THE CAR HAD A VERY SLIGHT MISS EVERY SO OFTEN (like carbon build up) Take it out on the express and blow it out!! Runs great and eventually comes back to very slight miss but still runs good.



SO I DID some maintenance to see if I could clean up the slight miss.

Here is what I did and is now happening.

1. Cleaned O2 sensors
2. Replaced EGR
3. Cleaned MAF
4. Replaced fuel pressure regulator
5. Cleaned throttle body

THE CAR RAN FANTASTIC FOR A SHORT TIME (several weeks) except that it would literally try to start almost immediately with less than a full revolution (sounded like it was starting to flood) but It usually started and ran great.

The first real issue was going around a curve and it died out. Stopped and restarted right up. Seemed to be okay. Drove home no light or codes

THEN

5. Replaced Injectors (after market rebuilt units) same as I had on the car for the last seven (7) yrs.

RAN GREAT AGAIN. SO SMOOTH !!

THEN

PUT HER UP IN THE AIR

Spent the next week under the car cleaning and polishing and recoating the undercarriage.. ( LOOKS FANTASTIC )

Started driving for about a week and it started sputtering again. Still starting almost immediately upon turning the key. I noticed that the exhaust pipe was sooty black and wet inside the pipe.

SO THEN


PULLED OFF THE PRESSURE REGULATOR AND REPLACED WITH THE ORIGINAL LUCAS UNIT.

Ran great for about a week then it happened again this afternoon and went into limp mode and I drove home

put my cheap OBDII and it indicated two (2) codes P1775 and PO727.

KIND OF SCARRY WHEN YOU GET INTO TRAFFIC!!!

SO I DON’T WANT TO DO THIS AGAIN UNTIL ISSUE IS RESOLVED!!


PLEASE PASS ON YOUR IDEAS ON WHAT YOU THINK MAY BE HAPPENNING.


Softball60/Paul

 

One thing I forgot to mention.

I bled the fuel tank pressure, removed the relay and started up the engine and ran till it died out…​​​​​…should have relieved all the pressure???

when I pulled the injectors I noticed a lot of pressure on the connection to the fuel rail. I probably had to bleed the fuel rail a number of times before gas stopped draining.


Thanks

Softball60/Paul

 

I found two things on my 96. First, I used to disconnect the battery after using the car and very often I experienced rough running and stalling for a time after reconnecting the battery. Second, I get a build-up of pressure in the gas tank that is released when I open the gas cap so that could somehow be affecting fuel delivery. Just a thought.

 

Pulled and cleaned the CPS.

STARTED RIGHT UP AND DROVE DOWN THE STREET UNTIL STOP SIGN AND FOOT OFF PEDAL ….ENGINE DIED!!

Started right up drove 100 ft. And it started to stumble.

died restarted and drove back to the house!!!!!!


POSSIBLY TPS??????

YOUR INPUT IS APPRECIATED.


Softball60/Paul

 

How old are the oxygen sensors? I know you said you cleaned them, but they have a finite life to them.

The CPS also has a finite life to it. It works by magnet that eventually begins to fail. Cleaning will not help you here.

I was never able to successfully clean the EGR enough to resolve a problem I had with mine. I doubt it's the cause of your problem because when the EGR did stall the engine out (while on the highway!!!) it did finally grant me a code indicating the EGR messed up. I think you are at the point where you would have seen the code by now, although these damn cars are so stingy with codes....

The TPS is certainly a possibility. It does create strange problems that will never show you an accurate code. It's just so expensive to throw money at, whereas the oxygen sensors are wear and tear parts. They are not made to go as long as people drive them for. If you aren't willing to buy new oxygen sensors, or CPS, you certainly will choke on the price of the TPS.

 

Sorry Softball60, I must have imagined I saw CPS in your list. When my CPS was failing, the car would run fine for miles and/or trips, then would just stall out for no apparent reason. Luckily I only try one fix at a time and my first replacement CPS was defective. After installing the second CPS, the stalling problem went away.

 

The CPS IS ONLY TWO (2) yrs. The o2 sensors are ~ 4 or 5 yrs old.

I think this is similar to a situation I had a while back with the TPS. I replaced it with a used unit…..so maybe that is what is happening again.

The least expensive TPS I SEE IS $378 for a new jaguar TPS

I can purchase a used TPS FOR ~ $75………


Softball60/Paul

 

Yes, you can keep buying used parts and maybe it gets fixed, and maybe it doesn’t. But you won’t know if the used part was working well or not, so you end up going round in circles. You never find out if you found the problem or not.

yikes.

Good luck.

 

Vee,

Lot’s of electrical parts cannot be returned once installed and seals broken (response to my question to an Ebay supplier). Suppliers are tired of individuals who purchase parts to see if the part works, if not, the part is returned and they have to sell as used.

I don’t totally disagree with you but I would rather make a mistake with a $75 part and have a good spare.

This part runs from the close to $400 ( I think this is a Standard Motor products aftermarket part) to over $520. I know a lot of individuals will take exception to my logic but I don’t have deep pockets.

I don’t have a lot of sophisticated analyzing tools to support my required repairs, so it’s logic and this site that helps me work through any issues.

Thanks for the help

Softball60/Paul

 

Has the fuel filter been changed?

 

Fuel filter was changed probably less than 5K miles ago.






Softball60/Paul

 

Paul,

I hear you, but you don’t have the tools to diagnose the engine, much less old used parts that have limited lifespans. So, like you, many of us resort to throwing parts at the car in hopes of solving the problem. The problem here is that the parts your throwing at the car are unreliable, because you don’t know their age or history.

You own a 26 year old car, with 26 year old parts. The used parts you are buying on eBay are most likely 26 year old as well. While they may have less miles on them (who knows) many magnetic sensors degrade with time. Using used old mystery parts works on a ten year old car, but I’m afraid at some point you gotta cut your losses and agree to finally update some of these parts that degrade with time.

There is simply no way of crossing off anything on your list if you are unwilling, or unable to replace with new. I can attest that the TPS is a part that tends to bench test perfectly well, but once replaced with new, resolves problems. The CPS and the coils also bench test well, but may not work when installed on the car. How would you even test the EGR or oxygen sensors?

I really do wish you the best of luck here. I just have no idea how throwing mystery used parts can result in any meaningful progress towards resolving any problem, much less the problem you’re experiencing. Very common causes include (in no order) EGR, TPS, oxygen sensors, coils, coolant sensor, MAF, CPS, even the ECU. Then there are injectors, fuel filters, pressure regulators, etc.

A discussion and investigation could probably help put those parts in some kind of order that would make sense, but with the use of old used mystery parts, you can never cross any suspected part as the cause with any certainty, unless it happens to work out that way.

 

Vee,


THAT IS WHY THE GOOD LORD MADE US ALL DIFFERENT! I KNOW AND UNDERSTAND YOUR POSITION BUT I’ll EXPLAIN ACCORDINGLY.

one thing that I have the option is that if the $75 part works, I am pretty sure that was the issue. Now I have the option to purchase the more expensive replacement. And keep the $75 dollar part as the spare.

Here is something that maybe you can look at.

I have been trying to find an economical replacement for the TPS. there is no reason for this part to COST upwards of $500. I know this because in my earlier days of work I ran an automotive insert molding operations in Michigan. (Lots of connectors just like the TPS)

MOST OF THE PARTS THAT I HAVE PURCHASED AND REPLACED ON THE XJS WERE AND WILL BE NEW.

MY issue is the following………

My model year xjs was owned by Ford Mtr.

My guess is that there is a $40-$50 dollars replacement that will work.

MY QUEST IS THAT THIS PART EXISTS BUT I JUST CAN’T LOCATE IT……..HELP ME FIND IT!

Please don’t stop trying to help me solve any of my potential issues!!!!

Thanks

Softball60/Paul

 

I spent a lot of time going through the various forums looking for a suitable alternative to the TPS. (OEM part was indeed stamped Ford)

There are only a few threads where people tried to use a TPS from other cars, but none were successful.

I hope someday someone does indeed find something, because you are absolutely right, there is no reason that part should cost so much. The ABS sensors are equally ridiculously expensive, with no known alternatives. I've gone down that rabbit hole as well.

 

VEE,

THANKS FOR YOUR HELP





Softball60/Paul

 

Have you tried to clean the TPS? Also cutting out while taking a turn tells me your fuel pump is starting to take a dump. Its classic fuel pump failure behavior. Time to clean up the fuel pump screen to see the condition of the tank. I bet its getting clogged, causing fuel cut off.

 

No I have not tried to clean. Not sure How or if it’s really a good idea. Isn’t it a totally enclosed molded part?




Thanks


Softball60/Paul

 

"I don’t have a lot of sophisticated analyzing tools to support my required repairs,"

You have a '96 with OBDII so I'd suggest making friends with a mechanic that has a good scanner and take a look at some live data.
I also agree with Brewtech about a possible fuel issue. Might be worth it to check fuel pressure or even install a fuel pressure gauge to monitor the pressure in real-time.

 

You should invest $20-$50 in an OBD scanner. It will help you narrow down the list. If you have one, you can watch the livestream data to see if your TPS readings are normal, if your o2 sensors are working, etc. And if you told us your fuel trims I bet we could help narrow down the issue relatively quickly.

 

Fuel pump is in the tank. To get to the pump...you need to get that tank out.

If you do that, I highly recommend replacing the entire pump while you're in there. I think a shop will charge you about 18 hours for that job.... Apparently others have managed to slide it out just enough to access the hole on top of the tank enough to get at that pump....but it will still take you a full weekend to do, I would think. Probably gets faster by repetition....hopefully you'll never get that good at it.

I have an OBD2 ELM27 reader. (Make sure it's WiFi if you use an iPhone, Bluetooth is only allowed on Android) It gives me readings, but hardly real time....it kinda just takes turns showing me what I want to see in intervals....but it should show if the sensors are at least within range. Not sure it will help show a "lazy" oxygen sensor, where the swings are just happening late. It was Jaguar first foray into the OBD2 world, so its pretty basic, but definitely a necessity.