JAGUAR XJR 6 CYL 1997
COLD START ENGIN WARM @TICKOVER 2000 rpm
FUEL SYS 1 OL cl CL
FUEL SYS 2 OL CL cl
CALC LOAD 25% 20.78% 12.54%
COOL TEMP 39 DEG 79 DEG 79
STFT B1 7% MINUS 25% -3.91
LTFT B1 MINUS 6.25% MINUS 6.25% -6.25
STFT B2 MINUS 4% MINUS 25% 0 to -7
LTFT B2 MINUS 6.25% MINUS 6.25% -6.25
ENGINE SPEED 700 700 2000
SPARK ADVANCE 16 BTDC 16 BTDC 31.5
IAT 22 DEG 35 DEG 39 deg c
MAF 0.09 0.06 11.93
TPS 12.94 12.94 18.43%
O2SL 1121 1121 1121
O2S11 0.07 - 1.220 FLUCTUATING 0.030 to 0.090v
SHRTFT 0.70 - 4.82% MINUS 25% minus 1.57 - -6.21%
O2S12 OBD TEST UNIT CUTS OFF WHEN TRYING TO READ???


these are the readings from obd scanner
I have fitted
6 new core packs
6 new plugs
new crank sensor
new air compressor
and a few other things
but still bad misfire on startup but gets better when warm but still misfires
any help much appreciated based in London UK

 

Is it really idling at 2000 rpm when hot? Your throttle position looks too high, there is an adjuster in the middle of the cable that I'd add some slack to the cable to bring the idle down and then see what it does.

I'd want to see a throttle position around 12% at all times with a true closed throttle instead of the 18% you've noted - or was your foot on the throttle?

Do you have 2 O2 sensors, or 4?

 

no soory if you missread my message

I copied it from a spreadsheet
so if yo go along the top it says cold start then warm and then 2000 rpm
go down the lis and try and line them up



I will try and repost but thanks

 

JAGUAR XJR 6 CYL 1997
engine at -------- COLD START ENGIN WARM @TICKOVER 2000 rpm
FUEL SYS 1 OL CL
FUEL SYS 2 OL CL
CALC LOAD 25% 20.78% 12.54%
COOL TEMP 39 DEG 79 DEG 79
STFT B1 7% MINUS 25% -3.91
LTFT B1 MINUS 6.25% MINUS 6.25% -6.25
STFT B2 MINUS 4% MINUS 25% 0 to -7
LTFT B2 MINUS 6.25% MINUS 6.25% -6.25
ENGINE SPEED 700 700 2000
SPARK ADVANCE 16 BTDC 16 BTDC 31.5
IAT 22 DEG 35 DEG 39 deg c
MAF 0.09 0.06 11.93
TPS 12.94 12.94 18.43%
O2SL 1121 1121 1121
O2S11 0.07 - 1.220 FLUCTUATING 0.030 to 0.090v
SHRTFT 0.70 - 4.82% MINUS 2minus -1.57 -6.21%
O2S12 OBD TEST UNIT CUTS OFF WHEN TRYING TO READ???

 

JAGUAR XJR 6 CYL 1997
engine at -------- COLD STart.......ENGIN WARM @TICKOVer.......2000 rpm
FUEL SYS 1 ...........OL .................................................. .........CL
FUEL SYS 2 ............OL.................................... ...................... CL
CALC LOAD ............25%..................... 20.78%...................... 12.54%
COOL TEMP ..........39 DEG ................79 DEG .........................79
STFT B1 ............7% ..............MINUS 25% ......................-3.91
LTFT B1.......... MINUS 6.25%......... MINUS 6.25%.................. -6.25
STFT B2 ......MINUS 4% .................MINUS 25%................... 0 to -7
LTFT B2 ........MINUS 6.25% ...........MINUS 6.25%................ -6.25
ENGINE SPEED......... 700 ...........................700.................... . 2000
SPARK ADVANCE...... 16 BTDC ..............16 BTDC ..................31.5
IAT ......................22 DEG ........................35 DEG ................39 deg c
MAF...................... 0.09 ...........................0.06 ...................11.93
TPS .......................12.94...................... 12.94...................... 18.43%
O2SL .......................1121 ........................1121...................... . 1121
O2S11 ................0.07 - 1.220 FLUCTUATING 0.030 to 0.090v
SHRTFT............. 0.70 - 4.82% ...MINUS 25.minus ............1.57 - -6.21%
O2S12 OBD TEST UNIT CUTS OFF WHEN TRYING TO READ???

 

What plugs did you use? These engines are fussy about spark plugs, they like the plain jane copper ones, no fancy plugs. Preferred is Champion R12's.

You readings look about right, is the voltages of both O2 sensors swinging between Low (0.05 or so) and high (1.2 or so)? Actual numbers are relatively unimportant as long as they are changing between high and low on a regular basis ( about once per second). The rate of change can also be a function of the refresh rate on your scan tool, so if you watch long enough you should see the full voltage range.

Your code reader should give you something like sensor 1, bank 1, sensor 2 bank 1 etc for the O2 sensors. It appears that bank 2 is having trouble because it gives you a steady 1.121 - although it does say closed loop, so that means there is some feedback working. They do get lazy over time, if they are original it might be worth replacing them. Best is NTK 25018, that is the OE part. Don't buy them from Jaguar, the markup is obscene. I'm in Canada and I bought them off Rock Auto for about 10% of what Jaguar was asking. Only difference was the box.

 

I would say your MAF readings are suspicious, and your STFT radings are jumping around which CAN also be related to the MAF.

Give it a good cleaning and watch for changes.