Hi All A buddy of mine has a 1990 348 (euro spec) which has recently developed a problem. The car loses power for no apparent reason and runs on less than its full complement of cylinders. To make matters worse the problem is intermittent and does not seem to be related to engine temperature or anything else for that matter..... The engine sensors and fuel pumps have been checked out and are fine. The car is currently at the local agent and he has advised that the problem is going to be difficult to trace. If anyone knows of a similar problem please advise as to where the guys should be looking? Many thanks Ken
Could be one of the engine ECU's, also check connections #62 in picture. Is the car a "cat" car? Image Unavailable, Please Login
Hi Malcolm Thanks for your post. It's not a cat car. Guess the ECU's would be a worst-case scenario? What do they cost? :-( Thanks Ken
Ken, if the problem can be diagnosed to one bank, swap the ecu's over an see if the fault moves with the ecu. Cost of an ecu is £860.00 plus shipping, so I hope for your sake it's something simple.
Thanks Malcolm Hopefully that's not the problem - could it be anything minor - ie related to Italian electrics? I had an issue with relays on a Lancia Integrale of similar vintage some years back. Re-crimping the spade connectors sorted it out fine... Cheers
Stuff like this can be difficult to trace, but I just go back to troubleshooting 101. You first isolate the area; sounds electrical but be sure it's not fuel delivery, etc. It's easier than you think to be "sure" the problem is in one area but it's really something else. Once you isolate it IS electrical, you start at one end and test each component in the line. For a 348 this may be difficult and expensive! But thrashing around randomly will likely take more time and money than a systematic approach. I would get a Ferrari mechanic who knows 348's unless you really are familliar with how these cars work. Ken
Ken, The exhaust ECUs can be erroneously measuring a temperature that is too high, and that could cut out engine power. That scenario, however, should send a "Slow-Down" light on the dashboard. Are you sure the exhaust ECUs are fine? On these cars, loss-of-power problems arise 99% of the time because of faulty sensors--the sensors turn out to be either defective or poorly connected (i.e., not properly connected or dirty).
Thanks Dave - unless I miss my guess the agents would have attended to the connection issue. Evidently there are some funnies related to the ECU. The agent will check again tomorrow. Cheers
When you say the sensors have been checked does this include the crank speed sensors. These are located just underneath and to the side of the crank pulley. These connections do go faulty/short out and will cause a bank to drop out - regardless of engine hot or cold. Their failure will prevent the ignition being fired. John
Thanks John Sounds like it's worth a look. At this stage we have dirty contacts, crank speed sensors, coils and ECU's - in order of piggy-bank breaking potential. Will follow up with the agent and revert. Cheers Ken
Hi Mike The car in question does not have a cat - unless I am wrong this would mean that there is no oxygen sensor?? Cheers Ken
Will still have O2 sensors since they feed back to the ECU's to adjust the air-fuel ratio. Cheers Kevin
That's true on a US-version 348 that has had its cats replaced with test pipes, but the standard (Euro) version 348 OM 595/90 shows there are 348 variants with a Motronic 2.5 injection system with no O2 sensors (but it's still got plenty to go wrong with each bank having separate ECUs and ignition modules).
Could be a faulty fuel pump, or faulty connection to the fuel pump. Remember, there's a fuel pump serving each cylinder bank (2 total).
Interesting question. If this is a European car, then the Motronics do not have the self-diagnosis function activated. If the car came without catalysts, then it doesn't have the famous exhaust temp ECU's, right? In post #4, I believe item #62 isn't an electrical connection, it's the rubber grommet where the wiring bundle for the Motronic ECU passes through the firewall. I would be inclined to believe the other suggestions posted here, that the problem is a faulty pin connector or a crank sensor. I'll be interested to hear what you find!
Hi All Thanks for all the advice - the car is apparently sorted out. Evidently my buddy had installed a piggyback computer - this has been disconnected and now everything works. The piggyback computer is not supposed to create issues - has anyone experienced this with 348's?? Will update the thread if anything further transpires. Cheers Ken
