Topic: higher rpm missing/ won't pass smog...

[Serenity now!]

i just put together a 90 22re 4runner. has a street rv with a 261c cam over sized valves. put in new vacuum lines and new fuel and new fuel filter after running it for a bit with 4yr old gas but new filter. adjusted valves and timing to factory setting.  when i got it running it runs fine. misses a little when cold above 2700 rpms. when warm misses quite a bit at same and more rpms. i have put seafoam thru the vacuum system before the smog test and i just added seafoam to the oil.that has helped a little bit. luckily the smog was a test only. but the h/c were way, way too high! any help??

[jl93221]

http://board.marlincrawler.com/index.php?topic=1119.0

[Snowtoy]

Post up some numbers.  

What type of Cat do you have, oem or after market?

[Serenity now! [OP]]

lets see... {%co2} {%o2 }{ hc max }{hc gp} {hc meas} {co% max} {co gp} {co meas}
      890       12.7      2.3        120       330        363            1.00        2.50       .71
    2432       12.9     1.8          180      270        788            1.00        2.50       .95               

timing was set at 8 deg. I have set timing to 5 now and replaced the pcv valve sense the test. the odom says 192xxx car fax says 224xxx i am sure it is the orig cat. i will replace that soon when the money comes ;need a new muffler as well(unrelated to smog i am sure:))

[junya92toy]

Ya you have 4year old gas.

[Serenity now! [OP]]

i replaced the gas with 91 oct before the test and ran it for 30 min then drove for 15. any thoughts on the carbon canister?

[Snowtoy]

By the looks of it you are running way rich, a new cat wont correct those numbers, not enough to pass anyways.  

Did you have the injectors rebuilt? Might check the cold start injector as well, it could be leaking fuel.  You could have an air leak somewhere after the AFM, that the ecu is try to correct by richening the A/F ratio.

How many miles a have you put on the rebuild, everything may not have seated by the test.  I know when I rebuilt my '91 22re it failed the first smog test, when took it back 3 months later it passed w/o issue, and all I did was drive it.  I would try to put another 500 miles or so on it, recheck the valve do an oil change and then test it again. 

Is the cam one of EB's, if so I think it is supposed to be CARB legal, if not that could be part of your issue.  

If the cat is original it might be fine, pull it off and see what it looks, given the cost of CA cats now, I wouldn't just buy one unless you are sure yours is shot.  

[Serenity now! [OP]]

snowtoy thanks for the input. i have put maybe 70 miles before the test just a lot of idle running and testing.... the cam and head is from eb.. i have duct taped the 3" black plastic piece from the air filter to plenum due to cracks. i was thinking of switching battery and air filter locations due to so much cracking. no i did not blueprint the injectors but cleaned them also fan seafoam through the fuel tank too.

[Serenity now! [OP]]

also**** i just replaced the pcv. less than $2... seems to help a little i will drive more tonight. I do feel as if I drove more i twill get better like snowtoy said. i had been sitting for 4 yrs!

[Snowtoy]

While idling can work an engine, it isn't working it very hard, not like 8-16hrs run time on the trail.  I know it is a waste of gas, but a trip down I-5 to Sac then 99 north to Chico would be good long drive to break the engine in, and you wouldn't have to push it like heading north.  It is to bad the the DMV limits you to only 60 days to before charging you for an extension, unlike in the past, if you don't drive a lot of miles/week it makes it hard to break in a rebuilt engine.

[Serenity now! [OP]]

drove it all around today, still has miss with over 2000 rpm less when i step on it more cruising at 2k and up. i have been reading up, maybe the egr modulator if malfunctioning? tested the carbon canister, and it tested fine. when i apply vacuum to the egr it dies unless i stop quick.

[Serenity now! [OP]]

well i changed modulator with a known working one and it still missed...... could it be fuel pump, injectors???

[sUckAfiSh22re]

injectors could be causing miss when getting on gas a bit, but timing could be an issue even with factory setting if new cam n such is different than factory. i'd try to clean injectors one more time, then play a bit with timing. keep driving it and break in that motor

[Joey88RUNR]

drove it all around today, still has miss with over 2000 rpm less when i step on it more cruising at 2k and up. i have been reading up, maybe the egr modulator if malfunctioning? tested the carbon canister, and it tested fine. when i apply vacuum to the egr it dies unless i stop quick.

I had a similar issue, I had the Egr vacuum lines backwards, Check vacuum lines are hooked up correctly

[Serenity now! [OP]]

went through all the vac lines and all good. i have adjusted the tps to fact settings(not that it was off) but i wanted to check still nothing. seems a little better. i will be replacing the large dist o ring between the cap and housing. the one i have is cracked and parts are gone... could this have anything to do with my problems?

[Snowtoy]

W/a bad O-ring, what is the condition of the cap and rotor?  If they have corroded or are worn, they could be causing some issues under a heavier engine loads.  If they have corroded, take a piece of sandpaper and remove the corrosion, if worn replace.

What is the age/condition of the plug wires?  An arching wire can sometimes cause the engine to act like it is missing.

Has advancing/retarding the timing effected the miss at all?  Did EB recommend a different setting than stock?

[Serenity now! [OP]]

cap and rotor new no corrosion, plugs and wires are new as well. eb said to set as stock. timing doesn't change miss.

[Tallchevy]

Did you install the correct size orifice for the egr valve? Having the work size could cause this problem.

[Serenity now! [OP]]

tallchevy*** i didn't change any thing on the egr just rebuilt the top  and put it back together. what orifice are you referring too? maybe some carbon crap got lodged in there somewhere. there was A LOT of build up in the emissions system, i cleaned the best i could with a gun cleaning kit and some seafoam.

[Snowtoy]

Have you checked the ecu for codes yet?, might help if anything is registering.

You can also try pin pointing which cylinder is causing the miss by pulling a plug wire w/the engine running.  If the miss goes away you have found the cyl.  If the miss doesn't go away, this means something is effecting them all, i.e., gas flow, injectors, poor air/fuel mixture, bad coil, etc.

If you haven't pulled the plugs yet, pull them and see what they look like, could have a bad/failing plug.

[Serenity now! [OP]]

pulled each wire, eng was affected each time. code 51 only when there is gas applied, at idle no codes.

[Snowtoy]

Did the miss go away at idle, or under load?

If you haven't done it yet, you might try the propane test along all of the intake tube, hose, vacuum lines, and along the intake manifold, you could have a large leak or a lot of small ones.  If you are unfamiliar w/the propane test, take a hand held propane torch(typical 1lb bottle and torch tip), crack the valve enough to let the gas flow out but not like you are going to use it, and run it along the intake system.  If the engine idles up, you have found the leak.

If you don't have it yet, here is an online '93 Factory Service Manual.  While it is for '93's it works well enough for the older engines.

[Serenity now! [OP]]

miss is only at "cruising", no load. at idle or with a load it does not miss. i haven't tried that test yet. i will though this weekend thanks. i am first going to try and adjust the tps. the code reads when the throttle is pressed even a little, even with engine off, 51. i checked the ohms and between e2-idl the ohms are off when i measure .85mm 

[Serenity now! [OP]]

ok so....... propane test nothin'   adj tps nothin'   tps is unable to be adjusted correctly. i can get either the e2-idl .85 mm or e2-vta correct but not both.

[emsvitil]

ok so....... propane test nothin'   adj tps nothin'   tps is unable to be adjusted correctly. i can get either the e2-idl .85 mm or e2-vta correct but not both.

I don't think it's possible to adjust the tps to exact specs...........

All you're looking for is that IDL-E2 has continuity somewhere around .57mm and less than .57mm

And is an open circuit somewhere around .85mm and above.

I think mine is at .5mm and .8mm...........


VTA - E2 should vary from a lower resistance to a higher resistance smoothly as you open the throttle.