3.9 efi starting problem need help

Hi everyone my 3.9efi cut out when driving and now intermittently when turning on the ignition the fuel pump runs but doesn't stop priming other times there is nothing I have run a feed to the pump and it runs and I get pressure to the rail but still won't start in completely lost

Andyslandys2017 said:

Hi everyone my 3.9efi cut out when driving and now intermittently when turning on the ignition the fuel pump runs but doesn't stop priming other times there is nothing I have run a feed to the pump and it runs and I get pressure to the rail but still won't start in completely lost

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if fuel pump doesnt cut out after 4 secs with just ignition on it would sound like an ecu issue

jamesmartin said:

if fuel pump doesnt cut out after 4 secs with just ignition on it would sound like an ecu issue

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Would that cause it not to pump intermittently and not start cheers

Andyslandys2017 said:

Would that cause it not to pump intermittently and not start cheers

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ecu controls the pump to run for 4 secs then cut out,until a cranking signal is recieved from the coil and pump is run again, if the ecu is doing that its likely not funtioning properly in several ways

I

jamesmartin said:

ecu controls the pump to run for 4 secs then cut out,until a cranking signal is recieved from the coil and pump is run again, if the ecu is doing that its likely not funtioning properly in several ways

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Is there a way of testing this at the ecu like a bypass of a pin or repairing the ecu

Andyslandys2017 said:

I

Is there a way of testing this at the ecu like a bypass of a pin or repairing the ecu

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id try a landy breakers foe another ecu

OK how hard are ecu chips to swap as mine has the tornado chip set.

Also my fuel pump relay clicks every time even when fuel pump doesnt

Andyslandys2017 said:

OK how hard are ecu chips to swap as mine has the tornado chip set.

Also my fuel pump relay clicks every time even when fuel pump doesnt

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ive no idea
for the second your saying relay works but pump doesnt , are you sure pump relay is clicking and not the ecu relay, if it is you ned to check wiring including earths etc from it to pump and the pump

Iv felt each relay and it clicks every time but fuel pump only runs intermittently and when does just keeps running but still no start

Andyslandys2017 said:

Iv felt each relay and it clicks every time but fuel pump only runs intermittently and when does just keeps running but still no start

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swap the relay

I'm a bit late to this one but had similar problems with mine at the weekend. Like James says, pull both the fuel pump and efi relays, maybe clean the pins while they are out. Swap the relays around. Also, and assuming this is an RRC pop the fuel pump cover off in the boot, pull the connectors on the pump and clean them up, also, carefully pull the earth connection, clean and reconnect, then dive in to the rear near side wheel well, look for an earth on the chassis and a connector, these feed the pump, pull the connections and clean then remake. I know that is all a bit of messing about but it will hopefully ensure all the connections are sound, if the problem persists then you will need to either try a substitute ecu or put a code reader on it.