Dan, yes the car has been working fine since. Has not shown any problems. Confirming i just unplugged the ECU of the side that was working fine and this forced the side that wasn't running to fire up. Then i turned the engine off and plugged the ECU back in. Full engine fired up right after. Perhaps a difference from mine to yours is that when half the engine wasnt running, there was bo fuel smells. And the injectors were not pulsing. ECU seems to have been down. If you have fuel but no spark, yours may be an igniton issue? Might need to check if you have spark
@Qavion Thanks for the reply. Yep, the check engine and slow down lights all work, to the degree, but I'd feel better about this if one actually did come on. I'll do the fuse swapping and multimeter checking this weekend, as well as checking for spark. ( @LP13 )Thanks! Qavion, I see your avatar and profile page has an Azzurro California F355, so I'll you say you're a man of great taste in car colors! Mine isn't quite Azzurro California, but close enough to give that compliment.
I don't have a wiring diagram for the check engine light, but it's common to have the light illuminated by a combination of power (12 volts) coming from the injector relay (which is controlled by the engine ECU) and a ground which is also controlled by the engine ECU. If the defect is currently a hard fault, see if the light still appears on startup. Or if intermittent, wait until the defect occurs, switch off the engine and then back on again to see if the light still illuminates (assuming the defect is still there). If it still illuminates, then the relay and at least some parts of the ECU are working.
The injector relay also provides a constant 12 volts to the fuel injector connectors with the key on. Are they easily accessible on the 456? Thanks. Yes, the colour seems to be quite popular. People have asked if it's an OEM colour. Apparently there are only 13 Azzurro California F355's in existence.
Just making sure that I'm following, but the normal cold start of the car when everything was working as it should would have the check engine light solid on for maybe 5 seconds right after starting it, then it would go out. With respect to my current situation, the light has never come on beyond what I'd call the usual 5 seconds after start up. I was able to check fuel-related relays and fuses, nothing looked amiss. I swapped relays for the different sides, and those weren't the issue either, unfortunately. I also am definitely getting spark on the side of the engine that isn't running. Thanks, Dan
What I'm trying to establish is if you have the bank issue from cold start. Is it a hard fault? If the issue is always there, then the injector relay (and the ECU) seem to be ok. Also, the crank sensor seems to be working, otherwise you wouldn't have a spark. We are now down to fuel. Is the pump working? Do you know how to jumper the pump relay to get the pump to run (for an audible check). Do you have NOID light to check the signals going to your injectors? I assume there's a Bosch type 2 plug on your injectors. If no NOID light, just make sure you have 12 volts at the injector plugs (key on).
Qavion - thanks for the continued help. Over the weekend, I was able to test: injectors with a noid light - the light flashes. Injectors are getting signal. spark with tester plug - the test plug fires when it's put into the boots fuel pressure - non-scientifically, the pressure check valve REALLY squirts when it's pressed in and the car is running compared to when the car isn't running the fuel pumps both click from what I could tell (not exactly what you asked, but it wasn't something I could check more thoroughly than this plus the pressure check) I wasn't able to check: compression condition of plugs I took it over to a shop this morning to keep investigating with more and better tools. I'll update as I get updates. Food for thought: This started while I was driving it on the hottest day of the year so far (~90°F), and the issue started after it had been parked for about 30 minutes after driving it for about an hour in stop and go traffic. While driving, the temperature gauges were higher than normal, but not in the "red," so to speak. There was no indication of issues when it was driving. After it was off for ~30 minutes, when I went to start it, it had 2 "clicks but no turnover" start attempts, then on the third, it turned over and very clearly was only running on half the engine, and it's been that way since. (~4 days ago). There was no clunk or unexpected mechanical noise. No funny smoke, water, antifreeze smell, or head gasket-adjacent suspicions. That side of the engine had A LOT of work done (new belts, tensioners, etc., etc.) to it a year ago related to having lost time — that could unfortunately be something, but there's nothing obvious like there was last time when valves were loudly hitting a pistons, and there's no sputtering or misses happening. Further complicating things: I'm getting married on Sunday, and as a dumb teenager in the late 1990s, I had "it would really cool to drive home with the bride in a Ferrari" as a really cool thing to think of, and I managed to make both(!) of those things possible, so I called in a favor to get the shop above to take a look at it ASAP, because I'm not sure "drive off from my wedding in a Ferrari with half the engine not working" is quite the same thing. They were awesome, and were able to squeeze me in to take a look at it. Ideally it's something gunking up the fuel on that side of the engine if that's at all possible. If "necessary," I can unplug the fuel pump and injector relays for the 'bad' side which keeps the gas fumes down (like for driving it to the shop this morning), but let's see how it goes. The car isn't "sporting" with half the engine running, but I've driven (intentionally) slower cars over the years than a 456 with half the engine off. Thanks for your continued help!
You mean it's cranking, but no signs of life (initially)? Unfortunately, because of its intermittent nature, your earlier checks may not have picked up the issue. I'm wondering if one bank is dragging on the engine so much, the engine couldn't start (rather than it being a starter issue per-se). I really hope you can get it sorted before Sunday. Unfortunately, you may need parts and they're not going to turn up overnight. Have you been able to identify the faulty bank yet? If not, can you trigger the one bank fault with a drive and then randomly pull one of the fuel pump relays to see if the engine stops. At least that way we know which bank is faulty, then we can swap components to see if the fault changes banks? Unfortunately, time is an issue here. If one bank is running, I guess the bad bank fuel relay can be jumped, even with a bent a safety pin (key off). Just wrap it in something as it will probably get warm. At least we will know if the pump can run continuously and if it's a relay control issue. Or, if the relay is metal, maybe you can see if there is a temperature difference between the left and right pump relay with one bank not running. Once we know which bank is faulty, if you have a multimeter, maybe you can check for power at various points. I've amassed a lot of spare parts for my F355, just in case (e.g. things like coilpacks and various engine sensors), but it's always something you haven't thought of with these cars.
At that exact moment, it didn't crank on the first two attempts, but there were the normal clicks. On the third attempt, it cranked, begrudgingly, but it did start, clearly with just half of the engine running. (not sure why I had the brainfart with the term "crank" in my previous message.) Honestly, I think this 'click instead of cranking' is just "one of those things that happens" with these fussy 30-year-old cars. Though, like you said, anything could be the problem. Especially because that corresponded with the engine no longer operating as it should've. Sorry if I wasn't clear earlier — the side of the engine that isn't running is the driver-side of in my LHD car, which I think is #7–12. I know there's complexity because the intake crosses the midpoint of the engine, but the #7–12 exhaust manifold is cold. As a sanity check for determining sides, I removed the fuel injector relays for the 'bad' side, and the car kept running. When I removed the relays for the 'good' side, the engine immediately stopped. If parts are needed, they'll likely have a long lead time, so I'll drive it to and from the wedding with the "bad side" fuel pump and intake relays unplugged, like I did on my 20-minute drive to the shop today, so I'm not pumping gasoline into the side of the engine that isn't running. Then I'll drive it back to the shop the next day. Again, thanks!
Ok, for now, let's treat this as a separate issue (and just one of those things that happens to old cars). No crank could be aftermarket (?) immobiliser, starter solenoid, start relay or general power issues. Thanks for the clarification. That should make diagnosis somewhat easier. Did you keep the pump and injector relays in their swapped positions? Do you have the time to swap the coil packs and ignition power modules? Or at least the power module. That might be more sensitive to temperature. Image Unavailable, Please Login I can't believe how expensive 6 plug coilpacks are these days. Not even the Bosch equivalent is cheap. At least the power modules are a more reasonable price. https://automotivesuperstore.com.au/bosch-0227100203? If you look at the relay panel plug wiring. Is there any sign of melting plugs/wires?
I didn't have a chance to do this test before I took it to the shop. Prior to the shop, one-by-one, I plugged all of the boots into an ignition tester (like the below), and it was sparking. I suppose there could be a "weak spark" issue or something like that, but I'd put money that the voltage is making it to the plugs in the engine, but maybe the plugs in the engine aren't firing for some reason. I didn't explicitly look for this, but I did look through anything connected to that cylinder head, and no melted wiring stood out. Yes – once I saw that there was no change after swapping the relays, I kept them in the swapped positions. Thanks for your continued time looking at this thread! ignition tester below Image Unavailable, Please Login
Did you test the spark when the bank was actually (currently) malfunctioning? i.e. when you put the car back together, did you start the car immediately and the bank was still bad ? I'm just wondering if you are running some of these tests when the fault is not present. If temperature is causing your fault and the car has cooled down, your test results may be somewhat misleading. Of course, if the spark is good and the fault is active, you would have to look elsewhere... e.g. fuel and timing. By the way, sometimes pen spark testers can give you a basic idea of whether you have (any) spark without pulling the plugs, so your car hasn't had the time to cool down. The test lights can be rather dim though, so you need to work in a darkened garage. Similarly, did you do your fuel rail "pressure" check immediately after the bank stopped working?
Apologies if I hadn't been clear throughout. The car hasn't been in a "no fault" state since last Thursday (June 6) when it started on half the engine. No testing or swapping of parts resulted in that changing. So, I don't have a nominal baseline for anything beyond "the car had been running really well." All of my testing (spark plug boots, noid lights with the injectors, fuel pressure check on the non-running side, swapping relays, checking fuses) has been with the car in this fault state. Any swapping of components showed that the components themselves weren't the source of the issue and engine continued running on only one side (and the same side that's been bad the whole time). Example: swapping the left-side pump and injector relays with the right-side resulted in the same fault state – the engine running only on the LHD passenger side (#1–6). Again, thank you so much for the time spent looking into this.
So getting progressively worse. Assuming these tests were done after June 6, there doesn't seem to be any reason why the left bank isn't running... unless the fuel pressure is not strong enough to activate the injectors. I guess you could jump the fuel pump relays (to see if the pumps sound the same). Fuel pump relay contacts (pin 30 or 87) tend to be live, so you can check the sound with the engine not running. Image Unavailable, Please Login Jumper 30 and 87 Have the fuel filters been checked recently? Rubber from disintegrating pump boots may find its way to the filter. Unfortunately, the only real way of checking pressure is with a gauge.
Correct – all of this testing was after June 6, after the engine entered this half-running state. BUT, good news (well, constructive news), the shop did an actual fuel pressure measurement, and it's low on the "dead" side. Tomorrow, they're going to swap left and right pumps to make sure that's what it is. I gave them a heads-up about bits of rubber disintegrating and clogging the filter. Thanks, as always, and I'll keep updating in here.
As you say, at least some constructive news. I suppose another possibility is a fuel pressure pressure regulator. I don't know which is the easiest to fix on these cars. There are a few YouTube videos on pump replacement. Assuming the pumps are the same as the 550's, hopefully your techs know about Kia replacement pumps.
They're not especially fluent in 90s Ferrari nonsense, but they're good troubleshooters and happy to listen to me about forum tips and install parts which I've sourced myself (previously, Superformance suspension bushings). I have a pair (1 for possibly now, 1 for possibly/inevitably later) of Bosch 0 580 464 990 pumps in a shopping cart based on their testing of swapping the pump sides. That number isn't an exact match for the Bosch number the "car wizard*" rattles off in the video above, but the one I'm looking at is usually sold as an Alfa Romeo pump, and with some sleuthing, the numbers cross-reference successfully for a 456 GT (not a 456M GT, which may be the one in the 550). *using scare quotes because his shop worked on my car right before I bought it, and I'll just leave it at "fully sorted out" means very different things to different people, but that's more a comment on the seller, not the mechanic. Thanks!
Since its likely the early style pumps, not the ones mentioned in that video... Just get the Fabio PTFE fuel supports... https://www.fiammenghiitalia.com/en/prodotto/petrol-pumps-support-2/ Also consider the metal fuel pump covers from GTCP. Or be aware these parts can be fragile and start to form cracks https://gtcp.com/product/upgraded-aluminum-fuel-pump-mounting-plate-for-ferrari/ Thread on the process and parts needed, and plenty of links to other links... https://www.ferrarichat.com/forum/posts/149542281/
I'm always telling people that I found over 30 faults on my car (after a rather expensive and useless PPI). I even found that someone had wired up the Check Engine light in the dash to only come on during start, but not if there was a fault. Anyway, I'd better hand you over to Nick now. Sounds like he has all the information you need
Like you, I just want to help people solve their problems in the most logical and efficient way they can. Sometimes its easy, other times i think we just provide a menu of different rabbit holes for them to fall into!
Welp, good news and bad news: The shop pulled the existing fuel pumps, manually tested them, and swapped them, and they were good, so those aren't it. They then swapped the left and right ECUs, and that moved the "bad" side of the engine to the other side. So, that points to an ECU and is promising. This didn't bring the original "bad" side back to life, which is actually started this thread, @LP13, which would've been ironic, at least. I'm not sure where the 'bad fuel pressure' note came from yesterday, but I truly appreciate that they kept digging instead of turning this into a parts safari. eBay currently has a new and a used ECU available, and I have a call out with Karman Auto in Oregon to see what services they offer. They list a "575M ECU Repair" service, and I would guess it's the same work and just a matter of not making an eBay listing for every car that's ever been made.
I'm not sure I share your confidence in these guys... even if the guy talking to you thought he was talking to someone else (and was talking about another car). If the symptoms were intermittent, then I suppose the ECU could have caused low pressure by not turning on the pump. I'm guessing these guys don't know if it's possible to do a test on the ECUs (in-situ). If there is a 3 pin plug on the ECU (as well as the big plug), it may be possible to jumper the pins on it for 2.5 to 5 seconds to start a test sequence. Then the CEL on the dash will flash in a certain sequence to produce a fault code.... and then hope that the code corresponds to something on 8 cylinder Motronic 2.7 cars (which we have a code chart for). Image Unavailable, Please Login Which 2 pins of the 3 pin plug, I'm not sure of on the V12. Ground and ??? @Aerosurfer Nick, have you tried this on your car and do you know which wire colours trigger the test?
