The number 1 cause of "air" bubbles is trash in the tank that gets clogged right at the fuel outlet of the pick up assembly in the tank. Don't mess with the check valve in the return fitting but the outlet (fuel going out to the pump) in early models had a check valve - you should drill that out. Even if it doesn't have the ball, there is a plastic ball holder that will clog. Drill that out and your problem will likely go away. The bubbles can be from an air leak but usually they are vaporized fuel due to the vacuum. Clean any trash from the bottom of your tank at the same time. Apparently if you want to replace the pickup assembly the Canadian unit is best PN: 1J0-919-183-H. This problem also causes hard starts (has to crank a bit before starting). I know from experience that it can flat stall the car on the road and it won't restart.
Fuel cavitates and produces some bubbles in return line which mixes with fuel being picked up by injection pump. Im not impressed with fuel pickup assembly.
The problem is solved. It was cavitaion caused by fuel overheating from hood bonnet sagin 2 inches not allowing enough air to flow into back of engine bay. Fuel pick up helped by increasing fuel flow which allowed fuel to cool down better. Removed hood bonnet, i didnt have engine cover when i bought car. Added modified skid plate. I have vid on skid plate. Conclusion remove hood bonnet, motor cover, add drilled out skid plate. Also had intermittent short in engine wiring leading to inj pump. Took about 10 mo to figure out and bout 7k in ruined parts from overheating, engine did not run hot but everything else did. AND water intrusion through shift lever on trans causing overheating of trans, crap vw design on shift lever. Dont wash ur engine bay, dont let water get onto shift lever, no seal just a junk nylon bushing.
Wow man. This might be my problem also. My under hood insulation is sagging like this. I notice it is hard to start the car after driving it and the weather is warm. I did lots of testing with the hood open and there is no problem if the hood is open.
I found what my problem was. I know I accidently knocked off the calibration of the quantity adjuster. You really need a code reader that will read the codes better. Such as the P0251 on a generic reader gave me a code 17970 Quantity Adjuster Upper Limit Reached. The Voltages for the initial quantity adjuster sweep can be found in Group19 if using a VCDS or similar tool. I will just cut and paste what I found on a forum. First I'll give the link. forums.tdiclub.com/showthread.php?t=327492&page=2 (under Houpty GT) I finished my QA rebuild and it works. The only gotcha I ran into was that there is a longer stud that needs to be installed next to the electrical connections. The cover will not go on and you will have to take the entire QA apart again to correct it. Here are my steps to set the position sensor: Visually set arm like it was on my other QA; Car will not start and has codes for Upper Limit Reached. Measuring block Group 19 Voltage is something like 0.4- 4.6. Move the arm clockwise. Car will not start and has upper limit and lower limit codes. Hammer the pump towards the transmission. Car starts and runs much better than it did before rebuild but has a occasional stumble during start and while setting into idle. IQ is 12.5. Car has code for p1563 Lower Limit reached. Measuring Block Group 19 Voltage is 1.060-4.820. 0.043” arm clearance Adjust arm counter clockwise; 0.039” arm clearance. Group 19 0.880-4.640 volts. Starts at 13 IQ. Hammer down to 5. Starts good and runs good. No codes. Group 19 reads the voltage of the arm when it does its sweep when the ignition is first turned on. This could actually be set without having to reseal and restart the pump every time. Here are the tolerances: Group 019 (Quantity adjuster) Block 1;Voltage from modulating piston displacement sensor: 0.500 - 0.970 V Block 2;Voltage from piston displacement sensor: 4.150 - 4.740 V I may make one more fine adjustment in a couple days. Thank you Deereman76
My 01 is crank no starting, sometimes it starts then almost immediately stalls, only had p1246 code and a maf sensor, cleared them and nothing changed, they didn’t come back and my mk4 alh is only cranking, fuel at injectors too
Change maf with oe, check throttle cutoff in intake is open with key on. Check vac lines no leaks. Checkvac turbo actuator. Check glow plug 109 relay. Get vcds. Never clear a code until repaired n running. ruclips.net/video/njskuPIhKCM/видео.html
Use lots of power master fuel injector cleaner 1st before any service drive for 1000 mile than see how it runs use 12ozs for each tank and unplug your temp sensor for morning startups only than drive and replace next day and repeat for two weeks. Careful when starting up after warm up in morning GLOW PLUGS will come on for about 35 seconds so WAIT until light is OFF BEFORE starting. May fix the issue. Did for me! Cheaper TOO!
Sorted my issues out by cleaning fuel sender which was blocked and drilling out the pick up pipe. Never thought it could be that till I saw this video. Thanks
paula mitchell you don’t know if a brand new sender would solve this do you? I keep hearing drilling out the originals but don’t know if the new revision will help. I’m sure I’m clogged pretty bad at 300k.
@@radzer0966 Get the revision H fuel sender if you don't have it already. It comes without the check valve on the supply side of the sender and only on the return. Older versions like he had need to be drilled. forums.tdiclub.com/showthread.php?t=236071
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The number 1 cause of "air" bubbles is trash in the tank that gets clogged right at the fuel outlet of the pick up assembly in the tank. Don't mess with the check valve in the return fitting but the outlet (fuel going out to the pump) in early models had a check valve - you should drill that out. Even if it doesn't have the ball, there is a plastic ball holder that will clog. Drill that out and your problem will likely go away. The bubbles can be from an air leak but usually they are vaporized fuel due to the vacuum. Clean any trash from the bottom of your tank at the same time. Apparently if you want to replace the pickup assembly the Canadian unit is best PN: 1J0-919-183-H. This problem also causes hard starts (has to crank a bit before starting). I know from experience that it can flat stall the car on the road and it won't restart.
Fuel cavitates and produces some bubbles in return line which mixes with fuel being picked up by injection pump. Im not impressed with fuel pickup assembly.
The problem is solved. It was cavitaion caused by fuel overheating from hood bonnet sagin 2 inches not allowing enough air to flow into back of engine bay. Fuel pick up helped by increasing fuel flow which allowed fuel to cool down better. Removed hood bonnet, i didnt have engine cover when i bought car. Added modified skid plate. I have vid on skid plate. Conclusion remove hood bonnet, motor cover, add drilled out skid plate. Also had intermittent short in engine wiring leading to inj pump. Took about 10 mo to figure out and bout 7k in ruined parts from overheating, engine did not run hot but everything else did. AND water intrusion through shift lever on trans causing overheating of trans, crap vw design on shift lever. Dont wash ur engine bay, dont let water get onto shift lever, no seal just a junk nylon bushing.
Wow man. This might be my problem also. My under hood insulation is sagging like this. I notice it is hard to start the car after driving it and the weather is warm. I did lots of testing with the hood open and there is no problem if the hood is open.
I found what my problem was. I know I accidently knocked off the calibration of the quantity adjuster. You really need a code reader that will read the codes better. Such as the P0251 on a generic reader gave me a code 17970 Quantity Adjuster Upper Limit Reached. The Voltages for the initial quantity adjuster sweep can be found in Group19 if using a VCDS or similar tool. I will just cut and paste what I found on a forum. First I'll give the link. forums.tdiclub.com/showthread.php?t=327492&page=2 (under Houpty GT)
I finished my QA rebuild and it works. The only gotcha I ran into was that there is a longer stud that needs to be installed next to the electrical connections. The cover will not go on and you will have to take the entire QA apart again to correct it.
Here are my steps to set the position sensor:
Visually set arm like it was on my other QA; Car will not start and has codes for Upper Limit Reached. Measuring block Group 19 Voltage is something like 0.4- 4.6.
Move the arm clockwise. Car will not start and has upper limit and lower limit codes.
Hammer the pump towards the transmission. Car starts and runs much better than it did before rebuild but has a occasional stumble during start and while setting into idle. IQ is 12.5. Car has code for p1563 Lower Limit reached. Measuring Block Group 19 Voltage is 1.060-4.820. 0.043” arm clearance
Adjust arm counter clockwise; 0.039” arm clearance. Group 19 0.880-4.640 volts. Starts at 13 IQ. Hammer down to 5. Starts good and runs good. No codes.
Group 19 reads the voltage of the arm when it does its sweep when the ignition is first turned on. This could actually be set without having to reseal and restart the pump every time. Here are the tolerances:
Group 019 (Quantity adjuster)
Block 1;Voltage from modulating piston displacement sensor: 0.500 - 0.970 V
Block 2;Voltage from piston displacement sensor: 4.150 - 4.740 V
I may make one more fine adjustment in a couple days.
Thank you Deereman76
My 01 is crank no starting, sometimes it starts then almost immediately stalls, only had p1246 code and a maf sensor, cleared them and nothing changed, they didn’t come back and my mk4 alh is only cranking, fuel at injectors too
Change maf with oe, check throttle cutoff in intake is open with key on. Check vac lines no leaks. Checkvac turbo actuator. Check glow plug 109 relay. Get vcds. Never clear a code until repaired n running.
ruclips.net/video/njskuPIhKCM/видео.html
Use lots of power master fuel injector cleaner 1st before any service drive for 1000 mile than see how it runs use 12ozs for each tank and unplug your temp sensor for morning startups only than drive and replace next day and repeat for two weeks. Careful when starting up after warm up in morning GLOW PLUGS will come on for about 35 seconds so WAIT until light is OFF BEFORE starting. May fix the issue. Did for me! Cheaper TOO!
Sorted my issues out by cleaning fuel sender which was blocked and drilling out the pick up pipe. Never thought it could be that till I saw this video. Thanks
paula mitchell you don’t know if a brand new sender would solve this do you? I keep hearing drilling out the originals but don’t know if the new revision will help. I’m sure I’m clogged pretty bad at 300k.
@@radzer0966 Get the revision H fuel sender if you don't have it already. It comes without the check valve on the supply side of the sender and only on the return. Older versions like he had need to be drilled. forums.tdiclub.com/showthread.php?t=236071