Cold Start Issue - M2.7 (1995) - SURVEY

Just to let others know this would not work in the F1 1999 model due to a ghost signal keeping the starter running

 

It can work if you use a more robust relay (motorcycle starter relays work great). The reason why the starter motor continues running even after you have released the key is the car's so called relief relay - the relay that disables the heater blower motor and perhaps some other things during cranking (to unload the battery). The coil of the inserted new relay for the starter solenoid remains in series with the coil of the relief relay when you release the key so the starter relay continues to have 6V on its coil (12V divided by two relays, each having about 85 Ohm coil resistance). If you use a standard cube relay, 6V on its coil is enough to still hold it in "on" position. A motorcycle starter relay will not be affected because it is not so sensitive and will de-energise since its coil is typically about 10 Ohm and needs a lot more current to stay "on" than what it gets through the coil of the relief relay.

 

How does turning the key on for 30 sec help? I thought the fuel pump does not come on until the engine cranks. Safety issue I think. Do you hear the pumps coming on when the key is on? Did the rewire the pump relays so they turn on with just the key on?

 

I actually tried a heavy equipment relay that was way more resistance but cannot remeber hiw much more. Then I just bought a new starter since mine was 20 years old.

When I get time I will post it. It was way more but I would be guessing as to the amount. I thought it was like 10 plus times.

 

No, I would rather punch my car in the face than wait 30 seconds to start it after turning the key on

 

You should use a relay with lower coil resistance (10-15 Ohm), not higher, to prevent the starter motor engaging as soon as you turn the ignition "on" or not disengaging after you have released the key from the "start" position. On the other hand, according to the wiring diagram posted here by one of the members, it appears that F1 cars already have a starter relay (see attached document).
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On my 2.7 348, the fuel pumps do not run with the ignition "on". It is possible that, if you wait for 30 sec or so, the ECU has more time to get "better prepared" to start and run the engine.

I am saying this because I had a very difficult start problem on my recently purchased 1999 Jaguar XJ8 - it would take 4-5 cranks, sometimes even more, hot or cold. Then, I discovered that if I keep the key in the "on" position for about 40 sec, it would start immediately every time. After further checking, I found out that the camshaft position sensor had been completely disconnected (its plastic "head" broken off). I then found out that the XJ8 engine can start and run without the cam position sensor as the ECU will, upon realising that there is no signal from the cam sensor, switch to the crankshaft sensor signal and calculate the camshaft position from there. But, obviously, to do the switching, the ECU needs a bit of time (it probably re-tries with the cam sensor a few times before going to the crank sensor).

I am not trying to say that a 348 or 355 which starts better after a 30 sec. wait has a problem somewhere, just that it seems that the ECU goes around all the sensors/inputs when the key is in the ignition "on" position and that maybe the more time you give it the better prepared it gets.

 

As an OCD 95 F355 owner I can happily report my car starts the first time every time if it sits one day or one month. Problem solved....