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?
