3rd gen Will

iTrader: (8)

Okay, I have been dealing with this a few weeks. The car has all required emissions equipment, no check engine light/trouble codes. Air Injection seems to be in good working order, pump puts out air. Brand new magnaflow #" highflow cat. Brand New EGR valve and I ran through the troubleshooting diagram that was posted in the EGR temp sensor thread. Car runs fantastically timing set at spec 6* btdc Brand new AC delco plugs, taylor 8mm wires, brand new cap/rotor, brand new fuel pump and filter, brand new 24lb for blue tops injectors. Fuel pressure is solid, i know it was over 40psi (42-44ish dont remember exactly) a month ago when I did the pump/hotwire kit.


1st try Ran the car through first time w/ a used and incorrect EGR valve and in the afternoon.

HC .54 of 1.0 allowed
CO .34 of 12.00 allowed
Nox 3.99 of 2.5 allowed

2nd try. New and correct AC Delco EGR ran it through first thing in the morning.

HC .41
CO .07
Nox 3.60

3rd try. Read about the "drill mod" to the EGR recommended by Dyno Don and ran 1/2 can of seafoam through it, went through in the evening it was cool and it had just rained.

HC .46
CO .15
Nox 2.82

4th try. Ran it through tonight, nice and cool outside. Pulled 4* timing. Now set at 2* base. Put 32oz of 70% isopropyl alcohol with about 1/2 tank of gas.

HC .43
CO .31
Nox 2.81

So did I do the rubbing alcohol thing wrong?

I have done lots of searching on here that is how I found out about the egr drill mod and the troubleshooting diagram. I am out of ideas. Any help would be appreciated.

BlackMamba

iTrader: (6)

I would check out the cat on your car, if you explain it already my bad. Usually replacing the cat for a new one makes a lot of difference.

3rd gen Will

iTrader: (8)

Oops, I forgot to list that.

Brand new Magnaflow 3" cat.

Thanks though!

paulo57509

I've been dealing with this same problem for three years. So beware that I'm not an expert at emissions diagnosis.

I was going to post that it's not the cat. Look at his HC and CO numbers.

High NOx could be either malfunctioning EGR system, the engine is running hot, carbon deposits in the combustion chamber causing localized hot spots or a lean mixture.

You verified that the EGR system is working, but this doesn't check the exhaust passages.

If you have a negative backpressure EGR, try hooking up a vacuum pump directly to the valve. With the engine running, apply vacuum. The engine should start to idle badly and stumble. This verifies the passages aren't plugged.

If you have a positive backpressure EGR valve, bring the engine RPM's up to 2000RPM or so and then apply vacuum. The engine should start to idle badly and stumble.

Make sure that the cooling system is in good shape. Clean radiator (internals not partially plugged), correct thermostat, etc. It might help to run 100% clean water for your test. Water has more heat capacity than 50/50 mixture of coolant and water.

For combustion chamber deposits, run a can of Seafoam through one of the vacuum lines. You might even want to take out the plugs (PITA, I know) and squirt a bit of Seafoam in the spark plug holes and let it sit over night before starting it up.

Do you have access to a scan tool that you can use to monitor your mixture? This is the easiest route to see what the mixture is doing. While I don't advocate throwing parts at something, O2 sensors are relatively inexpensive. You might just want to go ahead and replace it.

NOTE: If the test equipment the inspection place is using is a five gas type which will measure O2, you can't go by this to tell what your mixture is doing because of the secondary air being pumped into the cat. The O2 reading will always be high.

Oh yeah.....in my case I think it's deposits. EGR system works and passages are clear (I removed the upper manifold to visually check even though when manually opening the EGR valve stalled the engine); cooling system is clean, mixture is where it should be (verified with scan tool). The car isn't my daily driver so I just work on it when I find the time. Of course, I'm going to take it in the shorts $$$ when I try to register it again when all the fees and late penalties are added up.

paulo57509

Holy cow. That reply got wordy. Sorry about that.

3rd gen Will

iTrader: (8)

No problem paul, sucks *** that you are dealing with stupid smog also. I appreciate your input!

Has a brand new AC Delco 1 wire O2 sensor. Neg press EGR, Damn near stall's the engine on a forced open. Cooling system works well, I have a new 180 stat. With only one fan working it never really gets over 220* on the gauge, it's usually around what looks like 200* on the gauge when I go through emissions. It's at around 180* when being driven though.

Unforunately I do not have access to a scan tool that I am aware of. I will have to bug a couple buddies that work at shops still.

3rd gen Will

iTrader: (8)

4th try. Ran it through tonight, nice and cool outside. Pulled 4* timing. Now set at 2* base. Put 32oz of 70% isopropyl alcohol with about 1/2 tank of gas.

HC .43
CO .31
Nox 2.81 of 2.5

I think I did the rubbing alcohol thing wrong, After doing some reading I only put one bottle in most people seem to have ran 3 of the large bottles.

3rd gen Will

iTrader: (8)

A buddy of mine asked if there was a chip in the, not sure if he prev owner put one in. So I pulled the comp and it has a hypertech chip in it. It's a street runner chip pt no 121321

I am assuming advanced timing from the chip could cause my nox issue? I have already pulled the chip and want to run it through again, just want some other thoughts/reassurance. This damn car with it's emissions crap is driving me insane.

3rd gen Will

iTrader: (8)

Okay, removed the chip last night and ran it through this morning.

Nox 2.59

Really dammit! Almost there!

I would be out of ideas except!!! In my frustration I dropped my head against the steering wheel only to see that fact that the temp needle was all the way against the red. SO yea the car is basically damn near or actually overheating on the phuqing rollers! That explains my phuqing problem! Not sure why I didn't notice it before, just pissed off I guess.

A flex a lite setup is going in this weekend. I am quite sure this is the cause, I don't want to get my hopes up to high though

3rd gen Will

iTrader: (8)

Fixed the cars overheating problem Solid 180* on the emissions dyno.

Nox at 2.52

Double checked the fuel pressure, with the vacuum hooked to it it was only at 34psi removed the vacuum it shot up to 45psi. I don't have an adjustable regulator so I put a hose clamp on the return line to raise the pressure to 40 psi with the vacuum connected.

Still failed 2.68 this time.

I AM COMPLETELY DUMBFOUNDED!!

Please help me guys.

3rd gen Will

iTrader: (8)

Hooked a vacuum gauge between the EGR valve and the Control solenoid. Light throttle and cruise I have 6-7" of vacuum. Zero at no throttle and heavy throttle. This leads me to believe that the egr solenoid is being controlled correctly by the computer.

So that rules out my last idea. I could really use some help.

paulo57509

I skimmed through this thread again.

You've verified that the EGR vacuum system is working.

You said you have a negative back pressure EGR valve; have you tried hooking up a vacuum pump (MityVac) to the EGR valve to see if manually opening the valve will cause the engine to idle poorly or die?

This would verify that the EGR passeges are not clogged with carbon.

Sorry if you've already done this.

KNBlazer

have you checked the EGR's solenoid? If adjusting the timing did not help, and the EGR system is operative, and you say your CAT is good, then I would check to see if the Timing Chain is still good... I had problems with my chain having to much slack... my smog inspections were a PITA to pass... I'd spend over 1K on parts alone, now I'm researching parts to convert to FI... BTW is this your first time smogging this car? could the previous owner perhaps have made some internal upgrades?



Offsite, I just read that an ignition module could cause high nox, as well as a bad MAP sensor... hmm.. go figure...


Just did some more reading, if everything checks out, make sure that your CAT is California Emissions approved, apparently OE CATS have more of the crap that is required by the sniffer test... replace the O2 sensor, they're not that expensive...

bcmag

hmmm.might be interesting to run it w air inj. tube to cat unhooked and set timing connector unplugged.i think this would do it but that would be cheating huh?

3rd gen Will

iTrader: (8)

Timing chain is a brand new double roller. I am pretty sure its the stock cam, the PO didn't have a cam listed as being changed when he sold me the car (along with a plethora of other performance parts)
.
The cat is a 49 or 50 state legal cat, I can't remember. Should be fine either way since I am testing in AZ. Has Brand New AC Delco O2 sensor.

I have forced the EGR open, it damn near killed the car I let it back out. With the engine off you can vacuum open the egr valve, but at idle you can't open it with vacuum, this is correct according to the diagnostic test. This tells me the EGR passages are not clogged and it's a brand new EGR Valve.

I will definitely check out the MAP sensor. There were two in the car I put the nicer/newer looking one on, it could be the incorrect sensor. It didn't set and SES light so I assumed it is correct.

Running through with the air tube disconnected would reduce the effeciency of the cat increasing emission output. Also disconnecting the EST connector would illuminate the SES light and that is an automatic fail.

Honestly I could care less about cheating at this point if it enabled me to pass!

Thanks for you input guys! Any other ideas are VERY MUCH APPRECIATED!

3rd gen Will

iTrader: (8)

Bench tested the MAP, it tested out great. w/ a 6v batt. 6v w/ no vacuum 15" had 2.3v, 22" 1.3v. So the MAP is functioning correctly. I didn't check the car, but I am sure it has the 5v reference and the ECM is grounding it or I should have an SES light, I will verify that when I get home tonight.

bcmag

sorry forgot about light coming on w est diconnected.however these are oxides of nitrogen.the more oxygen you remove from exh. the better .catalysts do very little for nox.and you have plenty of room in co and hc. keep the air out of the cat and pull timing back as much as you can.nox is a product of high cyl/exh. temps .anything you can do to cool it helps.

3rd gen Will

iTrader: (8)

I FINALLY PASSED!!! 2.07 on the NOx

I pulled 12* of timing, I had a bottle of lucas fuel injector cleaner in the tank (on the side of the bottle it says it reduces NOx, I figured hey it can hurt. The car was running pretty crappy, in the back of my head I am like there is no way this works.

I think it sucks, I have everything set perfect the car runs great and fails. I make the car run like crap and it passes. I could care less because I am done dealing with this **** for 2 years!!!

MarineIROC

..

Rayzor32

iTrader: (1)

Just retarding the timing will lower NOx. You can retard it by just lowering the base timing when you have the EST disconnected. Retarding the timing lowers combustion chamber temperatures, NOx is formed when temperatures are above 2500*.

3rd gen Will

iTrader: (8)

I did it by manually retarding (rotating the distributor clockwise). I disconnected the EST and set the timing to 6* ATDC. Then hooked the EST back up. With the timing set to spec (6* BTDC) and the EST hooked up timing at idle was at 18* BTDC, after I retarded the timing it was at about 8-9* w/ EST.

I am not sure you can do that in Cali though, from my reading on here they check you timing and you can only be 2*+/- from the manufacturer specs. I don't know for sure though since I have never went through Cali Smog.

Rayzor32

iTrader: (1)

Wow they check your timing? In that case you might be screwed. Cali is ridiculous with the smog. Id say if that was the situation then you would probably have to check your egr and cat. I would retard it the max amount also. I have personally used the "guaranteed to pass" product and can say it significantly lowered the NOx. Also I had the guy run it in 1st gear only throughout the test. This was many years ago when I lived in texas.

Id say your about right having it at about 8* with the EST connected. Retarding the time will also lower the HC's a ton too.

3rd gen Will

iTrader: (8)

My HC and CO numbers were pretty much unchanged by the timing retard. I assuming the cat cleaned up anything that went un burnt due to retarding the timing.

3rd gen Will

iTrader: (8)

By the way, make sure you retard the timing, go right through smog and set it back correctly right afterwards. You can burn up the exhaust valves because your still burning the A/F mixture as it goes out of the engine.

Rayzor32

iTrader: (1)

Yes your HC and CO numbers are very good indicating your cat is operating well.

On my friends cutlass (carbureted no cat) we did a test on hooking the vacuum advance to manifold vs ported vacuum on the carburetor. When it was hooked to manifold (drawing full vacuum advance at idle now) the HC's were like 1200. We changed it to ported (just base timing) and they dropped to about 220. The CO went up though because we had to richen the idle mixture a little to make up for less timing. And CO tells you the a/f ratio.

3rd gen Will

iTrader: (8)

It damn well better be working good, it's brand new! haha. I do want to go to a (heated) 3 wire O2 sensor since i have headers on it. Hope it will help me get the max gas mileage and performance out of it til I get the blower put on.

Rayzor32

iTrader: (1)

How are you going to hook up a heated o2 sensor? The heater is usually controlled by the pcm it has to be duty cycled. It would definetly help with mileage if you could do it. Interested in how.

3rd gen Will

iTrader: (8)

It's not cycled. You just hook the heated side to 12v+ ign power and you are good to go. Quite a few threads on here about it.