pappatoad

I have a 1989 4Runner with a 22RE EFI that is not passing emissions. I have done all of the standard things, like tune up, O2 sensor, and timing adjustments. It is still failing the CO2 readings. The sad part is that I have tested 3 times and it has gotten worse each time. I have owned the truck for 17 years and have never had a problem with emissions until now. I have checked for a vacuum leak with the brake clean spray around the vacuum tubes listening for the idle to rev up. one thing I am curious about is that when I took the distributor cap off the O-Ring on the distributor was falling apart. Would this cause the vacuum advance to mess up and increase the amount of fuel constantly to where it is running too rich?

Any other ideas on what to look for would be greatly appreciated.

myyota

There is no vacuum advance on a 22RE, ignition advance is controlled by the computer. When you replaced the 02 sensor did you get an oem part (Denso), Bosch or other brands don`t work well in our trucks. Is the cat on your truck original with a lot of miles on it ?, it might be time to replace it.

pappatoad

Not sure iffy it was OEM. Got it at import parts warehouse here in Denver. Had correct connector.... but did not match the look of the OEM I replaced 6 years ago... so probably not. The cat is old but after calling a place to replace it he asked what on the emissions failed and he told me it was not the cat. Said either ignition or vacuum leak.

thook

Did they tell you whether or not the vehicle was going into closed loop mode?

Was there oil gunk inside the distributor cap? The o-ring seals the distributor shaft from the head to keep oil out.

bob hennig

what did the vehicle fail on? What were the readings, do you have available? What changes were made in between tests? Bob

pappatoad

there is oil gunk in the distributor.... and I got a puff when I sprayed the brake cleaner around the distributor...Closed loop mode I am honestly not sure what that is...but they made no mention of it.

CO2 readings are what is failing. Needs to be below .25 to pass
1st test failed with .52- changed plugs, oil, cleaned out K&N air filter massivly. reset idle to 750 and timing. - retested

2nd test failed again with .76 CO2 readings. this time cleaned mass airflow sensor and replaced O2 sensor. After O2 sensor replaced reset idle air spead as it was higher than before was at 1465 so reset idle air speed to 750 added fuel system cleaner with octane boost - retested

3rd test failed again with .91 readings after driving on highway for an hour using 1/4 tank of fuel.
I am at a loss... have read posts and have been curious on something. since this engine does not have vacuum advance (as was pointed out to me... thank you) I am beginning to wonder about the cold start injector. I am hearing a ticking sound at the top end of the engine and it does not seem to come from the side where the injectors are. I have had work done 3 years ago on the engine temp sensor ( at least that is what the shop said they replaced) and wondering... based on what I have read on other posts... could the temp sensor (not the one connected to the dash display) be stuck on cold and causing the cold start injector to be continuosly running? If I disconect the harness from the cold start injector while it is running.... and I get a lower rpm out of it... would this mean that the temp sensor is bad?

Also does anyone know of a way to test your own vehicle somehow before taking it for emissions?

pappatoad

also to note... the oring on the distributor is the one that sits directly under the cap not the one on the shaft that sits in the head.

pappatoad

well this is frustrating.. has all new tune up parts.. replaced cap and rotor also... replaced seal under cap on distributor. tested the cold start injector to see if it was running by disconnecting the harness from it... no change in idle at all. once again sprayed brake clean around all visible vacuum lines to search for leak. nothing found. Parts guy at toyota said that the fuel pressure regulator could be bad. not sure on that.... no blown head gasket... because no loss in power, no blue or white smoke, and oil is not milky.

Any one have any ideas on what would cause the truck to fail emissions 3 times and after each time more work getting done to help but only making the CO2 ratings go up? It runs smooth and has power, but it keeps failing emissions when a year and half ago it passed with flying colors. I am about ready to give up on this thing and scrap it.

myyota

Go over to marlin crawlers forums and click on the engine/drive train section, there is a long thread there on how to pass smog, it tell you what to do and gives all kinds of tips. It should help you out.

bkubisht

You are failing for Carbon Monoxide (CO) right? More Carbon Dioxide (CO2) is a good thing, you want that to be 12-14%. Is it a load test, or do they just test it idling there? What were the other gas readings (NoX, O2, CO, CO2, HC).

pappatoad

ok... sorry got them crossed... right off the emissions papers from the 3rd try (the worst one)
HC Failed 3.02 reading 3.00 limit (this passed on previous two attempts)
CO Failed 95.7112 reading 25.0000 limit
CO2 329.6126 reading
NOx Passed 1.6467 reading 5.0000 limit

was full test at our stations at idle and under load.

pappatoad

found my 2nd emissions test... everything but CO passed... and all I changed after this test was the O2 sensor.. well I think there is part of my problem... everywhere I see aftermarket O2 sensors dont work and I believe this is the case. I will have to spend more money to get the correct toyota O2 sensor. here is the kicker.. the results from the second test.
HC passed 2.6067 reading 3.0000 limit
CO failed 75.5697 reading 25.0000 limit
CO2 341.8834
NOx passed 2.7649 reading 5.0000 limit

bkubisht

Yep, you're running rich, but none of those readings seem really clean. I see there's some nox, so I'm guessing these numbers are under load? From these I would say look closely to be sure there's no leaks in the exhaust from the O2 sensor to the head. That would make it run rich, because the O2 sensor will think there's not enough fuel to use up the oxygen.

How far is your O2 sensor from the head, and is it a 1-wire or 4-wire type? Are you running a header, and if so which one?

Have you ruled out a leaky injector?

pappatoad

they were all lower the very first time it failed. after the first time I did a tune up. when I removed the old plugs.. all were fouled... replaced with new ngk...and did rest of tune up and timing resets. o2 sensor is about 3 inches away from the cat on the engine side... there is a header on it.. but I have no clue which one it is anymore... there could be a leak at the connection with the header and the exhaust pipes as we had to do a clutch fork last fall. I will check that out too....O2 is a four wire connector

bkubisht

OK, the header probably isn't the problem if it's a 4-wire sensor. Sometimes having the sensor so far from the heat source doesn't keep it hot enough to work, but your sensor is heated (4-wire).

A leak would only cause you to run rich if it's upstream of the O2 sensor. Or maybe a couple inches downstream since reversion does happen. Look closely around the header flange for leaks too.

If no exhaust leaks are found go back to thinking about why the efi system isn't in fuel control. A couple other things to check are temp sensors and cold start injector.

thook

Closed loop mode means the ECU is able monitor it's own output. This is accomplished by the O2 sensor in the exhaust. But, it can only do this when the motor is hot, the O2 is hot, and only under warm idle and light load conditions. During heavy load, acceleration, and when the motor is cold, the ECU is in open loop and exhaust is not monitored for fuel correction. Rather, an O2 signal is not yet generated (when cold) or the signal is just ignored.
,
http://www.autoshop101.com/forms/h44.pdf
http://www.autoshop101.com/forms/h58.pdf
http://www.autoshop101.com/forms/h56.pdf

boxer.fan

bkubisht and thook are on the right track. Your truck seems to be running rich based on the co and hc readings. although on previous tests you did pass hc it was still up there passing marginally. First, make sure your thermostat is working and proper temp. If you have the 180 degree it might be too cold of a stat, try the 195. Also where is your needle, on the dash, for temp? If its cold then you could still be in open loop, if thats the case your tailpipe will also be black. As bkubisht said, could be a leak upstream of o2 sensor creating a false reading of a lean condition and o2 sensor compenstating by adding more fuel.

pappatoad

I have an electric fan on it that comes on when the temp rises just above halfway on the dash monitor... I had it set higher before but turned it down recently I can turn it up again if need be. I was just under it tonight and found 2 exhaust leaks. One is right where the headers connect to the exhaust. The connector is black around the edges and I can feel puffs of exhaust coming out in several places along the circumference of the pipe where they join. it is up stream from the O2 sensor. I also found that where the pipes connect to the cat behind the O2 sensor there was a leak there because the flange was not properly bolted together. I re-attached the pipe but I am still worried that because the gasket is worn that i am leaking there and the tailpipe side of the cat. I see carbon marks at all locations. I think it is time to get it into an exhaust shop as I have tried several OTC remedies for exhaust leaks and they are still there. Since the timing is spot on and not jumping and it runs smooth, I am thinking it is leaking too much exhaust for the system to adjust correctly. I think the 1st tests were lower because the O2 sensor there was plugged up a bit and the mass air flow sensor was not cleaned... that it was not reading the correct amount of O2 and exhaust so was not increasing the amount of fuel input until they were changed.

thook

Very good troubleshooting. Yes....fix the leaks.

bkubisht

Fix, retest, and tell us what happens!