Dieselgeek
TDIClub Enthusiast, Vendor , w/Business number
Hey Y'all:
Recently I’ve been asked about the details required to swap in an ALH injection pump into the older 1Z and AHU engines found in 1996-1997 B4 Passats and 1997-early 1999 Jetta III TDI cars. Dieselgeek.com used to sell a kit to do such a swap but we no longer offer such a kit as all operations can be done locally by a machine shop near you.
The injection pumps in the earlier cars are getting older and are hard to find at salvage yards. The newer ALH engines were sold in all of the 1998-2003 New Beetles and mid-1999 through 2003 Golf and Jetta TDI cars. The ALH engines are much more plentiful and a good used injection pump is easier to find since these engines were produced in much greater numbers than the earlier 1Z/AHU. By using a later pump there is the added benefit of higher injection pressure that accompanies the newer ALH pump in comparison to the older pumps. This may reduce smoke and increase power, especially if you are able to source an 11mm pump from an automatic-equipped ALH engine. Please note that you may reduce your timing belt change interval if you chose to use an 11mm injection pump as it puts more stress on the timing belt. I cannot say what the interval should be in this case.
If you find that your 1Z/AHU injection pump is leaking to the point of losing its prime and failing to start the engine you do not have to replace the pump! Seal kits are available to stop the leaks. But if your pump is knocking or if multiple diagnoses point to a bad pump then you can source a good used ALH pump and with a little extra effort your car can be fixed and modernized at the same time.
Please note that dieselgeek.com no longer sells the kit to install the ALH injection pump into the older engine but I am making public the general details of this swap. Post all relevant questions to this thread. I will not answer PMs in reference to this thread. Also, Id like this thread to be a FAQ on the subject so I will only answer relevant questions and ignore any that are not moving this thread forward. Please refrain from posting anything if it does not act to clarify what I have written.
Unfortunately, I have no pictures.
Here's a simplified rundown:
1. Cut the cast iron 1Z/AHU pump bracket hole to 60mm at a machine shop. Test fit the new pump to the bracket before the bracket leaves the machine shop. You will need to source some longer 8mm bolts to bolt the ALH pump into the newly cut cast iron 1Z/AHU pump bracket. These are available at Home Depot or Lowes, etc. The thread pitch is 1.25. Your machinist should be able to measure the bolt length that is required to secure the pump to the bracket.
2. Cut sheet metal timing belt backing plate pump hole to 2.5” with hole saw. First use a 2" hole saw on a piece of hardwood to cut a 1/4" deep groove ONLY. Then set the sheetmetal ring in this 2" diameter groove in the wood and then use a 2.5" hole saw to cut sheetmetal to 2.5" where the pump protrudes through it. Your machinist may be able to do this job for you on his/her mill.
3. Machine down beveled side of ALH injection pump pulley (PN: 038 130 111A or 111B) to fit under the 1Z or AHU timing cover. Cut down the beveled side to the level of the edge of the timing belt teeth which means that the beveled side should be completely flat after machining. Attach pulley to pump with three pulley adjustment bolts N 903 285 04. The torque specification on these bolts is 18 lb/ft.
4. Swap all 10 of the electrical pins from the two plugs that are currently feeding your injection pump to the single ALH electrical plug (PN: 1J0 973 735) which is available at your dealer for around $9.00. The female receptacles can be removed from terminal housings with a medium sized safety pin but be careful not to bend barbs before they are fully depressed to release receptacles from plastic housing. There are special terminal tools to do this job but they are expensive and hard to find. Be sure to remove violet retainer on 1J0 plug before trying to insert pins. Replace it after pins are installed completely. You may want to practice on a junk yard plug before you attempt pin extraction on your wiring harness! You will be a more patient person after you practice
The equivalent terminal/pin numbers are as follows:
Terminal Position/Wire color-ALH/ Wire color/Terminal position1Z & AHU
T10/1 Lilac/black Lilac/black T8/1 (Ex: remove #1 wire on your 8-pin plug and insert into the #1 position on 10-pin 1J0 plug)
T10/2 Grey/green Grey/green T8/2
T10/3 White/green White/green T8/3
T10/4 Brown/blue Brown/blue T8/4
T10/5 Red/Lilac Black/Yellow T8/5
T10/6 Brown/red Brown/yellow T8/6
T10/7 Yellow/red Yellow/black T8/7
T10/8 Black/white White/black T3/1
T10/9 Brown/black Brown/black T3/2
T10/10 Yellow/black Black/yellow T3/3
You may use any ALH pump, 10 or 11mm. You will need to buy a pump pin for setting the pump to TDC from a fine vendor such as www.metalnerd.com (Tool PN: MN3359). Check start of injection after starting car for the first time. If necessary, adjust timing with three pulley adjustment bolts N 903 285 04 just like you would with any ALH engine.
Recently I’ve been asked about the details required to swap in an ALH injection pump into the older 1Z and AHU engines found in 1996-1997 B4 Passats and 1997-early 1999 Jetta III TDI cars. Dieselgeek.com used to sell a kit to do such a swap but we no longer offer such a kit as all operations can be done locally by a machine shop near you.
The injection pumps in the earlier cars are getting older and are hard to find at salvage yards. The newer ALH engines were sold in all of the 1998-2003 New Beetles and mid-1999 through 2003 Golf and Jetta TDI cars. The ALH engines are much more plentiful and a good used injection pump is easier to find since these engines were produced in much greater numbers than the earlier 1Z/AHU. By using a later pump there is the added benefit of higher injection pressure that accompanies the newer ALH pump in comparison to the older pumps. This may reduce smoke and increase power, especially if you are able to source an 11mm pump from an automatic-equipped ALH engine. Please note that you may reduce your timing belt change interval if you chose to use an 11mm injection pump as it puts more stress on the timing belt. I cannot say what the interval should be in this case.
If you find that your 1Z/AHU injection pump is leaking to the point of losing its prime and failing to start the engine you do not have to replace the pump! Seal kits are available to stop the leaks. But if your pump is knocking or if multiple diagnoses point to a bad pump then you can source a good used ALH pump and with a little extra effort your car can be fixed and modernized at the same time.
Please note that dieselgeek.com no longer sells the kit to install the ALH injection pump into the older engine but I am making public the general details of this swap. Post all relevant questions to this thread. I will not answer PMs in reference to this thread. Also, Id like this thread to be a FAQ on the subject so I will only answer relevant questions and ignore any that are not moving this thread forward. Please refrain from posting anything if it does not act to clarify what I have written.
Unfortunately, I have no pictures.
Here's a simplified rundown:
1. Cut the cast iron 1Z/AHU pump bracket hole to 60mm at a machine shop. Test fit the new pump to the bracket before the bracket leaves the machine shop. You will need to source some longer 8mm bolts to bolt the ALH pump into the newly cut cast iron 1Z/AHU pump bracket. These are available at Home Depot or Lowes, etc. The thread pitch is 1.25. Your machinist should be able to measure the bolt length that is required to secure the pump to the bracket.
2. Cut sheet metal timing belt backing plate pump hole to 2.5” with hole saw. First use a 2" hole saw on a piece of hardwood to cut a 1/4" deep groove ONLY. Then set the sheetmetal ring in this 2" diameter groove in the wood and then use a 2.5" hole saw to cut sheetmetal to 2.5" where the pump protrudes through it. Your machinist may be able to do this job for you on his/her mill.
3. Machine down beveled side of ALH injection pump pulley (PN: 038 130 111A or 111B) to fit under the 1Z or AHU timing cover. Cut down the beveled side to the level of the edge of the timing belt teeth which means that the beveled side should be completely flat after machining. Attach pulley to pump with three pulley adjustment bolts N 903 285 04. The torque specification on these bolts is 18 lb/ft.
4. Swap all 10 of the electrical pins from the two plugs that are currently feeding your injection pump to the single ALH electrical plug (PN: 1J0 973 735) which is available at your dealer for around $9.00. The female receptacles can be removed from terminal housings with a medium sized safety pin but be careful not to bend barbs before they are fully depressed to release receptacles from plastic housing. There are special terminal tools to do this job but they are expensive and hard to find. Be sure to remove violet retainer on 1J0 plug before trying to insert pins. Replace it after pins are installed completely. You may want to practice on a junk yard plug before you attempt pin extraction on your wiring harness! You will be a more patient person after you practice
The equivalent terminal/pin numbers are as follows:
Terminal Position/Wire color-ALH/ Wire color/Terminal position1Z & AHU
T10/1 Lilac/black Lilac/black T8/1 (Ex: remove #1 wire on your 8-pin plug and insert into the #1 position on 10-pin 1J0 plug)
T10/2 Grey/green Grey/green T8/2
T10/3 White/green White/green T8/3
T10/4 Brown/blue Brown/blue T8/4
T10/5 Red/Lilac Black/Yellow T8/5
T10/6 Brown/red Brown/yellow T8/6
T10/7 Yellow/red Yellow/black T8/7
T10/8 Black/white White/black T3/1
T10/9 Brown/black Brown/black T3/2
T10/10 Yellow/black Black/yellow T3/3
You may use any ALH pump, 10 or 11mm. You will need to buy a pump pin for setting the pump to TDC from a fine vendor such as www.metalnerd.com (Tool PN: MN3359). Check start of injection after starting car for the first time. If necessary, adjust timing with three pulley adjustment bolts N 903 285 04 just like you would with any ALH engine.
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