cbr600rx7

So if looks like the old owner by passed the EGR system on the 95 4Runner 3.0. From what I can see he unplugged the EGR and then added a resister inline with the factory wiring. I am in the process of returning the engine mostly back to stock and have considered wiring it back up.

Now currently there is no convertor on this rig and it's not throwing codes. Ami crazy for trying to hook the EGR back up or should I just leave it alone.

Please do not turn this into a EGR bashing thread. I know many people have different opinions on the EGR and how it effects the vehicle. Personally if it functions currently and is not problematic I would assume having it working would be best.

cbr600rx7

You can see in the pictures that the resister is in place. However the EGR still has a vacuum line going to it and is not blocked off as far as I can tell.

If the vacuum is what's controlling the EGR to open and close but the resister is trying to trick the ECU it may explain why she seems to be running a little off.

millball

The resistor is useless. It is between the leads of the EGR temperature sensor, while the temp sensor leads that go to the ECU are aparrently not attached to anything.

Who knows why shade-tree 'mechanics' do things???

A code should be set because the ECU does not see any temp rise thru the EGR piping.

The EGR could still be functional with the EGR temp probe disconnected, but who knows what other boneheaded mods have been made??

Charchee

I wonder why he didn't just remove the valve if he didn't want to use it. It should still function so long as it is getting vacuum and the valve isn't bad. Only thing I can think of is maybe the EGR wasn't working properly so he put in the resistor to try and get rid of the CEL he was getting. Hook it back up if you want and see if you get a CEL.

cbr600rx7

millball sorry the pictures might be confusing. The resister is conected to the ECU side of the harness. The pictures might be miss leading.

He used connectors on both ends one male and one female per side so I removed the resister and plugged them back in to each other. So far no code but I have not had time for a real test drive.

If the EGR was still functioning but the ECU was being cheated I wonder how that effects the fueling map. Probably worse if the EGR has failed and the sensor is Hotwired to think it's working properly.

Charchee

I could be wrong but I don't think the ECM makes fueling adjustments based on EGR temp sensor input. If anything, it might react to the O2 sensor readings which might be affected by the EGR or lack there of. I'm thinking the sensor is there to verify that the EGR is in place and functioning. Earlier 3VZEs like mine don't have that sensor but all of the other parts are the same.

cbr600rx7

Very interesting. I hope to get some time tomorrow to take a decent test drive.

cbr600rx7

So she kicked a code 71 today on her first long drive. I am going to pull and test the EGR tonight and hopefully it just needs to be cleaned. If not I guess we are going to start trouble shooting

az1320

Fuel curve and timing curve are adjusted by the o2. I am willing to be the pic in your other post showing your o2 is still the problem with it not running right.

I deleted my egr system on my 22re. Makes for a cleaner intake, And a cleaner fuel air charge.

cbr600rx7

Code 71 relates to the EGR specifically. Since the old owner had by passed the EGR temp sensor that trips the EGR trouble code it's safe to say this was probably a issue before but since he had a resister in place to trick the ECU it didn't show up.

As for the O2 sensor flange it never leaked and has been repaired so I suspect that is not related.

In response to your other post: Toyota engineers who get paid way more then we do created the EGR system to work with the fuel injection system. A properly working EGR system will not hurt perfrmance. The issue is when they do fail it definitely can have a negitive effect on how the vehicle runs. However the EGR main function is to reduce NOX emissions the most harmful product of our gas burning engine. The EGR can reduce NOX by about 10-15%. I see that you have kids so I would assume this is somthing you would be interested in.

As far as the convertor is concerned a properly functioning one will not rob any real power from the a naturally aspirated engine. Now if one is clogged or has failed of course that's a different story.

cbr600rx7

So back to the EGR. I pulled the valve off tonight and put the vacuum gun on the top port. At first I could not get any vacuum out of it so I sprayed some sea foam in the ports and was able to pull 20hg however it does drop down slowly.

millball

Now to see if any of the passages are plugged up, and whether the valve is actually opening.

scope103

There is a test procedure for the EGR. http://web.archive.org/web/201003261...77exhaustg.pdf

While you're at it, you ought to check the temp sensor itself.
http://web.archive.org/web/201003261...00egrgaste.pdf
I'm pretty sure the egr temp sensor does NOTHING but monitor the EGR, as Charchee said.

Kudos for worrying about the air we all breathe.

cbr600rx7

Thank you. Both of those are extremely detailed testing procedures and I will report back what I find. Thanks once again.

cbr600rx7

So good news so far is the EGR valve seems to be working properly but I did clean it very well along with the tube. The EGR temp sensor looks new but I will test the resistance in it tonight after work.

The filter is in rough shape. I am going to try and blow it out today but really wish I could just replace it.

scope103

One thing to consider (that doesn't show up in the manual) is that the plenum (upper intake manifold) can fill up with "gunk", mostly from the PCV system. This can be so bad that it can block vacuum ports, and eventually, the EGR tube itself. Disconnect the EGR tube (that goes into the plenum), and just pull it out. There's about 2mm of clearance, but on mine there was enough gunk that I had a little trouble pulling it out! If yours is that bad, you may have to pull the plenum for a good cleaning. (If it's that bad, you'll want to clean it for a lot of reasons that have nothing to do with the EGR.)

Below is a "sparkly clean" EGR tube (with about 10k miles since complete cleaning). The part with the gunk matches up to the PCV line. I'll bet yours doesn't look so 'pretty.'


In a sense, the monitor system for the EGR is simplicity itself. When the EGR is working, the tube into the plenum has some combustion product flowing through it, so it gets 'warm' to the touch. That's what the temp sensor is looking for; if you have code 71 your EGR tube probably feels cold all the time.

cbr600rx7

Thanks for the info. I did pull the tube when I had the EGR off. It was surprisingly not to horrible but did have some of that gunk you talked about built up on it but wasn't as bad as you would expect. I used MAF sensor cleaner on the tube and EGR since it's more plastic friendly.

I did pull the EGR modul and blow it out with air. Tons of junk came out of the filter and the housing. Unfortunately the 21 year old filter didn't fair very well and started to brake apart a little. Called Toyota and apparently they don't sell just the filter.

az1320

Probably not the smartest idea to bring peoplesome kids into things. Just a heads up. But thx for the Google info. Have fun with your project ankle.

cbr600rx7

Oh boy here we go. And this is why I said no BS.

It was smart of me because I hope some one else will see that post and understand why it is important. Just a heads up I didn't bring your kids into it. Just noted that you are a parent (as am I) and probably concerned about the future. In no way did I degrade you or your kids, or did I condem you for illegal activity or for any of that BS.

As for the EGR yes I have spent a lot of time reading different views on how it effects the 3VZE specifically. Looking at the system it definitely varies from a TBI SBC EGR or the old carb versions. Toyota continued to develop the system during the 3VZEs run and it continued to evolve. I think it's safe to say that Toyota tuned this motor to run with the EGR system and was not somthing just thrown on at the last second to meet emissions standards. Since the motor was basically built to function with the EGR and tuned around its function tricking the system may not be as beneficial as some think. Yes if yours is failing or stuck in the open position your vehicle is going to run poor and deleting a failed EGR will definitely improve the way the vehicle runs.


No not Google just my own experince over the last 14 years. I am a gear head and primarily a diesel guy but I do enjoy a good Toyota and the 22RE and 4AGE are close to my heart. Being a diesel guy I understand all to well the cons of a EGR especially a failed one. But I also care about the air my kids will be breathing hopefully long after I am gone.

If you had success with your EGR delete then good for you however running with out a EGR or convertor for that matter is not possible in most places. I could personally get away with not running a EGR or convertor for that matter but as I said before IF I can reduce what my kids and grand kids inhale both directly and indirectly I will


NOW..... Back on topic
You made a comment on the other post trying to suggest the 02 sensor was at fault and that has been your only relevant suggestion here as well. I will assure you that even with that poor repair job the sensor flange was not leaking and has been repaired properly. Since no exhaust leak is around the sensor, the 02 sensor is new and not throwing codes, in the stock location on the stock flange, and the only code seems to be the EGR code I think it's safe to rule out the 02 sensor and focuse on the EGR system it's self.

cbr600rx7

So strangely with the addition of the 13 inch long 2.5 inch diameter magna flow convertor the EGR code has not came back. I don't know if the extra pressure in the exhaust is helping slightly or what's going on. But in 3 days of driving since the convertor install no code.