Misfire, Running Rich

[exp500]

PID is a description number for each thing monitored. Go to the website for your scanner and look for Advanced or extra or new PIDs- They might not even call them PIDs. Try to learn it a little more, you have alot shown, but if you chose to monitor cylinders 1-8 missfires individually for instance, then a misfire at the coil would be equally distributed among all 8. A spark plug on #2 would be trouble code P0302. for #5 P0305 , trouble code P0300 missfire. Counts have to reach a threshold value to set as specific. P0300 VS P0301
MAO? Communist in your motor? MAP manifold air pressure 9.9 under light load ok. 14-19 inches no load.
Do you have a fuel pressure guage? Monitor fuel pressures when it misses. Change your fuel filter EVERY YEAR. Change it now.
It got better with Techron- A clue.
What I think- you posted above was live but a snapshot of everything monitored.
Techron and fuel filter I would do now. Fuel pressure gauge As soon as you can, Website or Utube for scanner.

 

[Donf]

Will do, thanks.
Honestly, last time I worked on this stuff EGR valves and smog pumps were state of the art and carburetors and points were the rule. But I can learn.

 

[wjburken]

smog pumps were state mandated

Fixed Your Post

 

[Donf]

PID is a description number for each thing monitored. Go to the website for your scanner and look for Advanced or extra or new PIDs- They might not even call them PIDs.

Website predictably useless

Try to learn it a little more, you have alot shown, but if you chose to monitor cylinders 1-8 missfires individually for instance, then a misfire at the coil would be equally distributed among all 8. A spark plug on #2 would be trouble code P0302. for #5 P0305 , trouble code P0300 missfire. Counts have to reach a threshold value to set as specific. P0300 VS P0301

I think I have learned a bit just playing with if for an hour. Cannot isolate individual cylinders but P0300 is constant, cannot get any other misfire code now.

MAO? Communist in your motor?

He seems to have left for the White house

MAP manifold air pressure 9.9 under light load ok. 14-19 inches no load.

See below.

Do you have a fuel pressure guage? Monitor fuel pressures when it misses. Change your fuel filter EVERY YEAR. Change it now.

No, recommendations?

It got better with Techron- A clue.
What I think- you posted above was live but a snapshot of everything monitored.
Techron and fuel filter I would do now. Fuel pressure gauge As soon as you can, Website or Utube for scanner.

Got an AC Delco Filter, changed it. No changes.
Sprayed a bit of carb cleaner around some vacuum connections (less than I thought would be there) but no change in idle.
Removed air cleaner and noticed no changes either.

I cannot copy and paste the graphic data, should have asked that specifically I guess.
Instead I have made use of a process utilizing paper and pencil (learned that in school right before slide rule practice). Maybe it will help.

Calculate LOAD Value
Idle = 2.9 to 4.3
1500 RPM = 9.0

Intake Manifold Absolute Pressure
Idle = 9.9 to 10.2

Spark Advance
Idle = 20 to 26 degrees
1500 RPM = 28 degrees
2000 RPM = 31 degrees

MAF
Idle = .9 lb/min
1500 RPM = 2.4 lb/min


Absolute Throttle
Idle = 0.0 to 0.4%
1500 = 4.7%

Short Term Fuel Trim
B1
Idle = -30.5, Constant
1500 RPM = Rose to -20 to -30 then dropped to -30
B2
Idle = -25 to -7, Avg -10.2
1500 RPM = Rose to -20 to -30 then dropped to -10.2

Long Term Fuel Trim
B1 and B2
Idle = -18
1500 RPM = Rose then dropped to -18 but B2 returned slower

O2 Output Sensor
B1S1
Idle = .88 to .91
1500 RPM = .15 to .79

B1S2
Idle = .9 to .94
1500 RPM = .07

B2S1
Idle = .065 to .91
1500 RPM = .5 to .8

B2S2
Idle = .04 to .1
1500RPM = .05 to .06

Found a graph with all 4 fuel trims but with sensor
designations

All at idle

Min Max
------ ------
B1S1 -30.5 -30.5
B1S2 99.2 99.2
B2S1 -23.4 -18
B2S2 99.2 99.2

At 1500 RPM B1S1 -20 to 25
B1S2 99.2
B2S1 -14 to -18
B2S2 99.3

Also found a button that said " Check Evap System", It said FAILED, but no code shows up. Never has either.



So, does that show anything useful? Bad Cat? Bad sensors? Both? Neither?

Thanks

 

[79jasper]

Take a look at this video. (Yes truck in video is a 01, but I think it still applies to your engine)

Sent from my SM-G988U using Tapatalk

 

[Squirrelsmith]

Not that my story has anything to do with your condition but i was running lean, missfiring etc and it turns out my 1 year old msd cap and rotor had gone bad. Replaced with a ac delco and runs fine now

 

[exp500]

On your original snapshot scan, fuel trims looked Hi, I was hoping by live data you could narrow down the P0300 to a cylinder or bank. Find a fuel perssuse guage, ( harbor freight, amazon, craftsman) $30-50. Get a long fuel hose so it can stick out rear of hood where you can see it. You want 58# minimum. let us Know what the key on eng off press is, running pressure, and when it it missing what pressure is. I was trying to eliminate Ignition before fuel misses. Seems easier for me to diagnose in that fashion. When the Intake gaskets done, was the Spider replaced? Upgraded? On Ignition, Distributor cap should be Delco or United DCR 820X only. And trere were some Chineese Delco plugs for a year or two that fail early. Inside of dist look at wires to cam sensor rubbing on bottom of dist. Plug wires /coil wire suspect also. Last is Coil failure when hot, but usually that fails completely. Same with ICM.
Try more live scans monitoring PO301- PO308 ,Fuel trims, see if it is just one or two acting up. You are getting close to a resolution .

 

[Donf]

Got the pressure gauge.
Engine running - a bit over 50 psi
Key on, Engine off - jumps up to a hair over 50 then drops over 20-30 seconds to near 0. Stops a second or 2 around 20.
Can't tell a difference when it is missing.
Notice a few things, the cement near the tailpipe is black and looks like liquid is coming out of the pipe(drops) I can't smell at all and didn't have a match handy to test if it is flammable or not.

 

[Tonyrodz]

Got the pressure gauge.
Engine running - a bit over 50 psi
Key on, Engine off - jumps up to a hair over 50 then drops over 20-30 seconds to near 0. Stops a second or 2 around 20.
Can't tell a difference when it is missing.
Notice a few things, the cement near the tailpipe is black and looks like liquid is coming out of the pipe(drops) I can't smell at all and didn't have a match handy to test if it is flammable or not.

That liquid is most likely condensation--water, which is normal.

 

[Fless]

Got the pressure gauge.
Engine running - a bit over 50 psi
Key on, Engine off - jumps up to a hair over 50 then drops over 20-30 seconds to near 0. Stops a second or 2 around 20.
Can't tell a difference when it is missing.
Notice a few things, the cement near the tailpipe is black and looks like liquid is coming out of the pipe(drops) I can't smell at all and didn't have a match handy to test if it is flammable or not.

I'm not all that familiar with the OBS gen, but it seems to me that the fuel pressure leakdown is pretty fast. That would indicate a leaky injector or a bad fuel pressure regulator, something like that. Really just a guess on my part.