2001ZR2
OBS Enthusiast
Have Wifi OBDII BAFX 327ELM scanner I use with my iPad. Using the DashCommand software
Trying to figure out what is going on in my 1997 Suburban with a 5.7L Vortec, 3.73 gears, 4L60E and LT265/75/R16 rig.
My mileage is horrible in the range of 10-12 mpg so I am looking at the fuel trims and timing to find a clue on where to look next.
The STFT (short term Fuel trim) will vary from -7 to +7 but at a stable speed settles in around -3 to +3 the LTFT (long term fuel trim) will peg at 9.4 and will vary downward as the engine load varies.
Things I wonder about is the Original Ignition coil but the secondary resistance is about 6.5 kOhms. I will check the primary resistance again as I had it on the wrong scale. The ignition control module is also original. The truck has 309k miles.
I also wonder about the fuel spider which is why I checking the fuel trims.
Things I have done without really changing the mileage...New Magnaflow cats and y pipe, Mangaflow muffler and cat back, new spark plugs ACDelco Iridiums (old ones had gray from fuel additive but not bad) and new ACDelco. Replaced the PCV and tubing. Yesterday replaced the air inlet hat at the throttle body as the clip had disappeared.
Also cleaned the throttle body and EGR Valve with a new gasket.
Checked the vacuum and have just under 20 inches at idle.
Cap and Rotor are not that old at less than 2 years. Fuel pump is also less the 20k mileage usage.
Trying not to use the parts cannon but are those fuel trims reasonable?
and I see +33 timing on the highway.
Almost forgot the coolant temp goes up to 194 F and stays there.
Trying to figure out what is going on in my 1997 Suburban with a 5.7L Vortec, 3.73 gears, 4L60E and LT265/75/R16 rig.
My mileage is horrible in the range of 10-12 mpg so I am looking at the fuel trims and timing to find a clue on where to look next.
The STFT (short term Fuel trim) will vary from -7 to +7 but at a stable speed settles in around -3 to +3 the LTFT (long term fuel trim) will peg at 9.4 and will vary downward as the engine load varies.
Things I wonder about is the Original Ignition coil but the secondary resistance is about 6.5 kOhms. I will check the primary resistance again as I had it on the wrong scale. The ignition control module is also original. The truck has 309k miles.
I also wonder about the fuel spider which is why I checking the fuel trims.
Things I have done without really changing the mileage...New Magnaflow cats and y pipe, Mangaflow muffler and cat back, new spark plugs ACDelco Iridiums (old ones had gray from fuel additive but not bad) and new ACDelco. Replaced the PCV and tubing. Yesterday replaced the air inlet hat at the throttle body as the clip had disappeared.
Also cleaned the throttle body and EGR Valve with a new gasket.
Checked the vacuum and have just under 20 inches at idle.
Cap and Rotor are not that old at less than 2 years. Fuel pump is also less the 20k mileage usage.
Trying not to use the parts cannon but are those fuel trims reasonable?
and I see +33 timing on the highway.
Almost forgot the coolant temp goes up to 194 F and stays there.