Hello all! 1st time post on this forum. I have a 1996 Passat and have a leak coming from either the cold start injector that is towards the bottom of the head on the injection pump, or its coming from the o ring on the head itself. I have watched the videos on how to change the o ring my only question is how do u know that the little cam gear thing on the inside is "on cam" without taking out the quantity adjuster? I don't have vag com so I'm concerned about getting it set correctly and it's not leaking there so I would prefer to not take that out. Thanks everyone.
Leaking injection pump
- Thread starter Tippsy20
- Start date
aNUT
Vendor , w/Business number
You can't know for sure you're on cam unless you have the QA off. Might as well do the QA and top cover seals anyway though. No reason for the middle QA seal to last any longer than the head seal.
You're saving $1200 over a new pump. Call it a good excuse to buy a VAG-com.
You're saving $1200 over a new pump. Call it a good excuse to buy a VAG-com.
JETaah
Vendor , w/Business number
If it has that kind of mileage you could be witnessing "old age" on a number of fronts.
- the smoke issue could be...to name a few
external turbo control hoses, the one in the ECU, and N75 valve (operated by manifold pressure)
waste gate sticking open
worn out injector nozzles
injection quantity setting
MAF sensor ...although less likely on your model
Also if the pump has been leaking for some time, your coolant hoses under the injection pump are probably bloated and near bursting.
Getting stuck on the side of the road could cost you nearly the price of VAGCOM set up. And with it, you are less likely to be at the mercy of a garage that hasn't got a clue about your car.
If one pump seal is leaking the others are not that far behind and you need VAGCOM to set things up properly.
- the smoke issue could be...to name a few
external turbo control hoses, the one in the ECU, and N75 valve (operated by manifold pressure)
waste gate sticking open
worn out injector nozzles
injection quantity setting
MAF sensor ...although less likely on your model
Also if the pump has been leaking for some time, your coolant hoses under the injection pump are probably bloated and near bursting.
Getting stuck on the side of the road could cost you nearly the price of VAGCOM set up. And with it, you are less likely to be at the mercy of a garage that hasn't got a clue about your car.
If one pump seal is leaking the others are not that far behind and you need VAGCOM to set things up properly.
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JETaah
Vendor , w/Business number
http://www.ross-tech.com/
cost varies depending on the package
cost varies depending on the package
oilhammer
Certified Volkswagen Nut & Vendor
More than likely the pump just needs to be rebuilt. Shame, because a lot of us would gladly spend the money on that car and motor on. 
There really isn't any such thing as a "cheap TDI" in my opinion.
There really isn't any such thing as a "cheap TDI" in my opinion.
JETaah
Vendor , w/Business number
I quit driving the passat over the winter because of a antifreeze leak. (which was coming from the 3 hoses under the leaky injection pump). But I do recall getting some trouble codes that said something along the lines of manifold absolute pressure when I had to get on the throttle fairly heavy. Does this narrow down a possible cause?
I am fairly good about working on a gas engine but this is my first diesel and I am lost.
JETaah
Vendor , w/Business number
If you look at the TDI 101 section in the "HOW TO and DYI" threads you should find info that will lead you to diagnostic procedures for low power and most every other aspect of problems with your car.
I did not see any "trusted mechanics" listed for Iowa but, if you are close to a bordering state that would have one you might try that for some one-on-one help.
https://docs.google.com/document/d/1Lucw8ALCkLtt79MMw9JOG1E_dX57-raBhbhIFdtHnEQ/edit?hl=en_US
I did not see any "trusted mechanics" listed for Iowa but, if you are close to a bordering state that would have one you might try that for some one-on-one help.
https://docs.google.com/document/d/1Lucw8ALCkLtt79MMw9JOG1E_dX57-raBhbhIFdtHnEQ/edit?hl=en_US
I'm going to try and change the seals in the pump myself. I talked to a friend of mine that is a diesel guy and he has vag com. I was just messing around with it and realized when it's running I have a lot of air bubbles coming through the fuel lines. Could that be an issue at higher rpms?
Baron VonZeppelin
Veteran Member
- Joined
- Mar 29, 2012
- Location
- CetaneCity, NorthCarolina
- TDI
- 98 Jetta TDI, 81 VW Truck TiDi, 85 Jetta TiDi
With the engine pre-set at TDC by the flywheel mark, you are where you need to be to loosen the injection head and replace the O-Ring.
But only loosen the bolts just barely enough to access the O-Ring , just like in the video. Don't forget that. Do Not Forget.
The Run On Beer video is of a Mk4 ALH engine.
Procedure is same for you, but some minor things shown will be/look different than under your hood.
Buy the BOSCH kit , and no other. Beware of imposters or cheapies.
The injection head O-Ring in the kit will be lime green.
You probably will need to do the others later, but at least do that one now.
Then move on to other diagnostics with your running conditions.
And post those in the dedicated MkIII / A3 / B4 section for best results.
Your car is a B4 with 1Z engine.
I have done 4 of these over the winter, including QA seals, without VagCom. And can help you do yours without VagCom.
Get the main leak for now. Then get it running right.
Then hit the QA seals.
Baron VonZeppelin
Veteran Member
- Joined
- Mar 29, 2012
- Location
- CetaneCity, NorthCarolina
- TDI
- 98 Jetta TDI, 81 VW Truck TiDi, 85 Jetta TiDi
You posted this while i was typing.
Sounds like you have it covered with VCDS - all the better.
Yes , the air bubbles will effect running conditions in various manners - but may only be part of your overall problems.
Have him set your IQ and Injection Timing properly - asap.
Baron VonZeppelin
Veteran Member
- Joined
- Mar 29, 2012
- Location
- CetaneCity, NorthCarolina
- TDI
- 98 Jetta TDI, 81 VW Truck TiDi, 85 Jetta TiDi
Might be worth doing yourself a favor and have the means to gravity prime the Inj Pump after the seal job. Mighty Vac just seems to be a burden trying to re-prime an empty pump on these. Almost to the point was afraid of sucking the seals into the pump. lol
After Inj Pump is primed and flowing out the return - I cut up sections of a clean white sock and put them between the injection lines and injectors.
Then crank on engine/starter to bleed the lines.
The sock material will contain the fuel from spraying all over everything - and changes color to let you know when each one is bled.
Will fire up instantly after that ... if everything was handled correctly.
Or at least really close to correctly .
After Inj Pump is primed and flowing out the return - I cut up sections of a clean white sock and put them between the injection lines and injectors.
Then crank on engine/starter to bleed the lines.
The sock material will contain the fuel from spraying all over everything - and changes color to let you know when each one is bled.
Will fire up instantly after that ... if everything was handled correctly.
Or at least really close to correctly .
How do u go about gravity priming? What do I crack loose to let the air out? Once I get the head of the injection pump on can I fill up the pump before I put the top back together? Might be stupid questions but I was told my whole life the only stupid question is the one that u never ask. Thanks in advance.
Baron VonZeppelin
Veteran Member
- Joined
- Mar 29, 2012
- Location
- CetaneCity, NorthCarolina
- TDI
- 98 Jetta TDI, 81 VW Truck TiDi, 85 Jetta TiDi
You can fill the pump to a certain level before re-installing the QA - if you wish. And then finish off the refill with gravity feed - or try the Mighty Vac.
I wait until its all buttoned up and do the refill with gravity feed.
1 gallon old fashion plastic "gas" can that has the vent nipple.
Supply hose connected to vent nipple.
Container propped up or hung by a bungee.
Return hose disconnected and routed into a container.
When fuel begins to flow into return hose container - pump is full primed to the top.
Other tips , usable at your own discretion -
Do some penetrating lubricant soak on the QA anti-tamper bolt ahead of time - they can be fussy. Make sure you have the specialized socket for that bolt ahead of time also.
I break them all loose on the QA at start , but I don't remove the QA until after the Inj Head O-Ring is completed.
You can remove the QA momentarily if you want to verify you have full spring compression before doing the injection head o-ring.
And then put it back in place.
Been drilled and grilled about never leave a pump open or exposed to any potential elements for any amount of time that is avoidable, by pro pump builders.
Those guys consider a couple specks of dust or a few grains of pollen to be a potential nightmare. I consider the prevention less expensive than the cure. So i do my best.
I wait until its all buttoned up and do the refill with gravity feed.
1 gallon old fashion plastic "gas" can that has the vent nipple.
Supply hose connected to vent nipple.
Container propped up or hung by a bungee.
Return hose disconnected and routed into a container.
When fuel begins to flow into return hose container - pump is full primed to the top.
Other tips , usable at your own discretion -
Do some penetrating lubricant soak on the QA anti-tamper bolt ahead of time - they can be fussy. Make sure you have the specialized socket for that bolt ahead of time also.
I break them all loose on the QA at start , but I don't remove the QA until after the Inj Head O-Ring is completed.
You can remove the QA momentarily if you want to verify you have full spring compression before doing the injection head o-ring.
And then put it back in place.
Been drilled and grilled about never leave a pump open or exposed to any potential elements for any amount of time that is avoidable, by pro pump builders.
Those guys consider a couple specks of dust or a few grains of pollen to be a potential nightmare. I consider the prevention less expensive than the cure. So i do my best.
Had a chance last night to tear into this project. I got the head seal and the lower and the upper in. No leaks!!! It seems to run better although I haven't taken it for a drive yet. I ordered a cable and software for vagcom and a serpentine belt and tensioner because I noticed the tensioner moved around a lot and the belt was extremely sloppy on the bottom while I was checking for leaks. I'll wait for the vagcom cable to adjust the quantity adjuster correctly and then I'll try and make it to work. I do still see a lot of air on the supply side coming to the injection pump. Gonna crawl underneath tomorrow and see if I can see a bad line somewhere. Thanks everyone for the help.
UhOh
Top Post Dawg
Have you checked for a cracked fuel filter "T" fitting or it's seal?
No I haven't. Is that a common place for it to suck air?
The T fitting looks good and fits on the oring pretty tightly. However the line that goes from the fuel filter to the injection pump had a hose clamp that was a touch loose. I tightened it up and all the air went away instantly. 5 minutes later all the air came back? Really thought I had it to!!! Any suggestions?
I just tried to start the car again to check for some more air leaks. It cranked over quite a few times before starting. Acted like the fuel bled off. I don't have my vagcom cable and software yet so I haven't set the quantity adjuster correctly. Would this be the cause? It's just weird that it popped right off until now.
Had this idea and please tell me if this is a dumb idea. If I take off the fuel lines and plug them around the filter and use the pressure side of the mity vac to pressurize the filter and surrounding fuel lines then spray with some soap and water will it bubble where it was sucking air while running or will diesel fuel push out where my air leak was? Will this help me find my air leak or will this cause me problems?
Abacus
That helpful B4 guy
That may very well help you find where your leak is, provided the leak is there and not upstream of the filter, like at the tank check valves.
Did you change the filter at all? How old is it? Who made it?
I have seen off-brand filters not seal properly on the B4's due to a bad o-ring. This is seen when you push down slightly on the Thermo-T while the car is running. If the bubbles go away or lessen, then it's a poor seal. I have known people to get by temporarily by applying some grease to the o-ring connection, which will help stop the air intrusion. The A4 fuel filter and the B4 are not interchangeable since the Thermo-T holes are different sizes and types, so you can't run the A4 filters unless you change the T as well, if you're thinking along those lines.
Your car may start hard if the QA is misaligned and the IQ is too high, like above 12. Ideally it should be 3-4 for stock injectors and 5-6 for larger injectors, adjusted for smoke of course.
I find it odd that the guy who says this: After Inj Pump is primed and flowing out the return - I cut up sections of a clean white sock and put them between the injection lines and injectors. Then crank on engine/starter to bleed the lines. The sock material will contain the fuel from spraying all over everything - and changes color to let you know when each one is bled.
also says this later on: Been drilled and grilled about never leave a pump open or exposed to any potential elements for any amount of time that is avoidable, by pro pump builders. Those guys consider a couple specks of dust or a few grains of pollen to be a potential nightmare. I consider the prevention less expensive than the cure. So i do my best.
Knowing the injectors are just, if not more, as particular to foreign object intrusion as the pump, I have to question why you'd think it was OK to possibly introduce a piece of fabric into the injectors. Wrapping a sock around it to reduce spray is one thing, but nothing should go between the injector hard line and the injector body, especially something like a sock.
The injector has a hole size of 184µm (microns) which is 0.007 inches (or 7 thousandths) and is much smaller than a cotton or nylon thread.
Did you change the filter at all? How old is it? Who made it?
I have seen off-brand filters not seal properly on the B4's due to a bad o-ring. This is seen when you push down slightly on the Thermo-T while the car is running. If the bubbles go away or lessen, then it's a poor seal. I have known people to get by temporarily by applying some grease to the o-ring connection, which will help stop the air intrusion. The A4 fuel filter and the B4 are not interchangeable since the Thermo-T holes are different sizes and types, so you can't run the A4 filters unless you change the T as well, if you're thinking along those lines.
Your car may start hard if the QA is misaligned and the IQ is too high, like above 12. Ideally it should be 3-4 for stock injectors and 5-6 for larger injectors, adjusted for smoke of course.
I find it odd that the guy who says this: After Inj Pump is primed and flowing out the return - I cut up sections of a clean white sock and put them between the injection lines and injectors. Then crank on engine/starter to bleed the lines. The sock material will contain the fuel from spraying all over everything - and changes color to let you know when each one is bled.
also says this later on: Been drilled and grilled about never leave a pump open or exposed to any potential elements for any amount of time that is avoidable, by pro pump builders. Those guys consider a couple specks of dust or a few grains of pollen to be a potential nightmare. I consider the prevention less expensive than the cure. So i do my best.
Knowing the injectors are just, if not more, as particular to foreign object intrusion as the pump, I have to question why you'd think it was OK to possibly introduce a piece of fabric into the injectors. Wrapping a sock around it to reduce spray is one thing, but nothing should go between the injector hard line and the injector body, especially something like a sock.
The injector has a hole size of 184µm (microns) which is 0.007 inches (or 7 thousandths) and is much smaller than a cotton or nylon thread.
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I changed the fuel filter when I first bought the car last spring/summer. I bought it from the local napa store. The only reason i suspect the air leak is from something around the fuel filter is because yesterday when i gave the hose clamps a little extra squeeze the bubbles disappered for about 5 minutes. Then they were back. I moved the T connector around and pushed down on it, took it off, removed the oring so i could get a better look at it....nothing made the bubbles go away after that.
Abacus
That helpful B4 guy
I have seen where the lines have become enlarged over time, so occasionally I trim about 1/2" off the end of the injector line and then reinstall it. People often put them on too tight and crank them down, which deforms the line and causes leaks later on. There is no need to since the feed line is under vacuum and not pressure.