One trick is to warm up the engine. Then clear the codes. Then run the engine for a minute or so and read the codes again. Often one code appears first, and that usually points to the culprit.

 

So far all the codes seem to appear at once each time after a clear. Just for gits and shiggles I was thinking of swapping all the coils in pairs at once. If the codes change then at least I will know it is a bad coil causing all this. If the codes stay the same then its probably the ECU. After I started smelling the unburnt gas I didn't want to leave it running. But that would say there is a dead miss and the gas isn't getting used and just blowing out the exhaust.
This last time I had it running it also made a sound like the power steering pump low on fluid but it isn't and hasn't made noise before. But when I got out of car to get near the engine to try and locate where it was coming from it faded away so I have no idea what was doing it.


Dave

 

I tried the coil swap with mine and the codes didn't change. That's when I decided the ECU was at fault.

 

I just found another thread here with the same exact codes and his fix was the ECU also, Guess I'll pull it again tomorrow and send it to ASI...



Dave

 

Before you go and send the ECU out you need to check your fuses for the ignition module. You have 2 modules one for each side that feed the coils. Chances are that you have a bad module.

Link to one line http://www.jagrepair.com/images/AutoRepairPhotos/jagxk1997.pdf page 32 fig 4.2

 

Ok it looks like each ignition module covers 2 cylinders on each side, not one side each so a bad module 1 could cause my problem. They likely do this so you can still limp home if one ignition amp dies otherwise the engine would be to out of balance to use. But I have found multiple threads here that all end up being bad ECM's on early XK8's with these same codes. I will try swapping the ignition modules tomorrow to make sure however.
I can only find one fuse for both ignition modules and if that was bad no cylinders should fire,



Dave

 

Went out to work on it today but with the stiff cold breeze was just to damn cold to get anywhere. I was just going to try swapping the connectors between the 2 ignition modules but one cable doesn't seem to be long enough to reach. So I will have to wait until its warm enough or the wind to die down to remove the modules and swap their positions.
I found another thread with the same codes and that persons problem ended up being jumped timing and the ECU interpreted it as an ignition problem. Hope thats not the case here.



Dave

 

Swapped the ignition modules. To bad they didn't make the cables to them longer so you could just swap the cables to them in place to check them. And why didn't they use screws or at least studs for the mounting? Makes a 5 minute job 30 minutes instead.
The codes stayed the same.
One thing different I notice from when it was running good is that now you can hear a slight noise of the chains running that I don't remember noticing before. I'm not sure how much is normal and the level of the sound is about the same listening from either side. I would think if a tensioner was bad it should be louder on the failed side. The noise sounds like the kind of noise a power steering pump makes when its low on fluid only not that loud.
So now I am very tempted to pull the cam covers but I might send the ECU to ASI first and see if it has a problem. I'm not really looking forward to taking the covers off with the car in the driveway in this windy cold weather if I don't have to.
So my question is - how much chain noise would be considered normal in a '97 with 98k miles? Its not super loud but if you are sitting in the car with the hood up and door open at idle you can hear it if you know its there. Hood down you can't hear it even standing next to it.


Dave

 

Dave, don't think you have any major tensioner problems. The two I heard that were bad left little doubt that something was amiss. Hope your ECU will be repaired and solve your issue and hope to see you soon. If you get a nice day while the ECU is away, pull a valve cover and see what you have, one can hope for good news.


Wayne

 

Ever since I removed and replaced the ECU its idling rough also but I figure thats because when I removed the power from it all the trims etc got reset, in fact the P1111 changed to P1000 after reinstalling it. Otherwise it still craps out over 1500 to 2000 rpm just like before.


Dave

 

Hmm, I called the Jag dealer and talked to a mechanic there and he thinks its a VVT problem... I can't find anything online that would back that up though.


Dave

 

Dave, Try this thread, item #32
https://www.jaguarforums.com/forum/x...a-26334/page2/.


Wayne

 

He wasn't complaining about any problems with the engine running badly and got a different code than I get. So maybe the mechanic there is guessing wrong?

I am still worried about the chain noise I never noticed before.

I guess I will have to wait and see what ASI finds with my ECU. If its not bad then I guess I have no choice but to pull the covers. I hadn't been to worried about the tensioners before as they were supposedly replaced in Sept 2002 at 57k miles but maybe they put plastic ones back in and now one of them has failed.


Dave

 

Pull the valve covers and look at the tentioners. I would have the ECM checked a small price to pay for piece of mind.

Gus

 

Dave I know it's not the weather to be working outside and you need to look after you right now. It's going to be in the teens tonight so wait for the ECU to come back and see what you have.


Wayne

 

Is your battery new? If it were me (and it is not) I would:
1. Replace the battery
2. Hard reset
3. Compression check
4. Remove and clean throttle body
5. remove and clean Ground straps
6. Remove and clean bulkhead connector
7. Check tensioners and cam timing

THEN I would look deeper into the electronics to see I could find a problem. The things above to check are *free* to do.

 

Battery is new and its a hard, repeatable problem. Also teh problem came up while driving a steady 35 mph in traffic. Car was warmed up after a few miles of driving.
Did a hard reset when I disconnected the battery to remove the ECU to examine it. All that did was make the engine idle rougher after reinstalling it likely because it lost all its trim values etc. However the codes stayed exactly the same.
I've cleaned all the connectors and throttle body etc. No difference.
Checking tensioners and compression check come after I receive the ECU back and it doesn't fix the problem
As you asked in the other thread what lead me to the ECU - I found many threads on this site with people getting the same exact codes I am getting and the ECU ended up being the problem in all but one case. In that case it was a broken timing chain.
I also swapped the 2 ignition modules which are the only thing in common with those 4 cylinders except for the ECU and again the codes stayed the same.


Dave

 

The ECU is off to ASI and Brandon there said he will let me know what he finds.


Dave

 

I just heard from ASI. They did indeed find a problem with the ECU. They wouldn't go into detail because I guess they don't want to give away what part they replace. They did say it was a part that commonly fails in these. I did look it over really well before I sent it to make sure it wasn't something obvious like a leaking capacitor etc and didn't see anything visibly wrong. So its being shipped put today and should have it by Thursday or Friday. And if I am really lucky the car will be back on the road.



Dave

 

Dave, Really good news. Keep us up to date. Hope it doesn't take to long to put in, it's going to be cold the next few days.


Wayne