TexFF

My 4Runner(specs in signature) seems to have a lot more power when the motors cold then hot. Also, it feels like a surging upon acceleration when hot. A couple months ago I did cap, rotor, plugs, fuel filter, Denso O2. Took my rig in yesterday expecting it to pass but it failed. Here's the numbers:
Standard: Mine:
15 mph
HC 155 137 Pass
CO 1.31 .59 Pass
CO2 13.7
O2 .9
NOx 1046 1291 FAIL

25 mph
HC 151 135 pass
CO 1.68 0.77 pass
CO2 13.6
O2 .8
NOx 956 2336 FAIL

Found 2 massive vacuum leaks. Repaired them. Checked EGR w/vacuum pump by having the engine running, pulling vac. on EGR & motor died. Mechanic thought it'd be good to go now so I went back about 15 miles later.
Standard: Mine:
15 mph
HC 15.5 134 Pass
CO 1.31 .63 Pass
CO2 13.6
O2 .9
NOx 1046 1260 FAIL
25mph
HC 151 128 Pass
CO 1.68 .75 Pass
CO2 13.6
O2 .8
NOx 956 2113 FAIL
My mechanic(a buddy) went out of town for the weekend so I won't be able to have him check(test per VSM) until next week but I need to fix this ASAP. Do these numbers tell you anything? I have no clue what they mean!

blake.nemitz

well i had the same problem here is how i passed with flying colors. the first time i retarded the timing to 0 degrees and it passed when at stock timing it failed high nox. the other rig ran like crap. i ran it almost empty put a quarter tank of e85 in and passed just fine, siphoned out the corn gas after and topped with midgrade to flush out the rubber harming alcohol.

blake.nemitz

try retarding the timing to zero and see what happens, should reduce cylinder pressures and the formation of nox

scope103

They tell me your EGR system isn't working. NOx is what it does, that's ALL it does.

With my '94, my NOx is 48 and 43, so you are WAY too high. (Your other numbers are a little high, so I can't rule out a weak CAT, but the CAT has only a small effect on NOx, and I really doubt it could explain your problem.)

Put your hand on the tube that enters the plenum. I'm told it should be "warm, not hot." One possibility is that the tube inside the plenum is so caked with gunk that the injected exhaust gas is going nowhere (though your pump-on-the-EGR-valve counter-indicates that).

If you want to know more about 5-gas analyzer numbers, http://www.autoshop101.com / technical articles / engine performance OBD I / emission analysis

scope103

In my neck of the woods (California), mis-setting the timing alone will fail smog. So whether or not retarding the timing would have an (very big) effect on NOx, it won't help pass smog (at least, not in CA).

TexFF

That tube is very warm. I can touch it & hold my finger on it for about 2 seconds then I have to take my hand off it. Also, pretty much all gas around here is E85 so it's already using that.

abecedarian

Mind you, CA's emissions tests don't cause the EGR valve to open- they know that if the EGR is open, your NOx should go town.
They only test you at idle and at 25MPH, and 25 isn't enough to open the EGR.

If you're failing at 25, it's your cat converter. It's the only thing affecting your NOx at that speed since the EGR valve is not on.

Thelast83inNJ

It's possible no EGR operation at 25mph depending on those wonderful engineers but Cats usually are the problem when borderline failures for Nox, not off the scale fails. I say tee in a vacuum gauge to the EGR and drive, look for 3-5 inches of vacuum on the gauge to eliminate a vacuum signal problem. If you have signal you can mostly know (although new Toyota VSV or EGR control solenoids have screwed me) that the vacuum side of the circuit works. I don't know how this vehicle works, but I've had cars that you could power brake and get vacuum, cars that don't give vacuum until high gear, VSV that opens to send vacuum (ECM shuts off VSV ground). Melted vaccum hose inside the protective sleeves. Plugged hoses all types of stupid. Eliminate the vacuum side first.

scope103

California tests at 15mph and 25mph. They haven't tested at idle for many years.

And as I understand the EGR system, http://www.ncttora.com/fsm/1990-1995...n/exhaustg.pdf, speed has nothing to do with whether the EGR is open (if you have your foot off the throttle and you're rolling downhill at 55mph, the EGR is closed). Since the CA smog tests are on a dynamometer, the throttle is certainly open far enough to open the EGR. Otherwise, what would they be testing with all that gear?

As Thelast83 says, the easiest place to start is to check the vacuum signals at various throttle openings. Compare to the FSM. Always do the easier stuff first.

ksti

I think Scope is right I failed smog about a year ago only because of high NOx, (sorry about pic's, crappy cell phone)

15 mph NOx 883 FAIL

25 mph NOx 618 FAIL



So I replaced the CAT for about $80.00 and re-tested later that day.

15mph NOx 0 PASS

25 mph NOx 4 PASS

sbagdon

"normal" gasoline used to be able to have up to 10% ethenol. The EPA tried to lift that to 15% for cars built after 2007 (not sure they succeeded or not). Not using E85 doesn't mean you're not using a fuel without ethenol.

Philbert

iTrader: (2)

I would triple check your vacuum hoses - not just for leaks, but that they are in the right places (get the FSM and check every one).

I failed twice on my 22RE, and did all the replacements you did, and also a new CAT. Cleaned my EGR, etc - still failed. Turned out that some dumbass (me) had incorrectly hooked up some vacuum hoses since his last smog check, causing the EGR not to work. I re routed them, per FSM, and passed with flying colors.

Good luck

22RE4WD

I just got my 91 smogged and failed twice. The first time it failed as a gross polluter (high NOx). The second time i rerouted a crossed vacuum line to the egr and cleaned out the clogged egr. For certain I thought it would pass but it had even higher NOx! The third time I passed...Here's the culprit:



This is the stock cat at 231,409 miles.

Replaced it with a 50 state Magnaflow and passed with flying colors. NOx came down to 20ppm compared to over 3787!

sbagdon

Most people don't realize that cat converters are consumables, it's just that they take a long time to consume. Local recyclers here have two price points for recycling a cat... full-weight (about $120, which is why so many get stolen), and half-weight (about $60). Some much older cars even have zero-weight (steel-by-weight).

Philbert

iTrader: (2)

Where can you sell your used cat... in California?

sbagdon

No sure about CA, yet i'm guessing you could sell one on CL, anywhere. On eBay, it's difficult to sell a used cat, they'll cancel the auction unless it includes lots of their required info (certification of applicability, warranty, gaurantee, returnable, and some other stuff). So I've given up on selling cats, and just go with recycling them.

Philbert

iTrader: (2)

Thanks - that's what I meant actually - I thought I heard once that you can sell your old OEM cat back to the state or something. I have 2 clogged ones in my garage but am not sure how to dispose of them properly (in CA).

sbagdon

Sorry, I'm in MI. Yet there's no issue here finding a metal recycler that will take them (for the platinum, presumably). Yet metal theft is so bad here, believe there's now a 3-day waiting period for payout checks, so it requires a double-visit.