My 1997 XK8 (33k miles) has not been driven for 9 months. I have started it from time to time and it has a new battery.
Now it will not run for more than a few minutes ..... it gives a Poor Vehicle Performance warning followed by "Engine Fault", followed by "Stability Control Fail" ..... this happen a few months ago and I removed the fuses in an effort to "reboot" the computer and it cleared the problem. I didn't actually drive the car. now it has happened again and the "reboot" has not helped ..... anyone know what the problem is?


Sean

 

I would say it needs a fully charged battery and a good thrashing down the freeway.

 

Can you read the OBDII codes and post them?

Gus
www.jagrepair.com

 

Sounds like time for a new battery. A poor battery will start the car but not provide enough juice for the electronics. Just about anytime stability control comes up after start up it is the battery. Mine kicks that warning every couple of years and a new battery solves.

 

Your battery is probably okay, but it loses charge to the electronics even when sitting. You should have a battery maintainer like CTEK to keep it charged.

Try disconnecting the battery and put it on a 2 amp charger for a day. If you don't have a multimeter get one and check the voltage after letting the battery sit for a day. It should read 12.75 V or better.

 

All the responses had a similar theme, which was the battery. Each time before I run it I charge the battery and last time it was worse than ever.
however, yesterday I charged it and stated it and it idled okay even though it gave a stability code error.


I checked the OBDII codes:
P0351 - Ignition coil "A" primary/secondary circuit
P0354 - same as 351 but "D"
P0356 - "F"
P1000 - II Monitor testing incomplete
P1367 - Not toggling after enable; ignition circuit open circuit; no signal in TDC2 sensor circuit.


I ran it up and down the drive several times and turned it off and restarted it and the warnings were gone. I then took it for about a 30 min spin, giving it plenty of gas .... lucky I didn't run into a cop. after about 20 mins it stalled at a junction but restarted okay. when I got back home I was only doing 35 mph for maybe 5 mins and it would not accelerate up the driveway. I limped into the garage with the stability warning on again .... it then let me rev it and I did so several times and the fault was gone again.


I checked the voltage at idle - 14.0V, with everything turned on (AC, lights, etc.) it was 12.5V at idle.


It acts like an electrical power problem but how to narrow it down .... BTW the battery is new.

 

Have you tried switching the ignition coils around to see if the P035X code changes with them ? Certainly coil failures are very common, Most of my original coils have failed and I have replaced all with new (2000 XK8 with 95,000 miles). Might not be your entire problem but certainly a place to start.

 

Swap your A1 coilpack with another coilpack in the car and see if the code changes also check the sparkplug at the same time. If this does not change then swap your ignition module. Your car is equipped with 2 ignition modules one for each side. I would swap them and see if the problem goes to the other side. If the problem si still related to the one side then I would look at having the ECM tested at ASI.

Link http://jagrepair.com/images/AutoRepa...%201997-99.pdf

Link http://jagrepair.com/images/AutoRepa.../jagxk1997.pdf Fig 4.2

Link http://jagrepair.com/images/AutoRepa...sb_09_2003.pdf

 

Based on the error messages he got listed in the first posts here, I am going with an ECM rebuild. My car had all the same codes. This is a 97 car, I would sent ECM to ASI.

 

Also make sure there is no coolant or oil in the spark plug wells that may be grounding out the coils in question. Be careful with the connectors on the coils as they like to turn to dust when distured.


Dave

 

Thanks to y'all for the prompt replies and Gus for the useful links.


When the weather warms a little I'll start with the spark plugs and move on to swapping ignition coils until I either find something or conclude its the ECM ....... who is ASI? What's the cost to have the unit refurbished or whatever it is they do?


I should mention that the car was running great then I got the "poor performance" warning, I checked the battery and it was a little low so I replaced it, but I didn't drive the car for months thereafter and the other warnings then started to appear.

 

Automotive Scientific. The 97 ECU had capacitors that leak eventually. If you send it to ASI they will test it for about $55. If it needs repair the total bill will be about $350, but I don't recall what I paid for certain.

Automotive Scientific Inc. | Quality Rebuilt Automotive Electronics | Rogersville, TN

 

Thx RJ,
I'm an electrical engineer with some past experience in component failure testing ...... capacitors could be the problem as then can have intermittent breakdown (electrolytic caps have the ability to self repair minor internal shorts).


The schematic Gus sent (Fig.4.2) has Ignition Module 1 controlling coils 1A, 4A & 2B (& 3B) ..... these are the 3 OBDII codes I keep getting, so I'll take a look there to see if anything is obvious. Switching module 1 with 2 should transfer the problem and the error codes should be 1B, 4B & 2A, if not then it eliminates the ignition modules as the culprit.


Thanks again to everyone for your help and if I don't get back promptly it is because I currently have a busy work life ...... working on fixing that too!


Sean

 

The problem with the caps in the ECU is that they leak and damage nearby etches. An early symptom is if the cruise control stops working and replacing the brake light switch doesn't fix it. When mine failed it turned the V8 into a V4 but it was flakey for a while before it failed solid. ASI repaired it and I had it back in about a week or so and the price wasn't to bad.


Dave

 

That's the worst thing that can be done to a car. Do not start the engine just to let it run. Either let it sit undisturbed or take it out for a good long run to allow everything to achieve normal operating temps.

If the car is going to sit for much more than a month, a battery tender is pretty much mandatory.

 

Swapping the ignition modules was the second thing I did after swapping coils. The faults stayed with the same cylinders, hence the conclusion the ECU was at fault.

 

thank you all for your input and assistance ....... the car is once again alive and well.


I contacted ASI and they gave me a few more things to try, which had no effect and so I sent my ECM off, got it back in a week and the problem was solved. The cost was $179 for ASI to repair and return the module and $13 to ship it to them ..... very reasonable all-round, again thanks to y'all.


Sean

 

On the road again.

 

Hi Sean, I just wanted to ask a question. You said in an earlier post that when you checked voltage at the battery at idle was 14.0v, and with accessories on went down to 12.5v, did you have the battery and alternator tested? It shouldn't be below 14.2v even with lights, wipers,ac on. I've seen many times where the positive cable coming off the alternator fails, causing charge problems, especially since you're in Texas. I'm from Houston myself, the heat takes it's toll on batteries among other things, even though it may just be the battery itself. Just wanted to point that out with your charging voltage, Jags are very sensitive to voltage drop. Just something else to keep an eye on.

 

As you stated, the electronics on these cars are very sensitive. I try to use my XK8 during the winter at least 1x per week. If weather prevents the road test I keep my fingers crossed the battery is charged sufficiently. Due to location I use a solar tender. Which I love. As long as its not cloudy for a few days. Recent poor weather for a couple weeks prevented my road test. My battery was too weak. I first removed the sealed for life caps and found the water level low. Refilled with filtered water, recharge the battery. Works great. Before you start your car if sitting for awhile, test the voltage. Mine now reads at least 12.5 volts even after sitting a week to 10 days. Rich