1987 22rec 4runner SR5 manual transmission sitting on 31s
340000 miles not sure if OG engine
Purchased 2 years ago and now smog/ emissions is due.

Problems:
Oil consumption is very high.
Gas mileage avg 14 mph
Emissions test failed at 15mph but passed at 25 mph
Emission test #1 failed HC
After valve adjustment and new O2 sensor
Emission test #2 failed HC and NOX

As far as I know everything is stock exept:
-P.O. said he put a "racing cam" in it
-LCE Street Header (CA legal)
-Walker Series 80900 Three-Way Catalytic Converter
-Magnaflow muffler

Compression (dry):
#1 155
#2 148
#3 148
#4 142

#1 Emissions 15 mph at 1600 rpm
HC PPM Max 131. Meas 234 FAIL
CO% Max .61 Meas .20 PASS
NO PPM Max 1085 Meas 972 PASS
CO2% 14.8
O2% 0.9

-Replaced O2 Sensor
-Adjusted valves
-Set Idle @ 750
-Checked timing with jumper in place and set at 5 BTDC

#2 Emissions
HC PPM Max 131. Meas 239 FAIL
CO% Max .61 Meas .37 PASS
NO PPM Max 1085 Meas 1334 FAIL
CO2% 15.3
O2% 0.1

This is what I've done since last test:
EGR Valve tested. Vacuum applied to egr at idle and engine stalled. Tested temperature vacuum control valve for EGR modulator. I smoke tested vacuum lines for leaks. The PO remove the AC compressor and lines by that plastic screw on the top side of upper intake has a small vacuum leak that I can correct with a new o-ring. Replaced plugs (NGK BPR5EY) wires (NGK), cap and rotor (Toyota). There is a strong possibility that one of the wires wasn't in full contact with the plug. Tested ignition coil. Checked for exhaust leaks, small leaks found after the cat. Tested cold start injector for leak by jumping fuel pump on without engine running. I checked and reset throttle plate .25 turn pat initial contact of stop screw. I set valve clearance cold using the tolerances for LCE I believe. I think that it was .007 and .013. I tested AFM. Changed oil and filter to 20w50 Castrol GTX
I made and installed a metal plate with a 2 inch hole to restrict the exhaust a little bit. From the research I've done I found that the diaphram on the EGR modulator requires some back pressure from exhaust to fully open. The exhaust that is diverted into the intake also requires some restriction in the exhaust to move through the EGR system to the intake. I installed a new Toyota coolant temp sensor.
I checked engine codes and got a 6 -RPM SIGNAL-NO SIGNAL TO ECU FROM DISTRIBUTOR ("Ne" OR "G") AFTER ENGINE HAS BEEN CRANKED
--DISTRIBUTOR/CIRCUIT
--STARTER SIGNAL CIRCUIT
--IGNITER/IGNITER CIRCUIT
--ECU
I cleared codes and will check again on Wednesday. At one point I recall bumping the ignition off for some reason on the freeway with engine running and in gear. May have caused the code
I plan to test it again on Wednesday. If it fails I plan on doing a piston soak then oil change with auto-rx to unstick oil rings. Old spark plugs are so clean it doesn't make sense with the amount of oil the engine is eating.

So this just hit me. Should I put some smaller tires on? The test is done on a dyno 1st gear 1600 rpm at 15 mph. Larger tires made the speedo about 10% faster than its actual speed shown. So as far as the motor is concerned the test is actually being done at 13.5 mph and 1440 RPM.


PO has never been able or willing to give me info regarding truck. The exhaust smelled rich like there excess unburned fuel making it through the system. At time of purchase I questioned him about any difficulty passing smog test and he said it passed no problem. He seemed like the type of guy that would know someone willing to bend the results for some extra cash. I just need to find that smog tech lol.

The day I bought the truck I looked it over pretty good. The dipstick and oil looked clean and the oil was at the full mark. I drove the truck about 150 miles the first week and had been doing a little research on what type of oil this engine likes as the valves sounded loud to me. I had the hood up and I thought I'd check the oil level. I checked it three times and it was dry. I took about 3.5 qts to get here topped off at full. Of coarse I reached out to the PO and he had never had this problem. I was pretty sure the engine was going to need a rebuild. I did a little research and discovered high mileage oil and tried it out. I've been using Royal Purple HMX 10W30 and would have to add a qt at every gas fill up which is about 200 miles. This became my Royal snake oil! I usually add about 14 gallons of fuel which puts her at about 14.3 mpg which seems low to me. So anyway at the time this was a success in my book for the oil consumption problem. Plus I never have to do oil changes now as I am continuously replacing the oil (I'm joking about the oil changes). Wow, I just did the math that's 15 qts of oil every 3000 miles.

Last year I had an ignition problem which after lots of testing and replacing parts I traced back to the ignition control module. The motor was misfiring very badly to the point it wasn't drivable and would through explosive fire balls out the tailpipe. During this endeavor I had removed the throttle body to test and ultimately replace the TPS I noticed a substantial build up of oily sludge in the upper intake. The sludge was about 1/4 inch thick. I replaced the cheap plastic PCV with a new metal OEM one although the one that was present seemed fine. I check for blockages in both front and rear valve cover hoses and at the connector ports on intake and valve cover. All appeared fine. I did 2 rounds of sea foam intake cleaner which produced a ridiculous amount of white smoke. I assumed this finding would correct some of the oil consumption but it didn't. I haven't had the throttle body off since to check the condition. I did Sea Foam it again last week but it didn't produce anywhere near the same amount of smoke as it did originally. So I'm assuming this isn't an issue anymore but may be wrong

There is not a drop of oil visible anywhere on, near, or around the engine. I have looked in every nook and cranny from top to bottom. Never a drop on my cement driveway. Smoke wasn't noticeable until I really looked for it. When shifting from 1st to 2nd qhen the clutch is in there a barely visible puff of bluish white smoke. 2nd to 3rd shift produces a little bit more smoke but again it is barely visible. You can only see it if the sun is setting behind you or if there's a car with bright lights at night. I really only notice this when I'm pushing the RPMs up to 4k getting on the freeway or up a hill. There is no smoke at start up no matter how long its been sitting.

She has quite a bit of power for the tiny beast that she is and idles very smoothly. When decelerating in any gear there's a snap, crackle, pop noise from about 2.5k-1k RPMs that is more intense after warmed up. I've heard similar sounds on big block cars that have similar mods. Not sure of the science behind that sound.

Anyone else with similar super high oil consumption with failed HC issues. Any ideas before I start seriously considering an engine swap? I'll try to figure out how to post pics. I have my old plugs and some shots of the camshaft I haven't been able to ID.

 

Don't recall if this has the pair or smog pump. I'd look into this, you have high HC and low O2. The pair/pump feed the catalytic system with fresh air to convert the unburnt HC.

NOX is dependant on temperature. It seems your flow restriction has backfired and reduced the effect of the EGR system.

 

No stock smog pump or air injector on this 22rec. I installed the exhaust flow restrictor after the failed NOX on the second test. I haven't been through emissions testing with it in place yet. I hope to retest tomorrow.

 

Something I did worked.

#3 Emissions 15 mph at 1600 rpm
HC PPM Max 131. Meas 126 PASS
CO% Max .61 Meas .02 PASS
NO PPM Max 1085 Meas 916 PASS
CO2% 15.1
O2% 0.5

So barley squeaked by so I'll probably be revisiting this same problem biannually.

My oil consumption is still really bothering me though. If I'm burning 1 quart every 200 miles why are my plugs so clean. Where's the smoke?

 

Yeah, that's a squeak! Something is still wrong with your EGR system (my NOx has never been higher than 51ppm in 10 tests over the years).

Oil burning will definitely run up HC. But I, too, would expect to see it on the plugs. Are you sure it's burning, and not just leaking somewhere?

 

No leaks, I have checked from front to back and top to bottom with a high power flashlight. I've owned it 2 years and never seen it leak a drop.