High nitrous readings/Help!

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

Hey everybody! I've been shadowing the boards since the Yahoo rebellion, just reading. My '90 Q45 (Eng. has 80k) won't pass our emissions test, just a little high on the NOX -.13 grams/mile. Last year (2k Mi. ago) new NGKs, plenum clean, EGR & tube clean, throttle plate clean, Det. sensors, hoses. Runs like a top. I haven't set the ignition timing since I put guides in last spring. Could this be it? Thanx in advance Squeefoo

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

In 2001 --- 26% of 1990 vehicles failed IM240 in Wisconsin on first try. The average repair was $275.

1. Improper operation of the EGR valve. Stuck open, obstructed, leaking, etc.

2. Plugged EGR passages. Carbon build up in passages.

3. Over advanced timing.

4. Fuel mixture to lean

5. Engines cooling system in poor condition, causing excessive temperature.

6. Malfunction of the electronic spark control (ESC), and knock sensor. Computer fails to retard timing.

7. Contaminated or bad catalytic converter

............in 2000 the California Fleet average was 2.0 grams per mile.

http://www.aircarecolorado.com...20MAF

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

Well as I ck'd my diagnostic trace reports there is an NOX spike at each accel. event ; Great link! Thanx a lot. Q Tech or any one have a safe proven way to clean my expensive MAF? Squeefoo

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

PS yes I searched.

Post by **maxnix** » Fri Jul 25, 2003 11:50 am

squeefoo wrote:PS yes I searched.

Then you found it!

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

Maybe I'm not searching properly, I spent 105 mins. looking through MAF/cleaning. Plenty on harness / connector (I'm an expert now). No couldn't find, ... it. Thx Squee.

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

Don't jump on the MAF yet without changing both O2 sensors first!......even a 10% sluggishness in switching time can create a 5% error in the AVERAGE 14.7 AF ratio which can double Nox.

Same as the MAF being off 5%.

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

Both o2 sensors are new as of 2 years ago (10k mi). Is the method for cleaning the MAF the same as mentioned in the link above?, really don't want to screw it up. ($$$$$$!!!) I need to pass this last test by next Thurs. the 31st or its extra $$$ for being late. Thx Squeefoo

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

The MAF sensor wire is EXTREMELY delicate, I wouldn't touch it with anything other than some highly evaporative brake cleaner.......not too much pressure or you will end up spending $500 for another MAF.

Make sure the ignition base advance is 15 degrees with a timing light.............hopefully nothing you have used has contaminated the cats................you said engine has 80k [like you might have changed it] how many miles do cats have - after 150k all bets are off

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

Thanks a lot. That's what I thought when I looked at it, I priced them a while ago. Timing is going to happen Sunday. I have a case of extraordinarily volatile electric contact cleaner for it; the screen is shiny and a few gauge sizes smaller now. So, I'm sure the wire has some crud on it. The cats have 159k on them, some how some shop hydrolocked a rod through the block (really bad swap - lots to fix). Some time this week I'll run it back through and re-post on this thread what happens. Thank you very much for the help. -Squeefoo

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

Bummer. The tests have gotten progressively worse, all nox. I'd be willing to trade some HC's or CO to get the Nox down. The limit is 2.0 grams /mile ---test 1) 2.13 2) 2.53 3) 2.67 . The car flies now with the timing reset. So far I've cleaned/ tested the EGR, cleaned the MAF wire, reset the timing, ran Techron through early this month, checked for vacuum leaks. The only thing left is a shooting spree at the test facility, but I've ruled that out. I do have another '90 Q which I can "borrow" parts from if necessary, or test against. That one passed the emission scam. Ideas, comments, suggestions? Thanx Squeefoo

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

Try resetting the base timing to 12-13 degrees, it would be nice to see the total advance at each stage of testing......when Nox spikes on acceleration.

Don't think that a single application of Techron [or anything] will clean injectors [rail flush] or 2-3 appplications of BG44k.

Give us all the other readings or scan the IM240 chart so we can see the relationships HC, CO, CO2,O2 to NOx at each rpm.

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

The state has a diagnostic facility, BUT not if you do the work yourself, according to the manager. BTW I have a '93 TCU, just so you know. --------PS...The damn website won't let me post the scanned trace graphs, it says the files (sent as eaches) are still too big.

I'll try again tomorrow. THX Squeefoo

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

Since Nox formation is a function of combustion temperature heat and mixture leanness.........make sure you cooling system is not overheating. In summer most easily creep above the ideal 176-185F as measured/read by ecu..........the inside gauge won't move till you exceed 200-210F. AC off during testing.

Hard to trace these things without a Consult and 5 gas analyser.

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

The test facility has a fan they "aim" at the hood, while they run it on a dyno, now that I think about it. I don't think my Q is getting adequate cooling while idling for 10 mins. in line, then being run. Btw in 24k mi since bought, Ihave flushed, replaced all hoses, changed Dexcool/ distilled 2x w/ block drained ea. time and there are no obstructions in front or in between rad. just had it out for timing guides. Never changed the thermostat or sensor though. Thanks Squeefoo

Website · Post by **s13sr20chris** » Fri Jul 25, 2003 11:50 am

dexcool sucks.

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

Dexcool is great if you have flushed the system totally free of the old green, use distilled water, and change it one per year but I change every type of coolant once per year. Red , orange, yellow, green and even clear formulations.

Website · Post by **s13sr20chris** » Fri Jul 25, 2003 11:50 am

for a short time i worked at a gm dealership(before i realized nissan was the best). every single car that had dexcool also had brown gunk. it seems that after a year or two dexcool turns into brown gunk everywhere. really thick stuff that imo prob causes some kind of problem with heat transfer. maybe if you change it often you are ok. now that i have opened my big fat mouth i guess i should do some research(quickly before q45tech busts out some crazy links:)).

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

Dexcool has problems when used on a mixed engine: iron block and aluminum heads not so with all aluminum.

Anyway the exact combinations of additives have to be balanced for the engine/rad material types.

Most Dexcool problems orginated from dealers/owners not using distilled water for fills/refills and the Dexcool reacting with the chemicals added to tap water.

The formula is used by Lexus and we see no problems after 70-100k of use if distilled water is used!

Post by **Q451990** » Fri Jul 25, 2003 11:50 am

Q45tech wrote:Dexcool has problems when used on a mixed engine: iron block and aluminum heads not so with all aluminum.

Oh boy... that's what my truck has (made in Mexico iron block and aluminum everything else. I went with DexCool and Distilled water. Flushed six gallons of distilled through before adding DexCool. Should I be concerned about this?

Heath

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

Not if you are a normal person who might check his radiator [inside] every 90 days. [Of course my definition of normal differs from most].

The 100k/even 50k mile fill and forget ..........never open the cap types are in for surprises.

Website · Post by **s13sr20chris** » Fri Jul 25, 2003 11:50 am

well that all sounds very good. anyone want to hear what i was told as a rookie tech back in my gm days? they told me that dexcool was formulated to corrode wherever leakage was happening in order to stop up the leaks. they told me this was to avoid using gm's old favorite cooling system too the pepper tablet. you guys remember those? tablets of compressed pepper in the early days then compressed paprika in the revised version. that stuff was even installed at the factory. naturally this gave me a negative slant against dexcool. i now see that it was the dealers fault. by the way, every dealership i have worked at uses tap water in their coolant and batteries.

Post by **Q45tech** » Fri Jul 25, 2003 11:50 am

Well the dealer has no interest in seeing cars last either " every dealership i have worked at uses tap water in their coolant and batteries". ......The factory fill is deionized water.....even GM!

T3 uses tap water unless the owner is smart enough to bring his own distilled water.........but our tap water tests more benign than other locations around US.

The "OAT" organic acid technology is very good if the system is burped of all air..............actually as long as the AF is low or no Sodium Silicate..........the water pumps and aluminum last almost forever if changed every year.

One must measure the electrical potential [with a VOM] by placing an electrode in the center of rad opening [in coolant] and the other to the engine block and rad metal body[ground]...........any millivolts means the coolant system is acting like a battery and the coolant is the electrolyte.

Measuring the PH of the electrolyte is a good chemistry experiment.............you can't have chemical corrosion of aluminum with a PH of 7.000000.

Coolant is graded by excess alkalinity [how much acid it can neutralize] without having a high PH which would be bad also [drano on aluminum].............so the VOM trick tells you immediately when the reserve has been depleted and time to change the coolant....................even the best show signs of acidity after a year or two..........by measuring the voltage you can calculate the corrosion per hour, per day, per year.

The alloy of the block and the alloy of the radiator are different thus a differing potential is created and isolated by the hoses.....the radiator is not grounded sits in rubber isolators.

Website · Post by **s13sr20chris** » Fri Jul 25, 2003 11:50 am

man you rock. by the way, one of my vehicles has a small controlled coolant leak. i have not yet bothered to fix it and find that as lont as i put about a quart of coolant/water in it every month everything is cool.

Post by **squeefoo** » Fri Jul 25, 2003 11:50 am

Hey Guys, Well what I did was pull a fast one on the bureaucracy.As outlined above I still have to figure out the leanness/cyl. temp/high Nox issues. The pressures off but I know my sweetie isn't running right. Got my sticker today, just in time to fend off the WiStaPo for the weekend. If anyone wants to know what I did E-Mail me, I don't want to ruin a good thing by volume. I s'pose I'll have the dealer run a consult check in a couple of weeks, then fix it $80 is cheap payback for all the pleasure my Q gives me. -Squeefoo

High nitrous readings/Help!

High nitrous readings/Help!

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