95PhoRunner

Hi Everyone,

I'm completely new to Yota's. I just picked up a 95 4runner v6 with the 3.slow 2wd with 123,000 miles. I need to pass smog to get it registered. This damn error 71 and high nitrous oxide levels resulted in me failing the smog test.

As part of general maintenance.

*I have replaced the dist cap, plugs, wires, and rotor.
*Oil & filter change
*Air filter change
*Tranny fluid and filter change
*New gasket for tranny pan
*Air filter change
*Replaced drivers side valve cover gasket
*replaced EGR vacuum modulator.

After all this I still have a couple of oil leaks somewhere. I need to trace those to the source. I am also getting code 71.

I have read that pouring the seafoam product in to the pcv hose may help. Can anyone tell me which hose that is? Or have a picture illustrating that hose?

I am not a mechanic or anywhere close to one but I can follow instructions. This morning I took out the gauge cluster on the dash to repair a light bulb for the check engine light. I followed directions I found here from another thread. After doing this i was able to attach the code reader to get the error code 71.

Any help would be greatly appreciated.

Thanks

90-3vzeslug

seafoaming can certainly help, however if you are throwing a code 71 the seafoam isnt' going to clear it. This is an egr system code. Did you hook the vac line back up to the new egr vac modulator? If so, sounds like the the egr valve it's self may be bad. Alot of people just unhook it, but they don't have to pass emissions like we do

95PhoRunner

I did hook all the lines back up to the new vacuum modulator. With the engine running I unplugged the vacum hoses from the egr valve and modulator and I didn't notice any difference in the engine. Should it stall. I did feel some suction from the vacuum modulator when I placed my finger over it.

Does anyone have a link with instructions on removing the egr valve to see if it's dirty?

RockMtn4Runner

High NOx is usually a result of too high of a combustion temp. On the 3.0 there is always the chance that you may have one or more valves (usually exhaust valves) out of spec (lash too tight). If you have valves that are not seating completely then the heat of from the valve is not adequately dissipated to the valve seat. Result? High combustion temperatures and in turn a high NOx reading. I think valve adjustment is probably something common that gets ignored on the 3.0 because adjusting the valves is a royal pain in the ass to put it bluntly. Therefore, it is something that most owners tend to ignore. It would be the FIRST thing I check and adjust after buying one of these 3.0s. The valves train on the 3.0 uses a "shim over bucket" adjustment system since it is a dual overhead cam motor. It's not impossible for the average Joe to do if he has the ability to follow directions, has the right tools, and some patience. YMMV.

As for your EGR valve, I would advise removing it and flushing it out thoroughly with B12 or some other throttle body cleaner and see if that solves your problem with your code 71. If not, then it may be time for a new EGR valve.

If all else fails, run your tank down to about a gallon of gas, throw a gallon of denatured alcohol in your tank, and drive straight to the emissions testing facility. It should pass with no problem. Make sure and drive straight to the gas station and fill up your tank with gas after you pass the test.

95PhoRunner

I figured out how to remove the EGR valve and return pipe by searching through some old threads. Very helpful information on this website. When I pulled out the EGR return pipe it was caked with black gunk. I pulled it out and cleaned it as best as I could. I also flushed out the EGR valve with some cleaner. I put everything back together and cleared the code 71 with the scanner tool. Then I put some seafoam in the gas tank. I've driven about 40 miles and it hasn't come back yet. The first time I cleared the code it took about 60 miles before the light came back on. I was going to go to the smog shop today to get retested but as I was going to leave I noticed my rear tire coming undone. Steel wires were visible. Damn it! 600 dollars later and I've got new tires and alignment. Good grief!

rainman88

yeah i just failed mine for the second time only the no part this time,i changed plugs,wires and oil and it got the co% and the hc to pass.the no ppm is 3268 of 1161 allowed.so what im getting is check the egr valve?and does the alcohol thing hurt the motor.it has 283,000.also it has a brand new catalytic.

1988 4runner v6 efi

Dirt Driver

The EGR is a big one, yes. Alcohol probably will not hurt anything, but too much will make it run badly.

As an aside, NOx stands for "oxides of nitrogen," not nitrous oxide. Nitrous oxide(N2O) is the stuff they put in those blue bottles that drag racers use and is not a typically a byproduct of combustion. Nitrogen oxides like NO and NO2 are what the EGR system and three-way cat converter are supposed to reduce.