Suzuki Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter #1
Hi Guys,

I recently got a Bluetooth OBD2 Reader which I access via a Freeware program in my Android phone. I got some readings which I attached here & I’m wondering if anyone have analyzed the values and maybe compare them? Or maybe if any values would stand out & raise warnings?

This is with my 2004 XL7 with H27A, 4WD, AT.

98802

98803
 

·
Registered
Joined
·
8,257 Posts
Total fuel trim is concerning. can you do graphs? I'd like to see LTFT & STFT banks 1 and 2 at idle and 2500 rpm please,
 

·
Registered
Joined
·
351 Posts
The O2 sensor voltages aren't useful as a snapshot. You want to see those going high and low in a steady cycle.
Total fuel trim is a bit high, but not indicative of a problem without more data, as mentioned previously.


Sent from my Moto E (4) Plus using Tapatalk
 

·
Registered
Joined
·
8,257 Posts
One word, yuk.....long term fuel trims should average around 0,
plus or minus 8 is ok, outside that you have an issue.
Common causes of High negative trims (rich mixture, negative indicates ecm is trying to remove fuel)
  • Excessive fuel pressure; test fuel pressure with a dedicated fuel pressure gauge
  • Leaking fuel injectors; test injector operation by performing a spray pattern and volume test
  • Defective MAF sensors can under report the volume of air passing over them, thereby causing rich running conditions
  • Exhaust leaks; repair all leaks found since exhaust gas contaminates the ambient air that oxygen sensors use for reference purposes
  • Loss of some compression on one or more cylinders; loss of compression causes poor or incomplete combustion, which results in unburned hydrocarbons “fooling” oxygen sensors into reporting a rich mixture
  • Marginal misfire; not all misfires are bad enough to set a misfire code, so check or replace suspect spark plugs, and check the operation of all ignition coils with an oscilloscope
  • Marginally defective oxygen-, or air/fuel ratio sensor(s); sensors may be stuck at reading rich conditions as a result of not reacting to switching signals from the ECU, or may be slow to respond to switching signals
Time to start checking and diagnosis

First step, clear any codes remove battery for 10 mins to clear ltft data, then drive for a week then recheck graphs, if still out, start diagnosis. STFT will bounce round depending on driving conditions, but sitting on the shop floor at 2000 rpms should hover around 0 as should the ltft after 30 seconds or so.
 
1 - 7 of 7 Posts
Top