacuum your engine is pulling while running. This has the larger hose connected to the VSV on the air cleaner housing.

  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. Gradually 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.

------------- Disclaimer: Your mileage may vary.

Reply to
johngdole

Throttle body: ============== Air blown into the hoses from the modulator's Ports P and R into the throttle body should flow freely into the throttle body.

To be tested: =============

Test 1 -- To rule out VSV as the problem. Test 2 -- Whether the EGR modulator is indeed the culprit.

Step 1 for VSV:

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.

Step 2 for VSV while also checking out modulator:

2A. Now your engine is warm in diagnostics mode from Method 1, tee Port R of the modulator to the MAP hose (getting full engine vacuum now).

2B. At 2500 rpm, you should measure about 13" at Port Q of the modulator.

If the numbers are the same at Port Q of the modulator and at the EGR end of the hose, then VSV is working.

But if Port Q of the modulator shows a higher vacuum than at the EGR valve, then the VSV or the vacuum hoses leading to VSV are leaking. Clean or change the VSV and hoses. In this case of higher vacuum at Port Q, a direct hose from Port Q to the EGR valve should cause the engine to run rough in the diagnostics mode at 2500 rpm. If not, you may have problems at both VSV and modulator.

----------------- Disclaimer: The owner and I had a number of iterations on trying to solve his problem. I think these summarized what we did. But your mileage may vary. ;)

Do refer to the technical document URL earlier (Auto101). Good theory and operations discussions.

Reply to
johngdole

So before you actually do the hard work of disassembling stuff, use the (hopefully correct) procedure to isolate the problem to either the EGR valve side or the EGR modulator side of things. And then go from there.

If the problem is with the EGR valve side, cleaning should solve the problem. It would be rare to have a defective EGR valve with a hole in the silicone diaphragm. Likewise, if on the EGR modulator side, check of hose obstructions, dirt, etc before replacing stuff.

Or just print out the mentioned Auto101 EGR article and hand it to a mechanically inclined friend. He or she should be able to figure it out from there. :)

Reply to
johngdole

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