I had this type of problem mixed between my 355 and my 348 i sold. My 348 had oil leak on the camshaft and the crank sensor was dirty because of this oil leak. Car work well at high revs only. On my 355 I had this problem too but it was due to 2 bad plug wire, that you could test to see if they are cut inside. (remove them and test the ohm resistor). you should find, here there are so many friends ready to help you. Hello Ernie and Nodoubt ! my 355 work well with your help !
Am I right in thinking if the crank sensors or cam sensor have failed it will missfire possibly causing fuel to be unburnt and hence the running rich smell. I changed the O2 sensors and it doesn't seam to be running as rich, but this is purely looking at the tail pipes and smelling the exhaust. Quote: Is his 348 running properly when cold? no, probably only running on 3 cylinders but doesn't improve when warm (faulty temp sensor??), Missfire is less when the revs increase to about 2000rpm and then pulls well over 4000rpm. Can't wait to get back in the garage (With Candellera's help ), moving house last weekend means I have a garage full of boxes which will needs sorting before I can get the car in. Busy weekend ahead !!
Duncan - i think this is where we go next. IMO prob is def fuel related and Idle air bypasses figure out as problem isn't occurring in excess of 2500 rpm
OK, after much thought............... Every 348 i've ever heard that's started from cold.........the Idle Control Valves kick in and provide a harmonic noise for about 5 mins until the car warms up enough. With two ICV's.......logic dictates not both would fail? On Duncans 2.5 Motronic 348 - the ICV's do not provide this harmonic resonance and maybe not operating? This would surely cause rough idling and misfiring at idle through to approx 2300 rpm? What is the function of the ICV's? What "switches" them on? and what are the symtoms of non functioning ICV's? Your opinions gladly welcomed Jason
ND, Yes mine does....but we think this might be the problem causing the mis-fire with LittleBlackFlashes 348. What switch activates the Idle Control Valves? as we don't think his are working
I don't know, sorry. I'd guess one of the water temp sensors, but you'd have to look at the schematic to be certain. Can you hot wire in 12v to one to see if it activates?
348's with the 2.5 Motronic system do not have exhaust manifold air injection, so they do not make the "gulping" noise during warm-up.
Oh for the love of pete! Will you good and check the doggon cam & crank sensors already! GO CHECK THE SENSORS!
I red many pages here about 355 crank sensor an this one could help you: CAS = crank angle sensor (position) -------------------------------------------------------------------------------- Found a broken part: Who is guilty? A cable to the CAS = crank angle sensor (position). We bypassed the rotten wire and the engine revs like cream now. These wire parts are really too weak in design, especially for this hot environment. I'm quite sure, the 355s are prone to fail this way. Test drive will be tomorrow to check the + 6.500 revs. Might be useful for the next 355 driver with a similar issue to check signals at pin 47 and 48: 47 CAS return: t2 cranking/running 0.25 max 48 CAS signal: t1 cranking: AC 4.0v+ (peak to peak) idle: AC 8.0v+ (peak to peak) cruise: AC 14.0v+ (peak to peak) Mille Grazie for all your input & mental support so far! Hopefully this italian electro-gremlin won't come back. (and no other error confusing the 355 engine) cinque http://ferrarichat.com/forum/showthread.php?t=105645&highlight=355+sensor+wire
Finally ! I've managed to get the car into the garage after moving house and found some time to start checking everything to cure this missfire.. I've managed to get a wiring diagram for the engine loom so I've started with the 5-8 bank pinning out connections on ECU connector. So far everything seams ok except the main earth for the engine was poor. This was traced down to the quick release conection between the battery and the engine (rear mounted battery). Not started it since because I had the ECU disconnected, could it be as simple as that? I tried reading the CAS because I feel these are most likely. I stupidly measured the resistance of the sensor and not the voltage. I measure 0.5kohms at rest and 0.53Kohms when cranking. Obviously it wont fire up because the ECU's are not connected. I'll have a go at measure the voltage tonight Does anyone have an engine wiring diagram that shows the lambda sensors and cat thermocouple wiring? Cheers Duncan
Hi Littleblackflash, Your symthoms are very similar to what happend to my 355 and just to give a warning, mine caught fire (re my post at 355 forum - my 355 caught fire). I havnt found the cause of it as yet but will surely keep you posted on it. Just be careful. cheers Peng
did you check if your crank sensor are clened or not ? Because cam seal leaking could put oil on the crank sensor and make it work bad. You only have to go under the car and remove the grill. I would love to read that you have found , I know how bad you can feel when the car is not working well even if you spent hours on it. For the lambda sensor i know you must hae oscilating voltage on it, it mustnt be same alle the time. The thermocouple you can test it unpluging the sensor from it, it must light on on dasboard "slow down" You can remove the sensor too ans connect the 2 his wires of the ecu both.
Thanks for the diagrams. I already have them but they don't show the lambda sensors or cat ecu's I'm hoping this weekend the weather will be nice and i can get in the garage (avoid chrimbo shopping). Will deffo check the crank sensors as a priority. Is their an easy was to tell which bank is missfiring? (Without pulling plug leads), that way I could swap over parts left to right. I'm concerned on it catching fire!! I had to replace the LH exhaust manifold about 100miles ago because it cracked and caught the fibreglass on fire. Can I assume the problem is with the LH bank?
good luck ! one thing you can do to know witch bank work bad is remove the bolts on manifolds to test CO/co2 culinder by cylinder.There are 2 bolt on the top and 2 bolts under. Or test the co/co2 at the end of the cat... klet us know what you found.
Did a few tests today but it's cold out (-2degC) From the CPS I am getting 1.5v and 1.2v AC when cranking. Not been able to test it when the engine's running because it didn't start. There is one relay in the foot well for each bank that controls the air idle valves, O2 heaters and fuel pumps. This relay is activated by each ECU. Problem is when cranking the engine these relays are not activating, hence the fuel pumps not working. Evenchally flattened the battery. Question is? What triggers the ECU to say to the this relay turn on? I guess it's the CPS. Is 1.5v enough or is this too low? Will continue the investigation tomorrow when the battery is charged.
Well its a little warmer outside so did some more work on the car. I removed the undersheild to get to the Crank position sensors only to find they look as clean as they did when I changed the cam belt. So I started to check the wiring to them but found no problems. The readings I get from the sensors is the same as I read at the ECU's. ie.. 4.4v Bank 1-4 but only 1.5v bank 5-8. So I guessed one CPS is faulty so I removed it. The face of the sensor looks dented but looks dented from the inside outwards. I was unable to get a replacement from my local autofactors until next Friday, luckily its a standard Bosch part. The sensors are shimmed away from the crank so that the gap is fixed. I removed the shims so the sensor fits closer to the crank pulley and I then had 2.6v (1.1v higher). I can't remove any more shims so I'll just wait for the new sensor. But......... Car still won't start. In fact it won't fire at all. ECU's are now telling the Fuel pumps etc to turn on but it only spluttered on one cylinder a few times in 5mins of cranking. With Candellera's help we think it's the TOAD alarm imobiliser playing up again. So I now have the dash out so I can get to the alarm wiring but I haven't found the circuits it imobilises yet. I'm hoping to just bypass the imobiliser. If anyone has a wiring diagram for a TOAD Ai 606 Car Alarm?
Still can't get the car started. Imobilizer is disconnected. Engine turns over ok Good Spark Good Battery Voltage, Correct Power going to ECU's Any ideas. I'm now guessing a fuel related problem. Fuel pumps are working I think, I can hear them making a noise.
1) Check to make sure you have fuel in the tank 2) Disconnect the catalytic converter ecu's 3) Check the connection going to the wiring harness for the fuel injectors 4) Recheck all your ground/earth wires 5) Check the fuses and relays
Back to basics. Had Spark No fuel coming out the fuel rail when cranking Fuel relay is clicking in after I found a dry joint, but the fuel pumps still didn't go. For some reason my car has been modified to have two pumps feeding one filter and one fuel regulator. Thus both pumps were not getting power. I put 12v directly to the back of the fuse box and the pumps worked. So it was just another case of finding the poor joint and fixing it. Imobiliser connected again and hey presto, it's working. So now I need to order a CPS so I can start to cure the misfire. Thanks for everyones help so far, especially Candellera who been helping me. Merry Christmas
Why in the world would your car be modified to have two fuel pumps (as standard) running through one filter and one pressure regulator? Do you have the parts necessary to return it to stock? I'm interested in your comment that you had no fuel pressure in the fuel rail when cranking. If the pressure regulator(s) are working correctly, there should be residual pressure retained in the fuel rail after the engine is shut down, for an indefinite period of time, so that the engine should be able to start up again right away without first building up the pressure again. Then, when you are cranking the engine over on the starter, the fuel pump relays do not engage until the engine speed reaches 30rpm. I don't know what the average cranking speed of the engine might be, but 30rpm is one revolution every two seconds, which should be easy to obtain with a properly charged battery. Just don't expect the fuel pump to engage when you turn the key on - the engine HAS to be cranking over. Now - in order for the ECU to read that the engine is turning at 30rpm, it has to be getting a signal from the engine rev sensors (the crankshaft sensors). If you have one or more defective sensors, then that might be your problem all along. And it seems that you have been changing the positions of your sensors by removing shims. Are you aware that there is a diagram in the workshop manual showing the setup clearance for the sensors (figure 4, page C7)? The gap is shown as 0.35 - 0.90 (this must be mm, not inches). If that gap is wrong, you will have a problem with the inductive readings of the sensors. If you are removing shims, you are increasing the air gap between the sensors and the toothed wheel on the crankshaft. Remember also, it isn't JUST the sensors themselves that can be bad, it can be the fragile wiring going to them. Check very carefully for loose pins and frayed or broken wires under the boots. Also, I wonder if having two fuel pumps running through one fuel pressure regulator is causing a problem? You may have too much pressure in the fuel rails, which are supposed to be individually regulated. Since the injectors have their opening time duration regulated by the Motronic ECU, then if the pressure is increased, while the opening time stays the same, then you get too much fuel injected into the cylinder on each cycle, and you are constantly running too rich. Good luck, don't worry about it on Christmas.
Thanks Miltonian No idea why it has been changed, but the car was converted for to a race car for one season in the italian cup here in the UK. The fuel pumps, FPR and cams/followers are the only non standard things that I can find. (apart from the uprated brakes, roll cage etc.) Don't think the fuel system should make much difference. The engine is still being supplied by 2 pumps and the fuel pressure regulator is adjustable and set a 2bar, so the injectors still see the same pressure and flow. It was working fine so I think as long as it does I'll keep it. I don't have the original parts but it's only a few pipes and 2new FPR so maybe one day I'll convert it. I'm hoping to get some std cams for when I next do the cam belt change due in 18 months. The cams have an extra 30deg of opening and higher lift, hence the air going into the engine should be more. A higher fuel pressure would help to get the fueling right. On the rolling road the fueling was good, gave stoichometric value of 0.95 which is good for performance, not so good for fuel ecconomy. oh and 340bhp which is about the limit for std injectors. Just to confirm, the fuel rail did hold a pressure as expected when I undid the pipe. The cranking speed is about 150 - 200 rpm so the relays both clicked in within 1/2 a crank (difficult to say but it's almost instant). The problem was the fuel pumps didn't start even though the relays were active. I've got it running by replacing a connector with a tempory wire with crocodile clips on. Over the next few days I'll replace this with some new connectors. Even so, I still need a new crank sensor because its reading the speed lower than the real speed. Removing the shims moves the sensor closer to the pully and hence reads higher. I've not measure the gap, I just did it to see if I could get it running better. Nothing to loose. When I put the new one in I'll set the gap correctly. Until I do this I don't think I'll mess with anything else. Many thanks for the help. Have a good Christmas
