Hi All, I am based in the UK and have a 5.2 355 which I have had for 17 years now with no issues .... Until yesterday... It had a major service in December and hasnt really been out since then. I took it out and all was fine until about a mile in then it lost power and the engine note changed, sounds like it went to runing on 4/5 cylinders but still drove ok and had no slow down lights on. Got it back, unplugged the Exhaust ECU's and they look ok, ran without them and it made no difference. Then turned off the battery switch and left it for 4 hours to hopefuly reset the ECU, the same thing happened when I restarted. Looked at the blue sensor on the back of the engine which had a bit of corrosion so claeaned that up put back together and again no better. It doesnt have a 16 pin OBD plug just the 3 pin ones so cant get a code reader there, there are connectors you can buy from amazon (16 to 3 pin) but not sure which ones work> In the UK all the garages are shut down so cant get any help there Can any one reccomend anything to try please Many thanks Phib
Sounds like something simple. Have you checked that all of the ignition leads are connected properly? Have you ever had the injectors cleaned?
Thanks, it does sound like something simple. It seems to have a stronger smell of fuel comming out of the right hand side. I need to tackle the leads later, they dont seem that easy to get to so will take my time. Not sure about injectors, I have never cleaned them. Not sure if garage has. Does the injector stuff you put in the fuel tank work or do they need to be taken out ? Many Thanks Phib
Google "Fiat 3-pin OBD2 adaptor". That should point you in the right direction. I put injector cleaner in my tank, but proactively. I haven't had any problems. Cleaner is going to help stop blockages. If you are getting too much fuel, it doesn't sound like a blocked injector. Not sure that would help with resetting the ECU. The 5.2 ECU has a non-volatile memory. It's odd that you're not getting any CEL/SDL lights, but there are some faults which don't produce them. If you can figure out which bank you're losing, then it will help with diagnosis.
Without having codes: If it smells like fuel, then I'd look into why you have unburned fuel.... meaning spark. Check the connectors on your ignition module and coils. If you have the means to do so, check the spark plugs. But if possible, get the codes. Should help diagnosis greatly.
It never is anything simple when one back shuts down. Unless you have a code reader, this is shooting in the dark and relying on getting lucky. The thing to try is: 1. Check to see if the TCU is plugged into the right connector (I am not sure if the Eu model has a third TCU that controls the bypass circuit) 2. Swapping Thermal Control Unit left to right to see if it switches side 3. Check the O2 sensors, their connectors, and whether the front O2 connection is swapped with the rear O2 connection 4. Is your SDL light bulb turning on at start up? 5. What is the cat temperature of the offending bank when it is running poorly? Compared to the other bank?
If you're sure it's 1~4, then start swapping things.... easier things first, like coil packs, although, after a major it's more likely to be human error than a component failure. Make sure your cat sensor wiring isn't sitting on a hot exhaust. Make sure that your CEL and SD light bulbs haven't blown. Do they appear on startup? (EDIT: Sorry, crossposted with Mitch)
Phil I'd be tempted to swap the coil pack on that side. Check the connections (you'll have to remove the cover) but they fail regularly. Luckily its a standard fiat / alfa part so not hard to locate or swap.
So a little further along .. or not !!! The SDL and CEL do come on so they must be working. Tried to get to the spark plugs, all the little screws out only to find the cover must have been glued in place !!! Then the Fiat three pin / 16 pin adaptor turned up .... and guess what that doesnt seem to fit the three pin plugs I have coming out of my ECU's it just wont plug in ... Very frustrating !! Phib
Well minor update !! Got the spart plug cover off !! Which seems like a major victory ... bloody car !! Need a beer now !! Thanks for all the advice so far Phib
Could you post a video with how the engine is sounding? Still amazed some people use sealant for the spark plug cover, had a terrible time getting rid of it afterwards, not to mention the cover was stuck as glue so i feel pain with you.
Bizarre. I noted you said "ECU's" (plural). The 5.2 only has one Motronics ECU behind the right hand seat under a leather cover. Are you trying to plug your new adaptor into your 4 pin thermocouple ECUs?
Phil If its suddenly running a bit rough, then its likely to be spark or fuel related. Spark is the simplest to check and address. The coil packs can go without warning and produce rough running and loss of power, especially under load and when hot (less noticeable when cold or under light throttle). They're also easy and simple to swap (just note what wire goes where). https://www.ebay.co.uk/itm/Bosch-0-221-503-407-Ignition-Coil-for-Fiat/184200732457?fits=Car+Make%3AFerrari%7CModel%3AF355+Berlinetta&epid=25034186770&hash=item2ae3381f29:g2QAAOSwqMteGS8U GSF, EuroCarParts all do them. If that doesn't work, try checking wires and plugs (but be careful taking wires off plugs as the boots tend to break - Hills do a dedicated tool which indicates the likelihood of issues). If the plugs were changed at the major then unlikely to be them (though not impossible). Wires can degrade which again, are an easy (if slightly pricey) change...
electrical connections at the injectors and around the engine, but that should be throwing a cel. I wouldn't do a lot of digging except swapping L&R parts until you get the code reader.
Thanks all, all is pointing to poor coil pack on 1-4, manifold is not getting that hot versus the other side. So I have ordered a new one that should (subject to lockdown) be with me on thursday ... lets hope its that simple !! If not its into compression tests etc etc Thanks Phib
I will take a photo later, i have one three pin out of the ecu and another one out of the hood cover in the middle of the car Neither fit the adaptor !! Phib
did you swap coil pack from bank 1 to bank 2. This would tell you for sure it’s the pack and not something else
A photo might tell us if the plug looks non-standard. I assume you removed the protective cap prior to fitting . If you can identify the wire colours on the plug, I might be able to help you fit a suitable plug to the car. ECU fault codes can be a vital key to diagnostics.
Compression test is the cheaper way. I am thinking you have a burnt valve. It’s the easiest thing to do as well.
I have the same problem when I bought the adapter, I ordered another one from a different supplier for Fiat and it fitted fine. If you look at the prongs on the three pin adapter you will probably notice they are flatter and wider than they should be this was the problem I had with my three pin adapter.
Thanks all, finally got a new coil today and am now trying it in both sides to se what difference it makes, initially it still seems to have the lumpy running but seems better. Wonder if its the leads ? Re the conector, I think I have the same issue as 355 OXO Image Unavailable, Please Login Image Unavailable, Please Login
