pplusent

1993 4runner, newly rebuilt 3.0 engine less than 100 miles on it. looks like factory bypassed EGR system most other sensors are new. Factory plug where EGR sensor plugs in. No code stored. Changed to duel exhaust system and when moving O2 sensor mount the O2 element ended up only half exposed to exhaust flow, out of time to register so don't have time to move it. Also I don't think the torque converter is locking at cruise steeds. 65 MPH yields 3000 RPM, a bit high, but let me know if this is normal for a 4runner.
emission numbers are NOX 26/ max 20 and CO 5.65 Max 4.0.
This is what I am doing so far:
1. new dist cap, rotor and plugs. should have done at rebuild anyway! should reduce CO.
2. retarding the timing two degrees more to cool combustion chamber and reduce NOX.
3. Adding 105 octane boost the cool chamber and reduce NOX. '
4. Rings may not be seated yet, but at the risk of them never seating I am changing the break in oil with 10-40 oil and a quart of Lucus oil stabilizer to get more compresion and get a more complete burn to reduce CO.
5. this time I will run the car on the freeway for 20 min tho make sure the catalitic converter flashes. the last time trough emissions the cat had not even discolored from heat yet.
Does anyone have any more ideas to reduce NOX and CO.
Also dose anyone have any recommendations on a good exhaust resonators that will get rid of the fart can sound from the exhaust? They need to be as small as possible, limited space.
Thanks

scope103

Can you give me the units on those numbers? In Calif, the CO is %, with a max of 0.49. NOx, on the other hand, is ppm, with a max of 373 (and an average passing number of about 37.)

You don't give your location, but I don't know of any state in the US where you can get smogged with removed/bypassed emission equipment. Different in your jurisdiction?

But the purpose of the EGR system is to reduce NOx. That's what it does. That's all it does. So without a working EGR system I can't imagine that you'd ever be able to get the NOx low enough.

Here's a good article on emissions chemistry. http://www.cygnusx1.net/Media/Supra/...taTech/h56.pdf Note that the most common cause of high CO is running rich (possibly mis-firing), a common cause of high NOx is running lean. Note that retarding the timing, or adding 105 Octane aren't listed as possible solutions.

Good luck!

pplusent

We are in Phoenix arizona. the CO is in grams per mile and so is the NOX. I know from racing that raising the octane lowers the combustion chamber temp which in essence is what the EGR does. The EGR system is all there and hooked up, it just does not have the EGR temp sensor. I would rather not have the EGR system due to the crap that it builds up in the 3.0 intake manifold and the cost of a new sensor is outrages. They just do a visual on the system so they think it is all there.
I just changed the dist cap an rotor and found the center contact in the cap for the coil was burnt and almost gone which could explain some of the CO being high, the all plugs looked normal but worn, they were a light tan color and all consistent. The car does not have a lean misfire and runs smooth.

scope103

$134 at RockAuto.

I'm going to guess that someone put in the BS resistor hack to keep the CEL off even when the EGR needs attention. If you're worried about "crap" build up, removing the temp sensor doesn't change that. It just keeps you from finding out when something is wrong.

I'm going to guess that your EGR system is not working the way you want it to, it's not able to hold down NOx, and your truck would have told you if it could. You might try putting your hand on the EGR plenum pipe; I'm told it should be "warm, but not hot." But that's not much of a substitute for a temp sensor.

Sorry I can't help.

bswarm

Apply vacuum to the EGR at idle, if the idle changes, the valve is good. Hook up a vacuum gauge tee'd into the EGR vacuum hose and go for a test drive, you should see vacuum on acceleration with the engine warm. If no vacuum, you'll need to check the hoses, routing, and solenoids.

pplusent

There is no resistor in the sensor harness. It is a jumper with zero resistance and the jumper is an exact match for the plug on the harness. It looks to be some sort of termination manufactured by the company that made the plug, it is an exact fit and color match and that is why I believe it is a factory item. I have never seen one like it or heard of anyone having one.
I guess I will just try the things I am already doing and see what it does. If it passes great, if not I will get an exemption I have already put 3000 in parts into this truck and am not investing any more. I think the vehicle is just cursed, this week alone the window motor stopped working, the lock broke on drivers side and the regulator stopped working in the alternator, oh and had to replace the battery. Anyone looking for good used 4 runner? Have a Tacoma too, the wheels keep falling off that truck, the balls pull right out of the sockets on the Moog ball joints and the control arm broke in half once (good thing I wasn't moving very fast at the time). I will post results on Monday after testing.
Thanks

pplusent

Will the EGR work without the sensor? I have tested the egr and it is good, but not sure on the solenoid or the other two vacuum diaphragms that are on the EGR system.
I have noticed on the web that the sensor is only on the California models, is this true? And will adding a sensor throw the system off.
Also how do you test the solinoid and the other parts of the EGR system?

pplusent

Chased the EGR problem down to a bad EGR modulator valve. That should take care of the NOX, but I don't know about the CO. I pulled the O2 senser and the deposits on it are a very light tan which should mean a near perfect mixture, so how can it be to rich?
I have ordered a new O2 senser, should be here next week, so I will put in some low obtain gas, check the timing again, put in a quart of denatured alcohol to 5 gallons of gas and run it through emissions again. If it doesn't pass I will demand to see thier calabration records on thier equipment. with the nature of the failure both NOX and Co being high just doesn't make sense. How can an engine be running both lean and rich through out the range. The high CO should have been so rich at double the legal limit that the head temps should be running very cool with unburned gasses flowing through the chambers.
Something must be out of whack with their equipment. Anyway we will see.

pplusent

I also put in an EGR senser I got for free, but I don't think the system is programed for it. Funny thing is I took out the plug from the harness and it does not throw a code, nor did the engine run any different when I plugged in the sensor. From what I read the sensor is only on the California cars. For all of you that want to bypass the EGR, all you have to do is plug the EGR vacuum port on the valve and no more gas will enter the manifold. Be aware that without the EGR chamber temps will rise and these engines already have a heat issue due to the crossover pipe putting heat into the number six cylinder. I seriously recommend getting rid of the crossover and putting duel pipes comming out of the engine. It's easy to do, just run the pipe around the back of the tranny, make sure you flange it so you can remove it for tranny work and don't forget a couple of small resonators or small glass packs other wise it will sound like a fart can!

bswarm

The EGR also helps reduce pinging. If you do that you have to use premium gas and/or retard the timing... or eventually replace the pistons that have holes burnt through them.

pplusent

Exactly, although I do understand how it would be nice to be able to remove all that hardware and gain more room under the hood. A better designed head and better water ports would have eliminated the need for an EGR system.
The best way around it would be to put a Chevy 4.3 under the hood (or equivalent). would be great power and fewer problems in such a light weight body. Saw a guy put a 351 ford motor in one, but that was way overkill and he lost any space that was under the hood. But with emissions the truck would have to be 25 years old or more, to not have to emissions test, at lease thats the rule in Arizona.

thefishguy77

iTrader: (1)

We are trying help him pass emissions. Not debate the EGR necessary\unnecessary topic. Many swear by it and many don't run it. Let's just help him get it passed

bswarm

I was a licensed Ca smog inspection and repair tech, as well as ASE certified. I'm just letting everyone know it's a bad idea to do an EGR delete as the original poster said.

Back to the subject...
Do you have the HC (hydrocarbon) levels from the smog test? That may help.
Some possibilities:
Coolant temp sensor may be slightly out of range.
Bad catalytic converter or cat not warmed up enough, driving on the freeway before getting a smog check helps get a lot of cars passed.

thefishguy77

iTrader: (1)

Easier to just walk away.

Unsubscribed.

pplusent

My Parts came in today and I retested, failed again but just barely.
Things I did before test. Found egr modulator valve not working,Replaced modulator, egr functioning. Added an egr temp sensor to make it a California standard.
Replaced O2 sensor.
set timing back to 10 degrees BTDC.
replaced rotor and cap (dist).
Added one quart of denatured alcohol to 5 gal of gas. runs great.
ran on freeway 10 before test to heat up cat.
Test results: HC .92 Limit 2.0 Pass. Nox 4.07 limit 4.0 Fail, CO 21.84 limit 20.00 Fail.

Things I noticed; started running rough at idle on way home, distributer plug must have pulled patualy out when timed engine. through code 12, was ok during test.
seem to have a small miss occasionally at idle. Will replacing plug wires tomorrow to see if that helps. smoothed out a bit when added 5 gal fresh gas.

Also threw code 71 on way home, egr exhaust temp to low, got me on that one? disconnected the temp sensor and put factory bypass plug back in.
One thing I'm not sure on, when I moved the O2 sensor boss to the new exhaust it ended up sitting a bit high on the pipe so the sensor only has about 3/8 of an inch in the exhaust flow. I don't know what effect that will have on test. I do have an extra Boss,so if I need to I can try and fit it little closer to the exhaust pipe to put more of the sensor in the flow. I don't know if that will change anything.
I only have one more try at the test, don't know what they do after that. Trying to find someone who has a OBD 1 testing rig to try to bring it down a little more with real time data.
Rebuilt motor now has about 50 to 70 miles on it, so rings may not be totally seated, compression may still be a little under par.

pplusent

Going to test tomorrow. Found out there is a restrictor in the EGR valve limiting the exhaust that can pass through. I am removing the restrictor , extra flow capacity should bring down the NOX and leaning out the air flow valve three clicks, should bring down the CO.
Will let you know what happens.
Also found the OEM part number for the bypass plug for the EGR temp sensor, for anyone who needs one. #32824-35020. If you remove sensor the EGR will still opperate. On mine I took out the bypass and put in the temp sensor due to NOX issues.

pplusent

Finally, ran it through emissions 4 times today. first two times only modest gains 3rd time got real close HC .62 max 2.0, CO 12.35 max 20.00. NOX 4.12 Max 4.0.
Was running out of options, so since the cat I put in was small to make due with the small space I had I figured maybe it's just too small. SO i went to my local wholesaler and bought a mgnaflow unit that just barely fit (half inch to spare) and welded that baby in there.
Ran it back through for the sixth try with no extra mods and it PASSED. HC 0.09 Max 2.0, CO 2.6 Max 20.00, NOX 0.92 Max 4.0.
They had to run it twice because the machine said to check the hose to see if it slipped off the exhaust pipe. Amazing what an oversize cat will do.
This project is finally registered and on the road!!!!!!!!!!!!

pplusent

Thanks all for your input!