5.7L running too lean (very high NOx), won't pass state emissions

I have an 89 Jeep Wrangler with a 95 Chevy 5.7L TBI crate motor mated to a 700R4 trans. The computer (1227747), wiring harness and all sensors are out of a 92 chevy truck. Since the 700R4 is non-electronic, it has the 1227747 computer. This setup was installed in 2000 but it only has about 8,000 miles on it since the vehicle was primarily used for off-road. The main problem is NOx are very high around 1300 (max allowed is about 800). California does emissions testing at 15mph and 25mph which is about 1600rpm on this vehicle - so part throttle. High NOx means the combustion chamber is running way too hot because the engine is running too lean. I had a certified mechanic check it out a few months ago. He thoroughly checked the EGR components, no vacuum leaks, TPS and other sensors, timing, replaced O2 sensor, replaced coolant temp sensor (the one that feeds the ECM), new catalytic convertor, switched fuel canister & purge system from Jeep to Chevy, etc. Engine starts right up, idles fine, and has plenty of power. Also, replaced P/N switch and wired it with a new starter relay so ECM B10 get a ground if shifter in P or N. So, I purchased the Moates Extreme ALDL hardware and cables and TunerPro RT (using $42-1227747-V5.2.adx). Data is streaming fine and I have attached my XDL file which shows cold engine through normal operating temperature (about 200 degrees). I am new to reading the TunerPro RT results, but it looks to me like the ECM goes into closed-loop mode when the coolant reaches about 115 degrees, BLM holds pretty steady around 128 but occasionally goes into low 130's. I did notice that once fully warmed up and at part throttle, the O2 sensor output seems to be quite low (100mv or less) and the Rich/Lean parameter pretty much stays Lean - event hough the BLM remains steady at 128. I don't quite understand this. So, can someone take a close look at my attached XDL file and perhaps explain what is going on? I haven't measured the fuel pressure since it is a pain to get to the metal line under the rear of the throttle body with the engine crammed in a Wrangler.

Lee

Hi bigmac:
Just curious about your O2 sensor: Is it a heated sensor? Is it located in or near the manifold or collector? Do you have headers or cast iron manifold?
What size exhaust pipes and are they dual going into a Y or crossover? One cat or two?
Bob

ps Didn't look at your .xdl.

O2 is single wire (non-heated). It is located in the rear of the passenger side ceramic header (just above the collector area). Driver side exhaust connector pipe runs under oil pan to a y-collector on passenger side. A single 3" diameter exhaust pipe runs from the y-connector to a new cat then to a muffler then over the rear Dana60 axle terminating under the bumper.

Lee

May not be getting hot enough? If nothing else is obvious you may want to go to a heated sensor.

Bob

Thanks Bob. I will look into converting to a heated O2 sensor.
Lee

If the 02 sensor was cooling off the engine would run rich, not lean. I would check your base timing and make sure it is set for TDC or 0*BTDC. Also check the base fuel pressure the engine is running at. These engines like to be in the 12-13 psi range even with a stock engine. Maybe as much as 14 psi with a higher flowing intake/exhaust setup. Finally check your injectors to make sure that you have the 61 lb/hr injectors, not the 46s or 55s from a 4.3 or 350. I would also suggest that dropping the coolant temp will help prevent the formation of NOx emissions. A 180*F thermostat will drop the numbers some as well.

Fast355, I will check the timing and fuel pressure. However, I have a question about the injectors. Since this is a throttle body with two injectors, how do I tell what size they are? If I remove them, will there be a number somewhere on them? I have attached two photos, one shows Rochester Products 155Z64 and the other a number 312. As you can see from the pictures, both are on the throttle body. I don't know if the injectors have separate part numbers.
Lee

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Originally Posted by bigmac

Fast355, I will check the timing and fuel pressure. However, I have a question about the injectors. Since this is a throttle body with two injectors, how do I tell what size they are? If I remove them, will there be a number somewhere on them? I have attached two photos, one shows Rochester Products 155Z64 and the other a number 312. As you can see from the pictures, both are on the throttle body. I don't know if the injectors have separate part numbers.
Lee

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If they are GM injectors the factory part number will be eteched into the top of them. Should be able to read the numbers without removing them.

I know my old TBI in my 1983 G20 van passed with a fraction of the allowable limits. It was also not stock at the time. Had an edelbrock intake, 454 TBI unit, open center TBI spacer, 1.6:1 roller rockers, and doug thorley tri-Y headers feeding a large high flow 3" converter.

This was the last smog test it ever had to go through.

http://i243.photobucket.com/albums/f...pssentmdzc.jpg

This part number is on the injector body AC 112. Next to it is another number 17064317. However, when I search AC Delco's website, it says both numbers don't exist. See
Lee

Quote:

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Originally Posted by bigmac

This part number is on the injector body AC 112. Next to it is another number 17064317. However, when I search AC Delco's website, it says both numbers don't exist. See
Lee

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If they are factory injectors where the injector connector clips there will be two painted strips. A 350 truck injector will be Orange/Black.

Quote:

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Originally Posted by bigmac

This part number is on the injector body AC 112. Next to it is another number 17064317. However, when I search AC Delco's website, it says both numbers don't exist. See
Lee

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If they are factory injectors where the injector connector clips there will be two painted strips. A 350 truck injector will be Orange/Black.

The pic you posted is for the fuel meter body. Each injector will be stamped itself. Under the injector connector.

These are Marine high pressure injectors. Pink/Purple....Notice the rusty looking area on them. That is the factory stamping ID.

http://i243.photobucket.com/albums/f...55_album/6.jpg

Well, here are three photos of my injectors. One of them shows the orange and green wires and an orange marking on the front side of the first injector. The second photo clearly shows a black marker on the back side of the first injector. The third photo is looking down into the bottom of the first injector where if you zoom the picture you can see a large number 5 on one side and I think a small number 02360. So, are these 60lb injectors?
Lee

Quote:

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Originally Posted by bigmac

Well, here are three photos of my injectors. One of them shows the orange and green wires and an orange marking on the front side of the first injector. The second photo clearly shows a black marker on the back side of the first injector. The third photo is looking down into the bottom of the first injector where if you zoom the picture you can see a large number 5 on one side and I think a small number 02360. So, are these 60lb injectors?
Lee

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Those are 61s.

So, injectors are good. I also tested the fuel pressure at the outlet of the fuel filter and it measured 14lbs. See attached photo. Since the fuel pump is in the tank and it is a pain to get to the metal fuel line connecting at the bottom of the TBI, I took the easy way and measured it at the fuel filter.
Lee

What BCC is in the ECM? 92 could have been a 305 bin which would run lean all the time. I know from experience, I fought it for years until I figured out a PO had swapped out the 305 for a 350. Just a thought.

Quote:

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Originally Posted by jim_in_dorris

What BCC is in the ECM? 92 could have been a 305 bin which would run lean all the time. I know from experience, I fought it for years until I figured out a PO had swapped out the 305 for a 350. Just a thought.

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The 92 G20 Van I had also did not have a 7747 in it. Had a 299' ECM in it. Almost every 92 I have run across truck/van/suburban/etc had a 299.

Also there is always a chance the 7747 does not have a stock chip in it. Could have something from someone like TBI Chips that has ZERO clue what they are doing.

I pulled the ECM and took pictures of the label and the prom itself (see attached). The BCC is an ANLW and the exact number is 86ANLW K182590103. My research says this cross references to a prom id of 66 ($42) 91-92 truck 5.7L TBI "K" LO5 w/0 4L80E. Sounds like the right computer for my setup since I have a 700R4 transmission. However, I think it does have a custom prom which is in a socket with a hand written label: HED 350 STK 4-22-04. Please see the attached pictures. I am going to load the ANLW 89 C-G-K-R-V Truck 5.7TBI 700r4 with 2.73 gears.bin file into my TunerPro RT.

Lee

Quote:

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Originally Posted by bigmac

I pulled the ECM and took pictures of the label and the prom itself (see attached). The BCC is an ANLW and the exact number is 86ANLW K182590103. My research says this cross references to a prom id of 66 ($42) 91-92 truck 5.7L TBI "K" LO5 w/0 4L80E. Sounds like the right computer for my setup since I have a 700R4 transmission. However, I think it does have a custom prom which is in a socket with a hand written label: HED 350 STK 4-22-04. Please see the attached pictures. I am going to load the ANLW 89 C-G-K-R-V Truck 5.7TBI 700r4 with 2.73 gears.bin file into my TunerPro RT.

Lee

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Definately has a reprogrammed prom chip in it. No telling what changes were made from stock. If you can get your hands on an OEM PROM, I would try running it first after double checking your base timing. I would start with ASDU myself. Does this engine have a smog air pump?

No air pump. I will set the base timing later today. Any suggestions on sources for purchasing an ASDU chip? I see a 1227747 ECM with ASDU chip on eBay for $85.
Lee

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Originally Posted by bigmac

No air pump. I will set the base timing later today. Any suggestions on sources for purchasing an ASDU chip? I see a 1227747 ECM with ASDU chip on eBay for $85.
Lee

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Local junkyard would be my first pick. Look in a 1990+ 350 TBI 1500 truck.

I ordered a known good used 1224747 ECM with original factory ASDU chip (see picture below). Should arrive in a few days.

In the meantime, I attempted to check the base timing. Originally, I didn't see an existing timing pointer so I purchased the Moroso pointer and bolted it to existing timing cover bolts (pain in the butt to install). Only then did I see the existing notched pointer in the center of the timing cover (actually, I could barely see only the right end - the big V notch). I also purchased the nifty device that you screw into the No 1 spark plug hole then tightened the inner screw so the top of the piston will contact it as it comes up on the power stroke. I put a piece of tape around the damper wheel and placed a black line all the way across where the factory line is. I then turned the engine by hand and placed marks where the piston hit the special screw device. I made marks for both the original pointer and the new Moroso pointer. NOTE: the Moroso pointer is about 2 inches to the right of the original V notched pointer. Attached is a picture of the two pointers - you have to look closely to the left of the black Moroso pointer to see the rusty original V notch pointer. And now the fun part: one of the attached pictures shows the comparison of the black marks on the two tapes that were on the damper (the upper tape shows the marks for the original pointer and the lower tape for the new Moroso pointer. Not only are the Moroso marks considerably further to the right, but the distance between the black marks is about twice as wide on the upper tape (original pointer) than the lower tape (Moroso pointer). How can this be? I know the piston was hitting the screw because in addition to me feeling it with the socket wrench on the crank pulley - I had a helper put his fingers on the screw in the spark plug hole and he could feel the it tighten). Also, I marked the half way point between the black marks with a silver line that should represent TDC. Both tapes would indicate that the base timing is way off (maybe 20 degrees). Note, the battery is disconnected so this was a purely mechanical test. Can someone explain which pointer is correct? I think the silver line in the upper tape says the engine is way too advanced, and the silver line in the lower tape way too retarded. I really look forward to someone explaining this mystery to me.

Lee

I think I maybe figured this out. The piston must be on the Exhaust/Intake stroke instead of on the Compression/Power stroke. I will retest today.
Lee

Quote:

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Originally Posted by bigmac

I think I maybe figured this out. The piston must be on the Exhaust/Intake stroke instead of on the Compression/Power stroke. I will retest today.
Lee

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Simce the cam turns 1/2 speed of the crank, TDC is TDC regardless of which stroke you are on.

I just did the retest, first turning the engine so top of the piston went around one full revolution before retesting the marks. Now, this comes out near perfect. It looks to me like base timing is about 2 degrees advanced. See attached picture). I assume the computer can make up for this amount. When I get the new computer with the ASDU (should arrive by Friday this week), I will take a new TunerPro log file and post it.

Lee

I can't follow what you are doing with the piston stop by your description and tape. The stop doesn't stop the engine at TDC so touching the stop and making a mark means nothing by itself.

You put the stop in and rotate the engine clockwise until it touches and make a mark. Then, rotate the engine counterclockwise until it touches and make another mark. TDC is in between these 2 marks.

The computer does not compensate for the timing. 2* advanced means the timing is always 2* advanced compared to the programmed timing curves.

Quote:

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Originally Posted by Fast355

If the 02 sensor was cooling off the engine would run rich, not lean.

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When I learned the 1-wire O2 doesn't work in the collector of long tube headers, the engine went badly lean at idle. It would start working correctly again once the rpm's were brought up to the 1500+ rpm range.

The engine also tended to run a little lean at cruise in the 1500-2000rpm range, but that was a lack of adjusting the loop for the headers since it still occurred with a heated O2 sensor. At cruise I could hear the engine pitch slightly change every time the O2 sensor voltage went low. Some integer delay and O2 switching point adjustments were required to fix it.

The procedure you described is exactly what I did. The two silver marks in my picture were the piston stop points. The line I labeled TDC is the halfway point. The other wider black line is the one on the damper. I just guessed that the difference between those two lines is about 2 degrees. Sorry, I didn't make this clearer in my previous description. You make a good points regarding the O2 sensor and the INT adjustments. After I install the new ECM with the ASDU chip later this week, I will retest and see where things stand. If still running lean, then my next plan is to switch the single wire O2 to a 3-wire heated to perhaps compensate for the headers like you stated. If it still is running too lean, then I will probably have to make adjustments to the tables. I will need help doing that but will post the latest log file you to look at first after the above changes. Thanks for the suggestions, I really appreciate them.

Lee

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Originally Posted by lionelhutz

I can't follow what you are doing with the piston stop by your description and tape. The stop doesn't stop the engine at TDC so touching the stop and making a mark means nothing by itself.

You put the stop in and rotate the engine clockwise until it touches and make a mark. Then, rotate the engine counterclockwise until it touches and make another mark. TDC is in between these 2 marks.

The computer does not compensate for the timing. 2* advanced means the timing is always 2* advanced compared to the programmed timing curves.




When I learned the 1-wire O2 doesn't work in the collector of long tube headers, the engine went badly lean at idle. It would start working correctly again once the rpm's were brought up to the 1500+ rpm range.

The engine also tended to run a little lean at cruise in the 1500-2000rpm range, but that was a lack of adjusting the loop for the headers since it still occurred with a heated O2 sensor. At cruise I could hear the engine pitch slightly change every time the O2 sensor voltage went low. Some integer delay and O2 switching point adjustments were required to fix it.

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2* advanced is 2* advanced over whatever has been programmed into the chip. The chip itself probably has additional advance over stock.

My experience was exactly the opposite with an unheated o2 sensor in a long tube. The o2 voltage would fall when the sensor cooled off, driving the Integrator and BLM up to their limits. It would run so rich it would actually blow black/grey smoke until the revs came up and the 02 sensor started working.

Once I receive the ECM and its stock ASDU chip and get it installed along with a new heated O2 sensor, I will set the timing to 0 degrees (with the ECM wire disconnected). Then I will run the TunerPro software and create a new log and post it here.
Lee

Hey I am providing an update. I received and installed the 1227747 ECM with the factory ASDU chip. It started right up and after a warm up period I disconnected the distributer connector and set the base timing to exactly 0 degrees TDC. Previously, it was 2 degrees advanced. Then i ran TunerPro and created another log file. There seems to be some significant improvements. First it idles at 750 or so instead of 1150, but much more importantly at part throttle is now seems to be operating much better flipping back and forth every few seconds between Lean and Rich and the O2 sensor output voltage also seems to be alternating above and below .500. Previously, part throttle seemed to stay just Lean most of the time.

I do have one question though. The vacuum and MAP numbers seem to pretty much remain constant regardless of throttle position. I don't understand this. Shouldn't the vacuum and MAP numbers drop as throttle increases?

If someone could look at the attached XDL file it would be appreciated.
Lee

What is your compression ratio and what plugs are you running? I know you've got other things working against you and you're sorting them out, but running plugs that are too hot will also have a huge effect on NOx

I cant open your file so im just stabbing, that engine is gonna run cold if the air gets under it, my 5 speed trucks' oil got so cold that it lost a rod bearing it was always at 1500-2000 when it was running I don't think you have a computer issue, U will be able to tell if the injectors are firing right. does it spray consistently through the rpm? Not saying that's an easy issue you have.

Good point. I am running Platinum E3's (4-prongs). I will probably go back to standard AC Delco's.

I don't think this is part of my problem as the engine actually runs on the hot side - probably because it is mounted in a Jeep Wrangler, I live in a warm climate, and don't go 4wheel'n in the snow during the winter months. But I will check the injectors spray pattern across RPMs.

There is a lot more experience in this thread than I have, but I will toss something out I ran into.

My suburban started running bad and I could see it in the data log it was running extremly lean and it was obviously much worse than yours is. I finally traced it down to one of the injectors being badly clogged and it wasn't flowing enough fuel. It was so bad you could see that one side wasn't like the other side. Both injectors were probably dirty and running lean, just one was really bad! I bought two new units and that fixed mine, if the chip doesn't fix that you might have dirty injector(s).

Lack of fuel would definitely cause it to run lean. As soon as I get my computer back, I will carefully check the spray pattern. Moates is replacing the 24 pin socket and soldering in a new 28 pin socket. Once I get it back, I will drop in the ARJU (California) chip then check everything out.