jonesy

Sean,

Yeah, I realize that, I was actually posting for theGodfather since he seemed to be looking for a solution using Methanol, distilled water, etc. Sorry, I should have directed the post his direction.

Glad we don't have an EGR test yet in Texas, but I am sure the gov is hard at work getting that rammed down our throats.

__________________
Ed Williams
'91 Acura Legend

 

Sean L

No Worries Ed....have a great weekend.

__________________
Sean in Norcal
'05 Infiniti G35 Coupe
'94 Mustang Cobra
'94 Legend LS Sedan (SOLD)
'97 Lex LS400 Coach Edition
http://www.mustangmods.com/data/4358/legendsig2.jpg

Cap

You might have one or both of your oxygen sensors going bad.

WRT the best fuel additives, the buzz I hear is that BG44K does wonders. My gf's car failed a test, and we ran some BG44K through it, and retested. It Passed.

Cap

jonesy

Yep, BG44K is supposed to be real good. My neighbor told me about it after I had done the Techron/Guaranteed to Pass combo. Probably wouldn't hurt to throw the BG44K in with the other 2.

__________________
Ed Williams
'91 Acura Legend

Merlin the Wrench

in answer to the earlier question re functional test etc. If applying vaccum to egr causes engine to stumble then EGR is Ok. Vacuum is only applied when engine is at RPM so that test was Ok also.

I would replace in order of cost:

air filter if not new already
run BK44 through for a tank
return exhaust to stock - ie, put pre-cats back in
retest.

if fails:
change Oxygen sensors
retest

if fails
either take it to an Acura dealer or replace catalytic convertor $$

by chance have the pistons been changed to higher compression, or the heads milled? Driving up compression increases NOX also. My guess at this point is that it is the missing pre-cats.

__________________
Best Wishes

Steve

theGodfather

Thanks for the input guys,

In response to Merlin's reply, I have K&N cone filter that could use some cleaning but I don't know how much of a drastic effect will it have on my NOx levels.

What is BK44? I've never heard of this chemical. I will research on the web and see what it is.

Puting pre-cats back in is IMPOSSIBLE the way my exhaust has been modified. I no longer have them, and even if I did, I wouldn't be able to put htem back in. TYPE I engines pass without any pre-cats. The part number for the main cat is the same for both TYPE I and TYPE II motors. My service manual states that the purpose of hte pre-cats is only to clean emissions during "warm-up" time. Meaning when you do a cold start on your engine, until the main cat can heat up and operate properly, the pre-cats are already heated up cleaning up emissions. But once the main-cat is operating 100%, the pre-cats are not really needed. How much of a difference in emissions between a TYPE I and TYPE II can there be?

O2 sensors I plan on running my multi-meter on them soon and see what readings I get.

It's interesting you raise the compression issue, I recently had my HG replaced, meaning a bit of machining was required on the head. Would the minimal amount o fmachine required on a head for a HG repair job increase the compression enough to raise the NOx levels to double?

Also I wonder if spark plugs would have an effect? I'm running NGK coppers with a very very slight difference in gap size (probably less than a mm). I wonder if this would create any extra lean A/F ratios.. i doubt it. Only thing it'll effect is detonation.

I want to get to the bottom of this.. however I do want to pass this test soon... so I am considering running methanol in the gas tank for this test which I heard works... just trying to verify if there are any ill-effects t using it... even though it'll only be a small amount in a one-time usage.

I'm glad I can find this help here.. it really helps me!

G

__________________

1995 Legend Coupe 6-speed
Carbon Black Metallic
208 WHP @ 6250 RPM
189 FT/LB @ 5250 RPM
MUSTANG Dyno
260,000mi and counting

WeaponR Secret Weapon Intake - Cold Air Box - Custom 2.5" stainless exhaust system - Remus Rev3 Universal muffler -SPEC Stage II clutch - 5speed flywheel - SR5GUY Chip - APEXi S-AFC - Pullies - MLS copy strut bar - Short Shifter -18" ICON W65 Wheels - KONI reds/Ground Controls - Slotted Brembo Rotors - SS Brake lines - Walbro 255 -ICE

theGodfather

Regaurdless if I pass with the methanol trick or not.. i want to clean out my EGR system.

I have a suspision that although upon opening the valve up on idle my engien stumbled and sometiems stalled... the ports might still be clogged up with crap only allowing maybe 50% of the gas to travel through. I'm sure this can be a reason for NOx levels to be high as it is not efficiently working.

Now I looked through my helmes manual and found out how to troubleshoot the EGR system.. but I cannot find anywhre on how to REMOVE the EGR valve.

It's a hard place to really get tools into from what I physicaly see so I need advice on removing the valve from you guys that done it. How many nuts/bolts hold hte valve in place? Other than the strut-bar.. what else needs to be removed to gain access? By looking at it.. the nuts/bolts look "rusty". Should I expect htem to be siezed therefore soak them with some liquid wrench and run the car (for the heat) to loosen them?

I'm definetely going to use the GM cleaner chemical mentioned.

Any tips other than what is posted here already?

Thanks! This thread will have enough information to make a DIY thread for EGR system cleaning

G

__________________

1995 Legend Coupe 6-speed
Carbon Black Metallic
208 WHP @ 6250 RPM
189 FT/LB @ 5250 RPM
MUSTANG Dyno
260,000mi and counting

WeaponR Secret Weapon Intake - Cold Air Box - Custom 2.5" stainless exhaust system - Remus Rev3 Universal muffler -SPEC Stage II clutch - 5speed flywheel - SR5GUY Chip - APEXi S-AFC - Pullies - MLS copy strut bar - Short Shifter -18" ICON W65 Wheels - KONI reds/Ground Controls - Slotted Brembo Rotors - SS Brake lines - Walbro 255 -ICE

Merlin the Wrench

I believe Sean is the one who started this post and he pulled his off several times in the process so he could tell you about it. I would consider a touch of penetrating oil to be sure the threads on the bolts don't seize. The GM combustion cleaner will dissolve any carbon overnight in those ports. Sean used a piece of heavy electrical copper wire to make sure the ports were open. One interesting thing to consider before you pull yours apart - his was completely clogged and he passed California Smog on the PPM but not when they physically tested it to see if it worked. If he can pass with his clogged, wouldn't you think that if yours was at least partially working it would pass too?

I believe it would take a substantial increase in compression to raise NOX to where you fail solely because of that. I think our engines are about 9-1 or about that. Maybe 11-1 would be enough. Racers typically run in the 12.5-1 range. Some go as high as 14 -1 when they are running alcohol. High levels of alcohol can damage some of the seals and rubbers in some engines so best talk to someone who has done it in a legend sucessfully. Just cleaning up the heads a bit would not drastically change the NOX. Taking the thermostat out when it was overheating and never putting it or the right temp one back in might cause the computer to treat the engine as if it never warmed up. That would cause some issues.

Have you ever passed smog on this car before when you owned it?

__________________
Best Wishes

Steve

Nathan_Rd

That's what I would recommend since your engine internals are perhaps running hotter than normal.

Sean and I had had low NOx reading despite having a dysfunctional EGR system. Besides EGR should operate under light load conditions.


Again try to focus on other possible culprit. Sean and I had good NOx reading despite having a dysfuctional....
Your engine is running hotter than normal. May I suggest detonation, preignition.


BK44, GM top cleaner should help clean out some carbon deposits that could lead to detonation and therefore high NOx levels.
I wouldn't worry about the O2 sensors since they're working or else your CO and HC would've been ugly. Besides ECU should go in rich mode when O2 sensors go bad and rich mixture does not lend to higher NOx readings.

Whoever did your HG did they put in proper coolant mixture?
How do your spark plugs look? Pics?

What octane do you pump her? How's your idle? Nice and smooth? Air leak can cause lean mixture and therefore your engine to run hotter than normal. Also check your KNOCK sensors, is it functioning up to specs. If not the motor may not be retarding accordingly. Your car had a bad headgasket at one time and I think some severe detonation finally cause it to pop, and may pop again if that problem isn't recognized. Hope that helps. So you can check for bad coolant mixture, dying knock sensor, bad spark plus, air leak and or the stinking cat.

Sean L

Removing the EGR valve takes about 5 minutes for me now, I've got it down to a science.

1) Remove strut tower brace
2) unplug all connections to EGR valve
3) I think the 2 nuts are 12mm, but they may be 10mm. The egr valve is actually stud mounted, so remove the nuts SLOWLY so you don't drop 'em and the egr valve lifts right off. You can clean the valve quite easily and check for proper operation.

However, to unclog the EGR ports, you will need to remove the EGR tube that connects from the egr mounting flange to the back of the intake. This takes an additional 10 minutes, but can only be done on a totally COLD engine. This also must be done carefully and slowly to avoid dropping the bolts and nuts.

The heater control valve cable bracket needs to be unbolted and tied (I used a zip tie) out of the way. 4-5 minutes.

Removing the tube takes some patience, but it's doable.

I then connected a clear tube to an aerosol can of GM Top Engine cleaner and fed the tube into the egr port in back of the intake.
I filled it up nicely and then let it sit for few hours. I then took a 12 gauge solid core wire (bought from home depot for 40 cents) and shoved it into that egr port in back of the intake as far as it would go. You should buy 4' of wire. Working slowly, I got at least 2 feet of wire into the intake. I pulled it out and cleaned a ton of crap off of it.

Rinse lather, repeat. I think I did this process like three times.

I bolted it all together, and went out for a nice freeway ride.

Ca ran fine (it ran fine before too). I applied 8" of vacuum to the egr valve and the engine stumbled....then stalled. Bam, it's now functional according the the manual (and the CA smog test).

I advise anyone doing this to go to Acura and buy an egr valve gasket and two egr_to_intake tube gaskets. I only needed one, but it was nice to have it in hand.

Good Luck.

__________________
Sean in Norcal
'05 Infiniti G35 Coupe
'94 Mustang Cobra
'94 Legend LS Sedan (SOLD)
'97 Lex LS400 Coach Edition
http://www.mustangmods.com/data/4358/legendsig2.jpg

theGodfather

Wow.. thanks for the responses guys!

It is funny how you guys passed NOx emissions test with non-functioning EGR systems. Everyone I look on the web though says the #1 curlpit for high NOx emissions is the EGR system. And in my case it actualy does function! I can't get it to stall the vehicle every single time.. but 1 out of 4 tries it'll stall (other times it's very rough almost stalling).

My compression probably wan't raised that much from the head being machines to make it true after doing my HG.

The coolant in my car is new and of proper mixture (since the HG job 3 months ago)

Detonation or pre-ignition.. wouldn't that cause enough knocking for my "check engine' light to come on? Or can it still be off and not cause this light to be on? Would running too lean cause this? How about using a spark plug that is about 1mm shorter gap than stock (I'm using copper NGKs).

Could my fuel injectors be clogged up enough that proper amounts of fuel isn't being delivered.. thus resutling in a LEAN A/F mixture? Then agian, my O2 sensors should pick that up and compensate by pushing more fuel... but if the injectors are clogged.. then not enough is getting through. I always use a minimum of 92 Octane though... but my engine has over 156,000 miles on it. Over that time I'd assume injectors can get clogged up.. or perhaps need replacing. I will try the BG44K stuff to clean them out.

Idle is good and smooth.

If I had an air leak... where would I be looking? Could the mechanic 3 months ago not tighten the intake manifold properly? I doubt it... he really did a good job.. but how do I detect an air leak?

If knock sensors are not functioning properly (like O2 sensors).. wouldn't my check engine light come on?

I'm hoping I can narrow this down and resolve this. Last thing I want this to be is the cat.... although I'm not using the precats... it should not make a difference once the car is at operating temperature.

I'm going to first run the BG44K stuff through, clean my air-filter (probably minimal results).. I think I need a new PVC valve (even though I doubt it effects NOx levels). The EGR cleaning is something I might leave for this weekend.. and thanks to Sean for those amazing instructions/tips to doing this job!!

What would you guys think about the chances of clogged injectors doing all this leaning out my A/F mixture? (thus raising comb. temp to reaise NOx).

Thanks a bunch guys! This thread is becoming a really good resource for everyone on this forums!

G

__________________

1995 Legend Coupe 6-speed
Carbon Black Metallic
208 WHP @ 6250 RPM
189 FT/LB @ 5250 RPM
MUSTANG Dyno
260,000mi and counting

WeaponR Secret Weapon Intake - Cold Air Box - Custom 2.5" stainless exhaust system - Remus Rev3 Universal muffler -SPEC Stage II clutch - 5speed flywheel - SR5GUY Chip - APEXi S-AFC - Pullies - MLS copy strut bar - Short Shifter -18" ICON W65 Wheels - KONI reds/Ground Controls - Slotted Brembo Rotors - SS Brake lines - Walbro 255 -ICE

jonesy

To put it simply, RUN THE CLEANER THROUGH THE INJECTORS

I will bet you $50 that it will be fixed. 1 can through the tank is all you need. The reason is the injectors get clogged and do not spray a good mist. In order to have good combustion, the fuel has to have a good surface area (mist) vs bad surface area (stream) in order to combine with the oxygen upon combustion.

I doubt any of this other stuff will fix your problem. Injectors get clogged, the good news is 1 can of BG44K or Techron (or both) will do the job, be cheap, and not require you to do anything but empty the tank. I know, I have a used car lot, and this fixes 95% of all emissions problems. Be like Mike, Just Do It.

The problem is, most people don't realize their injectors are dirty, becuase, when you car is operating correctly (like yours is) the car can mask the sympoms (sense knock, change fuel/air mixture, etc).

Good luck

__________________
Ed Williams
'91 Acura Legend

Nathan_Rd

Right on, proceed from there and see what happens and examine the color of your plugs as well. If it's stilling reading too high, then I suspect your TWC (3way cat) not doing a good job of reducing NOx. Usually the catalyst rhodium located at the very front of the converter is responsible for reducing NOx. Now you had a bad HG => burnt coolant/oil contaminant could've coated this part of the catalyst and so it becomes an ineffective NOx reducer. The precats would've taken the brunt of this effect had it been there. That's my guess and assumes the Legend TWC is fabricated with rhodium in the front while the platinum and palladium in the back is less coated. Other possibilty is the O2 sensor(s) giving false signal to cpu resulting in a "lean" attitude. That could explain why your HC and CO readings are within limits; that lean mixture with more air in the spent exhaust can overwhelm the rhodium catalyst ability to separate the N from the Os and so more NOx out the Remus. Hope that helps.

theGodfather

I'm having a hard time getting a hold of GM Top Engine cleaner and BG44K. I hope this stuff comes over the border

I went to a GM dealership here today and they never even heard of Top Engine cleaner. They had some other cleaning agent which gets rid of carbon deposites, gum, and sluggish crap.. but it's called "Cleano" if I remember correctly and it isn't an aerosol can. I did not pick it up in case it'll be useless to me.

Also for BG44K, no one here sells it I might try some performance shops on Monday to see if they might have it. I know Redline makes an injector cleaner.. is that any good? What is a good alternative that is comparable? I also went to Mercedes Benz dealership as I heard they usually carry BG44k but no luck. They had some otehr stuff that was $7 for the bottle (from what I heard... BG44k is expensive).

BTW Nathan.. when I had a blown HG I never did have my cat on my exhaust system. I was running a straight-pipe for the last 1.5 years so that cat was sitting around, that is why I don't think it's the cat as it has less milage than my car and was never exposed to any wierd exhaust contaminents from my HG blowout.

If my O2 sensors were off.. wouldn't my check engine light come on? Then again... they can still be off and still be within spec. Maybe I should disconnect my O2 sensors which will force my car to run rich (which is what happens when it detects an inoperable O2 sensor). This would probably pass the NOx emissions but will make me fail on the HC or CO side

G

__________________

1995 Legend Coupe 6-speed
Carbon Black Metallic
208 WHP @ 6250 RPM
189 FT/LB @ 5250 RPM
MUSTANG Dyno
260,000mi and counting

WeaponR Secret Weapon Intake - Cold Air Box - Custom 2.5" stainless exhaust system - Remus Rev3 Universal muffler -SPEC Stage II clutch - 5speed flywheel - SR5GUY Chip - APEXi S-AFC - Pullies - MLS copy strut bar - Short Shifter -18" ICON W65 Wheels - KONI reds/Ground Controls - Slotted Brembo Rotors - SS Brake lines - Walbro 255 -ICE

jonesy

I know PepBoys by me carries the BG stuff, not sure if that is nationwide or not.

Never seen the GM top engine stuff, maybe someone else can help?

__________________
Ed Williams
'91 Acura Legend