Chuck - you need to identify your car so we can help you properly without having to find your post with it in.- go to User CP (Screen top left)
Select 'Edit Signature' and put the details in there.
All DTCs are 4 digit so P171 probably = P0171 etc ie both banks too lean.
Causes
Engine misfire
Air intake leak between MAF Sensor and
cylinder head
Fuel filter / system restriction
Fuel injector restriction
IP Sensor fault (low fuel pressure)
Low fuel pump output
HO2 Sensor(s) (1/1, 1/2)
harness wiring condition fault
EFT Sensor fault (low fuel temperature)
MAF Sensor fault (low intake air flow)
Exhaust leak (before catalyst)
ECM receiving incorrect signal from one or
more of the following components:
ECT Sensor, MAF Sensor, IAT Sensor,
IP Sensor, EFT Sensor, TP Sensor

Almost always an intake leak due to a crack somewhere in the plumbing.
Both these code set a CEL

 

What is the Drivers Facia F7 fuse for? Trunk diagram says "BPM High SCs"

I parked the car and now it wont come out of park. Found the F7 fuse was popped and keeps popping immediately when I put a new one.

Thanks,

Chuck

 

Hi Chuck,
F7 is for the steering column motors. It is the B+ for the BPM.

As it is a 20A fuse, I would not recommend fitting a new one until the reason for the failure has been rectified.

 

Chuck,

Please add vehicle details to your Signature as Steve requested back in June.

The F7 protected circuits vary slightly over the model years. The Vehicle Care Handbook for your US spec 1997 MY shows F7 is a 15A fuse:



(click on the image to enlarge it)

You will need the XK8 Electrical Guide from JTIS to trace and rectify the fault.

Graham

 

It is a 15A fuse. Funny, I never use the steering column motors, I wonder why all of a sudden there is a short. Everything else seems to work on the car except overhead lights and shifter interlock. I will drop the steering column cover to see whats up.

I still never figured out the P0171(Bank-1 Lean) P0174 (Bank-2 Lean) code issue. Those codes only come up once a week or so, but car drives fine other than using a crapload of fuel. A rough estimate is about 8 miles per gallon. (Probably due to the lean condition and the ecm is compensating)

When I sprayed brake cleaner around engine, there was no change in fuel ratios except for when I sprayed around under the throttlebody then Bank-1 dropped from 18% to around 13% for but Bank-2 stayed the same at 18%.

Thanks a million.

Chuck

 

This may sound elementary, but the scourge of old cars is bad/intermittent grounds. It is cheap and expedient to rewire all grounds you can find, and then add some extra grounds.

 

Had a similar issue with my 1998 xk8. The fuel pump packed up following 3k run to south of france and was replaced, however, I hadn't time to get it sorted immediately and the car had to wait 3 months to get ramp time in my garage. When new pump was fitted the car wouldn't start and tests with niod light showed ignition pulses but no injection pulses. Diagnostics gave no recorded faults. The garage got busy with 2 other projects and only now did I get the xk8 back in.
Checked the wiring to the injectors and discovered power to the relay but no activation checked primary earth and found high resistance, removed earth cleaned it and reassembled. Relay now working, niod light showed injector firing and fuel rail with approx 48psi plugs getting wet but no start.
Checked ignition wiring and found high resistance to earth again, cleaned this also. Took a couple of hours and cleaned all the earth points and med good the main body to engine earth strap.
Tried again engine rumbling and spitting but no start, checked compression and none found, the working injectors had now bore washed the sod. SO plugs out 3 good squirts of oil thickened 50/50 with molly turn over for a few seconds, three more good squirts and turn again then comp test and 110 to 118psi on all cylinders.
Plugs in, coils on, induction refitted turn key and RRRR splutter, puff RRR splutter and then roar the old girl is up and growling again. made a hell of a smoke cloud but settled to nice even tick over and warmed up nicely. In brief when intermittent electrical gremlins hit CHECK THE EARTH POINTS.

 

if all else fails take it to the dealership. how did things turn out. Possibly a mis match between the engine and the computer

 

hi have you thought about sending your ecm to asi to have checked . just a few dollars to have checked and well worth it

 

well i can't be right there to see what is going on but, "no spark and one pulse" usually means no cam or crank position sensor, now when you say you unpluged and reconnected the plugs on the top of the valve covers have you considered that there is a break in the harness.

do you get a spark and a pulse as the key is turned on, or perhaps off.

is there any movement in the tach needle, if not, i would think the pcm doesn't know the engine is going round.

if you have at least one flash from a noid light, that would suggest the injector circuit is hot, this usually means that the ignition circuit is also hot.

normally to test a nonstart cranking engine, a noid light test confirms spark and fuel if one flash is detected at "key on" or "key off" with the absence of repeated flashes suggesting that the pcm does not know the engine is rotating.

Ford derived engine management systems will usually run on just a cam sensor but will not start without a crank sensor and a cam sensor.

i just took one of my coil covers off and all the coil wires were heat cracked to the point that i had to remake them back to outside the coil cover where the wire was still flexible.

i do have a little knowledge, i am a certified master tech with over 40 years experience and this is where i would look first.

 

You all do know that this thread was started 3/19/2013!

 

Yea Gus but with a Jag it may not be fixed yet LOL

 

You need to test carefully through each part and remove it from the list as you go. These cars will drive you to insanity if you don't.
First make sure the battery is fully charged and with a multi meter check it's output voltage under cranking by tapping an output such as the lighter socket. It should maintain 12.5 v under full cranking load. If not suspect battery issues. As a matter of course clean all earth connections at the battery end of the car and make sure they are sound. Check, clean and make good all earth points on the body espescially those relating to the processor module . With all earth points now in good order tick this off the list.
Second do a wiring check on the loom associated with the ecm, ignition amp units, crank sensor, coil packs and injectors. Do this by unplugging the ecm and carefully , using a meter searching for either high resistamnce at both ends or a leak to earth between the connector block end and a suitable point on the engine. This is boring repetitive work but worth doing, tick each circuit off your list as you go. Test the quality of earth connection on the ecm plug as well. When all is tested and ok clean the connector blocks with contact cleaner and compressed air and reassemble. With this done you will have certainty that the basic circuitry is good and individual components may be to blame. Again the can cabling connectors should be cleaned.
Pay particular attention around that burned board there may be burned cabling shorting out as well.
With all done check the following, fuel pressure at shrader valve and do a compression test on each cylinder.
To check the crank position sensor unplug it and introduce a meters probes into the connector, have a friend crank the engine and look for a few mvolts being generated.
If all this checks out I would begin to suspect the ecm but there are companies who can test these.
Don't be too trusting of noids either as not all pulses will light them they are simple LEDs and not always reliable.
In any case best of luck.