Could This Audi R8 Be Impossible To Fix? | Part 1

[@senco981]

Ricky: Manufacturers (car) know what they are doing, everyone else on KZbin: I'm going to outsmart them, look at me. Unfortunately, very few people here realize how knowledgeable Ricky is.

[@grantsutherland6798]

Yes but he just might be missing the obvious. Don't get too imbedded in complicated thinking

[@kn0t2brite]

I dont have or never will have an R8, but I just spent over an hour watching you fault find on this car and thought it was excellent. Cant wait to see what the fault is. In my job i often have prolonged fault finding and go home and think about it all night. Sometimes if you step away from it and have a break, you can think a bit clearer, come in the next day and fix it. Good luck.

[@STANLIZ4]

My sentiments entirely! thought the solution might come to you when retracing your logic path, it often dawns on you when you do that

[@StewartRudd]

Sometimes you need to clear your head and think through your steps. I find a half hour break to take a 💩 always helps the fault finding process!!! It makes all thoughts clearer😁

[@harveyfennell6251]

Sooooo, I like many (probably) have been musing on your problem overnight and while it seems that it’s the injectors would be the next logical step I can’t help to think that perhaps there’s a duff pin in the connector block. Perhaps swap out the wiring loom of the ecu if possible or rig it somehow so you can run it to check signal. Happy days

[@johnriley9214]

Have you not got another R8 v8 in the workshop to compare the pin positions to,seems to me a lot of misplacements and i would have thought it would have thrown up a few more fault codes

[@rickmelman]

@@johnriley9214 I suspect Rick was looking at the wrong plug - ie the left bank side cause once captain Misery was on hand all the colours appeard to match....

[@deschristie432]

I've just watched this video and it was like watching a day in the life of me. Fortunately I send the likes of an R8 to the likes of Ricky but I had exactly the same issues with a Seat and went through all of the same tests, everything pointed to a breakdown of the wiring between the ecu and the engine. I re wired the injectors and was confident this would sort the issue out. It turned out to be a miniscule amount of damage to the stem of an exhaust valve which was causing shutting the injector off but too quickly for the scope to catch it. Not a good couple of days at work.

[@wediditjoe]

Ricky you are an absolute car magician. After seeing the past few troubleshooting videos there is no wonder why your shop is as busy as it is. Such a refreshing take on things instead of the classic "try shit out and see what sticks" strategy. Big up!

[@kartakis]

Great video as always Ricky! So much detail in diagnostics, where other workshops just start by replacing parts and the customer has to foot a massive bill!

[@jasperj4607]

Customer , the diagnostic machine tells you what's wrong!!! Thanks for showing them that pain cars can be . Amazing content

[@robertwiddrington]

Ricky / Dav, I love this type of diagnosis video, as I feel I can learn so much more about how my car works. In respect of Ricky's comments a couple of weeks ago about the worth of these videos to his business, I also think this type of content shows Ricky's skills at their best, what is needed to diagnose problems on such complex machinery and his ability to fix them.

[@SandeepSingh-tp8xh]

Good content Ricky!

[@greengreenie55]

Yet another good video. Interesting watching your fault finding, can't wait to see the next video. I'm retired but can remember plenty of fault finding that went like this, middle of the night "bing" that light bulb moment when the brain says "Is it this?".

[@nickblake8041]

Simply the best car content bar none on KZbin!

[@stevebez9556]

One of your best videos - keep up the nitty gritty stuff.

[@SB-vb8ch]

Pico do a current clamp that you can use to monitor the current flow, if there is something odd with the waveform (voltage rise rate) that the ecu doesn't like then you could possibly capture it using that. If that is the case though you should be able to see it by monitoring voltage. I'm guessing the ECU is shutting that output down fairly quickly so it maybe tricky to catch. The reinitilisation might not be quite as basic as you think either,I've seen various strategies all the way up to a specific fe enable using an OEM diagnostic tool. As it's a high voltage circuit you've also got the continuity to ground to consider too, the driver circuits will be galvanically isolated from chassis ground so if you have any path (even in to tens of kohms range) between that would most likely cause the ECU to shut thst output down. To be fair it's rarely the ECU itself, wires & connectors are way more problematic as you know! Good luck.

[@yammy1000]

This is the first video of yours I've seen & 10 minutes in, I'm loving it! Straight talking with no bullshit.

[@andrewgroves8384]

Really loved listening to Ricky, fault find and chase the fault, he sounds the a proper old school engineer/tradesman. Im a radio enginner and was trained by morotora back in the day. excellent watch him work.Ill watch more of this

[@markmerrilees6044]

Absolutely glad I just watched this on my sky glass. Even though it isn't diagnosed as yet. It's given me a massive insight to auto electrics. Absolutely loved this video. Learnt a lot.

[@supra916]

Thanks for posting this. Your channel is an indispensable resource to the R8 community.

[@prebenlohse1684]

Good methodical fault finding and so glad to see the Pico scope being used. So rare these days. Looking forward to seeing the final fault and repair!

[@Steviegtr52]

An internal short on one of the injectors. Probably to earth so still checks out ok across the injector terminals.

[@REPerformanceUK]

Stay tuned! 😉

[@jerehada]

So much depends where you start. So experience intuition was ECU and wiring. But with hindsight was it better to test injectors or even coils by swapping around.

[@REPerformanceUK]

@@jerehadalots of work to get to injectors…..manifold off.

[@marcinkufel]

​@@REPerformanceUKtheoretically could be software fault since images were swapped. What is the idea behind testing under load? Electricy flows always path of list resistance and shorts open up only under the load?

[@Steviegtr52]

@@REPerformanceUK I stayed tuned & was correct. Wahoo. Steve.

[@andrewcruickshank2093]

Great video to watch, the anecdotes and running commentary is pretty hilarious. Like a glove 😂😂

[@matt.pinder]

What a great head scratcher! Maybe have a look at putting a reasonable load on the ECU feed power wires to rule out the ECU fuses aren't corroded and have high resistance and voltage sag when a load is applied to them. Not sure what the fuse values are for the ECU to know how much to load them up but something like a halogen headlight, mag ride resistor or invertor should wack some load on them depending how much you need. Maybe look at depinning the cyc 1&3 injector wires from the ECU plug, you said someone's already been there and maybe they damaged the pins in the ecu plug so they arent getting full contact onto the ECU pins. Could you depin injector 1 & 3 from the 14 pin one and start it, obviously it'll shut the cyclinders down after x seconds but before then it should give you the ability to probe the wires to look for that inital voltage on Pico. If you have a spare injector lying around, or similar, you could make a patch cable to one which would enable you to load the ECU up with something to hopefully determine an internal short in the injector.

[@Google_Is_Evil]

I would use a 5A (headlight) bulb and substitute that for the injectors. It's not 65v, but it will only get short pulses, so it will likely last a while. At least you will get a different error message if the bulb completes the circuit. It saves you pulling the inlet manifold. If the lamp doesn't work, maybe get a spare injector and put that in as a substitute?. Also, I am fairly certain you said you tested it, but just in case; test short (better, measure resistance in ohm) between each injector wire and positive/ground as well, not just between the driver and return wire.

[@ldtenenoff]

great idea

[@barry5138]

Don't understand any of that, but sounds like impressive knowledge 👌

[@johnhealy2001]

The trade electricians keep this information to themselves cracking video following every step brilliant

[@Zedhead_]

MORE MORE MORE This to me was like the famous viid called " Rockwell Retro Encabulator " I sat through every minute of this Ricky, faithfully trying to follow the thread. At one point I drooled and may have had a senior moment. One thing that wasn't missed by me was your calm and methodical approach to eliminating probable causes. Loved this and more of them Sir, Oh Hi Kate. xxx

[@dannyconway2612]

If I won the lottery and brought a super car I know where I would come for any advice or work. Another great video. 👍

[@geirstby4256]

I love the picking on each other, and the fact that Ricky looks like his mom fixed his hair prior to going to work.😂😂

[@johngibson3837]

I thought his mum had just given him a buying new helmet hair cut

[@DustyJacks]

Very interesting! I like to think I have a decent handle on mechanical things, but when it comes to electronics I go all smooth-brained. Also is there a way we could get Dav to subtitle some of the off-mic commentary? Especially when you're yelling across the shop to take the piss out of someone it would be great to see how they responded.

[@WarwickRoadAndy]

Not into high range cars but find the channel and this vlog fansinating, been watching since the first Guy Martin visit. As a Traffic Light Manager, its the same, trying to find a needle in a haystack, you keep going down rabbit holes to eleminate possibilities, it could take 5 mins or 5 days to identify the issue then repair it. Keep up t'gud work lad. :-D

[@emilsgargurnis]

De-pin injector 1 or 3 from the coupling connector, run engine, look at faults. Swap both engine ECU's relays. Dont ever disregard checking pins for grab while your at it. Voltage drop test is your best friend.

[@01bogwoppit]

Excellent video , can wait for part 2

[@GazVDS]

Carry out an insulation test on each injector pin and to the body of the cylinder head, ideally you want a high resistance reading or the O.L on the meter. Low resistance readings on insulation tester means a level of continuity between the injector pin and the cylinder head which would cause the injection circuit to malfunction.

[@andywilliams7510]

Found this really interesting video. Love to see more of this and some tool reviews of the kit you are using. I’ve said before I’m not a car man but through your channel I’ve got the confidence to do a lot more work on my bikes.

[@stevewall3246]

Bloody brilliant video it just gets better and better looking forward to part two the wheels on the bus are going round and round

[@samrodian919]

One of the very best REPerformance videos every Ricky and Davla! Hi Kate! I'm looking forward to part two of this as much as I ever have with one of your videos! Till next week!

[@stevensmith7021]

Really captivated by the genuine uncertainty of the outcome and following your fault finding logic. Seems to me you've got blinkered into investigating this as an ECU output issue. Does the fuel saving cylinder deactivation on audi V8 not cut off fuel on cylinders 1 and 3 and maybe 5 and 7 on bank 2? If so could this be an input issue? What inputs could fool just one ECU into thinking it needs to run in cylinder deactivation? Just a thought. Fascinated to see the part when you reveal how simple the fix is! Also surprised you're not used VCDS to monitor live parameters of ECU. Fully respect your incredible knowledge of VAG and I have no doubt you will figure this out once you've slept on it. Keep going with the channel. I know where I'll be bring my V10 R8 when I can get one!

[@REPerformanceUK]

It is an ecu driver issue….but there is a reason the ecu is shutting the driver down! Stay tuned! 😉

[@ultimateshinedetail]

What an amazing proof of what you do. That was amazing content

[@123reetlad]

Try final control to the injectors whilst pico connected this way your loading the circuit and can measure amp draw and voltage drop. If a mechanical imbalance is present misfire detection will disable the affected cylinders so its either voltage/ signal interferance or mechanical defect. I have had a similar issue with the inlet camshaft variator causing the same misfire conditions on one cylinder and shutting the fuel off so might be worth checking the variator phase and cam crank correlation. Love that even the best lads struggle and swear it's a bugger but you will sort it.

[@ineedthatcar7169]

Epic episode Ricky, I miss the technical teardowns with gearboxes et all!

[@chrishall4558]

I think someone at some point has had the inlet manifold off for some reason and has trapped the loom and crushed it, so you will get continuity but resistance and voltage drop under load

[@brian623]

Great workshop, great knowledge absolutely spot on

[@stefangustavsson6362]

I am not debugging cars often so this might be destructive :) take the wires with no signal from the ECU out, run the car and inject a voltage from somewhere else (signal generator, voltage supply etc. might need to be pulsed to not fry the injector?) onto those wires. Scope again and also measure the current draw. Good luck (sounds like you will need it)! Good videos btw! cheers

[@backwheelbob46rr]

Cheers for doing this in one long video look forward to seeing what's wrong with it 👍🏼

[@frederickgranado]

I was always taught to inspect the spark plugs as they will tell you what's going on with that cylinder. If the cylinder is getting fuel but a limited spark due to a coil pack (step-up transformer going bad) it will would make sense that there could be a misfire. Swapping ECU's and testing the wiring will all look normal. If the ECU determines the coil pack it bad and cuts power to the fuel injector (also a solenoid coil) to prevent the injector from continously dumping fuel into that cylinder then the signal on your pico (I use an Oscilloscope) would make sense at it looks like the signal it being clamped. Not sure if that's by design to protect the cylinder though - you may have the answer to that. The quickest thing is to swap out a coil pack from the misfiring cylinder with a coil from another cylinder and see if the misfire and/or error codes move to the new cylinder. Usually you get a P0302 or similar code if it's a plug or coil. If the fuel injector is bad removing the fuel rail and swapping the expected bad one with a different cylinder should be evident right away if the misfire moves to the new cylinder. If you have a know good fuel injector around (and my guess is you probaby do) I would connect a pigtail to the known good injector and connect the pico to that and see if the ECU will give the fuel injector the proper voltage to push fuel through the injector into a cup or bottle (away fom the exhaust of course). As someone who has spent a lot of time working on troubleshooting car electrical systems, I look forward to seeing what you find out is the answer. As an 2014 R8 V10 Coupe owner I always appreciate the detail you go into explaining what you do and why you do it. I appreciate your dedication and commitment to your trade and look forward to seeing what problem ends up being.

[@kevinobrien3063]

Hi I suspect a sort in the injector or wiring on the pos side. Remember the pos supply is paired so the problem may be on the other injector or loom. On start up it may always fire number 3 before its pair. The short may only be there when the plntle moves. Also this is a high voltage so it will jump a gap that will not on an ohm meter. You could try depinning no3 power supply at the ecu and see if it's paired injector now works I think you said no5. And then do the reverse connect no3 and depin no5 pos at ecu. You can see if this changes the code. You could also check no3 and it's pair with the current clamp to see if anything show. Look forward to the next video Kevin

[@cesil77]

Did you check ECU live and earth while under load? Also you could have a loose pin in the ECU multiplug? Hate getting problems like this that don’t make sense, from experience it usually ends up being something obvious you thought you had checked 😂

[@marcinkufel]

Theoretically could be fault in software since the images were swapped. What is the idea to test under the load? Electricy flow always the path of list resistance, so maybe the is short somewhere which shows only at the load?

[@ralphmillais5237]

Put it on Carbs and a Dizzy.

[@pjvenda]

Very interesting. Given my education, this all makes perfect sense to me. Good luck finding the cause. Goes to show why the cost of diagnosis often (usuallt?) outweighs the cost ofbthe repair. Smarts are expensive!

[@StewartRudd]

Hi Ricky Did you check for short circuits between the pairs for each injector? Although you have continuity you may also have a short to ground or a direct short between pairs. It seems weird that the injector seemed to fire normally for a few seconds about 30 seconds after starting. Being an electrical engineer, I would start by disconnecting everything and doing an insulation resistance check, but I'm not sure you can do that without running the risk of damaging electronics. Good luck with the fault finding from ooop north!!!

[@spudboy92]

Personally I would Disconnect the plug at the ecu and the injector , Load test the wiring from the engine ecu back to the injector. Using a power probe at one end and a bulb to ground on the other end to confirm wiring circuit once and for all . If this checks okay I would have the injectors bench tested otherwise your have to swap them and build it back up to find out if it worked or not . You can also put a bulb across the main lives and grounds on the ecu plug to confirm feeds in to save looking for the individual ground points Good luck

[@rjcharlick]

Brilliant video again please can we see your work shop and what you keep in stock and why ? Thanks Ross

[@Holstech]

Great videos. Before swapping injectors, eliminate a single injector at the wiring and check codes (theory being that if one injector is dragging the driver down you can eliminate it). Also if you do swap injectors wouldn’t you swap them to different drivers rather than as a pair?

[@miketilston1528]

Do the direct injectors have 'filters' like port injectors? I had a Porsche in once that was failing injectors randomly, turned out the owner had 'pissed off' the body repair man a week earlier who I suspect chucked a Mars bar in his fuel tank which blocked injectors one by one causing similar head scratching to what you have, If the fuel pressure does not reach the injector the injector is much easier to fire and the ecu picked this up as a missfire :)

[@davidgreenfield2981]

You could try unpinning 1 or 3 from the ecu plug. And if you want to test the loom, put 12v in at the ecu plug and measure it to the plug at the throttle body end

[@REPerformanceUK]

If the ecu doesn’t see a circuit it will shut the driver down as it’s over 65 volts to power a DI injector.

[@CrispysProjects]

Amazing retro cruising!! Still with the simple electrics compared the the '05 e220d the parents have!

[@christopherlloyd13]

Fascinating diagnostic process.

[@BrunelMotos]

Loved this video. Really good to know how to troubleshoot these effin electrical gremlins. Cheers from Chile!

[@REPerformanceUK]

Thanks for watching

[@davebartram1732]

Build separate loom from ECU to injector and swap injectors and see if fault follows is what I’d do, and would ilimanate wiring . this was my game many moons ago when we would trace faults in dealerships an not just replace parts. Sad thing is I understood everything you did and stepped back in time All else fails change valve springs 😂

[@basilwatson1]

I have a set of point and 2 pushrods to adjust .. 35 year mucking around with mobikes and no a fan of high tech, ( understand it , use it at work but my personal bike is an old brit single )

[@ridetwo]

if it is a wiring fault rather than checking with continuity could you use a insulation resistance tester to check the resistance of the injector wiring?

[@markaddy53]

great video lad keep at it lad im sure ul suss it owt next video please

[@jdmimportlogistics]

A bit off-topic but do these types of situations arise in the GT3/4 R8’s for example that have more sophisticated ECU’s and custom quick release looms? Also I would imagine the history of the car would be well documented and have more simplified systems. Great episode and obviously a lot of very smart electrical people chiming in. Definitely following this closely and a great reference video to go back to when one is having the same types of issues.

[@robertanderson-yx8mo]

It really could be a broken valve spring i have had this on a car the main dealer couldnt work out with their diagnostics. So i started to tare it down and it was a broken valve spring.admittedly it was just an astra gte but back in the day it was a cool car

[@kenrossaukrsa]

Main Fuse box has a short or arc underneath it or the bcm is storing a fault code , when a nEcu goes into limp mode or check engine light ,it switches off a cylinder (or reduces power ) and naturally a misfire fault code will appear too.

[@julianpalmer4674]

Great video, could you inject a known good signal into the ECU connector to the offending injector and see if it fired or dragged the signal down? I know you wouldn't see the injector squirt fuel at this stage, but it would test the wiring and the injector integrity.

[@darrenliddle7820]

As a bmw tech dose vag group not use test leads we have very similar engine hard to get to things and we would volt drop the line

[@jonofalltradesmasterofnone832]

Megger the loom that will give you cable failure if you can.

[@samrodian919]

And lock every ecu in the car in the office safe while it's being done!

[@6803U4]

Looks like a 12v supply issue causing the injector voltage fault code. The R8 manual states fuse 33 (15 amp) is the injectors fuse, so both ecus must have a dedicated power pin just for the injector supply (which gets boosted internally to get the required 60v). I think you need to back probe that ecu pin to confirm full battery voltage is present. The fuse end must be ok as second ecu appears to be getting its 12v ok.

[@RebelwithaRolls]

keep at this content mate it cracking - smart fella

[@REPerformanceUK]

Thank you

[@richardmildon2020]

What a very good and fascinating video thank you

[@davidreville7211]

Love the video - such interesting content, but makes me think twice about buying an R8 - particularly as I want 2 more cylinders than this 😢

[@alansheard553]

Love a good Detective story. Question, you said you were using a turbo trainer to increase fitness for the season, has it worked and if so what benefit if any have you found in racing the bike ?

[@OhLookaClutchPedal]

It has already had a new injector and an injector swap. But you might as well while you're there. The OEM plugs are fine. Possibility of live injector voltage and resistance display on vagcom?(but won't give you location.) Or do an organ transplant by borrowing a Syvec for an hour or two?(again won't locate) Everything is being done to avoid the cost of a full harness replacement. Partial harness surgery may be cheaper? I agree trying alternate harness on those 2 cylinders is the correct approach to rule out installed harness. Sorry couldn't be more helpful to the owner.

[@jacksmart8822]

Ricky, what do you use for your workshop floor paint wise ?😂 always stays well even with engine cranes etc. good video too!

[@sf48]

Brilliant video, thanks.

[@AshLongie]

Im at 1:09 i would put wires from ecu straight to injector to test if its working that way with resistance test wont always show shirting to other wires etc

[@AshLongie]

Lol you literally said straight after I typed lololololol 😂😂😂😂

[@Syncro16TDi]

Did you just swap the ECU files over from one to the other? Or load a fresh stock file onto each ECU? Is there a chance that there's an issue with the file that you've swapped over from ECU to ECU and therefore the fault has remained?

[@666markyboy]

I'm with Mitch and the broken valve spring

[@knight2425]

Somebody’s been there before lol. My guess is the inlet manifold has been off and there is an issue with the loom to the injectors where some wires are crimped or have been poorly repaired

[@Stephenc4877]

Live to ground fault on one of the injectors dragging volts down and amps up, ecu maybe has some sort of current protection?

[@paullangford7078]

Understand you swapped the ECU software over to prove if there was a Hardwear fault and nothings changed. What if it's a software issue, can you be sure the files are not corrupted. Other than that injector issue maybe. Great vids and love the tech heavy ones....... Why don't you like Porsche 😁😁😁😁

[@davidclarke7728]

Sometimes aftermarket parts are better than OEM, but you have to do your homework before switching, you said you were a genius and an expert, cars can be bewildering ,even for experts

[@detroit250]

@REPerformance Diagnostics is a Black art in Someren cases. You go on a hunch in most cases, but ive learnd That if your lost and cant tracé it, its in most cases somthing that you asume is goed. Like in this case, ricky saw that sombody had worked on the diverside loom, is the clamp tension of the terminals in the big connector on the ecu stil enough? Ive came across a likewise problem once, clamp tension of a DI injector terminal was " to loos" and that coused the voltage to spike, and the ecu flaged that as a faulty driver. Maby not the awnser but my 5cents

[@simonh2507]

Have you considered that the ECU/wiring is working perfectly, just shutting down those cylinders because of input from the engine/sensor. Not sure what parameters the ECU looks for to constitute cylinder shut down, but if those requirements are met would that mean that the ecu would stop sending voltage to those injectors?

[@brendaallison7924]

Can you do a relative compression test on pico to rule out cylinder compression issues

[@mrnolando89]

I have been down a very similar path on a bmw, it turned out to be a spun cam lobe on the eccentric camshaft (used to advance/retard the timing). I would be thinking the same as Ricky with either poor pin pressure on the ground wire or a fault in the loom OR possibly a mechanical fault causing injector shut off and knowing the vag valve springs it's probably that (if so it's a good shout from Mitch but don't tell him that).

[@davebartram1732]

Build separate loom from ECU to injector and swap injectors and see if fault follows is what I’d do, and would ilimanate wiring . this was my game many moons ago when we would trace faults in dealerships an not just replace parts. All else fails change valve springs 😂

[@KennethHarrison-ou2ok]

Next step... run a compression check or bypass the loom to 1 & 3.... I think the ECU may be disabling the duel injectors, I think you said it fires then detects the cylinder fault and the ECU turns off 1 & 3. both the direct and port runner injector.. as you have done so far I expect you to choose which step is smarter and hopefully easier to perform then verify.... Which is easier, compression check or, bypass the loom? On the loom side its rough someone's been in it... pin out was wrong its been probed... it may be pinched or cooked if it was not routed right when reassembled in the past and your going behind someone else... Verify 1st I don't see you shot gunning as its the last resort expensive when lucky and even more expensive when wrong. nested fault? pinout masked further loom damage..... cant wait for part 2 will you or did you compression test it to identify a valve train issue

[@Gotster]

disconnect the injector an put a load in the socket (brakelight) at that end and connect live and ground in the other end to se where the bottleneck is.

[@clockgarage8790]

Or like you say I temporarily splice in a wire on the suspect wire to rule out any resistance issues in that wire

[@gaelicstorm7]

Fantastic, completely baffling, but fascinating...

[@dazpreston9572]

Can't you put a voltage down the disconnected connector and measure at other end .Like u said belling out a wire does not show if there's a resistance ...

[@christasker_]

Look forward to part 2.

[@REPerformanceUK]

Thanks for watching

[@davidgare9238]

I actually know Jack shit about wiring and fault finding but was totally glued to this! Great content 👍🏻

[@carlhamm4461]

Maybe check terminal tension on connectors IDK MAYBE WRONG

[@RoryMacdonald-pfff]

CLIFFHANGER!!! Is that your new angle on YT? Works. 🍿

[@NoName-gr1gl]

Im going valve spring also.

[@stevepond2807]

Wire in 2 injectors externally and see if you get output from ecu?

[@grantsutherland6798]

Coil packs tested on 3 & 1? Or can you swap around to see which ones might be faulty??

[@My_father_was_a_toolmaker]

De pin the injector wiring both ends and move to a different cylinder and see if the problem moves that then rules out a wiring faut.

[@KevL5967]

Hi Rick, any chance the vehicle has got any 3rd party electrical equipment crashing the can-bus through incorrectly spliced wiring? Are the 2 ECU’s on the same loom?

[@Russell_Duncan]

Is the ECU detecting excessive current flow through the defective injector circuit and shutting the driver off? Could you substitute a known good injector by de-pinning at the connector at the rear of the engine and connecting your substitute injector in there?

[@Drones_and_more]

You mentioned the 3 lives that feed the ecu, do all 3 have correct voltage to them at both ends? Could it be getting 10.8V(example) on one and thats feeding Inj1/3 driver circuit with a undervoltage?