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EGR fix with standard 12v Relay - it works

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EGR fix with standard 12v Relay - it works

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Old 04-03-02, 07:45 PM
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EGR fix with standard 12v Relay - it works

All,

With some help from spooledUP7, I have sucess using a relay to trick the ECU to think that the EGR is present! In other words, no more codes! Here is what I did.

1. Remove EGR and use a block off plate - make sure that you keep track of the wiring that originally goes to the EGR valve.

2. You need to get at the solenoid under the UIM. Note the soleniod we are talking about is the 4th one from the front of the car. I believe that it is yellow in color. If you want to make sure, please refer to any vacuum diagram that you have access to. To get at the soleniod, so I found it easier to just remove the UIM.

3. Okay now for the wiring: EGR side - The harness from the EGR needs to be tied to pins 87a and 30 of the relay. Any standard 12v relay will do. To make sure, putting a meter on these pins will give you continuity. Attach couple of female spades to the wiring an hook it to the relay.

4. Solenoid side (under the UIM) - disconnect the solenoid harness and then use 2 male spade connectors to tap into the female side of the solenoid harness. Polarity does not matter. The other side of this connection goes to pins 85 and 86 of the relay. Pin 87 of the relay does not come into play so leave it alone.

5. That is basically it. Mount the relay, reinstall the UIM and you're finished. Now would be a good time to do the hoses.

Here is how it works. With the EGR harness connected to 87a and 30, the EGR has continuity. When there is a signal from the ECU to open the EGR circuit and the relay switches from the 30/87a connection to 30/87. Since 87 is not connected there is no harm done and the ECU is tricked into thinking the EGR valve is there. Basically, the ECU believes that the relay is the EGR valve itself.

Hope this helps..... I'll keep everyone posted if this setup turns out to be bad, but so far I am good to go.

dlee
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Old 04-03-02, 10:02 PM
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Very happy that it works for you. I have never installed one myself, but the mechanics are all there.
Another note to this EGR mod; It's not necessary to remove the EGR valve if you still want to pass visual. There is no real harm in leaving it. In fact, rather than spending money on a block off plate, you could buy a sheet of gasket material, and trace the outline of the EGR.
As far as the 87a, and 30 numbers dlee is talking about, the numbers refer to the markings casted into the relay case. I'm sure they vary from relay to relay, but most come with a schematic to desipher the lingo. All you really need is a 12 volt, Double pole double throw (DPDT) relay. The OHMs on the coil should be 29-33 ohms.
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Old 04-03-02, 10:15 PM
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Great! however, once you passed visual, and the 16 code stops flashing, do you think that it would still pass emissions? My problem is that I use an PFC so the EGR doesn't even matter one way or the other normally, but the old ECU has to be hooked up to pass CA smog, and if the stupid (and very expensive) EGR is not working, then I would hate to have to pay big bucks for the thing just to pass smog and then go back to the PFC that doesn't even use the thing.

However, if the thing passes no mater what with the stock ECU and the EGR bypassed, then thanks very much and I'll have a beer in your names with the money savings (that is if there is anything left after the next mods 0 )
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Old 04-03-02, 11:00 PM
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If your main cat is up to par, and your car is not running rich from some enhancement you performed, you will pass the sniffer with or without the EGR working and here is why.

EGR at idle = off
EGR at high speed = off
EGR at deceleration = off
EGR at heavy load = off
EGR in 5th gear and above 1700 RPM and below 3850RPM = On

Fact... No lies
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Old 04-07-02, 09:32 PM
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Yeah, but what about this --> car throws a 16 code (EGR) and the idle hunts. $145 part later = no more code and idle settles down, and cleared code does not return.

So if the EGR if off at idle, how come it effects it and caused hunting??
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Old 04-20-02, 01:37 AM
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Originally posted by Leadfoot
Yeah, but what about this --> car throws a 16 code (EGR) and the idle hunts. $145 part later = no more code and idle settles down, and cleared code does not return.

So if the EGR if off at idle, how come it effects it and caused hunting??
You may have been the first person to have actually had a bad EGR valve. Sounds like it was stuck open or you had a leaking gasket, or your code was causing safe mode. There may have been something else that caused your idle problem and you some how fixed it.
When I frist bought my FD, I had the 16 code and I bought and installed a new EGR. First disapointment was the new gasket which had a 1/32" hole as opposed to the 5/8" hole the old gasket had. The second dissapointment was when I saw the engine code 16 come back. That's when I decided to take appart the old egr sensor to see what was going wrong. That was my third dissapointment when I saw how it had a cheese ball on off switch in it. My final disapointment was when I found out how small the actual manifold EGR path is. It's about 1/8" and fully plugged with carbon build up.
What a mess. So, don't feel bad about buying the EGR and just be happy that you now know how to fix the problem when you get the engine light again. I estimate 2 more months before you see it again.
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Old 04-23-02, 05:21 PM
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I changed the EGR several of years ago and it hasn't thrown a 16 code again. Now with the PFC, that disables the EGR (or something like that, according to my understanding) it should just be getting bypassed and not getting fouled. maybe, at least in theory.

Although, when I have to smog it, and with the stock ECU on there, it might throw a 16 again, but if it does I will check the manifold for carbon fouling.

Thanks a lot, you probably just saved me. Better to clean out a manifold than have to buy another EGR.

PS. I am surprised that no one ever mentioned that before. I don't even think that is in the manual, it just says to replace it. boy, they sure knew alot about this car when they put it on the market, and printed the manual. There are lots of little tweaks that are easy fixes the manual never even hints at. Oh well, I guess that is why we are on this forum.
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Old 07-03-04, 09:57 AM
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From the dead...anyone have pics?
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Old 07-03-04, 01:58 PM
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of what? It's really simple, just follow directions. I did it not too long ago and it works for me as well. I even passed emissions without it.

Amel
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Old 07-10-05, 02:37 PM
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do i have to block off the egr or just leave it alone?? just a thought instead of wiring the relay in the engine bay can you wire it up on the ecu side in the car??
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Old 07-11-05, 09:35 PM
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Harness color

That relay trick is awesome.
One quick thing:
The color of the connectors of the EGR harness are blue and for the colenoide yellow, is that correct?
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