can't pass smog. at wits end.

[iitywygms]

This is one last call for help before I choose another route to get my car to pass smog.
I am posting in the general thread so more eyes see this.
This is basically a continuation from this thread.
248-232-cam-swap-cause-lean-condition-t493848.html
93 240 with a stock ka24de. California car.
I have replaced with new. maf, catalytic converter, back pressure transducer valve. egr, o2 sensor, ecu, plugs, plug wires.
Fuel pressure checks fine. car runs well. Slight misfire at idle because of lean condition. No exhaust leak
cannot find a vacuum leak anywhere. Ran fuel injector cleaner through injectors.
Accelerates well, runs smooth at 55mph.
Engine is now completely stock. Cams are now back to stock.
Problem is that at very light throttle or no throttle the car runs very lean. Almost to a point that it misfires.
I get high nox at 15mph.
this car has been in 2 different shops for last month. Both mechanics are stumped. So am I.
If anyone has a suggestion or anything that will fix the car I would greatly appreciate it.
If not, I have to go another route. I want the car to run right, but I may not have any other choice.

[badbob2121]

offer the guy 60 bucks on top to pass it... happens more often then u think...solution..lol

[iitywygms]

that may be my only choice but I would still like to fix the problem.

[Klits562]

isnt high nox a sympthom of a bad egr system? has anyone looked at your egr system

[iitywygms]

egr system checked for leaks and egr replaced with new.

[jkollerS13 :]]

i went through emissions so many times well im in arizona idk if its different or not but yeah i replaced everything twice (exaggeration) and i just dissessembled my engine to find a cracked head and the previous owner never tightened down the cam gears which didnt help either but i still dont know the results because ive in the process of rebuilding the head but ill let you know what happens.

[motoman399]

maybe open the plug gap a little bit, if you havent replace the cap and rotor, temp sensor, knock sensor, use di electric grease on every connection to make sure its a good one. make sure there is no corrosion on any of the connections.

sorry to hear you are having such a hard time with it. cali sucks. i live in nor cal...

[iitywygms]

Yeah the smogs do suck, and I can get my tags some extra cash.
It is just frustrating cause I want it to be right. I hate half azz fixes.

[Klits562]

did they replace everything in the egr like the silenoid and what not? I dont know everything about the egr just a little so sorry if you already did all this but atleast im tryen lol
also hows your cooling system cause high temps can cause higher nox if i remember correctly.

Also you can try seafoaming your car i used it a few months ago on an oil change(didnt use it for smog) but it makes a noticable difference in performance and i've heard people use it to help with smog.

[motoman399]

Ran fuel injector cleaner through injectors.

you didnt do this right before the smog appointment did you? a smog shop told me its a bad idea to it before the smog appointment.

[iitywygms]

No the injector cleaner was tried after failing for about the fifth time.

Cooling system is okay. Never overheats and the coolant looks okay.

I am not sure what solenoid you are referring to. I know the entire egr was replaced.
Thanks to all for the suggestions.

I seafoamed thru the brake booster line about a year and 1/2 ago. My engine internals are pretty clean as you can see from my previous thread. At least under the valve cover is clean.

[Klits562]

Ran fuel injector cleaner through injectors.

you didnt do this right before the smog appointment did you? a smog shop told me its a bad idea to it before the smog appointment.

Probably cause the injector cleaning hasnt had time to run through the engine.
depending on the cleaner most you pour into a close to empty gas tank fill tank up with 10-12 gallons then run it all that gas so everything gets clean, then refill and your good to go.

Where did you hook up your pressure gauge to when you checked your fuel pressure?
Have you changed your fuel filter recently? You should try a brand new one anyway they're only 10 bucks get a i believe 96 300zx tt fuel filter they're bigger and they fit.

[iitywygms]

The cleaner I used was the good stuff you hang from the hood and pressurize, not the stuff you pour into the tank.

Fuel pressure was checked right before the fuel rail, after the filter.
Will change the fuel filter cuz it is so cheap to do.

[iitywygms]

Okay, I have done some more trouble shooting. I noticed that if I check the resistance of the tps, there is none. It seems to be open.
Could a bad tps cause all of this?

Okay scratch that. I had the meter set wrong.

However, following this how to
ka24de-checking-tps-and-adjusting-idle-t161700.html
It states.
Completely released Approx. 2
Partially released 2 -10
Completely depressed Approx. 10

Mine is the opposite of this. Meaning that at rest it is 10.
And holding the throttle wide open it is at 2.1

Is my tps bad or am I reading the how to wrong?

[iitywygms]

Please answer the above post if you know the answer for sure.

[OutToWinPAHC]

A bad TPS can cause a lot of issues because now your relying on the 02 sensor and MAF to figure it out alone. Maybe try a new TPS with calibration. If nothing.... Put one SR injector

[iitywygms]

I have checked the tps 15 different ways. Standing on my head, with my eyes closed. According to the fsm and several different forums, it is reading backwards. I don't know how that can be since it is just a variable resistor, but it is.
I will change it in the next few days and let you know what happens.
Has anyone ever had this happen?????????

[zer0c123]

any update on your smog? Your NOx numbers are very similar to mine.

[iitywygms]

Ya, now my nox are over 3000. Unreal. I got a exemption but I have to fix it before the next smog. 1 1/2 years.
If and when I figure it out I will post up the results.
And, my tps was fine. That article I referred to is bas ackwards.

[Biggins240sx]

Did you try taking apart you AIV and cleaning it up. That does mess with your emissions test

[LoserCard]

Step 1: Get a spray bottle with water in it. With the engine running, spray water all around your intake manifold. If you RPMs drop after spraying in a certain section, you have a vacuum leak there.

Step 2: Are you absolutely positive that your EGR is working AND are you sure the vacuum lines setup for it are properly? EGR plays a part in lowering your NOx emissions.

Step 3: Is your timing set at 20BTDC?

Step 4: Are you running stock plugs? (BKR5E-11 Copper Plugs) How is the health of your cap and rotor?

Step 5: Are your injectors flowing properly? Simply running a fuel injector cleaner will not fix this. Take it to a school/college auto shop for cheap flow testing. Also check to see if your injector O-rings are in properly.

Step 6: Is your MAF clean?

Step 7: Are you 110% sure your timing chain is correct?

This is just a list of stuff (from what I understand) that you haven't done. If you've already done these, I am boggled...

[iitywygms]

Step 1: Get a spray bottle with water in it. With the engine running, spray water all around your intake manifold. If you RPMs drop after spraying in a certain section, you have a vacuum leak there. did that with carb cleaner, no noticeable change

Step 2: Are you absolutely positive that your EGR is working AND are you sure the vacuum lines setup for it are properly? EGR plays a part in lowering your NOx emissions. 3 different mechanics besides myself have checked it

Step 3: Is your timing set at 20BTDC? yes

Step 4: Are you running stock plugs? (BKR5E-11 Copper Plugs) How is the health of your cap and rotor? using same plugs I have used the life of car. ngk, always passed smog no problems using these plugs. cap and rotor less than 1 year old.

Step 5: Are your injectors flowing properly? Simply running a fuel injector cleaner will not fix this. Take it to a school/college auto shop for cheap flow testing. Also check to see if your injector O-rings are in properly. have not done this, Maybe try later when I have time?

Step 6: Is your MAF clean? swapped with know good maf

Step 7: Are you 110% sure your timing chain is correct? 110% sure

This is just a list of stuff (from what I understand) that you haven't done. If you've already done these, I am boggled...

[RustspecS13]

If you have a lean missfire at idle that needs to be fixed.

You should pull your intake manifold replace every thing that breaks down. IE replace all the rubber vac lines and coolant lines on and under the manifold.

Also I would by pass the throttle body coolant lines, it helps keep the engine from heat soaking and it will not affect your emissions.

I'd almost guarantee one of those rubber vac lines are leaking, or all of them are a little. Every time my friends get a new 240 the first thing we do is rip off all the emissions since we don't have emissions check of any kind here. And every time all those vac lines are in bad shape.

~Alex

[motoman399]

that is true, my vac lines were in real bad shape when i redid them. one was split wide open. that motor was thrashed though. plug wires were melted in the head.............