I'm new to these Forums, so I apologize for any offenses as I learn to participate. I have a 99 xj8 that developed these codes immediately after the check engine light came on. Started engine, idled rough and then died. Have not been able to get engine to fire since. It does crank over, I've cleared the codes, even disconnected the battery for a while. Still no fire.
I would appreciate any advice on where to look for my cause and possible solutions to get me up and running again. I am mechanically inclined and have always done most of my own car repairs. Although, the jag is pushing my limits, both knowledge and special tool inventory.
Thank you. RAE

 

Ok, I've extracted my foot from my mouth. I know that the P0172 is a rich bank 1, & P0174 is a lean bank 2. Makes no sense to me. I may have called out the wrong codes (P0172). I have also, read many threads, and Gus's advice and links. I've, cleaned the MAF sensor, removed, ck'd and cleaned air inlet between MAF & TB, appears ok. Also, ck'd part load breather 3/32 hole, and quick visual on related vacuum hoses. I will ck fuel pressure next and update. Engine does seem to crank with little compression, from reading threads, I guess the cylinders could be washed. How can I verify if my engine was subject to this problem? Upper 90's and short trips week it died. Thanks in advance for any input. Ralph

 

I am not sure where to start For the P0172 & P0174 I would suggest reviewing the trouble shooting procedure on my page that Brian put together I feel it is a good start http://www.gusglikas.com/AutoRepairTroubleShooting.htm . As for the cylinder washing / no start you are going in the right direction. Fuel and spark are the main components and should be check first after then read this for the no start http://www.gusglikas.com/AutoRepairNoStart.htm I hope this helps.

 

Finally got around to checking fuel pressure today. With ignition on it would get up to 38psi, cranking it would rise to 44 psi. I would presume based on reading threads here that lack of fuel pressure is not my problem. However, I have bought a fuel filter and will swap out at earliest convenience. Tried tonight, no go, too long of wrenches to accomplish.
Checking spark is next, which is where my stupid question comes from. In the old days, you would remove plug, and lay on outside of engine while hooked to plug wire. With these coil over plugs, do you essentially do the same thing, just on a shorter leash?
As a side note, I am beginning to question the amount of compression. Engine seems to crank over smoothly without much resistance from compression. Engine currently has around 90k miles on it, and service records do not indicate that upper tensioners have been replaced. Have not heard any unuasual sounds from upper end valve train. I hope I don't have multiple root causes here.
Regards,
Ralph

 

First off, I hope Gus and other members that have replied to similar post see this. Thank you, thank you, thank you for putting up with us novices and repeating replies to similar problems. I could not have gotten thru this problem without this forum!
Got the car started today, after five cycles of cranking (20 sec), rest (5 mins). Prior to this exercise, I replaced fuel filter (although pressure seemed within limits) may have been the original (152k on car), no wear and tear marks on fittings etc. My Son loves to run on vapors, and I'm sure that contributed to problem. I confirmed my engine is a 2003 model via engine numbers(replaced earlier), so My concerns for cylinder washing were diminished. Although I wasn't happy with lack of perceived compression.
As Paul Harvey would say, and now for the rest of the story. I have some codes showing up, I presume resulting in the CEL light showing. I also have an ABS & Traction Control Failure message. The ASB/Traction Control Message has shown up before, and I presume are tied to one another. Possibly a subject for another forum, especially since it's summer out. No codes relating to these.
My codes are:
P0102: MAF or VAF Sensor Circuit Low Input (could this be due to cranking with MAF & intake removed from engine, makes sense to me?)
P0112: Intake Air Temp Circuit Low Input (same thoughts as above)
P1000: Undefined. I think I've read here where this is of no concern.....
Can I clear codes and see how she runs????? My thoughts would be yes...?
Again, my heartfelt thanks! Ralph

 

Often you can get false codes when the battery gets low or the demand on it is great. Document the codes and then clear them and see what comes up. With a little luck it will all be ok!

PS Thanks for the kind words!