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gomi_otaku
gomi_otaku, VW Technician
Category: VW
Satisfied Customers: 3378
Experience:  VW FastTrack '00-'01, VW Academy Chicago and Seattle '00-present, VW Certified
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Volkswagen Jetta: I just bought a 91 Jetta Eco diesel (TD)

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I just bought a 91 Jetta Eco diesel (TD) that had sat for six months. It turns over but will not start. I cracked open one of the injector lines and there was no fuel during starting. No fuel being pumped through the filter either. The VW guy at the dealer said that there is no fuel pump and fuel is drawn by the injector pump. But on mine there is what looks like an in tank fuel pump that you can access from the trunk. It has a fuel line going in and out. There is also some kind of resevoir underneath next to the tank that the line runs through. Just need to know if that is a fuel pump and what the resevoir thing is. I took the out hose off and turned on the ignition and heard nothing, and no fuel pumped out. I checked the connection and it only showed 10.2 volts. Is there a relay for it? Fuse is good. Looking at the relay panel that you sent a few years back to another custumer it does not look like there is a relay. So I really need to understand how the fuel system works on these eco diesels since I have gotten so many different opinions and what you would suggest next

gomi_otaku :

You need to attach a vacuum pump (hand pump) to the return side of the injection pump, and draw fuel through. It has drained down and you can't suck a fluid if there is air in the lines. Once the fluid draws through, then you need to bleed the injector lines. Loosen all of them slightly (this works best with a partner) and crank the engine- when fuel starts spitting at any line, close it. Once you get 3 purged chances are it may even start, so be ready to close that last one quick.

Customer: replied 3 years ago.

OK thanks understand. But need to know about the in tank "Fuel Pump" in the rear and the resivoir underneath next to the tank. Please see my original post. I have already tried to suck fuel through the in line to the filter with no luck.

Customer: replied 3 years ago.

I really need to understand how this fuel system works is it a pull system from the injector pump, a push system from the in tank fuel pump or a combination of both. Have no clue what the "resivior" thing is next to the tank but it has a valve tht when opened drains fuel

It is a "pull" system from the injection pump. Diesels never had an in-tank pump until about 2005 when they went to the "common rail" with individual pump injectors (pumpe duse)
Of course, on top of the tank you will have a feed line and a return line, but you should only have 2 wires at the connector, for the fuel level sensor. The reservoir underneath sounds like a water trap, to drain out water from a low point (later incorporated into the bottom of the fuel filter in the engine bay, where it is untraceable to drain.
If you are pulling with a vacuum pump to the filter, take the fuel cap off to allow it to flow. If pulling through the injection pump you need to turn the key on to open the shutoff valve.
Customer: replied 3 years ago.

thanks makes sense now. did not know about the shutoff valve (key on). will try and let you know. water trap makes sense. it is a big plastic box with a valve. I just seems like it would break super easy if it by a stone.

Gas vehicles from the same years had an in-tank pump, then an external reservoir under there with another pump. They did tend to get broken!
Customer: replied 3 years ago.


ok got it started thanks. lots of white smoke for about 30 seconds. It seems to idle fine but when I give it any fuel it shuts down. Bad fuel, air still in the lines, or what?

It could be bad fuel. Diesel goes bad just like gas, you may want to see if you can get some kind of diesel additive to clean out the system (Seafoam?) and then add new fuel to fill it up in order to dilute what is there. Just letting it idle should help in getting the cleaners through the system.
Customer: replied 3 years ago.


thanks will try it. Looking to replace the hoses between the injectors. They are nylon braided fuel lines (5/32?) that tie into the fuel return line. Neither of the auto parts stores around me have nylon braided line. Can I just use normal fuel line or would you reccomend ordering some braided line of line. Any guess on the right size?

It's actually better NOT to have the cloth overlay, as it can hide cracking. Fuel approved hose is fine. Take a piece of the old stuff with you to match it up, it is pretty small inside diameter
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Customer: replied 3 years ago.

thanks swapped out the hoses starts and run pretty good now thanks. Not much power. Whats the most likley cause. plugged injector, restricted trubo, or what? . Since it sat for over 6 months is there anything a need to clean in the trubo portion. If so how do I do that. Also whats the best way to clean the injectors on these 1.6

Yeah, these 1.6 liters were not very peppy- not only did the ECO diesel cut off the fuel enrichment, but the smaller size engine doesn't help. I would mostly count on running some kind of diesel additive every few tanks to see if that helps anything. With this engine, it's more about the MPGs than the performance.

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