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Ezk116 ignition

Aurelius

word
Joined
Jan 24, 2009
Location
SoNoCal
Hi,
Looking for help to bring nox down about 200 points here in California for the 15mph run. Ezk pin 19 is grounded for a -6 ignition timing and knock sensor is unplugged. Cam is retarded by 1 tooth. e85. Brand new California approved cat. M cam also put in. Passing nox is about 550 for my 1990 240 at 15 mph. It is a na +t. o2 sensor changed with a bosch back in February.
 
A new cat with properly working fueling control should give close to zero NOx.

Do you have a wideband O2? What does it read during idle and the emissions test conditions?

Any diag codes posted?

For a cat to work correctly, the air/fuel ratio needs to be held very close to stoichiometric. The stock LH2.4 & chips continuously adjust fueling up and down a little bit (roughly one cycle per second) to monitor the narrowband O2 sensor to keep the air/fuel ratio correct. If the enging is running continuously lean, the cat can do almost nothing to reduce NOx.

Do you know the details of your chips? Are the setup for E85? Do they retain closed loop O2 lambda control? Have you checked for a big air leak at the intake manifold gasket?
 
It is a brand new cat bought about a month ago.

The wideband reads about 14.6-14.8 on idle. It reads closer to 15 on acceleration but then goes back down to 14.8 ish.

No diagnostic codes.

I do not know the details of my chips. Originally not made for e85 just in the past people were using them with e85. I do not know it it retains closed loop o2 lambda control. Smoke test showed no leaks at the intake manifold area.


I tried changing to a 4 bar fpr then down to a 2.5 bar with similar results.

The hc and co readings were close to 0 on 15 and 25 mph and passed. The limit is about 550 at 15 mph. I am averaging about 700. Occasionally will dip down to around 400 and climb back up as 15 mph is maintained. At 25 mph it sometimes goes beyond the limit of about 500 and sometimes it can pass below the limit.
 
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Yes and yes. Im thinking a blend of e85 and unleaded may be the ticket. The maximum limit for nox has gradually gone down for my car over the years in california.

I wonder if there something I might be able to add to e85 that will lower the nox.
 
Couple tricks are change motor oil, soak air filter in alchyhole. Run car on highway in second gear get cat hot right before you pull in. Ohh check valve clearances.
 
Couple tricks are change motor oil, soak air filter in alchyhole. Run car on highway in second gear get cat hot right before you pull in. Ohh check valve clearances.

Going to try the air filter trick. Had no idea. That may just do it!
 
What temp thermostat is in your car? A 92C thermostat could make some more Nox than a cooler engine temp like an 82C thermostat.

I have the 82? thermostat. Running an efan that I can also manually control. Maybe I should turn it off so the thermostat can work. My brain is fried so I can miss anything at this point.
 
Disconnect the wastegate and wire the flap open.

I'll try. I have the boost set around 24 with a manual controller so it hardly opens at the moment. Do you think if I leave the wide band 02 sensor bung open would help? It is about 10" downstream from the o2 sensor, before the cat.
 
It is a brand new cat bought about a month ago.

The wideband reads about 14.6-14.8 on idle. It reads closer to 15 on acceleration but then goes back down to 14.8 ish.

No diagnostic codes.

I do not know the details of my chips. Originally not made for e85 just in the past people were using them with e85. I do not know it it retains closed loop o2 lambda control. Smoke test showed no leaks at the intake manifold area.

I tried changing to a 4 bar fpr then down to a 2.5 bar with similar results.

The hc and co readings were close to 0 on 15 and 25 mph and passed. The limit is about 550 at 15 mph. I am averaging about 700. Occasionally will dip down to around 400 and climb back up as 15 mph is maintained. At 25 mph it sometimes goes beyond the limit of about 500 and sometimes it can pass below the limit.

Has it passed in previous years? What is different then-to-now?

What injector flow rate and fuel pressure are you running (e.g. 30lbs/hr @ 3bar)? Did you change this when you went to E-85?

I don't have any experience with the TLAO chips. They might have problems with CA emissions and E-85?? Maybe someone else can chime in, or some searching for old posts. You could try going back to 93octane gas, but you'll need to disconnect the battery and drive it for a while to re-learn. I'd reconnect the knock sensor too.
 
Has it passed in previous years? What is different then-to-now?

What injector flow rate and fuel pressure are you running (e.g. 30lbs/hr @ 3bar)? Did you change this when you went to E-85?

I don't have any experience with the TLAO chips. They might have problems with CA emissions and E-85?? Maybe someone else can chime in, or some searching for old posts. You could try going back to 93octane gas, but you'll need to disconnect the battery and drive it for a while to re-learn. I'd reconnect the knock sensor too.


It passed all previous years. The difference between them to now is the gradual decrease in passing nox limits. I barely squeezed by for nox last smog. This year I am about 200 points over.

42lbs@4 bar. About 10 years.

I have been using tlao chips for around 12 years. 10 or so years with e85. All in California.

In addition to all the things to try, if only the ignition timing could be pulled back about 15 degrees. With the knock sensor disconnected it is around 10 degrees. It is plugged back in for now. I am going in for a re smog on my next day off, Wednesday.
 
Back in April, I failed Colorado emissions for high NOx. There was a thread all about it, but it got lost in the May crash. Here's a brief recap.

I bought my '85 245 GLT KJet in April of 2015. The cat had been deleted and I failed the CO Emissions visual check, but barely passed the actual emissions. I added a used cat to pass visual, plus it improved the HC & CO, but did almost nothing for NOx. I ran the KJet setup, with the original ~330K mile engine, for a few years. In early 2019, I swapped in a rebuilt B21FT and converted from KJet to LH2.4 ('937 ECU / '148 EZK / green 30lb turbo injectors and r-pack). This failed emissions in April of this year for high NOx (the CO limits dropped from 4.5 grams-per-mile to 3.5 GPM at the start of the year). Before replacing the cat, I had a free retest that was about to expire, so I re-ran with -6deg of EZK advance. This still failed, but did have better NOx.

After replacing the cat, HC and CO emissions were reduced by ~90% and NOx went almost to zero! Hence why I think there's something fundamentally off with your setup and new cat.

Colorado uses an IM240 4-minute dyno mixed driving test for emissions, and measures average GPM grams/mile of pollutants over the test. Sorry, there's not an easy way to convert GPM to PPM.

Colorado IM240 Emissions Testing Results:
<table><tr><td></td><td></td><td>4/18/15</td><td>4/25/15</td><td>4/15/17</td><td>4/9/22</td><td>4/16/22</td><td>4/23/22</td></tr><tr><td></td><td>Limits</td><td>NoCat</td><td>UsedCat</td><td>StillKjet</td><td>LH2.4</td><td>-6deg</td><td>NewCat</td></tr><tr><td>HC GPM</td><td>2.50</td><td>2.47</td><td>1.35</td><td>0.85</td><td>0.59</td><td>0.56</td><td>0.053</td></tr><tr><td>CO GPM</td><td>20.0</td><td>19.7</td><td>12.4</td><td>10.7</td><td>9.6</td><td>8.7</td><td>0.94</td></tr><tr><td>CO2 GPM</td><td>n/a</td><td>403</td><td>407</td><td>424</td><td>404</td><td>424</td><td>424</td></tr><tr><td>NOx GPM</td><td>4.50</td><td>4.37</td><td>4.21</td><td>4.48</td><td>5.52</td><td>4.53</td><td>0.0026</td></tr></table>

Here's the first IM240 failure chart from April:
Failed-IM240-Emissions.jpg


And here's the matching ECU/EZK log:
IM240-Emissions-Test-Log2.png



(Sorry, they can't give out the IM240 chart if it passes. I'd have loved to see what it looked like.)

-Bob
 
Back in April, I failed Colorado emissions for high NOx. There was a thread all about it, but it got lost in the May crash. Here's a brief recap.

I bought my '85 245 GLT KJet in April of 2015. The cat had been deleted and I failed the CO Emissions visual check, but barely passed the actual emissions. I added a used cat to pass visual, plus it improved the HC & CO, but did almost nothing for NOx. I ran the KJet setup, with the original ~330K mile engine, for a few years. In early 2019, I swapped in a rebuilt B21FT and converted from KJet to LH2.4 ('937 ECU / '148 EZK / green 30lb turbo injectors and r-pack). This failed emissions in April of this year for high NOx (the CO limits dropped from 4.5 grams-per-mile to 3.5 GPM at the start of the year). Before replacing the cat, I had a free retest that was about to expire, so I re-ran with -6deg of EZK advance. This still failed, but did have better NOx.

After replacing the cat, HC and CO emissions were reduced by ~90% and NOx went almost to zero! Hence why I think there's something fundamentally off with your setup and new cat.

Colorado uses an IM240 4-minute dyno mixed driving test for emissions, and measures average GPM grams/mile of pollutants over the test. Sorry, there's not an easy way to convert GPM to PPM.

Colorado IM240 Emissions Testing Results:
<table><tr><td></td><td></td><td>4/18/15</td><td>4/25/15</td><td>4/15/17</td><td>4/9/22</td><td>4/16/22</td><td>4/23/22</td></tr><tr><td></td><td>Limits</td><td>NoCat</td><td>UsedCat</td><td>StillKjet</td><td>LH2.4</td><td>-6deg</td><td>NewCat</td></tr><tr><td>HC GPM</td><td>2.50</td><td>2.47</td><td>1.35</td><td>0.85</td><td>0.59</td><td>0.56</td><td>0.053</td></tr><tr><td>CO GPM</td><td>20.0</td><td>19.7</td><td>12.4</td><td>10.7</td><td>9.6</td><td>8.7</td><td>0.94</td></tr><tr><td>CO2 GPM</td><td>n/a</td><td>403</td><td>407</td><td>424</td><td>404</td><td>424</td><td>424</td></tr><tr><td>NOx GPM</td><td>4.50</td><td>4.37</td><td>4.21</td><td>4.48</td><td>5.52</td><td>4.53</td><td>0.0026</td></tr></table>

Here's the first IM240 failure chart from April:
Failed-IM240-Emissions.jpg


And here's the matching ECU/EZK log:
IM240-Emissions-Test-Log2.png



(Sorry, they can't give out the IM240 chart if it passes. I'd have loved to see what it looked like.)

-Bob

My next day off is Wednesday. I was looking through my wiring and found a bad connection from the battery to the fuel pumps where a 25 amp fuse was installed. Changed that out today. Definitely a fuel related issue. Could have been making the engine run lean. Surprised I could not see it with the wideband. Very similar setup. Thank you for sharing your graphs.

I am running 19 on the Ezk grounded for a -6 spark advance, very close but the nox always begins to climb. Even with the knock sensor unplugged, from around 375ppm to around 700ppm ish. About 500ppm is a fail.
 
Passed emissions today. After many hours there was a bad connection with on of the o2 sensor wires. My 15mph nox was about about 400ppm, fail is around 550. At 25 mph nox was about 70ppm, fail is around 500. I'm going to dig in to see what else I can find.something is going on at low speed low load.
 
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