Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Omnitec dash control module etc - 2011 Plus 4

Yes, as you say the Omex needs a minimum cranking speed to recognise that the engine is starting and set things in motion.

Although, with the Omex setup , you should hear the fuel pump run for about 2 seconds when you initially turn the ignition on.

If you don't, that's where to start looking.

Lowflyer, are you the chap I was talking to in Hemsley last week?

David Byrne (green +8)

Indeed David, plus 4 in intensive care just but rear of dash wiring beginning to look better

Yes Bob, I'm on the case again, I've had the starter motor off and tested, its fine and if i take a live 12v+ to the solenoid coil it pulls in and cranks the engine over. If I turn the key to start, the starter relay clatters in and out and i dont get the 2 second pump run, the pump does run if i pull the relay and link the contact terminals (85 & 86 i think). I'm now suspecting that I'm missing a supply to ECU somewhere which is not allowing the fuel pump relay to pull in which (and I'm now guessing) allows a bit of logic in the ECU to engage the start relay.....after my rewiring exercise.
Everything else that I identified as being controlled from the Omnitec seems to be working ok; heated screen, heater blower which was just "through wired" anyway, rear fog light, and my 2 Cibie LED driving lamps which I'd originally wired via the spare relay and switch on the Omnitec (1.2 Amps each), oh and the new "conventional
Indicator/hazard warning lights system.
Regarding the warning/status lights, I've got the following working; the indicator tell tales, the lights on status, the handbrake/brake fluid level, the high beam, the rear fog light.
Just need to get the alternator/battery status and the engine light functioning. I was going to separate the hand brake and brake fluid on to separate lights but second thoughts had me reckoning that operation of the hand brake gave a partial verification of the brake fluid alarm, it offered easy confirmation that the light was ok!
The Omnitec dash control module, black box, is still intact and is next for decommissioning...I hope.
The Caerbont "mystery box is still plugged in and I don't intend at this stage to decommissioning that as it appears to be the interface for the field sensors to the gauges, don't think it has any control function, I hope not, we'll see.

Hi Richard it was the wiring info I was after, I've got Durite diode type relays. I have checked the operation of the piggybacked solenoid and all is ok when i energize it by linking the main motor +'ve to the solenoid terminal +'ve. Problem is when i operate from the key, the starter relay just clatters in and out. As mentioned above I think I might have "mislaid" an ECU 12v feed or wiring harness connection.......tomorrow is another day🤐

Sounds like something in the start chain is not latching. Not sure if this 3.7 Roadster start system schematic helps although it may if your car had the option of start button to trigger start sequence, part of auto stop/start on other applications.



Note the BCU is not involved with key start. Also the PCM (ECU) controls both legs of start relay coil.

Lowflier, it was nice to meet you, it is always good to put a name to a face. I live just down the road in York if you ever require a spare pair of hands.

David Byrne

Thanks David, ditto, I've promissed myself there be less oily hands, at 73 its time I did less underneath the cars and a little more on the road whilst faculties are with me🤐

One thing I'm a little unclear on Bob, I think that the Omex ECU switches the fuel pump relay on the -ve side of the fuel pump relay, I.e. what Omex call the fuel pump control output in the terminal 5b actually goes to earth in order to energize the fuel pump relay.....and thus upon powering up via the ignition switch a bit of timer logic in the ECU puts that output to earth for 2 secs to run the pump in order to pressurized the fuel rail, then, upon further operation of the starte/ignition switch cranks the engine and it fires up which , I guess initiates a permanent earth to terminal 5b ( "permanent" whilst the engine is running!)......sorry...thjs verbiage is for my benefit, I'm thinking aloud, time I was holding a cheap Chateaunuef du Pape instead of this tablet!

A cheap Chateauneuf du Pape