I've been smoging my 87 22re 4Skinner here in Las Vegas for almost 10 years. Last 3 or so it's been harder and harder to pass. Just found some good info that might be contributing to the standard 22re miss. The cold start air valve in the throttle body maybe stuck open. No other vaccum leaks found anywhere.... But:
while researching that, kept reading about egr delete. I'd love to clean up lines and take out possible vacuum leak potential and trouble shooting complications. However, here in LV we do have a SMOG test. So, I've never had a smog tech inspect my engine, they do open the hood for a rpm and timing check but dont jump t1/te1 or even check CEL record. My thought is: can I delete the EGR and still be under whatever our emissions limits are? Or without the EGR system does it just send your emissions into a global warming machine that will have no chance of passing anywhere?

Short of it: witiout having to pass a visual inspection and only having to be under the numbers, COULD a well running 22re pass a non-california number limit only test? Could it be close enough to try?

 

I don't live in Clark County, so I don't know the exact numbers you're trying to hit (why don't you tell us?).

I assume you have a tail-pipe test. In that case, you're being tested for NOx emissions, and the chance of passing that test without an EGR is just about nil. That's what the EGR does; that's ALL it does.

If you think a "miss" is connected with your difficulty passing, I'm guessing your problem is HC emissions. An EGR delete won't help that at all.

If your truck is running so poorly that you're having trouble passing a smog test, what is the attraction of "cleaning up" the parts of the engine that are designed to help you pass?

 

It will not pass without the EGR in good working order. Toyota put it on there for a reason. I would go through the factory service manual and test each emission system.
When is this engine miss accuring?
What have you done tune up wise and what brand of parts did you use?
A failing igniter can cause a random miss at idle, seems to be common on these old Toyotas.

 

Round about 185,000 miles I pulled the EGR off my 92 22RE, and it was about 3/4 of the way clogged. Yours probably needs cleaning if it has lots of miles.

 

If you're truck has been gradually getting worse and worse with respect to emissions, I would suspect the O2 sensor is getting tired. I don't normally recommend just replacing parts, but the O2 sensor is fairly cheap (<$50, I think), and easy to get at and replace unless rusted badly. When the O2 sensor gets old, its response time increases, and emissions go up. It may still "pass" the FSM tests, but the switching action from 0V to 1V and back again will be sluggish instead of crisp. My truck was still passing emissions with the original O2 sensor, but HC and CO dropped by about 3x when I replaced it with a new Denso sensor a couple of years ago.

I agree that cleaning your EGR system, and replacing any vacuum lines that are cracked or brittle is your best bet in that area. The truck won't run better with an EGR delete vs a properly operating system. While exhaust gas recirculation does rob power, the EGR system is designed to deactivate during full throttle operation when you need full power, so it gets out of the way when it matters.

 

I rebuilt engine top to bottom about 5 maybe 6 years ago probably 40ish k on it. Three years ago sent injectors into witch doctor and that fixed emissions to pass. Last year hc failed again, did full tune up from fuel filter, pcv, wires, plugs, cap, rotor, plenum upper and lower removal and bath, same with erg pipe, new O2 sensor, timing, and idle set, cleaned out air intake box and k&n filter, checked for leaky cold start, replaced most vaccum lines, checked for vacuum leaks with an actual gauge kit and old fashion starter fluid spray, starter relay upgrade from quick fire/fast fire/sure shot or something like that, tested VSV, BVSV, and ABCDEFG valves, everything was within spec or working and not leaking.Resisted sending in injectors again, but did and then after 3 tests, still had an audible small mis every so often at idle, but passed with flying colors.
This year time to smog again, still has an audible idle small mis dont see it on the rpm gauge but can hear it and see the shift vibrate slight different for a split second ever 20 to 40 sec or so. Just found out for the first time about the cold start bypass valve in the throttle body actuated by the coolant heat coming in and out letting air around the throttle while closed. Maybe thats where extra air is getting in causing miss and high hc that the tsp isnt adjusting for if that valve is stuck open. Found a possible test for that in placing aluminum tape over the valve intake hole in the throttle intake and see if miss gets better, but not very measurable or precise test... My TB doesnt have a removable bowl to check on that valve so not sure how to check it....
I broke my TPS sensor connector recently, so just took it ofd and the spring was sticking dropped a little oil in it but only help not sticking still sluggish rotation. So just got a new one and replaced it taking the TB off and setting it, per 4Crawler, on the bench. Have a new connector ready as soon as I have time to splice in and solder to the wiring harness. When taking out the TB noticed the throttle body coolant bypass hose is all but ready to fall apart. Trying to find a source and part number for that hose now. Was on the phone with LCE for 45mins for them to try and find what I was describing since I have a pending order with them for some other hoses. They couldnt find it. 22reperformance has it but only in a kit with 2 other hoses I wont need for a while, cross fingers.
Solid running engine other than small mis and eating coolant somewhere. Can't complain about 310kmi power/feel/response, just doesnt like the smog machine. Coolant needs to be topped every 3 or 4 weeks, but no perceivable leaks under hood, on the under carriage, in the driveway, or at parking lot at work. I guess if head gasket leak let in a little coolant which cooled combustion just enough to hinder full combustion would cause miss and high hc's...... Did I just figure this out?!?

 

Need to do a leak down test to verify if you have a head gasket leak. Only way to know for sure. Do leak down test with engine cold, rad cap off. When you pressurize each cylinder look/ listen for bubbling. It is my understanding that a failing igniter can all so cause a slight miss at idle. There was a member here I think that had the same problem with the idle miss. He found a NOS igniter and installed it and it fixed his miss. Since the igniters are near impossible to test its hard to say for sure how or what fails on them.

 

Thanks, that's an interesting theory, I just gave it a test drive after full tuneup and timing after the new tps installed per 4Crawler. All sounded great, nondrips any where after a 15min smooth idle at about 800rpm. Drove a 5 miles up the freeway very smooth 70mph@3k rpm steady up and down small rises and falls without having pedal to the floor. Got off the freeway to turn around and did great only dropping to 60mph up the last pretty good hill to the house exit in 5 gear.

But as soon as I stopped at the exit light, my old problem of the tach gauge reading 200-300 rpm but a healthy sounding engine still idling & sounding "normal".

Searched the web for "where the tach gets its signal" and it brought me to a not well explained thread that seemed to infer that a stereo glitch and gauge cluster issue were linked. I did have a stereo short problem and a complete gauge cluster fail that ended up being the transmission reverse sending unit wires shorting on the exhaust pipe and blowing my engine fuse. But now its just my tach going crazy.

I read another article about the tach getting signal from the ignitor. So if the ignitor from what your saying is going bad and causing my intermittent small miss it may also be effecting my tach??!??