How can I test the ECU/ECM? Can I replace it without having to take it to a dealer to have it programmed?

I had a set of security bits but it just stripped out the bolt. I guess I can try to get it out of the connector and maybe cut a line across it with my dremel and maybe use a regular screwdriver. It didnt seem to want to come out, it has a clip or something that holds it in? Does anyone know? It seems like it has to be the connection for that many problems or some short that I dont see.

If I make a pin hole at the end of the wires to check wire to ecu pin how can I seal it?

 

You can use liquid electrical tape to cover any pin holes in wiring.

 

I cut a line in the bolt that holds the wiring harness in to the ECU and tightened the connection really well. No change!
The car starts but is missing on cylinders 1, 3, and 5. Still. I am going to switch bank 1&2 coils and check the plugs again. I will also try to check continuity of wires and pins related to codes. I don't know what else to do. I will report my findings.

 

Ok, bad news I guess. Pinpoint test A says I should replace the ECU. Is that expensive, I can't afford much more right now but, need to drive this baby. My backup doesn't have AC and it is hot in St. Louis this time of year. Can someone please give me some info on my choices? Thanks!

 

Ok, I followed the advice of Itmax. I removed the manifold again and swapped all the plugs and coils from bank 1 with bank 2 and rechecked the plug gaps. Now instead of codes 351, 353, 355 etc. I have 354, 356, and 1000. I am going to see if I can find 2 new coils tomorrow and put them on cylinder 4&6. Does this make sense? If so, what could have caused coils originally on cylinders 1,2,and 3 to all go bad? I still cannot find any bare spots on the harnesses or wires so what the heck?

 

Sounds like you found you problem. Coil pack failures are pretty common, I think it's actually the spark plug boot that is part of the coil that goes out most of the time not the coil itself and once they get brittle from all the heat they are exposed to sometimes just unbolting them and pulling them off the spark plug is enough to damage the assembly.

With luck, a few new coils should have your kitty purring again in no time.

Sorry it took so long to figure it out, but I'm glad you're finally getting close to having it back on the road again..

 

Well, I changed coils 4&6 and put it all back together confident that this was it. I guess I couldn't be more wrong. I have codes 304, 306, 354, 356 and 1000. What do I now? I haven't driven it in over a month. I bought it 9 months ago to be my everyday car and it has been down more than I have driven it. 😝😝😝😝

 

Ok so when you swapped coils and plugs the trouble codes moved with them, and at present they are on cylinder 4 and 6. These are the two cylinders closest to the radiator and in the middle/drivers side.

If the new coils didn't fix it, (might be a stupid question but did you clear the fault codes after swapping the coils?) than it may be something even more simple like those two spark plugs, or maybe the #2 coil is actually the one that is shorted and for some reason the computer thinks the other two on that circuit are bad when it's the other one.

Don't give up now, you're too close. Clear the codes again, swap 2 and 4 plugs and coils around and see if anything changes.

 

Good idea. I have 3 new coils on 2,4,6 cylinders. I did clear the codes more than once because I couldn't believe it. I checked the resistance on each plug when i swapped them but that may not be a good test but they were at least all the same. It has taken the wind out of my sail for today.

 

It is definitely still bad because it won't even idle very well. Definitely missing on more than one cylinder. I'm thinking maybe an exorcism.

 

Which Plugs do you recommend?

 

Any quality double platinum or better plug should work great and provide 5 or more years of service. I've used all of them over the years and have had good luck with the NGK, Bosch and Autolite double platinum and irridium plugs.

The only plugs I've had bad luck with are the cheap Denso iridium's that only cost $3.00 each, as they have fouled out on me in several different engines.

 

Ok, I switched the plugs and coils on cylinders 2 & 4 with each other. I didn't have time to get new plugs. I am so confused at this point but here goes. I had 304, 306, 354, and 356. After switching cylinder 2 and 4 plugs and coils I now have 352 and 356. Unless I am completely lost I presume you are going to tell me that I should now switch coils and plugs on 4 & 6. At this point does is show that I have either bad coils or plugs or both on 2 & 6? I know that you can get a bad coil or plug occasionally but both?

 

If you already put 3 new coils on it, and the problem stayed the same, and then when you switched plugs/coils around the problem moved, most likely it's the plugs that are bad.

 

Ok, that follows deductive reasoning but, what happened to my 351 code that did not show up as a 352 when I swapped bank 1 and bank 2 plugs and coils? Not that I want more problems...... I will get some new plugs and swap out cylinder 2 and 6 plugs and see what that gives me.

 

Ok. New plugs in cylinders 2 & 6. No change, same codes 352 and 356. Any more suggestions? I don't want to take the wires off of the ECU again. I feel that it was part of my problem originally or was it? Since cyl
4 seems to be ok I should be able to check continuity of the wires from 2&6 to it correct?

 

How should I test cylinders 2&6 to decide what to do? I have replaced the plugs. Is there a way to test the wiring or the coils or something?

 

Okay, I switched coils on cylinders 4 & 6 with each other. I had 302,306, 352, and 356 prior to switching. I now have 302, 304, 352, and 354. I am assuming that this means in light of all the prior switching that I only have one good coil which has made cylinders 2,4, and 6 all work properly when it was on those cylinders. Even though all 3 are new; coils on 2 and 4 are bad. How could I get so lucky? Two are from autozone and one is from O'Reillys auto parts. The one that works is from auto zone. Does this make sense? It has been a crazy ride and has been very confusing, so I may be wrong. Any advice or suggestions would be greatly appreciated. If it hadn't been for Itmax I would still be looking at a new ECU.

 

Okay one more time. I assumed that 2 of the coils were bad. The one "good coil" would make cylinder 2, 4 or 6 fire when on it but the other two would not bib replaced the "bad coils" and no change only the one cylinder fires. The plugs have all been changed. I am very frustrated and confused. Does anyone have a suggestion that will help me get my baby back on the road?

 

Could it be something as simple as the spark plug? I used Autolite APP103 with 0.050" gap. Could the spring inside the boot not be long enough to ignite the plug? I am grasping at straws I know but, I am over my head here. The Jaguar is winning!