got a slight problem with the fuel pump which i think is ecu related, im hoping someone on here knows the answer or has had the same problem before?

when turning the key once theres no prime, turn again no prime, then on cranking the fuel pump runs, then when started it runs continuously

i put a light on the fuel pump feed wire from the ecu and it doesnt light up on 1st or second turn of the key so theres no feed from the ecu to tell the fuel pump to prime, is this a nackered ecu or a sensor possibly causing a problem?

cheers nick

 

Hi mate been a while since i rewired one of these, the fuel pump im sure gets its feed from the dizzy for the pump onces its turning over/running, the prime like you say comes from the ECU from a trigger wire, you need to see if you have the trigger wire at fault from the ECU (chase it from the relay) or a fault with the relay itself mate hope that helps you.

 

It won't illuminate seen as there is no supply!

Pin 28 is the ground for the relay, input from the CPS is required for the pump to prime, in addition, the duration of the prime can vary with temperature.

It has nothing to do with the phase sensor, this as the name suggests gives information on the 'phasing' of cylinders, used for SFI.

I am guessing it has not always done this?

Martin

 

its a new build mate, so first time its all been wired in and having problems, new fuel pump loom, standard ecu, new ahmed bayjoo engine loom, all sensors new except map sensor and yet im having problems, wiring is a massive headache for me!!! dont understand it atall

 

Most people do not realise that the fuel pump relay switches the earth connection, not the live.

 

I thought the CPS would only affect a pump once cranking. On ignition it should still prime?

 

Check the fuel pressure as we had this on my mates saph cos a few months back and he said the fuel pump won't prime but the thing was it had primed and was up to pressure and holding it so it wouldn't prime anymore. When he cranked the engine over then the pump started running. Turned out the be the immobiliser playing up :-(

 

Just done mine on Friday......

Pin 87 off the fuel pump relay feeds the pump. Run a cable direct to the pump from here if you don't have continuity.

Double check the fuel pump cut off switch as I was on 2 hours re checking all wiring as my pump wouldn't prime and the switch was up

Saph is in the spare wheel bowl and I think the 3dr is in the kick panel

 

No, it needs CPS input to prime, period.

It will prime regardless of the pressure.

3DR does not have a cut out, 2WD is in the wheel well and 4x4 is behind the kick trim

Martin

 

Everyone I've worked on and owned once it gets to a certain pressure the pump just sort of clicks as it's up to pressure enough to start it. Just had this on my mates saph that wouldn't start and he thought it was the fuel pump but wasn't as it had already primed and wouldn't run anymore untill it started.

 

The ECU has no conception of the FP, so what you are saying is impossible!

The duration of the prime can vary with temperature, none the less it will always prime.

Martin

 

I didn't say anything about the ECu? If the fuel systems up to pressure it isn't gonna pressurise it any more is it? Yes the fuel pump still "clicks" but obviously it is up to pressure so won't do a prolonged prime which is what people are listening out for. I'm not gonna play word games u know what I mean by saying it clicks it is trying to prime but only a split second, people listen out for a prolonged buzzing which they won't get if it's up to starting pressure. That's the confusion

 

You didn't and neither did I, you said if it's "up to pressure it won't prime", which is incorrect, as the pressure is irrelevant, like I said.

Martin

 

There we are ECU in your quote. I can play word games too!

 

To be fair everyone knows what I meant, people listen out for a prolonged buzzing prime I meant

 

Mines 4x4 and in wheel bowl

Did someone mention ECU ?

As above ecu has nothing to do with fuel pump......

 

Yours is an early 4x4 (YBJ)?

The ECU does actuate the fuel pump.

WRONG, which is what I was referring to, the pressure makes NO difference to the prime duration, (I think I have mentioned this ) so no nobody understood, as it's duff information!

Yes as I was (trying) to educate you on your bad post, but you clearly don't understand!

Martin

 

I'm not very good at writing etc and just trying to help people, I know what I meant and obviously didn't write it properly so sorry to the guy who owns the car don't listen to me I don't write things down well to what I actually mean. I just meant people I've come accross expect when the fuel pump primes for there to be a prolonged buzzing like the old xr3is did, cossies I've found tend to just make a little 'click' or 'thud' noise when they prime and people don't hear it. That's what I've come accross with a few of my customers and mates anyway. Just trying to help, thanks.

 

I appreciate that and it wasn't a criticism (as you seemed to have took it) I was merely correcting your post, the very reason we are here is because we are enthusiasts and eager to learn, as well as share our own knowledge.

FYI, in the case of the Cosworth (and probably others), the pump duration can vary with engine temperature, this is logical because a cold engine is going to need a longer duration, that one that is at running temperature

Martin

 

Thanks for all the replies, sorry I haven't replied to the thread sooner, hopefully this weekend I'll find this gremlin, I plan on taking the fuel pump loom out as it's a new one from ebay and doing some checks to see if relays etc are working, and then checking if the wire that connects to the ecu fuel pump feed on the fuel pump loom is running a permanent live or negative as I think it may be wired incorrectly, failing that I can only see it being an ecu fault, as the engine loom was newly made by Ahmed bayjoo and all labelled and I've double checked and that's all connected up and working fine as the Amal valve clicks as should

 

The ECU is working correctly, by the fact the Amal works (pin 28, switches the ground, if the polarity was wrong, it would cause a short or possible damage)!

Martin