97 Jetta Tdi not getting fuel to injection pump

nick1rankin

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chattanooga tn
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jetta
I just got the the car and the previous owner has an electric fuel pump hooked up with a clear inline fuel filter. It will run without the pump running but barely has fuel going through the filter. It also has a surge or jerk of the engine when revved in neutral and also some bucking when going down the road whether the electric pump is hooked up or not. I'm at a loss other than maybe something is wrong with the injection pump. It has me baffled because it still starts runs and drives. Also the car has plenty of power. Any input would be great before I start troubleshooting.
 

KLXD

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Lompoc, CA
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'98, '2 Jettas
Does it still have the original filter too?

I'd start with new filters and making sure the hoses aren't letting in air.
 

Giberish33

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May 30, 2017
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Montreal, Qc
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1997 Jetta TDi 1z
There should be a "clear" fuel line running from the fuel filter to the injection pump (it might be more amber color now if its old), put a flashlight or phone light behind the line so that you can see into it and check for large amounts of air bubbles passing through the line especially long bubbles or tons of small almost foam like. A few smaller ones is normal but not "long" bubbles or tons of foamy ones.

I don't understand why the owner would have hooked up an electric pump? Was it not able to pull fuel from the tank on its own? Also does that inline clear fuel filter go directly to the injection pump or does the car also have the standard fuel filter canister with the mickey mouse clip T fitting?

It sounds almost like the IQ is set too low with the bucking and jerking / issues in neutral and driving but also sounds like its not able to pull enough fuel or has a massive air leak making it not able to pull enough fuel.

If possible record a short video showing the "inline fuel filter" and the behavior of the car jerking / bucking. A video would help a lot and save lots of back and forth in this thread trying to determine what it looks like when happening.
 

Steve Addy

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Iowa
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97 Mk3
The fuel systems on these must be completely sealed and without air infiltration in order to allow the lift pump (inside the IP) to pull fuel from the tank.

If there's too much air getting into the fuel line then the IP cannot bring enough fuel into the pump and you won't get any fuel injection.

The best course of action is to revert back to the way the car was originally setup (no electric fuel pump inline) and start from there.

It can be difficult to isolate air leaks in this system, especially if the hoses at the fuel tank are old. First task I would take is to replace all rubber hoses on the fuel system along with the filter (original type filter) and hoses leading to the filter and see if you can get a solid fuel pull that way.

At the same time take a look at the check valves at the rear to see if they are working properly. Also note that fuel lines are direction specific because of the check valves, the supply will only work coming to the filter and the return will only work going back to the tank. That is due to the check valves (one way valves) near to the fuel level sender.

The best course of action is always to undo what past owners have tried as 'repairs' and first try to fix the problem using what the factory originally intended.

A video would be a good thing to do to see how it's setup now but I can tell you that the added fuel pump and clear filter are likely not helping things.

Steve
 

nick1rankin

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Location
chattanooga tn
TDI
jetta
Can you replace the internal lift pump for the injection pump? I know the ve pumps that were ran on cummins engines had a manual lift pump block mounted. I've been assuming that it had something of the sort. It's not getting enough fuel. That's the reason for the inline electric pump. That's why I was saying if its unplugged little to no fuel that is going towards the injection pump. No bubbles or anything. Just not getting fuel like something is either stopped up or not working like it should.
 

Mongler98

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Mar 23, 2011
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COLORADO (SE of Denver)
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98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
The only fuel pump worth getting (besides the in tank mod pickup, if your willing to do more work just for a stealth thing IMO) is a walbro. If they stop pumping for any reason they do not restrict the flow of fuel.
it sounds like your getting air in the line. causing a break in fuel prime. it could also be that the 109 relay is havving issues. My relay had some issues like that (corroded connecitons) and had some bucking followed by a stall, wiggle it and i was on my way again. Probably not the issue but not ruled out.
Seeing as its a New TDI for you, there are a few things right off the bat worth checking out seeing as your having some issues. Most of these probably are not the issue but are defiantly the top things we all do to newly purchased old TDI's
Timing belt
check static timing
Fuel Filter
check intake manifold for extreme clogs ( you would be surprised at how clogged they can get and not cause much power loss)
Check the lines and check-valves at the tank
change all the fluids, Break fluid flush, trans, oil, steering, etc...
Air filters and such
basically you should go over everything regardless of who sold you the car and what they said they did or have receipts for. You dont know if he took it to some shade tree mech to service and was not done properly.
Do you have VCDS and a Vag-com cable?
it would be very good for you to check the timing and Q.A.
What other mods have been done to the engine? It does not make a bit of sense that a fuel pump was added other than to band-aid over an issue unless other mods called for it. Larger injection, cam and bigger turbo with a remap and IP mods is a set of mods that usually leads up to a fuel pump added as the stock IP could use a bit of help at much higher than normal revs (5-6K). When i did my remap after all of those mods and then some, i gained 29HP at the very top end just from adding my walbor pump. 4800-6400 RPMS was the only place i saw a bump on the curve worth noting and that is at 238HP on stock internals. SO a fuel pump has no place unless your trying to gain a few more at the top end.
Either PO was just putting dumb parts on for (RACE CAR STRIPE HP GAINS) or PO was covering up an issue.
 

nick1rankin

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Location
chattanooga tn
TDI
jetta
I have another one of these cars that I never had any problems out of except the egr which I deleted. I work on vehicles every day. I know it doesn't need an extra fuel pump. I simply want to know if there is a simple thing that goes wrong on all of these cars that would cause it not to pull fuel from the tank. Like a lift pump that's built into the injection pump that can be changed.
 

KLXD

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Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
A simple fix would be clean filters. I don't believe you've said how old they are.

Another simple fix would be replacing the several hoses between the tank and pump. They're 20 year old rubber.

I seem to recall something about a check ball in the fuel pickup in the tank causing a problem. Don't recall what years.

The internal lift pump can be replaced but I doubt it's the problem. New parts would prolly cost more than a good used pump. It's not a simple fix; it's the last thing to remove from the pump other than the input shaft itself.
 
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oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
The suction pump inside the injection pump is likely trashed, and to that end, the entire innards of the pump are probably suspect.

Crappy fuel, neglected filter, etc. all can add up. I just did a '98 AHU and its pump was completely tooefed inside. DFIS fixed it up, but they had to get some other parts from another pump to get it all back working.
 

nick1rankin

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chattanooga tn
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jetta
I think this ones problem was junky biodiesel. I'm good with leaving the electric pump if It works but the surging at higher rpms bothers me. It's just a work car. Does anyone know what psi the pump needs coming in on the low pressure side?
 

oilhammer

Certified Volkswagen Nut & Vendor
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Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Zero psi.

The suction pump inside the injection pump is just that: suction. It sucks. It PULLS the fuel from the tank through the filter.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
I'd have thought the lift pump, being a relatively low tolerance assembly that sees the most fuel flow, would be the last thing to wear out.

I wonder why the external pump. Was there a problem or did the previous owner run out of fuel, have trouble starting it and said "I'm never going through that again?
 

oilhammer

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Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Usually when people add an inline "lift" pump to a VE TDI, it is to mask a problem with the injection pump. If the injection pump, and the rest of the fuel system, is in good proper working order, a band-aid is not needed.
 

iluvmydiesels

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Nov 21, 2015
Location
phila area
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AHU
looking at this topic, above what oilh- points out, was one of my first thoughts about whats going on with OPs pump problem.
he says there 'may have been' a clear fuel filter.(??) wheres is the real fuel filter?(??).
by running with out the correct fuel filter PO probably clogged the pump, and possibly injectors.
one way to tell is to bottle feed. for one you can use a can of purge, if fuel, i get an old bug gas filter, run fuel thru, put filtered fuel in bottle with additive, or purge and try to run. then again if injectors are also clogged, you wont have luck with this.
on a bench make a clean area, take apart injectors and try to clean them up first. becareful when doing this. keep-& get everything (inside) clean, dont drop anything, its not hard for a pin or piece to come apart with things and drop. keep in order. put back together like came apart. if in doubt use manual for reference, and correct assembly info.

like somebody already suggested, put in all new fuel lines, remove that external pump.
 

oilhammer

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Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
You can get a reasonably good idea of the condition of the fuel system by simply taking the top section of the pump off. If it is dirty, full of rust, or slime, then there's your problem.
 

nick1rankin

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Sep 9, 2014
Location
chattanooga tn
TDI
jetta
looking at this topic, above what oilh- points out, was one of my first thoughts about whats going on with OPs pump problem.
he says there 'may have been' a clear fuel filter.(??) wheres is the real fuel filter?(??).
by running with out the correct fuel filter PO probably clogged the pump, and possibly injectors.
one way to tell is to bottle feed. for one you can use a can of purge, if fuel, i get an old bug gas filter, run fuel thru, put filtered fuel in bottle with additive, or purge and try to run. then again if injectors are also clogged, you wont have luck with this.
on a bench make a clean area, take apart injectors and try to clean them up first. becareful when doing this. keep-& get everything (inside) clean, dont drop anything, its not hard for a pin or piece to come apart with things and drop. keep in order. put back together like came apart. if in doubt use manual for reference, and correct assembly info.
like somebody already suggested, put in all new fuel lines, remove that external pump.
The original filter is there. The guy I got it from put the extra filter on to see the fuel flow. I work on vehicles everyday. I dont need someone to tell me to change a fuel filter. I was simply wanting to know if there might be a simple fix that someone who fools with the alh motors everyday might know.
 

nick1rankin

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Location
chattanooga tn
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jetta
Update...Found a leaky injector and fixed that issue. Still no suction from the pump. I'm going to try the sending unit later on or tomorrow.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
One so knowing might have mentioned in his first post that the filters were clean and saved us less experienced guys some speculation.

I assume an experienced fellow such as yourself tried disconnecting the inlet line at the injection pump and running the electric pump to see the flow.

Since there was flow when you tried that you might have mentioned it since it would pretty much point to a bad IP.

If there wasn't flow it would seem to indicate an air leak or a plugged line or fuel pickup.

But maybe you didn't do that. Seems like a simple thing to do to me.
 
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nick1rankin

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chattanooga tn
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jetta
So I'm assuming it's the ip as well. Is there a way to do that swap without any special tools? I made my own injector tool today so that's always a possiblity as well if need be.
 

Mongler98

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Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Does anyone know what psi the pump needs coming in on the low pressure side?
THIS
Zero psi.
The suction pump inside the injection pump is just that: suction. It sucks. It PULLS the fuel from the tank through the filter.
If you mean what PSI is safe to push into the pump, 1-3 is happy, 8 is pusshing it and i dont know of anyone running more than 12. Im running 11PSI on my walbro, did so for 20K miles with no leaks or issues what so ever. (i need a new 11mm pump!)
The best course of action if you insist on running a pump is to put a bypass fuel regulator and put it as low as possible.
 

nick1rankin

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Location
chattanooga tn
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jetta
THIS
If you mean what PSI is safe to push into the pump, 1-3 is happy, 8 is pusshing it and i dont know of anyone running more than 12. Im running 11PSI on my walbro, did so for 20K miles with no leaks or issues what so ever. (i need a new 11mm pump!)
The best course of action if you insist on running a pump is to put a bypass fuel regulator and put it as low as possible.
It's going to return what it doesn't need. It's like any other pump with excess fuel just cooling the pump and returned. I'm talking minimum needed for it to do its job.
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
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98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
It's going to return what it doesn't need. It's like any other pump with excess fuel just cooling the pump and returned. I'm talking minimum needed for it to do its job.
Look, the IP is its own pump and will draw fuel by its self with NO issues if the pump is working properly and not damaged.

The solution here before you add regulators and pumps and what not, is to rule out ALL other causes for this issue.
Go out and do your filter and fuel lines first.

After all other scenarios and stock parts have been gone over and ensured proper functionality, and things like timing, Q.A., and so forth, then you can safely assume that the IP is at fault because you have no leaks, or loss of prime and so forth.
dont just put on a part assuming its fixing a problem you do not know about. NOTHING worse than doing all that work and spending all that money for no reason.
Now you can start addressing the repair of the IP or putting some bandaid on it with some pump and what not.
I hate to see other ghetto hack to keep a good engine on the road. If its not worth fixing, don't and part it out or whatever your going to do, do it.
You have more than enough information to get started.
 

nick1rankin

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Location
chattanooga tn
TDI
jetta
Look, the IP is its own pump and will draw fuel by its self with NO issues if the pump is working properly and not damaged.
The solution here before you add regulators and pumps and what not, is to rule out ALL other causes for this issue.
Go out and do your filter and fuel lines first.
After all other scenarios and stock parts have been gone over and ensured proper functionality, and things like timing, Q.A., and so forth, then you can safely assume that the IP is at fault because you have no leaks, or loss of prime and so forth.
dont just put on a part assuming its fixing a problem you do not know about. NOTHING worse than doing all that work and spending all that money for no reason.
Now you can start addressing the repair of the IP or putting some bandaid on it with some pump and what not.
I hate to see other ghetto hack to keep a good engine on the road. If its not worth fixing, don't and part it out or whatever your going to do, do it.
You have more than enough information to get started.
You seem pretty clueless to me actually. This is literally a work car. My main question was if there was a simple fix. I determined there wasn't and I dont want to pull my other perfectly good engine apart so I put a lift pump inline and the engine runs perfect. I asked for a solution and got some kind of lecture because you assume any fix that isn't done by so called vw gurus is hack when in reality they are usually people who tell everyone that vws are too hard for the normal guy to work on so they can charge outrageous prices.
 

Giberish33

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May 30, 2017
Location
Montreal, Qc
TDI
1997 Jetta TDi 1z
You seem pretty clueless to me actually. This is literally a work car. My main question was if there was a simple fix. I determined there wasn't and I dont want to pull my other perfectly good engine apart so I put a lift pump inline and the engine runs perfect. I asked for a solution and got some kind of lecture because you assume any fix that isn't done by so called vw gurus is hack when in reality they are usually people who tell everyone that vws are too hard for the normal guy to work on so they can charge outrageous prices.
So you put an inline electric fuel pump and not the previous owner?
 
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KLXD

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Aug 22, 2009
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Lompoc, CA
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'98, '2 Jettas
You seem pretty clueless to me actually. This is literally a work car. My main question was if there was a simple fix. I determined there wasn't and I dont want to pull my other perfectly good engine apart so I put a lift pump inline and the engine runs perfect. I asked for a solution and got some kind of lecture because you assume any fix that isn't done by so called vw gurus is hack when in reality they are usually people who tell everyone that vws are too hard for the normal guy to work on so they can charge outrageous prices.
Previous. I just cleaned up the mess
I'm cornfused.

In one post you say you installed it in the other you say the previous owner did it.
 

nick1rankin

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chattanooga tn
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jetta
Jesus christ. It was on it when I got the thing. Then I took it all apart and made it look better after I realized it had to have the pump or a new ip.

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