I am new to this forum. I already went through the FAQ's and the stickies including the one about not starting.. After that I am still stuck. Things don't quite seem to add up on this one. The car had a transmission problem and I limped to the dealer who told me it needs a new trans (P1722 P1730 codes I think). Limped it home got my OBDII scanner and confirmed the codes, then erased DTCs. Turned off iginition waited fifteen minutes and rescanned and the codes were back (as expected).

Put it on ramps and started checking all cable and vacuum hose connections and found a loose vacuum hose (leading from Fuel pressure regulator tee to ECM compartment). Started car and the Trans message disappeared. This time I cleared codes and the trans codes remained gone. I crawled under inpected trans and saw no leaks or any indications of fluid problems so I decided to drive test it to see if the codes came back or it went into limp mode before tearing into the trans.

I tried to start it and found that the car would not start and it has refused to run since. When I tried to restart it the Engine Fault message apepared with an Amber indicator, Check Engine lamp, and ABS lamps on. The OBDII scanner showed no codes other than P1000/1643. I tried the battery post cleaning, attached a booster to make sure the voltage did not drop too low but the car cranks well and doesn't start. I hit the inertia switch just in case and then connected a fuel pressure guage to the schraeder valve and got 42PSI when cranking (but not when key switch in on position). I also used NOID lamps to test FI and all of them fire one pulse as cranking starts. There is no smell of fuel, so I got some starter fluid and sprayed it into the Throttle body. The car sputtered and tried to start but died out as soon as the spray was consumed.

I turned the iginition off, disconnected the battery, and reseated all of the engine electric connectors for the TPS,Throttle motor, MAF sensor, all Injector connections, and Pedal position sensor. Then I reconnected the battery and tested all the fuses and made sure I could hear the ignition positive relays engage when the key was turned to on. Still no start.. Still an engine fault message, and the only codes I see on the scanner are pending codes of P1000 and P1643. The first is because I have not run a drive cycle since the erase but I'm not sure what the second means.

Since the engine sputters with starter fluid and there are no ignition related codes showing I assumed this is a fuel system problem, but the NOID lamps and fuel pressure seem to indicate otherwise.. The Check Engine light shut off when the starter fluid was used but came back after the engine sputtered to a halt.

Th only other oddity I noted was that while checking the fuel pressure I noticed that the Throttle motor seems to be 'buzzing' when the ignition is in the on position. I know it is a servo motor, but is buzzing normal ?? (The throttle seems to move freely from the pedal or from the cable). The fuel pressure also seemed to only be present when cranking and not in the key-on position.

Not sure what to try next.. Any suggestions would be appreciated..
(XK8 has 76K and was bought used so I don't have a full history on it.)

 

Oops, forgot one detail. In addition to Engine fault it says 'Stability Control Failed' whihc also seems odd since it has not moved except rolling it off the ramps.

 

As you seem to have a fuel related issue, and you replaced a loose hose on the regulator, you might try reversing your action to see if connecting that hose caused the no start problem. Maybe a long shot but seems logical.
Non starting can also be due to the transmission harness connector, at the top of the bellhousing, accessible from te rear of the engine bay. Water can get in and corrrode the contacts.
Check the gearshift position indicators, making sure that they all illuminate as the lever is shifted between gears.

 

X100 may be on to something.

P1000 = OBD Systems Readiness Test Not Complete

P1643 = CAN Link Engine Control Module/Transmission Control Module Circuit/Network

 

I tried removing the vacuum cable and the car still failed to start 3 times so I reconnected it. I also found that code in Gus' docs last night. I will try to reseat the cables on the engine Harness this evening after work..

What I didn't mention originally is how the Trans fault started. It did not build up slowly, but came on suddenly and it was not during any hard driving. I was driving under 15 MPH in a parking lot going up a ramp and suddenly the car dropped into limp mode with a Transmission Fault message. I managed to park it, but when we got back to the car after an hour it still had the message and still limped.

Now I found P1634 means the ECM cannot communicate with the TCM...

Since the original problem started with Trans codes could they have just been early signs of TCM failure ?

Does anyone know if a dead TCM would trigger a Fuel cutoff ?
(that could explain being unable to start, and why Starter fluid works).

 

I did check J-Gate illumination early on and again last night. I saw several postings mentioing the fault and limp could be caused by D4 switch or J-Gate issues so I tested that early on. Did not find any problems with that, but I don't have IDS/WDS to really solidly confirm that the switches are all working.

Does the J-Gate console come apart from the top ??
Are there any diagrams on that out there for the XK8 ?

(I tried downloading the JTIS but it was corrupted)

 

At the top of this forum in the FAQ sticky there are technical references that get down to pictures of how to remove the shift console. I assume you tried the 'start in neutral' solution.

The third requirement in starting is compression. Sure you don't have Nikasil cylinder wash? Starter fluid may be much more volatile than gas and ignite with little compression.

I have a downloaded copy of JTIS that I will send if you give me your 'off-forum' address. It has never been installed so I cannot certify that it is any better than this site download.

 

Thanks test point - I'll look for that sticky.

I read about the nikasil problem several times and with the short runtimes during this process I dreaded that it was possible.. Is there a specific oil recommended for that, or just the regular oil used in crankcase ?

Right now the P1643 code has me worried most.
If that is causing a fuel cutoff than the work to check the nikasil problem would be a rather big waste of effort.. Has anyone had experience with that code ??

 

test point, I did try to start in Neutral as well..

for the JTIS I was trying to figure out how to send you a message with my email address, but as a new junior member I could not find a way to do it.

I just changed my profile to allow emails from members though.

 

following your progress bigdude

 

I have to admit when reading all the info in the original post, I thought cylinder-wash loss of compression too. (But guys, I don't know what Nikasil has to do with that.)

You have a spark (evidenced by the "sputtering"), you have fuel pressure, so then assuming your timing is correct (no sudden loss of tensioners, etc), what does that leave ... compression.

All the other stuff, codes, connections, etc may just be distracting you. You ran the engine for a short time cold, and that is the classic cause of cylinder wash.

A small squirt of whatever clean motor oil in each spark plug hole to seal the rings.

 

Sorry for dropping out for a while, Knocked down by the Flu.. Anyway, I tried the oil in cylinder/cylinder wash fix and it did not seem to help. I saw some white puffs of smoke when I tried to start it so I am pretty sure the oil just got combusted away in that first spurt of fuel. I think I'm back at the fuel system again.. Has anyone seen a failing fuel pump or clogged filter cause this kind of thing ?

The pressure is fine when tested at the start of cranking, but could the engine fault be due to a loss of fuel pressure (could that be a condition that generates an internal jag code and no OBDII code) ?

I would like to really eliminate the possibility of cylinder wash from the list, does anyone know what the compression readings should be for 1997 4.0L XK8 engine (non-supercharged) ?

 

You tested for fuel pressure and have that as required, so you have ignition and fuel. What you may not have is compression. Check that next. If I had to guess, you either have low compression or have lost timing for some reason.

 

Several may differ with me but let’s see where this goes. You say you have fuel and spark, do you know if the Throttle Body (TB) has been changed? You may want to check the TB plugs http://www.gusglikas.com/AutoRepTB.htm . I just recently went on a trip and the car died. Went to the TB and moved the plugs and it started and continued down the road. If this is not the solution I would suggest you look at the cylinder washing http://www.gusglikas.com/AutoRepairNoStart.htm . I am not sure that the codes you are getting are sympathetic faults and they will take you on a long trip. As for the starter fluid I would not use in on my car. I have heard several people mention possible problems that it could cause if used so I stay away from it.

I should also mention the shifter “P”, “N” locations, check your relays are seated properly and plugs and also check the fuse bus in the trunk and see if the block is broken. I know of two cars that the fuse block prevented the car from starting. Note; before you start messing with it disconnect the battery.

 

Hi Gus,

I actually checked the TB connector early on. I used contact cleaner and tightened one side of the connector using a pair of needle nose pliers to make sure it had good contact. I saw an older service bulleting on this that mentioned contact problems because one side had gold connectors and the other had copper. On my car they both seemed to be copper so after cleaning and tightening them I thought they were fine (the stays are intact).

I also checked voltages on both sides of the fuses and reseated all of the relays with the battery disconnected. Since the voltages showed on both sides of the fuses I did not think there could be a fuse block problem, but how would I look for one ? (is there a particular place those break).

I could still use a compression reading spec for testing the cylinders, I was going to pull each plug and check spark and compression throughout...

 

From what I found the block is cracked and the voltage is intermittent across it. The cause is the tire in the trunk not being secured and striking and braking the block. Consider adding oil and give it a try. Consider that you are dealing with a 1997 Nikasil block and in my opinion the OBD codes at this point are most likely misleading..

 

From my experience, the voodoo cylinder wash is often the problem.
You've been through, it seems, in following up the other leads; so it wouldn't be <that> much more trouble, to pull all the plugs and give each cylinder a teaspoon of....you guessed it....Marvel Mystery oil - reinstall the plugs, hook up a large battery charger / booster, and hit the starter. (Outside, please)
Generally....after 10 or 20 seconds....one cyl will light...then a few seconde later, another....then another, etc. whilst spewing great clouds of smoke and clatter.
Mysteriously, one car that did this to me (98 XJ8) was immediately after a trans. fail / repair......

 

Older Nikasil motors often get down to 70 - 80 psi compression but still seem to run okay....Hint: fast cranking speed, almost like the plugs are out.

 

Pictures are a must during said startup.

 

Well I was out of town for a while and have returned to this again. While I was gone I researched some more and I 'punted' I went ahead and bought AutoEnginuity with the Jag add-on. While under regular OBDII I only saw P1000 in the Jag manufacturer mode I got P1517 as well which is a Park/Neutral Cranking error. Read through the tech guide on engine and trans and this passage leapt right out at me.

Start Inhibit

The rotary switch also provides the start inhibit function to the ECM, which will not allow an engine start until the gear selector is in either Park or Neutral

Saw some postings about this from Jag mechanics on FixYa and RoadFly as well that said the process 'denies fuel supply to the engine' so you get cranking but no start.. I then did a dry cycle of gear positions about five times with the key in the on position and got a new code P0706 (trans position switch range problem). Both of these codes tie back to the rotary switch as the crank no-start condition I am getting does, so I am hopeful that I may be on the right track.

I read about the connector filling with water on one forum, and about the switch failing on others. Before replacing it I want to disconnect it and check the connectors. The problem is that it is a real B_tch to reach. I was wondering if any of you might know how the connector actually unlatches. I can just barely get my hands into it, and I have to work blind once I do.. This is a black ten pin connector clipped onto the driver side of the engine harness block [LH Drive] (and as luck woudl have it this is the only connector I could not reseat before because I could not get it apart !).