Weird data.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Lou Merrell

I'm Awesome
Joined
Jan 5, 2022
Messages
145
Reaction score
118
Location
Ohio
1996 K1500 vortec 5.7
New dizzy, plugs, wires, mpfi upgrade and throttle body gaskets, cat (need to install the other because it's started to rattle/ pos flowmaster cats), timing chain has 6* total slack, new fuel filter.
Starts up right away, fuel pressure may be a bit low/ 56 psi at key on, 46 psi at idle.
No codes.
Fully warmed after driving 15 miles so I plugged in my scanner to see what was causing a short lived but high idle (1500 rpm) when truck is put in park. No such luck, idle normal. But I have weird numbers and still have major ignition retard in #1. Truck runs really well but I can feel a miss or slight 'bump' at stop light or idle. Following data is from last mile and park in driveway.
 

Attachments

  • Screenshot_20230114-075008.png
    Screenshot_20230114-075008.png
    153.7 KB · Views: 17
  • Screenshot_20230114-075023.png
    Screenshot_20230114-075023.png
    144.1 KB · Views: 16
  • Screenshot_20230114-075050.png
    Screenshot_20230114-075050.png
    124.5 KB · Views: 16
  • Screenshot_20230114-075102.png
    Screenshot_20230114-075102.png
    143 KB · Views: 17
Last edited:

Schurkey

Supporting Member
Supporting Member
Joined
Jan 14, 2018
Messages
10,970
Reaction score
13,756
Location
The Seasonally Frozen Wastelands
fuel pressure may be a bit low/ 56 psi at key on, 46 psi at idle.
There's a potential problem. OTOH, the fuel trims are showing that at least in the active cell when the photos were taken, there's enough fuel.

still have major ignition retard in #1.
-21 doesn't sound like "major retard" to me.

I bet that's actually signifying the ignition is 21 degrees ahead of ( - ) TDC, where as retard would be TDC "+" some number of degrees. May want to verify with the operator's manual for your scan tool.
 

Lou Merrell

I'm Awesome
Joined
Jan 5, 2022
Messages
145
Reaction score
118
Location
Ohio
Oh yeah, that's right. Egg meet my face.
I'm using the dash command app with bluetooth reader.
I'll be pulling into the garage this weekend for a pitman arm and the other cat replacement. I'll see where I'm at afterward. Don't know if the crank sensor has ever been replaced with over 180k on the truck.
 

Lou Merrell

I'm Awesome
Joined
Jan 5, 2022
Messages
145
Reaction score
118
Location
Ohio
Would the knock sensor counts be caused by the loose elements in the bad cat?
 
Top