My 99 vortec 5.7 STINKS, has a subtle miss but no Codes or CEL

[brycebba]

Ok, my logging didnt work capturing raw data but here are the new charts that are more split out so the area isnt huge

This is the O2 data

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[brycebba]

Here is the Fuel Short and Long Trims

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[Schurkey]

Again, I don't have experience with that graph style of results. I can't make sense of it because there's no way to correlate what the lines mean--there's no vertical axis labels. The up-and-down sawtooth is meaningless without some idea of vertical scale. Only the first O2 sensor graph has a vertical scale.

I'm seeing that over two and a half seconds horizontally, the O2 sensor is going from rich to lean and back about twice. This, to me, is extremely lazy reaction.

Do you have an "O2 crosscounts" output from that scan tool?

What are the fuel trims in numeric form--128 is neutral, higher or lower indicates "correction" to the fuel trim.

 

[454cid]

Take a look at some of Schroedinger's Cat videos on Youtube. He goes through the logic on trouble shooting various problems, and specifically how to rule stuff out, by checking output from various sensors and tests.

 

[brycebba]

Again, I don't have experience with that graph style of results. I can't make sense of it because there's no way to correlate what the lines mean--there's no vertical axis labels. The up-and-down sawtooth is meaningless without some idea of vertical scale. Only the first O2 sensor graph has a vertical scale.

I'm seeing that over two and a half seconds horizontally, the O2 sensor is going from rich to lean and back about twice. This, to me, is extremely lazy reaction.

Do you have an "O2 crosscounts" output from that scan tool?

What are the fuel trims in numeric form--128 is neutral, higher or lower indicates "correction" to the fuel trim.

Hey I appreciate your help and sorry for the data issues. I was able to get a log file created but because its just a cheap bluetooth obd2 dongle it doesnt give much in depth access. Here are links to the 2 log files. The data is in the left sheet at the bottom of the spreadsheet and chart is in the right tab

In this file that represents 20 seconds, I held a steady 2000 RPMs for the first 15 seconds and then dropped back to idle. https://docs.google.com/spreadsheets/d/1vqIArz0WyoeJQuKUkEjuntoDNoZIH_Qn0_Qb9pRY980/edit?usp=sharing

In this file over a couple of minutes it was left at idle. At point 14:10:01-ish it hit 150 degrees on the engine coolant temperature and thats when the readings became much different. Does something happen in our computers at 150 degrees? Does the loop mode change at that temp? I also find it interesting that at idle, Bank 1 LT Fuel Trim is exactly 2x the reading of Bank 2 LT Fuel Trim, what would cause that and is it a concern?
https://docs.google.com/spreadsheets/d/1wPzhTXc6AJeC9uxLT92RXzwikk1yhn5j7qSX3IF8WyM/edit?usp=sharing

I discovered that the logging was happening too frequently to fully log all the sensors I had selected so if the o2 sensor voltages would be helpful, please tell me what would be good setup. I can control frequency of logging, .2, .5, 1 seconds, etc. and I can only find the voltage values for them but I could also rev it up, let it idle, etc. THANK YOU SO MUCH!!!

Below are some temperature readings in case they are helpful. Temperatures were taken in this order within 20-30 seconds maybe. This was after 5 minutes of idling

This is about 4-6 inches before the cat

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Temperature of the cat

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Temperate at inlet side of muffler case which is about 10 inches past the cat outlet

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About 6 inches past the muffler output

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Temperature at tail pipe exit

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[Jake_Caulley]

Have you checked compression? I had one injector that had been failing for some time finally go and took the valves in that cylinder with it. I replaced the injector assembly (before I realised I had further damage), you could hardly breathe in my garage when I fired it back up. I did have a misfire logged for that particular cylinder once the valves finally gave up. With the smell of gas in your oil, level coming up and therefore fuel in your oil I wonder if a leaking injector didn't cause damage to your rings.

 

[brycebba]

Have you checked compression? I had one injector that had been failing for some time finally go and took the valves in that cylinder with it. I replaced the injector assembly (before I realised I had further damage), you could hardly breathe in my garage when I fired it back up. I did have a misfire logged for that particular cylinder once the valves finally gave up. With the smell of gas in your oil, level coming up and therefore fuel in your oil I wonder if a leaking injector didn't cause damage to your rings.

I have not checked compression. Would the plug from a low compression cylinder look different than others on the same bank?

I'm fairly certain nothing major has gone wrong. It runs awesome other than stinks and has the subtle miss. I can't imagine it would run great if something catastrophic had happened. Also, the last time I smelled the oil was about 5 miles or so after I changed it and it smelled like gas still. I just checked it again and I really can't smell the strong gas odor. I'm going to smell it again in a little bit to see if it is ok or maybe the wind was blowing or something

 

[df2x4]

At point 14:10:01-ish it hit 150 degrees on the engine coolant temperature and thats when the readings became much different. Does something happen in our computers at 150 degrees? Does the loop mode change at that temp?

I'd say that's a pretty good possibility. I've heard people say they go into closed loop around that temp.

Also I'm no expert but isn't the temperature of the cat supposed to be higher than the rest of the system if it's working properly? I'm starting to think that may be at least part of the problems.

 

[Tavi]

Also I'm no expert but isn't the temperature of the cat supposed to be higher than the rest of the system if it's working properly? I'm starting to think that may be at least part of the problems.

Yes. They usually start working around 400 degrees. But I would suspect it’s just a symptom, not a cause.

 

[df2x4]

Yes. They usually start working around 400 degrees. But I would suspect it’s just a symptom, not a cause.

As far as the running issues I'm inclined to agree. Could be part of the reason he's smelling gas, though.