Fuel Problem

[dave_clutterbuck]

After a most enjoyable Sunday at Stoneleigh, my Marlin with a 2.0ltr EFI engine ceased to function approx 1 mile from home due to fuel starvation. Today I have fitted a new Bosch 0580464070 fuel pump which looks the same as the old one I have removed. It happily pumps fuel directly out of the pump however when I turn the engine over fuel is not reaching the filter near the engine. I have checked for leaks and unable to find any. Any suggestions on what the problem maybe ?
Regards
Dave

[danny_nelson]

Re: Fuel Problem

Hi Dave,
Try it without the filter.

[dave_clutterbuck]

Re: Fuel Problem

Thanks Danny not tried without filter but have checked it, it is clear as I can blow through it OK.
Left it for an hour turned key fuel pumped out switched off and restarted pump but nothing kept trying but no fuel pumping out at all. It is baffling me at the moment may be something preventing fuel reaching pump from tank, another look on Friday or Saturday.
Regards
Dave

[keith_h]

Re: Fuel Problem

Try running without the petrol cap on - are you creating a vacuum in the tank?

[philcoyle]

Re: Fuel Problem

I don't know how familiar you are with the EFi wiring and the sequence of events regarding the ecu and fuel pump, a rough guide is this.
Turn on ignition, pump relay energises pump and the ECU runs pump for 1 or 2 seconds.
Crank engine, ignition module tells ECU the engine is turning.
ECU tells injectors which pair to open.
Return wiring from injectors to ECU relay energises relay, it is also connected to the pump relay which will also energise and fuel will flow.

The ECU relay and the pump relay are usually together and possibly yellow!
In the return wiring from the injectors to the ECU, there is a diode encased in a rubbery plastic thingy,(it is there to stop any electrical or magnetic signals bouncing back to the injectors) these tend to corrode and can give misleading problems, as in pump not working because there is no return signal from the injectors. Also if no signal from the ignition module.
Have you tried your old pump on a battery to see if it is duff.
There are a number of things which can give pump not working defects, so check each one carefully.
If it is the diode you can get them at Maplins for pennies
Good luck and try not to stress out
Phil

[dave_clutterbuck]

Re: Fuel Problem

Try running without the petrol cap on - are you creating a vacuum in the tank?

Thanks Keith tried late last night not the problem.
Regards
Dave

[dave_clutterbuck]

Re: Fuel Problem

I don't know how familiar you are with the EFi wiring and the sequence of events regarding the ecu and fuel pump, a rough guide is this.
Turn on ignition, pump relay energises pump and the ECU runs pump for 1 or 2 seconds.
Crank engine, ignition module tells ECU the engine is turning.
ECU tells injectors which pair to open.
Return wiring from injectors to ECU relay energises relay, it is also connected to the pump relay which will also energise and fuel will flow.

The ECU relay and the pump relay are usually together and possibly yellow!
In the return wiring from the injectors to the ECU, there is a diode encased in a rubbery plastic thingy,(it is there to stop any electrical or magnetic signals bouncing back to the injectors) these tend to corrode and can give misleading problems, as in pump not working because there is no return signal from the injectors. Also if no signal from the ignition module.
Have you tried your old pump on a battery to see if it is duff.
There are a number of things which can give pump not working defects, so check each one carefully.
If it is the diode you can get them at Maplins for pennies
Good luck and try not to stress out
Phil

Thanks Phil
Not too familar with EFi workings your advise with the Sierra Haynes manual I have just acquired looks like I will be haeding in the right direction to slove the problem. Battery on charge at present intending to set about it again on Saturday morning. I obtained a new pump as the old one was rather noisy on start up and also whilst running.
Regards
Dave

[philcoyle]

Re: Fuel Problem

Have you come across the "jiggle" test.
Get someone to crank up the engine while you dash about jiggling every connection and wire you can find and every switch and fitting on the engine you can find, Lambda, coolant sensor,etc.
Is it the SOHC or the DOHC.

[Dane_Rescueman]

Re: Fuel Problem

Check the plug to the AMM/AFM. As they said, the pump runs for ~ 2s on initial switch on. The EEC IV waits for an airflow signal from the AMM during cranking to re-energise the HP Pump relay. This plug could theoratically have become loose.

[Mike]

Re: Fuel Problem

I don't know how familiar you are with the EFi wiring and the sequence of events regarding the ecu and fuel pump, a rough guide is this.
Turn on ignition, pump relay energises pump and the ECU runs pump for 1 or 2 seconds.
Crank engine, ignition module tells ECU the engine is turning.
ECU tells injectors which pair to open.
Return wiring from injectors to ECU relay energises relay, it is also connected to the pump relay which will also energise and fuel will flow.

The ECU relay and the pump relay are usually together and possibly yellow!
In the return wiring from the injectors to the ECU, there is a diode encased in a rubbery plastic thingy,(it is there to stop any electrical or magnetic signals bouncing back to the injectors) these tend to corrode and can give misleading problems, as in pump not working because there is no return signal from the injectors. Also if no signal from the ignition module.
Have you tried your old pump on a battery to see if it is duff.
There are a number of things which can give pump not working defects, so check each one carefully.
If it is the diode you can get them at Maplins for pennies
Good luck and try not to stress out
Phil

Phil

This is a revelationary piece of information!

There are three of us builders at the moment building BMW powered Cabrio/Sportster's and we have been discussing/debating the electrical circuitry for the HP pump. Looking at the circuit diagrams it shows the ECU using a transistor to trigger an earth to a relay for the HP pump.
When we tested the earth with the engine not running, there was no earth - so we concluded there was perhaps a problem with our ECUs. However, when the ECU was wired up correctly the HP pump appears to work. We could not understand why

From your information above, and I am now making an assumption (which is always dangerous!) that the BMW ECU works in a similar manner, then I can now understand how, and why our ECU's test as though there is a fault, yet work in practice.

Thank you for solving a little mystery!
Unless you are going to tell me the BMW ECU is completely different of course?!

Mike

[philcoyle]

Re: Fuel Problem

Hi Mike
I am going from my own experience with my EFi ford powered roadster.
Ford and Bosch got together at the very start of fuel injection, and I would imagine that the basics are the same.
The transistor you mentioned may be a diode, the diode being oneway only will stop any magnetic spike from the relay going back to the ECU, they don't like it up'em.

[Mike]

Re: Fuel Problem

Hi Mike
I am going from my own experience with my EFi ford powered roadster.
Ford and Bosch got together at the very start of fuel injection, and I would imagine that the basics are the same.
The transistor you mentioned may be a diode, the diode being oneway only will stop any magnetic spike from the relay going back to the ECU, they don't like it up'em.

Hi Phil

It is definitely a transistor, but we do not know what triggers it? Your description of the workings of the Ford unit do sound logical for the BMW variant. Once I get my new diff put in, and can refuel my tank I'll have an experiment and see if it does indeed mimic what you have descrided.
Thanks again for the insight.
Mike

[dave_clutterbuck]

Re: Fuel Problem

Thanks very much for all the advice looks like I have got it sorted tried new pump direct to fuel can pumps perfect reconnected to fuel tank no fuel pumping through.
By my calculations the tank could not be empty fuel guage rather hit & miss, anyway put another 10 ltr in again nothing. Decided to take fuel sender out to look in tank found to have plenty of petrol in, but also some black rubbery lumps these apppear to what the people who repaired the tank two months ago used to seal the sender assembly. I imagine some of this rubbery stuff is blocking the pipe that goes to the pump. Tank out again and a thorough clean out and some petrol resistant sealant for the sender assembly looks like the solution.
Regards
Dave

[philcoyle]

Re: Fuel Problem

David
Do you have an in-tank filter on the pickup pipe, looks like a flat nylon teabag and will clog pretty quickly with anything gloopy

Phil

[dave_clutterbuck]

Re: Fuel Problem

Hi Phil
It appears I do not have an in tank filter steel pipe goes to a pot at the bottom of the tank. Whilst siphoning the tank I thought I would try and start it must have disturbed something as it fired up first time. Taking the tank back to company that welded it and put the seemingly poor quality sealant on the sender fittings to give it a thorough clean without incurring any cost. Hopefully back up and running by the weekend.
Regards
Dave