Any updates, Sir Fart?

We've all been following your issue, and we need closure! I hope everything is running smoothly and you can enjoy the car as its meant to be enjoyed.

 

I'm curious how much this has all cost so far?

 

I'm on a business trip until the end of the month, so the car is parked and there won't be any new developments until I return.

Based upon past experience, I'm hesitant to say that the Failsafe problem has been corrected. But it's been over a week without any failsafe events - so maybe.

But there's still something not right, as the car continues to suffer from intermittent performance problems. In the space of one 15 mile drive, it will cycle between good "normal" performance, and poor performance a half dozen times. Poor performance being a lack of throttle response and acceleration. And the difference between good and poor performance is very evident. One minute you're driving a V8 sports car and then you're suddenly driving a 1963 VW. Actually, I had a 63 VW, and I think it had better acceleration than the Jag does when the Demon asserts itself.

I have yet to understand any reason as to what's triggering the poor performance. It will occur both from a standing start when leaving a stop light, and when just driving along at highway speeds. You depress the accelerator peddle and discover you're driving a dog that just doesn't want to go, at least not until you engage the kick down switch.

I've thought about a new ECM, but I defer to this groups far greater knowledge about these cars. All of your help has gotten me this far. Hopefully I've only a little farther to go.

Thanks guys.

 

After the new throttle body I purposely just stopped keeping track of the cost. But between all new hoses, troubleshooting, smoke testing, knock sensors, camshaft position sensor, PCV tube, intake manifold gaskets, diagnostics between fix attempts, steam cleaning the radiator, flushing & cleaning the cooling system, etc., etc.......

I'm guessing between $5,000 and $6,000. Which means I have way more in the car than it's worth. So it's a matter of dedication to the car & wanting it to be right so I can just drive it and enjoy it, rather than a strictly monetary equation.

Or a fool and his money are soon parted - you choose.

 

I think this is the best way to look at it. I was just wondering because I typically find these forums so I can learn how to do the work myself (since I can't afford the big bucks a shop would charge).

It occurred to me that your mechanic sold the shop shortly after finding his best customer! Well hopefully you won't be needing anymore services in the near future and you can enjoy the car. An aspiration of mine is that in the coming years we will move into a house with a garage so I can park the jag for a complete restoration and buy my wife a newer vehicle for day-to-day use.

Just came off a trip to NY and she fell in love with a rental and now I see the wheels turning already.

 

Well the Demon is winning. I returned from my trip and have been driving the car more than usual, and with no Failsafe events. So on the way home from work, I'm thinking "It must be cured. I'm nearly 100 miles with no failsafe. I'll post that that's solved & start a new thread on the poor performance."

I stop for gas and beer, fill up, start it and pull away from the pumps & go inside for a 6 pack (it's been a long hard day), come back out and try to start it .....yep...Failsafe yet again.

And I just don't know what to do to cure it.

 

The car is better and no doubt due to all the help I've received on this site. But the Failsafe problem has not been resolved and it's still stranding me. So if anyone has any further ideas on what might still be wrong, I'd really appreciate it.

Restating the problem:

You drive the car long enough for it to reach "normal" operating temp. Stop and turn it off. When you try to re-start it gives a readout of "Failsafe engine mode" and will not restart until it cools down, with the temp gauge needle nearly into the blue portion of the gauge. Then it will restart and run - until the next time it happens, which appears at this point to be entirely random. And it will not throw a code. The only code has been P1111 "system check - pass". Between the random failsafe events, the car will run perfect sometimes, then other times will have a rough idle and poor throttle response - kind of like that commercial where a car is dragging an anchor, it just has no acceleration and you'd think you're driving an old tired 63 VW instead of a V8.

Whats been done so far:
1. Replaced all coolant hoses, both radiator and heater hoses.
2. Replaced Thermostat and housing and temperature sensor.
3. Steam cleaned radiator.
4. Replaced crank sensor.
5. Replaced knock sensors.
6. Replaced throttle body with new OEM in the box.
7. Smoke tested vacuum system.
8. Replaced PCV tube
9. Replaced Intake manifold gaskets.
10. Checked every wiring connection plug that can be touched. Lubed female ends with dielectric grease and reconnected.
11. Pulled every relay, lubed female plug with dielectric grease, switched positions on all like relays.
12. Checked plugs on ECM, lubed female connections with dielectric grease, reseated plugs.
13. Removed and cleaned MAF with maf cleaner, changed filter.
14. Checked coolant temps - well within range.
15. Checked fuel pressure - good.
16. No doubt a few things I've forgotten, as this has been going on for 5 months at this point. Every time I think it's fixed - it does it again.

Any ideas? I'm near the end of my rope on this and I'm open to any suggestions.

Thanks for all your help guys. It's appreciated.

 

I think I mentioned this before. I'll not be happy until that fusebox by the washer fill neck is substituted. Internal connections in there can get intermittent, especially when hot.



Cheers,

 

Okay, I had to run an errand. Came out after 10 min and "Failsafe Mode" and it won't start. So I'm thinking I've got the ususal 1 hour wait for it to cool down before it will start. Out of desperation - (Key is in 2nd detent position where dash is lit up) I moved the gearshft from Park to Neutural - the Failsafe disappears, the milage readout comes on - AND IT STARTS RIGHT UP!!!!

Hopefully, this means something to someone and points to a reason that can be fixed.

Thanks guys

 

I remember reading in Nigel Thorley's book that the rotary switch on the early XK8's transmission can give a lot of trouble with oddball problems and messages. Don't know if there's a way to test it though.

 

And I thought I had problems (with my XKR)! Good luck with your search for answers. I probably would have done what Elvis did to his Pantera when it wouldn't start one morning, HE SHOT IT! You must be one patient soul. Hope you get things resolved.

 

There are two hoses that heat the Throttle body. They enter and exit the TB on the backside by the firewall. Make sure they are not kinked or collapsed, replace with regular hose, no need to buy $$$ formed hoses, just use enough to make nice round corners.

Make sure coolant is flowing through them.

Also, make absolutely sure that the 4 wire plug on the TB is seated and remains seated while operating. I put a set screw in mine.

Good hunting!

Good luck

 

Are you able to capture the FailSafe code?

 

This is what he really needs, the non-generic code or codes that are generated after a no start/engine failsafe incident. The code we are interested in may not be visible to generic scantools sometimes.

For the most part I would discount the trans rotary switch for this, in my experience that throws a 'Restricted Performance' message. That is not concrete though, it still could play a roll.

For some reason oldfart's car is entering 'shutdown mode', which prevents it from running. The attached excerpt of a bulletin helps explain the various faults and messages. When reading it thoroughly you get the idea that he is dealing with a 'multiple failure' situation, which is why I am stuck on that fuse box; or relays actually. I know he says he has moved the relays around, I would like to see them substituted.

Cheers,

 

Steve,

You know we keep dancing around on this project with TB, MAFS, Eng Temp and a host of other stuff but we keep getting a Failsafe and a no start until it cools down. So many things were covered I lost track. I personally keep going back to the TB. Why? I recently had Restricted Performance that did not bring up a code so I plugged in my OBDII and went for a drive RP came up and cleared on the dash but I caught it on the OBDII reader and it was the knock sensor, replaced it and all was good. It seems that every time this car gets up to operating temperature it shuts down and will not start. If this were my car I would plug in the OBDII reader and when it stopped or failed to start I would install a fuel pressure gauge and check for spark on the spot. I went to the onelines briefly and was unable to find anything that would prevent the car from starting that has not been covered. Is it electrical or mechanical? I like your flow chart and might be the answer to the problem. Right now I could not get there because I am overwhelmed with what was done so far. As for the transmission switch I was working with another guy trying to find a problem with his transmission and we found that the wire that is solder in the plug inside the trans was loose, re-soldered and he was up and running…

 

Being a 98 model, my money is on the ECM!
Your sequence of events is real close to my issues in my TRIPLE CROWN TITLED THREAD.

 

My horrors with my Jag.....
https://www.jaguarforums.com/forum/x...ay-97-a-40766/

My mech thought it was the TB, he put several on it, still same issues still after that, fail safe this, abs that, trac control this, restricted performace, trans fault, even got as bad as the cruise control button on the console just started staying lite up on all by its self, I was like WTF. Run great for a bit, then back to the crapper, etc. Read my story very close to yours.
AS I recall the 97/98 models the ECM was a issue for many. I was told a new one was 2k, I opted for a rebuilt by autoecu.com they bench tested it, rebuilt it, car has been fine since.
Funny thing in all this was that the cars orig TB when we first started in on this mess was sent out to be bench tested for a rebuild and it failed. So that is when we tried other used units and they all had same issues as did with the orig one it. I thought, now come one, no car has the same issue with 3 diff smae parts. That is when I said give me my F'g car back and out went the ECM.
May not be the issue in your case but sure sounds like it, ECD rebuild is 400 bucks and has a limited lifetime warranty.
Just trying to spend your money for you

 

You may be correct but the question is will we ever know?

 

sure seems like it to me. To many diff things all going wacky more or less at the same time, that was a ECM for me.

 

It has the smell of something important. Hopefully someone familiar with that area will notice and comment. If not, there are other threads about that area from before.