That switch and blinking light sound like an aftermarket alarm; my advice is REMOVE IT.
I have bought non running cars for aftermarket alarms that no one could figure out; most interrupt the ignition or fuel pump- on a Jaguar, probably wired into the inertia switch.
Restore the wiring to factory and verify voltage at appropriate pins on ECU connector, fuel and injection relays, and coil.
That was the one thing the previous owner showed me. The inertia switch was removed and hot wired. I dont know how the alarm system operates though, but a good spark, good fuel pressure and the injectors operating confuse me. Removing that alarm isnt a bad idea though, may save me trouble in the long run. Thanks for the idea.
Not a good idea to have the inertia switch bypassed, in the event of an accident you want that to trip to cut off the fuel pump.
Itâs not just a not bad idea, itâs the first thing I would do.
Hopefully there was not much butchery involvedâŚ
Ooooh, gotta wonder about that. I donât recall anyone having a lick of trouble with that inertia switch, hence Iâve never heard of anyone removing it. That makes me think the PO was blaming it for something.
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Ive had it running without it and when I get it running again Ill look into reinstalling it for safety sake. Aristides, Im going to look on the internet to see what it involves to remove that. It makes sense that the wiring is already suspicious on these XJSs that I donât need any aftermarket butchery to sort through too. Kirbert, that was the impression I had gotten when he showed me the two wires twisted together with a wire nut holding them together for the inertia switch but I wasnât very concerned about it as long as it started and now again, not starting. You and I are in agreement about the ECU being the culprit, with the injectors testing as they do. I have another ECU (not new, used again) coming and hopefully that will be the cure. If not, the deeper I`ll dig. Thanks Rod
Aristides I dont think I answered your questions. Hopefully I answer them here and a few others. My ECU is a 16CU. I tried to upload a picture or 2 of the solder job but couldnt do it for some reason. I traced the circuit back to the resistor. I did try to resolder bad joint no difference. I do have cats and o2 sensors and I have an ECU coming from California any day now but I am going to check rebuild the harness because of todays test.
I checked the continuity in the wiring to the injectors. The way I tested today. I unplugged the harness wiring from the from the connector in the wiring just before the resistor. I checked A1,A3, and A5, A bank A2,A4 and,A6 All wiring to these cylinders had continuity. So to me A bank checks out being okay. I was thinking A bank was not right. It had fluctuating and eradict reading but Im thinking they were working as they were meant to work and the B bank is the culprit with the steady readings. I tested B bank B1,B3 and B5 tested as they should with continuity but when I tested B2 and B4 both connectors each lit from 2 different pins at the other end of the harness yet B6 tested ok. So something on the B2 and B4 injector wiring is crossed up I dont know what it means but it isnt right. I dont believe this is enough to keep it from running but I`m sure it will run better when I do get it started. Thanks
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Eureka part 2. Running again after much hair pulling. I rebuilt the harness with high heat 18 ga. wire, new fuel injector connectors and mounted the harness tucked under the coolant rail. Nice and clean look. While I was that far into it I checked the fuel injectors for about the 5th time (all good) and checked plug gap again, all good at .025. Installed new spark plug wires while I had it apart and cleaned every thing a bit more then put it all back together with high hopes. Turned key, fuel pump pumped up, cranked it and no start. went to my last resort, the new to me 16cu ECU. Popped the old one out , put the new to me one in and bingo, fired right up and it runs I would say at 85%.
Changed oil, and Im flushing coolant as I speak. My vacumn gauge shows 10 which I believe is low so Ill be looking for vacumn leaks tomorrow. Ive brought it to temperature a few times to smoke off the spilled oil and cleaning residue. After running and idling for about 10 minutes I give it some throttle and it then will surge a bit, but Im still waiting on my two micro switches on the throttle tower and find the vacumn leaks and Im hoping to get it dialed in enough to at least move it under its own power for the first time in about 15 years. Thanks to everyone for your excellent insight and reliable information. Im sure to be back with more questions in the future. Thanks Rod.
By the way, this is a new laptop I am on and I see my posting is still convoluted even though my text is normal it posts weird. If I ever get it figured out I will fix it. If not, oh well.
Congrats! I ended up buying an injector harness, helped solve my intermittent misfire that was the final issue driving me crazy with a rough idle. Thatâs cool you made youâre own. I stink at electronics, gorilla hands.
These Lucas V12s with dumb fuel injection (because they donât have much in sensors) have to have everything just perfect, eh?!
Low vacuum isnât caused by vacuum leaks. Vacuum leaks cause high idle speed and high vacuum.
Yes, more likely incorrect timing?
On a healthy warm engine should be 16" - 18" (with auxiliaries off)
Rotate the distributor and see if it makes a difference.
Incorrect fuelling would do that too, better check and adjust your base fuel map of your new ECU.
Details in the Book and here.
Also check CTS, ATS and your full throttle switches, there are two, that they are not permanently âonâ
I see. The things I should have known and probably did at one time come back to me with all your help. My idle is steady at about 900 rpm ,a little high I believe, I`m thinking things will come around when my micro switches come in and I get them installed. Thanks
My local tech says 900 RPM is good, so that it will be 600 when in drive and with AC on.
Rob
My idle when warm in P is 800-850rpm (supposed to be 750-850), 600rpm in D. When cold, idle in P is about 900-1000rpm depending on temps.
I had a low vacuum, about 10-12 in Park, when I had an over-rich running condition and terrible idle. Once I fixed that (ended up being ECU), and getting everything timed and running well, I now hit 18 inHG in Park.
It should be max 750 RPM Robert, 900 RPM is too high.
It doesnât heart the engine one bit but does put lots of unnecessary strain on the gearbox, i.e. every time you put it into gear.
It doesnât help consumption either.
I recommend this to all:
Get a second auxiliary air valve and connect to the start inhibit switch (green/black cable at the firewall/starter relay) so itâs off in P and on in D.
I now have a 600 RPM steady idle either in P or in D. I never heard a âclangâ from my gearbox ever again.
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Yes, 900RPM warm idle is too high. But all my books, and even the sticker on the hood, say 750-850RPM is correct.