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Discussion Starter #1 (Edited)
2005 tdi jetta 5spd. 550 000 km.
Purchased a well used tdi jetta with a bad turbo for cheap. Had a used turbo at home and changed it out.
One of the things i noticed during car inspection was the in tank pump wasn't working. No problem,had another used one but the plastic case was broken. So I took the bad one out of the car and tried to get the working pump into the none working pump case. This was NOT an easy task. The major problem was I didn't want to cut the corrugated fuel hose , because i wanted reliability, the car was for my daughter. I used a heat gun to soften the top fuel hose at the discharge port. This worked, and I was able to remove the hose, swap parts around and install the working fuel pump motor. On assembly, the hose that i first removed with the heat gun, pressed back on to its fitting. It wasn't bonded on like the factory installation but didnt slip off. And if it did leak a bit,i thought, it would leak in the tank, no problem. Pump made some noise but worked, all good. This choice would come back to haunt me.
Going forward, car back on the road for a few weeks, all is good then get the "car wont start" call. Check the car over, electric fuel pump working but wont start. I have rpm indication so the crank pickup is good, the glow plug light comes on so they are working. I check computer for codes with VDCS program and none found. I checked for fuel injection quantity and yup there is fuel, but still no start. After cranking over and over again and getting quite upset I finally put the gas pedal to the floor and it started. Idled fine and all was good. Changed the fuel filter. Next day get the same call, "car wont start". Told my daughter to put the pedal to the floor and it started.
At home I make an adapter to check fuel pressure at the engine driven pump, using old banjo fitting and bolt. At engine start pressure goes to 75psi,book calls for 51psi minimum at 1500 rpm. As engine warms up pressure keeps dropping and settles at 35 psi at idle with the needle on the gauge bouncing. If i rev the engine to 2500 rpm pressure goes to 75psi, at 1500 rpm its 45 psi. On occasion the pressure would go to 55psi at idle but slowly back down to 35psi. Grrr need a new engine driven pump.
Going forward again, new pump installed, use mityvac to draw fuel through pump at the return line at fuel filter. Takes a long time but get bubbly fuel coming out. Try to start the engine and no start. Keep cranking but still no start. Now pissed, gas pedal to the floor and fires up. Idles like it was brand new. Check fuel pressure at pump and showing 105 psi at 1500 rpm and 75psi at idle. Yup pump was bad I think to myself, but as engine warms up, fuel pressure drops to 35psi at idle, weird. But car starts ok, has lots of Malone tuning stage 1.5 power, all is good again. Or so i think.
Next day get the call "Car wont start"!!!
I now suspect the in tank pump and when checked, this time its not working.I checked for power when key is turned on, and get 12 volts for a couple of seconds so power supply is good.
But this car should still run by sucking the fuel from the tank. I have two other tdi jettas and both had failed in tank pumps and started and ran fine.
I remove the supply line from the filter and try to draw fuel from the tank and get lots of air and a little bit of fuel, then I remember the fuel line i installed on the in tank pump. Now I suspect that if the fuel level is low enough and electric pump stops working, if there are any air leaks in the supply line, the engine driven pump will not draw enough fuel to run the engine. I checked the fuel gage and level was just above the red refill point on the gage.
I purchased a new in tank pump and find that this aftermarket unit does not have bonded fuel hoses like the factory pump and suspect it may also leak air.
SO, I replaced the in tank fuel pump, cycled the key on and off a few times, I could hear the new electric pump working and started the engine. It fire up after a few moments of cranking and idled like a new engine.
Seeing the fuel level was low in the tank I tested the idea that if this new electric pump stop working ,if the engine would continue to run. I took the electrical
connector off the electric pump and started the engine again. It ran for about 15 seconds and then died, and would not restart. Plugged electrical connector back on, cycled key a few times, cranked engine and after a few rotations it fired up.
Conclusions and lessons learned.
-If your PD tdi wont start and it ran fine before, check your fuel level ,just because you hear the electric pump running does't mean it stays running after engine starts. Filling the fuel tank to half or more will submerge all in tank fuel connections and should get you running again until repairs are done.
-Even a brand new electric pump can leave you stranded if you blow a fuse and pump stops working and the engine needs to suck the fuel from the tank when levels are low. Check your cars condition, unpluged the electric fuel pump connector when tank levels are low, just above the fill warning point to see if your car will stay running. If it doesnt you have air leaks in the fuel supply line, if the in tank pump quits , it will leave you stranded.
-When checking pressure on a new engine driven fuel pump , 60-75 psi at idle, 100 or more psi at 1500 rpm. Minimum psi at 1500 rpm is 51 psi. If lower electric fuel pump may not be working and you maybe sucking in air, check for air leaks by drawing fuel from the supply line at fuel filter, should have very little air (fuel level in tank must be low.).

Hope this helps someone.
 

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2005 tdi jetta 5spd. 550 000 km.
Purchased a well used tdi jetta with a bad turbo for cheap. Had a used turbo at home and changed it out.
One of the things i noticed during car inspection was the in tank pump wasn't working. No problem,had another used one but the plastic case was broken. So I took the bad one out of the car and tried to get the working pump into the none working pump case. This was NOT an easy task. The major problem was I didn't want to cut the corrugated fuel hose , because i wanted reliability, the car was for my daughter. I used a heat gun to soften the top fuel hose at the discharge port. This worked, and I was able to remove the hose, swap parts around and install the working fuel pump motor. On assembly, the hose that i first removed with the heat gun, pressed back on to its fitting. It wasn't bonded on like the factory installation but didnt slip off. And if it did leak a bit,i thought, it would leak in the tank, no problem. Pump made some noise but worked, all good. This choice would come back to haunt me.
Going forward, car back on the road for a few weeks, all is good then get the "car wont start" call. Check the car over, electric fuel pump working but wont start. I have rpm indication so the crank pickup is good, the glow plug light comes on so they are working. I check computer for codes with VDCS program and none found. I checked for fuel injection quantity and yup there is fuel, but still no start. After cranking over and over again and getting quite upset I finally put the gas pedal to the floor and it started. Idled fine and all was good. Changed the fuel filter. Next day get the same call, "car wont start". Told my daughter to put the pedal to the floor and it started.
At home I make an adapter to check fuel pressure at the engine driven pump, using old banjo fitting and bolt. At engine start pressure goes to 75psi,book calls for 51psi minimum at 1500 rpm. As engine warms up pressure keeps dropping and settles at 35 psi at idle with the needle on the gauge bouncing. If i rev the engine to 2500 rpm pressure goes to 75psi, at 1500 rpm its 45 psi. On occasion the pressure would go to 55psi at idle but slowly back down to 35psi. Grrr need a new engine driven pump.
Going forward again, new pump installed, use mityvac to draw fuel through pump at the return line at fuel filter. Takes a long time but get bubbly fuel coming out. Try to start the engine and no start. Keep cranking but still no start. Now pissed, gas pedal to the floor and fires up. Idles like it was brand new. Check fuel pressure at pump and showing 105 psi at 1500 rpm and 75psi at idle. Yup pump was bad I think to myself, but as engine warms up, fuel pressure drops to 35psi at idle, weird. But car starts ok, has lots of Malone tuning stage 1.5 power, all is good again. Or so i think.
Next day get the call "Car wont start"!!!
I now suspect the in tank pump and when checked, this time its not working.I checked for power when key is turned on, and get 12 volts for a couple of seconds so power supply is good.
But this car should still run by sucking the fuel from the tank. I have two other tdi jettas and both had failed in tank pumps and started and ran fine.
I remove the supply line from the filter and try to draw fuel from the tank and get lots of air and a little bit of fuel, then I remember the fuel line i installed on the in tank pump. Now I suspect that if the fuel level is low enough and electric pump stops working, if there are any air leaks in the supply line, the engine driven pump will not draw enough fuel to run the engine. I checked the fuel gage and level was just above the red refill point on the gage.
I purchased a new in tank pump and find that this aftermarket unit does not have bonded fuel hoses like the factory pump and suspect it may also leak air.
SO, I replaced the in tank fuel pump, cycled the key on and off a few times, I could hear the new electric pump working and started the engine. It fire up after a few moments of cranking and idled like a new engine.
Seeing the fuel level was low in the tank I tested the idea that if this new electric pump stop working ,if the engine would continue to run. I took the electrical
connector off the electric pump and started the engine again. It ran for about 15 seconds and then died, and would not restart. Plugged electrical connector back on, cycled key a few times, cranked engine and after a few rotations it fired up.
Conclusions and lessons learned.
-If your PD tdi wont start and it ran fine before, check your fuel level ,just because you hear the electric pump running does't mean it stays running after engine starts. Filling the fuel tank to half or more will submerge all in tank fuel connections and should get you running again until repairs are done.
-Even a brand new electric pump can leave you stranded if you blow a fuse and pump stops working and the engine needs to suck the fuel from the tank when levels are low. Check your cars condition, unpluged the electric fuel pump connector when tank levels are low, just above the fill warning point to see if your car will stay running. If it doesnt you have air leaks in the fuel supply line, if the in tank pump quits , it will leave you stranded.
-When checking pressure on a new engine driven fuel pump , 60-75 psi at idle, 100 or more psi at 1500 rpm. Minimum psi at 1500 rpm is 51 psi. If lower electric fuel pump may not be working and you maybe sucking in air, check for air leaks by drawing fuel from the supply line at fuel filter, should have very little air (fuel level in tank must be low.).

Hope this helps someone.
Good useful article - i changed tank fuel pump a week ago.By any chance, do You know a location of fuel pump relay? VW TDI, 2004, BEW. Here is the only relay panel which i found. Regards, Valery
8346
 

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Brilliant post,
I was not even looking for it, but this is exactly the post I needed: I have 2 Golf MKIV not starting because of fuel problems, I'll try your diagnosis and keep updated in case I can add further details or symptomas.
Cheers
 

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2005 tdi jetta 5spd. 550 000 km.
Purchased a well used tdi jetta with a bad turbo for cheap. Had a used turbo at home and changed it out.
One of the things i noticed during car inspection was the in tank pump wasn't working. No problem,had another used one but the plastic case was broken. So I took the bad one out of the car and tried to get the working pump into the none working pump case. This was NOT an easy task. The major problem was I didn't want to cut the corrugated fuel hose , because i wanted reliability, the car was for my daughter. I used a heat gun to soften the top fuel hose at the discharge port. This worked, and I was able to remove the hose, swap parts around and install the working fuel pump motor. On assembly, the hose that i first removed with the heat gun, pressed back on to its fitting. It wasn't bonded on like the factory installation but didnt slip off. And if it did leak a bit,i thought, it would leak in the tank, no problem. Pump made some noise but worked, all good. This choice would come back to haunt me.
Going forward, car back on the road for a few weeks, all is good then get the "car wont start" call. Check the car over, electric fuel pump working but wont start. I have rpm indication so the crank pickup is good, the glow plug light comes on so they are working. I check computer for codes with VDCS program and none found. I checked for fuel injection quantity and yup there is fuel, but still no start. After cranking over and over again and getting quite upset I finally put the gas pedal to the floor and it started. Idled fine and all was good. Changed the fuel filter. Next day get the same call, "car wont start". Told my daughter to put the pedal to the floor and it started.
At home I make an adapter to check fuel pressure at the engine driven pump, using old banjo fitting and bolt. At engine start pressure goes to 75psi,book calls for 51psi minimum at 1500 rpm. As engine warms up pressure keeps dropping and settles at 35 psi at idle with the needle on the gauge bouncing. If i rev the engine to 2500 rpm pressure goes to 75psi, at 1500 rpm its 45 psi. On occasion the pressure would go to 55psi at idle but slowly back down to 35psi. Grrr need a new engine driven pump.
Going forward again, new pump installed, use mityvac to draw fuel through pump at the return line at fuel filter. Takes a long time but get bubbly fuel coming out. Try to start the engine and no start. Keep cranking but still no start. Now pissed, gas pedal to the floor and fires up. Idles like it was brand new. Check fuel pressure at pump and showing 105 psi at 1500 rpm and 75psi at idle. Yup pump was bad I think to myself, but as engine warms up, fuel pressure drops to 35psi at idle, weird. But car starts ok, has lots of Malone tuning stage 1.5 power, all is good again. Or so i think.
Next day get the call "Car wont start"!!!
I now suspect the in tank pump and when checked, this time its not working.I checked for power when key is turned on, and get 12 volts for a couple of seconds so power supply is good.
But this car should still run by sucking the fuel from the tank. I have two other tdi jettas and both had failed in tank pumps and started and ran fine.
I remove the supply line from the filter and try to draw fuel from the tank and get lots of air and a little bit of fuel, then I remember the fuel line i installed on the in tank pump. Now I suspect that if the fuel level is low enough and electric pump stops working, if there are any air leaks in the supply line, the engine driven pump will not draw enough fuel to run the engine. I checked the fuel gage and level was just above the red refill point on the gage.
I purchased a new in tank pump and find that this aftermarket unit does not have bonded fuel hoses like the factory pump and suspect it may also leak air.
SO, I replaced the in tank fuel pump, cycled the key on and off a few times, I could hear the new electric pump working and started the engine. It fire up after a few moments of cranking and idled like a new engine.
Seeing the fuel level was low in the tank I tested the idea that if this new electric pump stop working ,if the engine would continue to run. I took the electrical
connector off the electric pump and started the engine again. It ran for about 15 seconds and then died, and would not restart. Plugged electrical connector back on, cycled key a few times, cranked engine and after a few rotations it fired up.
Conclusions and lessons learned.
-If your PD tdi wont start and it ran fine before, check your fuel level ,just because you hear the electric pump running does't mean it stays running after engine starts. Filling the fuel tank to half or more will submerge all in tank fuel connections and should get you running again until repairs are done.
-Even a brand new electric pump can leave you stranded if you blow a fuse and pump stops working and the engine needs to suck the fuel from the tank when levels are low. Check your cars condition, unpluged the electric fuel pump connector when tank levels are low, just above the fill warning point to see if your car will stay running. If it doesnt you have air leaks in the fuel supply line, if the in tank pump quits , it will leave you stranded.
-When checking pressure on a new engine driven fuel pump , 60-75 psi at idle, 100 or more psi at 1500 rpm. Minimum psi at 1500 rpm is 51 psi. If lower electric fuel pump may not be working and you maybe sucking in air, check for air leaks by drawing fuel from the supply line at fuel filter, should have very little air (fuel level in tank must be low.).

Hope this helps someone.
Dude. Congratulations! VERY well done trouble shooting! This might help me. I have a non running, purchased cheap 159k pump duse.
Found out after the fact Injectors in the trunk... after installing jectors. Car started 5 sec.. then did proper PM/ Belt tensioner pump etc. Replaced lift pump. Every thing by the book here..cleaned tank fresh Diesel new bet still no start..10 months! Id love to have your opinion.?
An congrats on a job well done.
I just wont give up.
 
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