In the previous posting I described my problem with my Mondial. I fixed one problem by replacing the relay that fuel injects on start up. I think my last problem is related to the fuel pump circuit. Here are the symptoms.... The car starts and idles rough before it quits. When it is running for a short time the Tach isn't working. I swapped out the fuel pump relay but that didn't fix the problem. Can anyone point me to a website or can explain to me how the fuel pump circuit works? I suspect there is a gremlin in the wiring, although the fuse box has been upgraded to the slotted type fuses. What are the conditions for the circuit to work? I suspect I still have another pump problem but don't know where to start trouble shooting. thanks bruce
To start with, I have NO Mondial information. But if one assumes it's fuel pump circuitry is akin to the other 308 injected cars... Once the key is turned to 'Start' - voltage from ignition switch 'Run' position energizes 'Start' relay coil so that 'Start' voltage passes through 'Start' relay contacts to energize the 'Fuel Pump' relay coil. It's contacts send voltage to the fuel pump. As soon as the engine kicks, sucking air, the 'Air Flow' switch opens and the 'Start' relay de-energizes, and it's contacts open so that 'Run' voltage now continues to energize the 'Fuel Pump' relay coil. Remember, key is still at 'Start'. Key is back to 'Run' with the engine is now running. The 'Start' relay is still de-energized by virtue of the air flow switch indicating that the engine is running. Once energized in this fashion, the 'Fuel Pump' relay will continue to stay energized providing the fuel pump with voltage until either the key is turned 'Off' or the air flow through the fuel distributor ceases. A full set of 3 drawings are in the wiring package. Start phase is shown below without fuses help understanding of an overly complicated circuit to simply turn the fuel pump on. Carbed cars don't have relays and don't really care. They have switches under the driver's seat which turn the pump off if the driver is thrown from the vehicle. __________________________ http://www.FerrariDiagrams.com Image Unavailable, Please Login
This may (does?) indicate that one bank of your ignition is not working -- so the first thing to do is confirm/deny if you have spark on both banks (e.g., with a timing light) during the poor running period. Since you only have one fuel pump, the fact that the engine does run at all indicates that it is less probable that you have a fuel pump problem IMO. If your 1985 is a US version, also confirm/deny if your Frequency Valve is vibrating/buzzing during the poor running period. It should always be vibrating/buzzing whenever the engine is running. Every Owner of a K-Jet with Lambda model should learn/know how to do this IMO -- it's very easy to do just by touching the FV with a finger while the engine is running, or by unplugging the safety switch and putting the key in the "on" position (when the engine isn't running) and touching the FV with a finger (this will also run the fuel pump so you can at least "listen" to confirm/deny if the fuel pump runs). Another clue that the problem lie in the electrics (the protection relay) running the FV would be if you have to give it a little throttle action to just keep it running.
You hit it right on the nail head. I did further troubleshooting this morning and one bank of cylinders are not firing. I got wet spark plugs out of it and my timing light did not strobe when I attached it to one of the plugs, nor did it strobe when I placed it on the cable feeding the distributor. The label in the door says it was built in 1984, and it is a US car because its got California smog stuff installed on it. Now if you could tell me where I can find the FV, protection relay and safety switch I would very much appreciate it. bruce
Thanks for the kind words, but I'm taller and not green Not a good sign for either the TDC flywheel sensor for that bank or for the Digiplex ignition ECU running that bank. One approach would be to swap the Digiplex ECUs and see if the problem moves to the other side or not -- if it does move = bad for that Digiplex ECU; if the problem doesn't move to the other bank, swap the TDC flywheel sensors -- if it does move = bad for that TDC sensor; if it still hasn't moved, must be something more subtle (lets hope we don't go there ). Here's a jpeg showing the TDC sensor locations: Image Unavailable, Please Login "year built" and "US model year" are two different things. You can determine your US model year by decoding your VIN at www.red-headed.com (although 1984 and 1985 US model year Mondial QV are virtually identical). None of these items can cause you to lose a bank of ignition, but glad to help (you can also search on those names for many prior threads). The FV is near the CIS airflow metering device and fuel distributor: Image Unavailable, Please Login Image Unavailable, Please Login The safety switch is mounted on the airflow metering device (push the wire strap "in" to release the connector): Image Unavailable, Please Login The protection relay is in the trunk near the Jetronic Injection ECU (item C in this 308 OM illustration): Image Unavailable, Please Login
My problem has been found. I swapped the digiplex connections and the problem did not go with it (thank goodness). I then disconnected and swapped the tdc's... I couldn't tell anything from that because the car wouldn't start. However when I swapped the connection back the CAR STARTED.... looks like my problem were some dirty tdc plugs. Guess I'll go clean them really good and spray the connectors with a coat of insulation protection. Thanks to all who helped. bruce
Glad that you got it sorted, but I wasn't clear enough in my description so if you have to do it again: For the Digiplexes, you can just swap the connectors -- the physical positions of the Digiplexes has no meaning. For the TDC sensors, you have to swap connectors and trade their physical positions too as this does have meaning to the system.
Thank you for the clarification.... Upon further inspection I found a wire that came out of the plug which tells me that it was the culprit that gave me the intermittent problems. You would think that if you were paying that much for a car back in 1984 they would have used a better method of connecting things especially in that area of the car. bruce
