Fuel pump not priming how to bypass immobilizer?
Discussion
Cars not had a Mot of a while, booked a mot then went to start it the other week and had a small fuel leek so had to cancel it. Jacked up and fuel hoses changed along with a few other jobs. All back together for mot toady and now cant get the pump to prime.
Have swapped the ECU and fuel pump relays, also got a new one to try. Still not working. Applied power directly to the fuel pump and it works.
So have taken the top of the dash off to look at bypassing the immobilizer, but could do with a hint, if some one could PM me some hits I would be very thankful.
Have swapped the ECU and fuel pump relays, also got a new one to try. Still not working. Applied power directly to the fuel pump and it works.
So have taken the top of the dash off to look at bypassing the immobilizer, but could do with a hint, if some one could PM me some hits I would be very thankful.
I was still hoping to make the Mot today but think that’s out the window now :-(
Thanks for the suggestion, I have looked at the inertia switch and seems to be ok, nothing is sticking out.
Was hoping the immobilizer would be a quick thing to disable, but guess that goes against the point of the thing.
Just really want to get it going, can look at making it right later on.
Thanks for the suggestion, I have looked at the inertia switch and seems to be ok, nothing is sticking out.
Was hoping the immobilizer would be a quick thing to disable, but guess that goes against the point of the thing.
Just really want to get it going, can look at making it right later on.
well after lots of poking about, taking the dash off looking at the immobiliser and alarm checking all fuses and relays, putting 12v on the pump and hearing a sound. Multi meter on the terminals showing no 12v. i retraced all my steps and took more time to go over everything as i was rushing a bit before for to try for the MOT.
although the pump was making a sound when external power was applied it turns out it was not pumping.
when attached to the car and power coming from the terminals very low voltage of 1v at the terminals of the pump. Once i disconnected the wires from the pump 12v were present.
guess the pump was taking to much amps for the car wiring to even get it to make a noise. removed the pump and tried bench testing it with a 12v power supply, although it made a sound no pumping! so new pump ordered and fitted, car is now back to normal. nothing was wrong with the immobiliser.
was quite a leaning experience, got a lot better idea of the electrical system now! and first time to remove the dash and radio.
Nice new pump now with screw terminals instead of the spade connectors fitted, proper boots covering the terminals that i have packed with silicon grease should be a good improvement on what was before. also replaced the suppressor capacitor as the wire on the old one broke when removing. Hopefully get a MOT booked this week.
although the pump was making a sound when external power was applied it turns out it was not pumping.
when attached to the car and power coming from the terminals very low voltage of 1v at the terminals of the pump. Once i disconnected the wires from the pump 12v were present.
guess the pump was taking to much amps for the car wiring to even get it to make a noise. removed the pump and tried bench testing it with a 12v power supply, although it made a sound no pumping! so new pump ordered and fitted, car is now back to normal. nothing was wrong with the immobiliser.
was quite a leaning experience, got a lot better idea of the electrical system now! and first time to remove the dash and radio.
Nice new pump now with screw terminals instead of the spade connectors fitted, proper boots covering the terminals that i have packed with silicon grease should be a good improvement on what was before. also replaced the suppressor capacitor as the wire on the old one broke when removing. Hopefully get a MOT booked this week.
Thats an interesting point, I have had a starting problem which is still unresolved, I connected a 12v battery to the pump (still connected and under the car) and it did whine as in priming, but still no start, how did you find out it wasnt pumping fuel when you actually had the pump off and on your bench to test,,,
I was told if its pumping there will be fuel at the fuel rail, well in my case there was but is it possible that there was/will be some fuel sitting it the fuel rail that would give the impression that the pump is pumping,,,
I was told if its pumping there will be fuel at the fuel rail, well in my case there was but is it possible that there was/will be some fuel sitting it the fuel rail that would give the impression that the pump is pumping,,,
Well before I removed it from the car, I disconnected the outlet from the pump and applied power no fuel came out, that's when I removed it. As it already looked like it wasn't working I gave it a test to make sure, I connected about 1m of hose to the inlet with a funnel on the end poured in a good amount of petrol and put power onto the pump. Nothing came out.
As I didn't know how old the pump was and was keen to the car working I thought I would see how much a new pump was, rang up euro car parts, they had a bosh one in stock locally so I picked it up the same day. Bosh one was apox £80 odd i think, Can find the receipt tomorrow if you want to know the exact cost. they had another make for £45 but I decided to stick to the bosh one.
How are you looking to see if fuel is at the rail?
I was going to before trying the pump off the car or disconnecting the outlet pipe. Look into getting a fuel presser gauge, I have seen the valve on the fuel rail, from googling its a normal shrader valve. Think once I have the MOT out of the way, I may still look at doing this to see what pressure is present.
As I didn't know how old the pump was and was keen to the car working I thought I would see how much a new pump was, rang up euro car parts, they had a bosh one in stock locally so I picked it up the same day. Bosh one was apox £80 odd i think, Can find the receipt tomorrow if you want to know the exact cost. they had another make for £45 but I decided to stick to the bosh one.
How are you looking to see if fuel is at the rail?
I was going to before trying the pump off the car or disconnecting the outlet pipe. Look into getting a fuel presser gauge, I have seen the valve on the fuel rail, from googling its a normal shrader valve. Think once I have the MOT out of the way, I may still look at doing this to see what pressure is present.
When the pump spins there are 4 vanes that get thrown out into an eccentric housing to pump the fuel. An old pump may either have vanes that are worn out or more likely gummed up and jammed in their slots. The result is often a pump which will make all the right noises and may even shift a volume of fuel but at the same time not get it up to pressure.
The only real test is a tyre pressure gauge on the valve at the fuel rail. 38psi is what you are looking for.
Steve
The only real test is a tyre pressure gauge on the valve at the fuel rail. 38psi is what you are looking for.
Steve
The fuel rail as says in the last post has a pressure valve like an inner tube valve at one end, when I turned the car over fuel came out of the said valve, well thats what I tried as It was explained to me on this site a long time ago now lol, the fuel pump was replaced with the Bosch one about 300 miles ago so it should be ok also,,,
Steve_D said:
When the pump spins there are 4 vanes that get thrown out into an eccentric housing to pump the fuel. An old pump may either have vanes that are worn out or more likely gummed up and jammed in their slots. The result is often a pump which will make all the right noises and may even shift a volume of fuel but at the same time not get it up to pressure.
The only real test is a tyre pressure gauge on the valve at the fuel rail. 38psi is what you are looking for.
Steve
As the man says- but you can dirt in the vanes so the pump jams- the fix is to reverse to polarity on the pump so it spins backwards, this can be enough to free it up.The only real test is a tyre pressure gauge on the valve at the fuel rail. 38psi is what you are looking for.
Steve
I had similar problems with my S1 with a cossy 24v engine - also uses the Bosch 044 pump. I fitted a new pump and prefilter then also purchased ebay (cheap) pressuser gauge and sender along with a digital voltage gauge.
I connected the gauge to the +ve connection at the pump and fitted the pressure sender inn the flexible hose supplying the fuel rail. So now if the fault happens I should be able to see straight away if it is the electrics or the pump.
I connected the gauge to the +ve connection at the pump and fitted the pressure sender inn the flexible hose supplying the fuel rail. So now if the fault happens I should be able to see straight away if it is the electrics or the pump.
As Mark says pulsing the pump forwards and backwards can work.
I've submerged a pump completely in a bucket of water to do this. You will be amazed at the amount of s
te that comes out of both ends.
Not an option when working on our customers cars as you can not be sure the problem has not just 'hidden' for a while waiting to pounce when the customer is half way home.
Steve
I've submerged a pump completely in a bucket of water to do this. You will be amazed at the amount of s
te that comes out of both ends.Not an option when working on our customers cars as you can not be sure the problem has not just 'hidden' for a while waiting to pounce when the customer is half way home.
Steve
magpies said:
I had similar problems with my S1 with a cossy 24v engine - also uses the Bosch 044 pump. I fitted a new pump and prefilter then also purchased ebay (cheap) pressuser gauge and sender along with a digital voltage gauge.
I connected the gauge to the +ve connection at the pump and fitted the pressure sender inn the flexible hose supplying the fuel rail. So now if the fault happens I should be able to see straight away if it is the electrics or the pump.
,I connected the gauge to the +ve connection at the pump and fitted the pressure sender inn the flexible hose supplying the fuel rail. So now if the fault happens I should be able to see straight away if it is the electrics or the pump.
Can you let me know what you used gauge wise as I want to do this?
magpies said:
I had similar problems with my S1 with a cossy 24v engine - also uses the Bosch 044 pump. I fitted a new pump and prefilter then also purchased ebay (cheap) pressuser gauge and sender along with a digital voltage gauge.
I connected the gauge to the +ve connection at the pump and fitted the pressure sender inn the flexible hose supplying the fuel rail. So now if the fault happens I should be able to see straight away if it is the electrics or the pump.
,I connected the gauge to the +ve connection at the pump and fitted the pressure sender inn the flexible hose supplying the fuel rail. So now if the fault happens I should be able to see straight away if it is the electrics or the pump.
Can you let me know what you used gauge wise as I want to do this?
I seem to remember when I had the chassis refurb done on mine by Willow (now part of Str8Six), Nick recommended replacing the fuel pump because he said they often fail when the fuel system is drained down or otherwise disturbed, or shortly thereafter. Sounds like this is what has happened to the OP.
This may not be that helpful but I have had the same fuel pump issues as the op. The best way to test the wiring is to use a 12v bulb as if you use a voltmeter or even an led all will look fine. A bulb needs current and this is where the wiring fails. I changed relays and checked the immobiliser all to no avail. The one step I didn't take was to replace the immobiliser. The way I sorted it for quite a while was to run a live feed to the pump via a hidden switch. When I fitted a new fuel pump last winter I installed a whole new wiring feed complete with relay linked to the ignition, but I do also have a KMS ECU so can take the pump feed from that. Not ideal perhaps but it works.
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