Hi friends!

Do you happen to have a slightest idea what could have caused the issue as described in the topic of this post?

I bought the car recently, like a month ago. It has just been serviced for things like oil change, transmission lines slightly leaking but nothing major. After service drove it for a week zero problems.

Today, during a 100miles trip got "Check fuel cap" caution on the dash for the second time. After the ride turned off the car for literally 30 minutes, then when trying to restart it was cranking but not starting. Tried to start it for like three times and it was "catching" for a glimpse of a second but nothing there (surging due to lack of fuel?)

Connected iCarsoft, read OBD and it threw two codes - P0455 and P1000 (latter not relevant). Decided to clear the codes and after clearing them car started like nothing happened, weird. Before that, like a month or so I got P0456 but I decided to clear it and see if it is fuel cap or not. Previous owner told me after I contacted him regarding this issue that he has been getting this EVAP intermittently during last year or so. I don't smell any fuel fumes in the car and during emission in my country nobody really cares about EVAP, so he drove it like that no problems.

Could P0455 code throw me some issue with starting a car or there must be some other reasons behind it? As per my knowledge there shouldn't be any problem starting car with P0455 but with Jags, who knows...

I get different IDLE RPMs on P or D gearbox setting, don't know if it should be like that but mechanics did not comment on that and it was like that since I bought it. I recorded following fuel trims (tried to average them)

LONG TERM BANK 1/2 and SHORT 1/2

IDLE: 0; -10,2%; ~3%; ~2% (short 1/2 decreasing to 0% over 3-4 seconds)
RPM 1500: 1,6%; -3,2%; 7-10%; 2-4%
RPM 2500: 7%; 1,5%; 7% and decreasing; 3,2% and decrasing

With ignition on from scanner fuel rail pressure was ~300kPa. Warm start after another half an hour was like 2 seconds of cranking and then it kicked in. Weird...

Edit://
Battery was reading 12,2-12,3V with ignition on

Appreciate any help!
Bart

Thanks!

 

I am really having trouble understanding the data that you are presenting. What do you mean by decreasing? But bank 1 (passenger side?) seems to in worse condition. Did you check the vacuum lines and EGR valve lines on bank 1?

 

Hi pkoko,

thank you for reply. I meant, it was kind of hard to get a steady reading of those trims and they seemed to fluctuate a little bit with decreasing tendency as RPM were "held" constant. I am away from home ATM so as soon as I'll get back I'll try to record a video with them for better reference and check the visible lines.

I was told it did it once again yesterday, with warm engine after ~100 miles trip it didn't want to restart after car wash visit for like 10-15min.. after 3 attemps of cranking it started like there was nothing wrong. No fault codes, fuel pressure from scanner prior startup 335kpa on key turn to ignition, dropping to 320kpa and steady after a second, upon startup >410kpa if I recall correctly.

With the engine on idle only LTFT for bank 2 is way off and on the negative side, if it was for EGR/vacuum lines leak wouldn't it rather show positive trims?

The engine seems to idle well, ~650rpm, acceleration is kind of as what I expected from this engine especially when on 2 and higher, only it is hesitant when at low gear and I put pedal down it seems to "think" what to do... I don't know if that isn't maybe transmission?

I was reading some posts, some guys claimed vapor lock phenomena could be present when check valve in the fuel pump assy is not working as designed, some fuel drains back... Problem starting is only when heat soaked. Starting right back within a minute or two when engine is shutdown warm is possible, thought sometimes feels sluggish but starts within 2 sec max. When engine is cold it doesn't make any troubles starting (hope it stays this way!). Or maybe some injectors leaking...

Besides that I think tank level indication seems not proper, via scanner "fuel level one" indicates 56% and "fuel level two" 11% with car being level. If tank cap is 85L then judging by the fuel avg burn I should have 38-40% when it indicates merely 25%. I was checking it with fuel top-ups to the brim and sometimes with fuel indicator only half tank left all I could top up was 30L...

Scanning REM gives a code U1262 (SCP J1850 Comm bus fault) but I don't think it should cause problem starting up only on warm...

I don't honestly know...

 

check ckp signal with a scope. they can quit when hot

 

Does that mean with the engine running? The Alternator should be sending over 14VDC to the battery when the alternator is spinning. As you probably know from all the zillion of posts regarding the battery, our XJ8s (X350s) do weird thing if the battery is not at peak voltage and amperage. Let's remember too that decent voltage does not mean all the cells are producing the amperage the car is looking for.

 

A com fault randomly occurring could cause all of your faults. Remember every bus runs throughout the car. A hot engine may cause connector or module problems pulling the bus down. A ground or power fluctuation could degrade the signal enough to get a com loss. It would be interesting to see a scope trace of the bus signal to see if it fails because of ground or power.

 

Thank you all for the responses, sorry it has been a few days since last reply but I've been completely buried with work and the car was behaving nicely recently.

Maybe not related to the problem but in the meantime I replaced MAF as cleaning the old one did not change anything (at idle mass air flows > 6,2~6,5g/s) and car sometimes felt heavy during acceleration (like... hard to explain but looking like this: pushing pedal (not kickdown but way in), car reving up, then sitting at 3k rpm for a brief moment and "thinking" and after a while continuing to accelerate). As a result of MAF sensor change registered values of mass air flow changed to those more resembling table provided in some technical manual of Jaguar. Engine seemed to be more responsive actually and have like more power with the transmission working smoother, especially on 5-6 shift. This could be just "my feeling" that it is better but really, driving with new MAF for a few days I felt like I am sitting in a different car especially when it came to reaction to gas pedal and transmission shifts in general (would it be possible though? . Registered air intake temperature sits a little high (60C region) with engine fully warmed up and parked, but I suspect thats due heat soak so I am not really concerned about it, especially that MAF has been just replaced.

@xalty - actually I am planning to replace CKP as well as CMPs - probably they are not faulty given I never had any problem with those with any of the cars we have in family, but if they are, that would be cheap fix. Those sensors are kind of cheap, maybe given the age they could fail (at least intermittently?). I forgot to take a look whether RPMs are registered properly during cranking when the problem occurs, will see next time it happens
@rsa760041 - the voltage is with engine switched OFF, just when the ignition is turned to ON - alternator is working fine, should not be the problem. grounds have been checked as well, seem fine
@OldKarz - could be a way to go, thanks for the input! though figuring out a scope I can use could be difficult

I had this warm-start issue happen twice since I last published a post in this topic, today again at the end of a day full of driving (but 4 warm starts during breaks on the trip were problem free). When it occured, again, the engine was just cranking and during one attempt for less than a second the engine was kind of "grabbing" but then it was just cranking and cranking... Three times trying to start and no luck so I connected code reader, checked pressure, seemed fine (as in the posts above), P0455 pending (cleared last time so it is going again), no MIL. Fourth time I turned the key, started in a blink - like no problem. Drives me crazy, always when I connect this bloody code reader it just starts but I doubt it is related . But at least it finally starts... Will post updates should anything change. Thank you guys, have a good day

 

tldr:

• new RH CMP (aftermarket NGK), new CKPS (aftermarket Intermotor)
• hard reset (disconnect battery, touch leads, etc.)
• idles fine (no RPM drop on idle, sometimes before there was like 50RPM drop but only noticed that because I was too focused on every sound car makes)
• start problem when warm not gone (pending P0335 flagged for the first time, never before, after CKPS was replaced - possibly would come up before as well but I might not be cranking the engine before for the same, extended period of time)
• P0335 pending flagged twice, on one start RPM was displayed zero, on subsequent trial within 5 seconds ~130RPM but still no start, then after few minutes started (engine warm)
• today's morning longer than usual start (2-3 seconds) while usually it took slightly less; like a one-second break between turning key and hearing solenoid of the starter to actually having starter crank

Now long version:

Replaced RH side camshaft sensor produced by NGK, LH produced by Delphi still failed to arrive so probably I will be ordering one from another source and cancelling this order. Replaced as well crankshaft sensor yesterday produced by Intermotor (the OEM was around 170USD). Problem did not go away, still seems to be present. After replacing sensors, did "hard reset" with disconnecting battery leads, touching them, following instructions from various posts on this forum and car was and is behaving nicely, though no-start problem is still there.

Yesterday, after 40 min drive with stop for about 10-15 minutes, tried to start. Nothing, just cranks. I believe I kept the key in start position longer than usual, because like never before car showed RESTRICTED PERFORMANCE and flagged pending P0335 "CKP Sensor A". Cleared code, cranked one more time and after a few seconds car started. Washed the car, went to sleep, whatever.

Today morning, cranking for like 2-3 seconds, started. Oddly, tachometer gauge was working smoothly (before it the gauge was sometimes jumping 100rpm back and forth, like it was sticking). Drove for four hours today, smooth gear shifts, smooth idling, smooth operation. Sadly though, problem with starting warm came again. After 5 minutes stop, cranking car - nothing happens. Tried again, went on. After that drove for few minutes more, crank again. Nothing - bo... again, cranks but no start. After a few seconds of persisting cranking, restricted performacne again. Checked codes, P0335 pending again + P0442, P0456 (evap leak, ongoing issue for some time now). Live data (though my icarsoft seems to have slow update on the checked data points) showed 0RPM when cranking for 2-3 seconds, then on another trial ~130RPM when cranking. Waiting a few minutes, car started...

I don't know how the ECM works but I am getting puzzled. I would believe CKPS have to work constantly for the engine to operate while CMPs are needed during startup. Engine works smooth, idling as I said nicely, acceleration wise I would say I was very happy for 90% of the ride, whereas at the end of my journey today the tachometer RPM gauge started to be "sticking" again only on downwards movements and I felt like maybe... the car was little sluggish?

With old CKPS it never flagged P0335 (at the same time maybe I was not cranking it for so long period as now + I've read people writing that their bad sensors sometimes did not flag anything as well). Order another CKPS (I saw Vemo aftermarket part, heard good opinions) and install it, install old one, probably OEM and throw this intermotor to trash or what? I would assume new one should be working flawlessly but who knows. The CKPS plug was clean on the inside, outer plastic "casing" of the wire was oily on the outside as I had some oil leak recently and it was blasted on the entire bottom area, cleaned that. Visually old CKPS was looking normal as well. Btw. still no scope in my equipment. I would go to an Iindy, however I believe they would just start a car few times, see it is working and just disregard the complaint. Shall I try another CKPS sensor, check some grounds (G26 below air filter?, G30?), maybe this oil on the cable casing is something to follow or some A/C condensation dripping closeby? I am having basically no access to the lifting equipment, no channel underneath the car (I used my friends garage this time just to replace this CKPS).

Getting tired of this no start, SOMETIMES... Cheers guys.

 

I have not read the whole thread. Have you checked the ECM connector for corrosion from clogged drains?

 

Happy to report that starting issue has been solved! Just want to resurrect this old thread as maybe somebody will be dealing with something similar in the future.

Solution:
Very poor contacts on starter (I'm not native speaker so I don't know if that is proper phraseology) - replaced them. Cleaned ECM connections with contact cleaner (found no corrosion, no clogged drains, no water ingress... relief @OldKarz), cleaned all grounds found along the way, reattached and protected. Battery recharged - it is one year old, previous owner replaced it. However, battery is too weak imho (77Ah, low CCA), planning on replacing that in the future especially given the fact that autumn starts now. Anyway, car starts fine, cold or warm without problems..

Turns out, original CKPS sensor was doing fine, I've replaced it just for the test purposes with an aftermarket "INTERMOTOR" piece of $%^& and it was behaving weird. Tested original CKPS, proved to be fine, put it back.

Fuel gauge seems to work more reliable after work I've done, I don't know if cleaning ground had anything to do with it or these poor starter contacts but hey... seems to work. Trims on idle still high on bank 1, if it idles for like 20+ minutes it pops too lean code. Some small vacuum leak I cannot trace... Anyway, happy that I can go on trips without worrying about starting issue*.

*Not really, since now time to battle newly emerged C2302 and car not going up on rear driver corner lowered down to mechanical stop... but that's another subject...

Anyway... Good day to all of you! Thank you for your feedback, always appreciate your support!