Audi A8 with LOTS of new parts soon parting out
08-30-2018, 11:40 PM
#32
AudiWorld Senior Member
Fuel pump. Should I replace the fuel pump myself or hire it out? First, and I've said this before, you have to know and just accept that the Germans never really forgave us for the war. This little ****er is one of the many ways- including braided vacuum hoses - that they get even with us. It is the mechanical equivalent of waterboarding. That said, If your idea of foreplay is "Brace yourself Maureeen!" then don't do it.
If not, remove the carpet floor in the trunk, remove the access door on the right and note well the position of the fuel pump assembly. Take some pictures. Remove the electric plugs. Undo the plumbing, soak up the dribble. Remove the little round cap, and remove the plastic silo that is the fuel tank level sender for the right side of the tank. How? Needle nose pliers held firmly pointing straight down and a lever to turn the legs of the pliers and turn the retaining ring counter clockwise. Remove and eyeball it suspiciously thinking, "If I ever get this back together, will this damn thing still work." It might, maybe, probably.
Break the securing bolt loose, back it out half an inch, but DO NOT remove it. Undo the big black plastic retaining ring. This may/will require knocking the edge of the nubs with a dull screwdriver to Remove the plastic ring. Lift the assembly slightly, an inch or two, and remove the big fat rubber gasket ring. Support the assembly with your hand or the skinny edge of a 2x4 and Whack the head of the retaining bolt with a brass mallet or rubber/deadblow hammer. Sparks bad.
Hitting the bolt separates the pump assembly from the "Cup" assembly inside the tank. Once the bolt drops down, undo it and remove it completely. If the bolt just keeps spinning, then you are well and truly screwed - The captive nut inside the tank has broken loose and Audi says you need a new fuel tank assembly. Eff that. Happened to me. Two beers later, I welded up a foot long hole saw to fix it. I've loaned it to two fellow forum members over the years who had the good manners to overlook my ****ty welding and mail it back. Unlikely, but fixable.
Assuming you dodged that particularly unfortunate bullet, Double up on the Ritalin and pay close attention to the next bit: Note any alignment marks when you start and where you are when the assembly finally comes out.. You are going to lift the pump assembly straight up , then start rotating it a few degrees, counterclockwise, and lift and rotate, and lift and rotate, and... out. Disassemble the bit you removed, swap in the PROPER pump. Use fuel injection clamps... continuous and overlapping , not worm drive. Observe the small diameter male pipe pointing straight down at the bottom/ side of the assembly? That has to fit into a corresponding female receiver inside the tank.
To reinstall it, pretend it is a big screw. You are going to rotate it in while you lower it down. The trick is to hold it up as high as you can while you rotate it in and down, until the alignment triangles line up, then push it straight down. You want to rotate the male pipe clockwise over the female receiver in the tank first, then push straight down to mate them. Many, including factory mechanics, screw this bit up. Once it is mated, drop in the bolt and it should thread in cleanly. If it is fighting you, then you are cockeyed and missed the port. In other words, your johnson is beside the promised land, not in it.. Rotate it fully first, then lower it straight down. If you foul this up, the tank will run dry just below 1/2 a tank. the male/female mating is essential for ... not going there.. pulling fuel out of the lower portion of this saddlebag tank.
The rubber ring likes a little lube. I used WD-40. It was within reach. As the limeys like to say assemble in reverse order. Did you line it up right? Test it. Audi says drive around and run out of gas. Sounds like they are trying to kill us, right?
They are. Plan "B" Pump out the tank by pushing the FP relay closed ( under passenger's feet), and turning the key to RUN. I used a threaded hose barb on the output side of the FP assembly. I suppose you could pump it out from the hose feeding the fuel rail with a male-to-male barb splicing in some cheap low pressure fuel-safe hose into a container. Once you pump it all out, switch off, pour in a gallon, pump nearly all of it out. You are good to go. If you can't pump all but the very last cup or two out, your assembly is misaligned, Try again. Unbolt an inch, knock the bolt head, remove bolt, Remove and reinstall. Lift up while rotating clockwise, then straight down.
It all sounds a lot harder than it actually is. Once you've done it and understand it, it's child's play. You've got this.
If not, remove the carpet floor in the trunk, remove the access door on the right and note well the position of the fuel pump assembly. Take some pictures. Remove the electric plugs. Undo the plumbing, soak up the dribble. Remove the little round cap, and remove the plastic silo that is the fuel tank level sender for the right side of the tank. How? Needle nose pliers held firmly pointing straight down and a lever to turn the legs of the pliers and turn the retaining ring counter clockwise. Remove and eyeball it suspiciously thinking, "If I ever get this back together, will this damn thing still work." It might, maybe, probably.
Break the securing bolt loose, back it out half an inch, but DO NOT remove it. Undo the big black plastic retaining ring. This may/will require knocking the edge of the nubs with a dull screwdriver to Remove the plastic ring. Lift the assembly slightly, an inch or two, and remove the big fat rubber gasket ring. Support the assembly with your hand or the skinny edge of a 2x4 and Whack the head of the retaining bolt with a brass mallet or rubber/deadblow hammer. Sparks bad.
Hitting the bolt separates the pump assembly from the "Cup" assembly inside the tank. Once the bolt drops down, undo it and remove it completely. If the bolt just keeps spinning, then you are well and truly screwed - The captive nut inside the tank has broken loose and Audi says you need a new fuel tank assembly. Eff that. Happened to me. Two beers later, I welded up a foot long hole saw to fix it. I've loaned it to two fellow forum members over the years who had the good manners to overlook my ****ty welding and mail it back. Unlikely, but fixable.
Assuming you dodged that particularly unfortunate bullet, Double up on the Ritalin and pay close attention to the next bit: Note any alignment marks when you start and where you are when the assembly finally comes out.. You are going to lift the pump assembly straight up , then start rotating it a few degrees, counterclockwise, and lift and rotate, and lift and rotate, and... out. Disassemble the bit you removed, swap in the PROPER pump. Use fuel injection clamps... continuous and overlapping , not worm drive. Observe the small diameter male pipe pointing straight down at the bottom/ side of the assembly? That has to fit into a corresponding female receiver inside the tank.
To reinstall it, pretend it is a big screw. You are going to rotate it in while you lower it down. The trick is to hold it up as high as you can while you rotate it in and down, until the alignment triangles line up, then push it straight down. You want to rotate the male pipe clockwise over the female receiver in the tank first, then push straight down to mate them. Many, including factory mechanics, screw this bit up. Once it is mated, drop in the bolt and it should thread in cleanly. If it is fighting you, then you are cockeyed and missed the port. In other words, your johnson is beside the promised land, not in it.. Rotate it fully first, then lower it straight down. If you foul this up, the tank will run dry just below 1/2 a tank. the male/female mating is essential for ... not going there.. pulling fuel out of the lower portion of this saddlebag tank.
The rubber ring likes a little lube. I used WD-40. It was within reach. As the limeys like to say assemble in reverse order. Did you line it up right? Test it. Audi says drive around and run out of gas. Sounds like they are trying to kill us, right?
They are. Plan "B" Pump out the tank by pushing the FP relay closed ( under passenger's feet), and turning the key to RUN. I used a threaded hose barb on the output side of the FP assembly. I suppose you could pump it out from the hose feeding the fuel rail with a male-to-male barb splicing in some cheap low pressure fuel-safe hose into a container. Once you pump it all out, switch off, pour in a gallon, pump nearly all of it out. You are good to go. If you can't pump all but the very last cup or two out, your assembly is misaligned, Try again. Unbolt an inch, knock the bolt head, remove bolt, Remove and reinstall. Lift up while rotating clockwise, then straight down.
It all sounds a lot harder than it actually is. Once you've done it and understand it, it's child's play. You've got this.
08-31-2018, 06:07 AM
#33
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Fuel pump. Should I replace the fuel pump myself or hire it out? First, and I've said this before, you have to know and just accept that the Germans never really forgave us for the war. This little ****er is one of the many ways- including braided vacuum hoses - that they get even with us. It is the mechanical equivalent of waterboarding. That said, If your idea of foreplay is "Brace yourself Maureeen!" then don't do it.
If not, remove the carpet floor in the trunk, remove the access door on the right and note well the position of the fuel pump assembly. Take some pictures. Remove the electric plugs. Undo the plumbing, soak up the dribble. Remove the little round cap, and remove the plastic silo that is the fuel tank level sender for the right side of the tank. How? Needle nose pliers held firmly pointing straight down and a lever to turn the legs of the pliers and turn the retaining ring counter clockwise. Remove and eyeball it suspiciously thinking, "If I ever get this back together, will this damn thing still work." It might, maybe, probably.
Break the securing bolt loose, back it out half an inch, but DO NOT remove it. Undo the big black plastic retaining ring. This may/will require knocking the edge of the nubs with a dull screwdriver to Remove the plastic ring. Lift the assembly slightly, an inch or two, and remove the big fat rubber gasket ring. Support the assembly with your hand or the skinny edge of a 2x4 and Whack the head of the retaining bolt with a brass mallet or rubber/deadblow hammer. Sparks bad.
Hitting the bolt separates the pump assembly from the "Cup" assembly inside the tank. Once the bolt drops down, undo it and remove it completely. If the bolt just keeps spinning, then you are well and truly screwed - The captive nut inside the tank has broken loose and Audi says you need a new fuel tank assembly. Eff that. Happened to me. Two beers later, I welded up a foot long hole saw to fix it. I've loaned it to two fellow forum members over the years who had the good manners to overlook my ****ty welding and mail it back. Unlikely, but fixable.
Assuming you dodged that particularly unfortunate bullet, Double up on the Ritalin and pay close attention to the next bit: Note any alignment marks when you start and where you are when the assembly finally comes out.. You are going to lift the pump assembly straight up , then start rotating it a few degrees, counterclockwise, and lift and rotate, and lift and rotate, and... out. Disassemble the bit you removed, swap in the PROPER pump. Use fuel injection clamps... continuous and overlapping , not worm drive. Observe the small diameter male pipe pointing straight down at the bottom/ side of the assembly? That has to fit into a corresponding female receiver inside the tank.
To reinstall it, pretend it is a big screw. You are going to rotate it in while you lower it down. The trick is to hold it up as high as you can while you rotate it in and down, until the alignment triangles line up, then push it straight down. You want to rotate the male pipe clockwise over the female receiver in the tank first, then push straight down to mate them. Many, including factory mechanics, screw this bit up. Once it is mated, drop in the bolt and it should thread in cleanly. If it is fighting you, then you are cockeyed and missed the port. In other words, your johnson is beside the promised land, not in it.. Rotate it fully first, then lower it straight down. If you foul this up, the tank will run dry just below 1/2 a tank. the male/female mating is essential for ... not going there.. pulling fuel out of the lower portion of this saddlebag tank.
The rubber ring likes a little lube. I used WD-40. It was within reach. As the limeys like to say assemble in reverse order. Did you line it up right? Test it. Audi says drive around and run out of gas. Sounds like they are trying to kill us, right?
They are. Plan "B" Pump out the tank by pushing the FP relay closed ( under passenger's feet), and turning the key to RUN. I used a threaded hose barb on the output side of the FP assembly. I suppose you could pump it out from the hose feeding the fuel rail with a male-to-male barb splicing in some cheap low pressure fuel-safe hose into a container. Once you pump it all out, switch off, pour in a gallon, pump nearly all of it out. You are good to go. If you can't pump all but the very last cup or two out, your assembly is misaligned, Try again. Unbolt an inch, knock the bolt head, remove bolt, Remove and reinstall. Lift up while rotating clockwise, then straight down.
It all sounds a lot harder than it actually is. Once you've done it and understand it, it's child's play. You've got this.
If not, remove the carpet floor in the trunk, remove the access door on the right and note well the position of the fuel pump assembly. Take some pictures. Remove the electric plugs. Undo the plumbing, soak up the dribble. Remove the little round cap, and remove the plastic silo that is the fuel tank level sender for the right side of the tank. How? Needle nose pliers held firmly pointing straight down and a lever to turn the legs of the pliers and turn the retaining ring counter clockwise. Remove and eyeball it suspiciously thinking, "If I ever get this back together, will this damn thing still work." It might, maybe, probably.
Break the securing bolt loose, back it out half an inch, but DO NOT remove it. Undo the big black plastic retaining ring. This may/will require knocking the edge of the nubs with a dull screwdriver to Remove the plastic ring. Lift the assembly slightly, an inch or two, and remove the big fat rubber gasket ring. Support the assembly with your hand or the skinny edge of a 2x4 and Whack the head of the retaining bolt with a brass mallet or rubber/deadblow hammer. Sparks bad.
Hitting the bolt separates the pump assembly from the "Cup" assembly inside the tank. Once the bolt drops down, undo it and remove it completely. If the bolt just keeps spinning, then you are well and truly screwed - The captive nut inside the tank has broken loose and Audi says you need a new fuel tank assembly. Eff that. Happened to me. Two beers later, I welded up a foot long hole saw to fix it. I've loaned it to two fellow forum members over the years who had the good manners to overlook my ****ty welding and mail it back. Unlikely, but fixable.
Assuming you dodged that particularly unfortunate bullet, Double up on the Ritalin and pay close attention to the next bit: Note any alignment marks when you start and where you are when the assembly finally comes out.. You are going to lift the pump assembly straight up , then start rotating it a few degrees, counterclockwise, and lift and rotate, and lift and rotate, and... out. Disassemble the bit you removed, swap in the PROPER pump. Use fuel injection clamps... continuous and overlapping , not worm drive. Observe the small diameter male pipe pointing straight down at the bottom/ side of the assembly? That has to fit into a corresponding female receiver inside the tank.
To reinstall it, pretend it is a big screw. You are going to rotate it in while you lower it down. The trick is to hold it up as high as you can while you rotate it in and down, until the alignment triangles line up, then push it straight down. You want to rotate the male pipe clockwise over the female receiver in the tank first, then push straight down to mate them. Many, including factory mechanics, screw this bit up. Once it is mated, drop in the bolt and it should thread in cleanly. If it is fighting you, then you are cockeyed and missed the port. In other words, your johnson is beside the promised land, not in it.. Rotate it fully first, then lower it straight down. If you foul this up, the tank will run dry just below 1/2 a tank. the male/female mating is essential for ... not going there.. pulling fuel out of the lower portion of this saddlebag tank.
The rubber ring likes a little lube. I used WD-40. It was within reach. As the limeys like to say assemble in reverse order. Did you line it up right? Test it. Audi says drive around and run out of gas. Sounds like they are trying to kill us, right?
They are. Plan "B" Pump out the tank by pushing the FP relay closed ( under passenger's feet), and turning the key to RUN. I used a threaded hose barb on the output side of the FP assembly. I suppose you could pump it out from the hose feeding the fuel rail with a male-to-male barb splicing in some cheap low pressure fuel-safe hose into a container. Once you pump it all out, switch off, pour in a gallon, pump nearly all of it out. You are good to go. If you can't pump all but the very last cup or two out, your assembly is misaligned, Try again. Unbolt an inch, knock the bolt head, remove bolt, Remove and reinstall. Lift up while rotating clockwise, then straight down.
It all sounds a lot harder than it actually is. Once you've done it and understand it, it's child's play. You've got this.
08-31-2018, 06:12 AM
#34
Remember the incorrect fuel pump is easy to get, the correct one takes a few days to order in. $140-ish from europaparts or partscontainer. If you go with Europa, skip the Smartpost shipping option, it is very slow.
08-31-2018, 08:36 AM
#35
AudiWorld Member
Post if you get hung up. I just did one on an A8L over the weekend so the pain is fresh on my mind. The "twist and swirl" into position as you try to wiggle the pump assembly back into the right spot seems tricky... but, when it eventually places correctly, it will oddly feel "right". There is only ONE spot for it and once you have found the spot, the bolt will line up perfectly. It settles nicely down into the well it was meant to occupy.
I'm still skeptical this is it, but with this number of miles it's worth doing no matter what.
I'm still skeptical this is it, but with this number of miles it's worth doing no matter what.
08-31-2018, 11:22 PM
#36
AudiWorld Senior Member
I'm by no means certain the pump is the problem, but this whole car is mystery meat, and absent something definitive, its a bit of "Round up the usual suspects" I'm all for throwing inexpensive POSs at it because cheap an easy to install, and the guy testing it usually gets shocked which never stops being funny for me.
I would try and conjure up some output tests for the pump. Pressure and flow will tell the tale. I'm surprised no one makes a small tank that you can fill with fuel, connect to the injector rail in lieu of the fuel line and pressurize with an air compressor set to 50lbs and let er rip. Unplug the fuel pump power and use this as an alternate testing source to run the engine for a minute or so. Probably stupid dangerous.
I would try and conjure up some output tests for the pump. Pressure and flow will tell the tale. I'm surprised no one makes a small tank that you can fill with fuel, connect to the injector rail in lieu of the fuel line and pressurize with an air compressor set to 50lbs and let er rip. Unplug the fuel pump power and use this as an alternate testing source to run the engine for a minute or so. Probably stupid dangerous.
09-01-2018, 08:20 PM
#37
AudiWorld Member
Yeah, I keep trying to think of "stuff that would only impact one bank"... assuming both the exhaust and intake cams are both now properly timed.
Common ground on that side's injectors?
Igniter connector/harness/wiring/grounding for that unit-- assuming the unit itself is fine
Common ground on that side's injectors?
Igniter connector/harness/wiring/grounding for that unit-- assuming the unit itself is fine
09-01-2018, 08:25 PM
#38
AudiWorld Member
It sure feels like you are "close" if the timing's good and you've checked everything out fine. For fuel pressure (and I fully admit this is hillbilly style) I've taken to installing a T-adapter to 1/8" NPT female opening inline on the pressure side of the high pressure line to the fuel rail. It's a short stub of hose that links the hard line to the actual rail. I've then got 1/8" NPT mechanical (cheap Summit grade) and nice electronic 12V MaxTow 100 PSI gauges to screw into the fitting to make sure I have adequate 3+ BAR pressure up to the rail.
BTW, have you tried clearing the misfire codes and pulling the battery cable to reset everything... then before firing it up again, SWAPPING those new ignitor modules for each other? Meaning, does the error STAY in PLACE on that bank if you swap ignitors? Or does it move to the other bank when you swap sides with the two modules?
I'm just spitballing here but hope you track it down. It will drive great once you track this one down.
BTW, have you tried clearing the misfire codes and pulling the battery cable to reset everything... then before firing it up again, SWAPPING those new ignitor modules for each other? Meaning, does the error STAY in PLACE on that bank if you swap ignitors? Or does it move to the other bank when you swap sides with the two modules?
I'm just spitballing here but hope you track it down. It will drive great once you track this one down.
09-02-2018, 08:09 AM
#39
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It sure feels like you are "close" if the timing's good and you've checked everything out fine. For fuel pressure (and I fully admit this is hillbilly style) I've taken to installing a T-adapter to 1/8" NPT female opening inline on the pressure side of the high pressure line to the fuel rail. It's a short stub of hose that links the hard line to the actual rail. I've then got 1/8" NPT mechanical (cheap Summit grade) and nice electronic 12V MaxTow 100 PSI gauges to screw into the fitting to make sure I have adequate 3+ BAR pressure up to the rail.
BTW, have you tried clearing the misfire codes and pulling the battery cable to reset everything... then before firing it up again, SWAPPING those new ignitor modules for each other? Meaning, does the error STAY in PLACE on that bank if you swap ignitors? Or does it move to the other bank when you swap sides with the two modules?
I'm just spitballing here but hope you track it down. It will drive great once you track this one down.
BTW, have you tried clearing the misfire codes and pulling the battery cable to reset everything... then before firing it up again, SWAPPING those new ignitor modules for each other? Meaning, does the error STAY in PLACE on that bank if you swap ignitors? Or does it move to the other bank when you swap sides with the two modules?
I'm just spitballing here but hope you track it down. It will drive great once you track this one down.
https://youtu.be/8qV18MpUqPA
09-02-2018, 08:12 AM
#40
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I'm by no means certain the pump is the problem, but this whole car is mystery meat, and absent something definitive, its a bit of "Round up the usual suspects" I'm all for throwing inexpensive POSs at it because cheap an easy to install, and the guy testing it usually gets shocked which never stops being funny for me.
I would try and conjure up some output tests for the pump. Pressure and flow will tell the tale. I'm surprised no one makes a small tank that you can fill with fuel, connect to the injector rail in lieu of the fuel line and pressurize with an air compressor set to 50lbs and let er rip. Unplug the fuel pump power and use this as an alternate testing source to run the engine for a minute or so. Probably stupid dangerous.
I would try and conjure up some output tests for the pump. Pressure and flow will tell the tale. I'm surprised no one makes a small tank that you can fill with fuel, connect to the injector rail in lieu of the fuel line and pressurize with an air compressor set to 50lbs and let er rip. Unplug the fuel pump power and use this as an alternate testing source to run the engine for a minute or so. Probably stupid dangerous.
https://youtu.be/8qV18MpUqPA