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mcfly

Fuel not reaching engine, 6N 1,6 AEE -98

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mcfly

Hey guys!
Got a problem with fuel not reaching the engine. It all started with a spontaneous trip where the engine started to loose it's power during acceleration and after a while it basically just died as I pushed the throttle pedal down. Started some simple tests to see what could have gone wrong and noticed that the fuelpump didn't pump any fuel as I turned the key to ignition. I tried to start it a couple of times and noticed that it would fire up but died just shortly after because of fuel loss in fuel lines. I measured the voltage from the plug for the fuelpump and it did get 12 volts as the key was turned to ignition and as i tried to start it the voltage was at 9,5 volts.

10 Days later i changed the fuelpump to one with the exact same product number (VDO 6N0 919 051L) which should be a 3bar pump. It started on the first try and I took it for a spin and it worked flawlessly for 6km (and also the 20km trip home). The next day however, when I was driving to work, it started to do the same thing again so directly after work I went and bought some Redline Fuel Injection Cleaner and it now ran better, but sill not perfect. Went straight home and changed the fuel filter which hadn't been changed a single time (1997-05-06 was the production date of fuel filter, the car is at approximately 240000km) and it then got a little better again. 50km more and the car started to missfire or die (felt like during some engine strokes, one ingredient for combustion was missing) and a couple more km after that it died again and stalled completely. The car didn't want to start... AGAIN! The fuelpump did not run as the key was turned to ignition but if you left it for a minute and tried to start it it fired up for a second or two but died shortly after. Now... here's my question:
Could it be something with the fuel in the tank? Like if there's something mixed with the fuel that makes the pumps destroy themselves? Could I have a blocking somewhere in a line or hose? Could it be a relay problem?

 

I will lift out the battery from the car and test the old pump directly on the battery's poles as I wont even bother to start it anymore until I've reached some sort of conclusion. Maybe I should try this on the new pump too that is fitted in the car?

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vwfan3

Hi

Take the fuel pump relay out, clean the contacts and then push it back in. Then check the battery voltage. Then check the voltage at the fuel pump when you turn the ignition ON. The two voltages should be very similar.

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mcfly
6 hours ago, vwfan3 said:

Hi

Take the fuel pump relay out, clean the contacts and then push it back in. Then check the battery voltage. Then check the voltage at the fuel pump when you turn the ignition ON. The two voltages should be very similar.

 

removed the relay (167), cleaned the contacts (even thou they looked clean) and also tried holding a finger on it while turning the key to ignition and it clicks as it should. Battery Voltage @ 12.58 Volts and the pump was receiving pretty much 12 Volts when ignition was on. The pump was actually pumping today so i got it to start but I had no throttle response at all, it cuts itself and stalls as i push the throttle pedal down. But now in the end the pump stopped completely again.

 

Also tried to start the old pump by hooking it up directly to the cars battery but it wont turn at all, not even when i reverse the polarity.

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caretakerplus

There are several possibilities, but as that filter had never been changed, I am wondering if it has passed crud into the rest of the system, possibly blocking injectors - injector cleaner wouldn't remove solid obstructions.

Although you have found 'normal' voltage at the pump, if there is high resistance somewhere in the circuit (the actual contacts inside the relay, for example) you would still get a 'normal' open circuit voltage, but under load, the high resistance could be 'swamping' the pump.

To check for or eliminate the above, read the voltage at the pump whist it is actually running - this will probably mean you having to extend the cables that connect it in order to be able to connect your meter.  Do a similar check at the relay.

It might also pay to check for fault codes, as it is possible that you have other problems as well as the pump.

 

Regards

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mcfly

Strangest thing today, I tried hooking up the old pump to the battery again and it actually worked! So i reversed it to get all the (possibly) bad fuel out from it and removed the new (to be honest, used) pump and replaced it with the old one and now it runs better than ever. I'm clueless, I mean... I haven't changed any broken components or anything. I know that it's working now but for how long? I don't want to drive around with some sort of anxiety over how far away the car is from next fuel related breakdown. I might actually buy a brand new pump and install it.

Edited by mcfly

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mcfly

Just wanted to tell you guys that the old pump only lasted for a week until it stopped again. I now tried to hook up the pump that was still in the gas tank directly to the battery to see if there might be an issue with relay, fuses or wiring but it still wont work, the pumping action did sound very strained. I bought a new Bosch pump + housing to see if I could manage to fix this problem but as i had teared down the pump I had lying beside the car I saw that it would never be able to fit, even thou the web site I ordered it from were able to match it to my vehicle, it even matched my chassis number. My guess is that some manufacturers pumps might not fit other manufacturers pump fittings (Since I have a VDO pump + fitting). I am now considering buying the whole thing brand new so I know I wont have an issue with that again, but then I'm concerned if the lid has the same size and will fit the hole of the tank.

 

Many thanks to every bodies suggestions so far!

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