Just ran a pre-test on my 86 4runner 22re:

15mph/25mph -

RPM = 1544/2351
%CO2 = 13.3/13.6
%02 = 0.00/0.00
HC (PPM) = 163/151
CO% = 3.67/3.40
NO (PPM) = 29/17

Timing = 10 BTDC
Failed on the functional Fuel Cap.


Prior to this test, I did valves, new 02 sensor, new exhaust manifold, gaskets, etc, new cat, new plugs and wires.

Old test before I did this stuff was:

0 mph/15mph/25mph

RPM = 0/1516/2443
%CO2 = 7.0/11.3/11.0
%02 = 9.6/2.3/0.5
HC (PPM) = 669/218/196
CO% = 2.75/4.26/6.37
NO (PPM) = 103/193/259


Any ideas on what else to change to get this thing to pass smog? Smog guys said it was air/fuel mixture... Can you even change that w/o a computer?

Thanks,
Eton

 

What are the standards for your truck, what does it need to be to pass?

 

15/25mph MAX TO PASS

HC = 131/103
CO = 0.61/0.77
NO = 1085/1120

 

check the afm to be sure it is in specs. the fuel wheel inside can be messed with as a last resort.
http://personal.utulsa.edu/~nathan-buchanan/93fsm/
read this.... if this doesn't help.... move to an area without smog testing...lol

 

Thanks. Just had a thought... could it be because I have 91 gas in it? Not burning everything? Or would that not cause the truck to run that rich...

 

How does it run and drive? How's the fuel mileage? Have you done a compression test? What brand o2 sensor, plugs and wires? "I did the valves" is a little vague. Care to elaborate?

 

Leave the VAF alone, unless you know it's been tampered with (it's in a sealed container, so it will be obvious if anyone has messed with it.)

HC a little high, CO very high: You're running too rich. www.autoshop101.com/forms/h56.pdf You could have fuel pressure too high (bad FPR), and you'll need a fuel pressure gauge to test that. You could have a leaky injector (examination of plugs may give you a clue. You could have misfire (that will usually run up the HC more than CO).

Or your catalytic converter could just be the wrong one.

Air leak in the exhaust (not induction) can cause a rich condition; the O2 sensor thinks (incorrectly) it's running lean and pumps up the fuel. You have very high O2 readings; worth checking out.

 

Runs and drives great. Not sure of mileage yet, since I just got everything done on Saturday. No compression test, but it has new heads on it. o2 is a bosch, plugs are from toyota, wires are import direct (best ones they sell at the local auto parts store). Valves were set at intake .20mm/.008in exhaust .30mm/.012in

No misfiring at all... no popping or lugging. Runs great... The catalytic was cleared and worked hence the low NO readings. I fixed all exhaust leaks. I had a cracked exhaust manifold, hollow catalytic, and rusted out welds around the cat. Fixed by purchasing a new manifold from Dorman (gaskets and everything), bran new cat, no air leaks at all. No pinging, no popping even on a heavy downshift.

What would a leaky injector look like on the plugs? I may look into the FPR... any idea what the fuel pressure should be? Could it be the 91 octane gas?

Thanks!!!

 

Fuel pressure (engine off, fuel pump running on jumper) is 38-44psi. Do I make these numbers up? http://personal.utulsa.edu/~nathan-b...28fuelpump.pdf

A leaky injector could leave a wet or carbon-y plug. What you are looking for is a difference (all 4 won't leak at the same time).

 

Thanks... Ill check these things out... wish I could go wheelin' to relieve some stress... haha

 

Could be bad Cat.
I had similar readings

eg.
first test 15mph/25mph
HC 190 (max 127), 74 (Max 75)
CO .71 (max .55), .24 (Max .69)
NO 1429 (max 721), 397 (max 623)

Second test w/ New Cat
HC 49 (max 127), 12 (Max 75)
CO .03 (max .55), .01 (Max .69)
NO 59 (max 721), 4 (max 623)

This 3vz has 305K mi.

 

91 octane fuel should have little effect. Is the fuel old? What do the plugs look like? Any of them black? New head? Or rebuilt? First thing I would test is compression. I would also be suspicious of the bosch O2 sensor. I prefer denso.
Next on my list to check: Coolant temp sensor (the one for ecu not the gauge one),
Leaky cold start injector,
thermostat(stuck open)
Leaky Fuel pressure regulator diaphragm(pull the vacuum hose and look for fuel)

 

I will pull the plugs today and see what they look like. Not sure of the head is new or rebuilt, previous owner did it. After checking the plugs and running a compression test I will go down the list. Thanks.

Maybe I will try the denso sensor... anyway to check of the bosch is working properly?

 

You can check the waveform of the o2 sensor using an oscilloscope. I would imagine it looks normal if you have no trouble codes. Curious to see what the plugs look like. Any black soot around the tailpipe? I suspect either its dumping too much fuel, or it has the right amount of fuel, its just not being burned, either from poor quality/contamination, weak spark, low compression.

 

Just so you know the high CO means you have a lot of partially burned fuel in the exhaust and the high HC means completely unburned fuel. I have to hop on the running rich train especially since your NO is so low (lots of fuel equals low combustion chamber temps equals low NOX) also absolutely no 02, while common, also could point to running rich, all 02 is burning and when there is none left no more fuel can burn. You'll be able to get a lot from inspecting the plugs. Post some pics of them, clean them up and gap em!

 

Will do. I am also thinking it maybe the AFM. I tested resistance on it, and on terminal came back on the low-end of acceptable.

Thanks,
Eton

 

So... had a compression test done. 1 and 3 are low. Next I will have them do a leak down test to pinpoint if its the head or rings, etc... I hope its just the head...

Anyone have a good rec for a new head? Also, how difficult is it to replace a head myself?

Thanks,
Eton

 

1 and 3 are low? How low? First thing I would do is check/ adjust the valve clearances. Hopefully if they're tight, they're not burnt

 

I do not know if I'm to late to help but the one thing I know why a lot of 22r fail is the egr tube are plug up just remove the tube and clean it out and put it and also get that hot real hot before the test are the best tip I known for a long time. And I live in the smug state. But in the mountain

 

I've seen that as well, but plugged egr would cause high nox. He is well below the standard.