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Unkown fuel system component leaking fuel 84 Jetta


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RoboDisko
User

Jan 7, 2014, 5:45 PM

Post #1 of 21 (1302 views)
Unkown fuel system component leaking fuel 84 Jetta Sign In

Hi everyone. I recently noticed that my car was leaking fuel! The car is an 1984 Volkswagen Jetta with a 1.8L engine and a mechanical fuel injection system (CIS).

Anyways, some cylindrical object mounted behind the right rear tire becomes wet with fuel, and it drips off. I really am not sure what this thing is. I am pretty certain it isn't the fuel pump or fuel filter, because I have separately located those. It has 2 hoses on it, on goes to the fuel pump, and the other goes towards the engine. I cannot see any electrical wires on it. Is it possible that it is a second fuel filter? I find it odd that it is mounted further away from the engine than the fuel pump is.

As far as the leak, It has a rather slow drip when the vehicle is running, and it continues after the vehicle is turned off for a while. Presumably this is the fuel system depressurizing, and possible draining itself as well. The draining could explain why the vehicle takes a long time before starting after resting for a while.

With this leak, I calculated my fuel economy at about 18mpg. This car is rumored to get 30+ mpg, and I think I can get better than that after fixing this leak. Anyways, I can't afford to drive this thing @ 18mpg, plus it is probably a rolling bomb, so I would like to get the leak fixed.

Here are some pictures of this mystery item. One of the picture is of the fuel pump, another is of the fuel filter, and the rest are different angles on the mystery item.

The mystery object:


A small puddle of fuel under the mystery object:


Side angle when wet:


And a pic when dry:

Another angle dry:


Pretty sure this is the fuel pump:


And pretty sure the fuel filter is the black fuel-filter shaped object on this picture: (gotta love the 4 gauge unfused wire hot glued to the battery that feeds my subs and the hot glue-repaired vacuum joint in this picture :)


You guys are the pros. What is this mystery item? Will it need replaced, or can I repair it myself? How should I go about repair/replacing it?


(This post was edited by RoboDisko on Jan 7, 2014, 5:48 PM)


Discretesignals
Ultimate Carjunky / Moderator
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Jan 7, 2014, 6:43 PM

Post #2 of 21 (1284 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

That is the fuel accumulator:







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RoboDisko
User

Jan 7, 2014, 7:48 PM

Post #3 of 21 (1280 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

Awesome!

and ouch....those things can be a bit pricey. $75 is the cheapest I've found, and that's almost how much my subs and amp costed. Is it going to need replaced? Or will it be repairable?


Discretesignals
Ultimate Carjunky / Moderator
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Jan 8, 2014, 5:25 AM

Post #4 of 21 (1259 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

There is no service procedure for repairing it, so your probably going to need to replace it to be on the safe side.





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RoboDisko
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Jan 9, 2014, 6:55 PM

Post #5 of 21 (1227 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

Ok, I have a friend who has a brother that owns a junkyard that has a newer Jetta that I can probably grab a matching part for free off of. In return I'll probably do some computer work for the owner.

Anything special I should know about taking it off? I would rather keep the estimated remaining 1.3 gallons of gas in the tank.


Discretesignals
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Jan 10, 2014, 5:38 AM

Post #6 of 21 (1217 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

To be honest, I am not sure. Don't have any information on replacement of it. The fuel pump replacement procedures is this, so the accumulator is probably similar:


Quote
ELECTRIC
1. Remove fuel tank cap to relieve tank pressure.
2. Clean fuel pump and fuel line unions thoroughly to prevent entry of dirt into fuel system.
3. Disconnect fuel lines and electrical connections from pump.
4. Remove retaining bracket and clamp, then the fuel pump.
5. Reverse procedure to install.




Might be a good idea to have a container handy to put the line for the tank in just in case it decides to pour out.





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RoboDisko
User

Jan 14, 2014, 6:59 PM

Post #7 of 21 (1199 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

Ok, the junkyard didn't have an identical match. I found a similar one that I think broke when I tried taking it off. Anyways, I googled around and it didn't seem like it would be a big deal to bypass it, any second opinions on this?


Tom Greenleaf
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Jan 15, 2014, 2:02 AM

Post #8 of 21 (1192 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

May I suggest putting PB on all the fasteners now needed to replace this thing? By-passing might make it run but the thing is there for a reason. The parts assortment to make up a "U" line properly would cost about as much as just doing it right with a new one,

T



Hammer Time
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Jan 15, 2014, 3:39 AM

Post #9 of 21 (1189 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In


Quote
and ouch....those things can be a bit pricey. $75 is the cheapest I've found, and that's almost how much my subs and amp costed.


Well, of course the stereo is more important than the fuel system.



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Discretesignals
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Jan 15, 2014, 5:40 AM

Post #10 of 21 (1182 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

I don't think it would be a wise idea to bypass the accumulator.


Quote
It improves hot starting by helping to maintain residual fuel pressure when the engine is turned off. It also helps to reduce fuel pump noise by its damping action and protects the metal diaphragms in the fuel distributor from rapid pressure build-up when the pump begins running.






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RoboDisko
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Jan 15, 2014, 8:14 AM

Post #11 of 21 (1174 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

to tom: I was think of just putting a double sided fitting on it, or even just putting the fuel line on the pump. minimal or 0 new part count.

To Hammer Time: Of course the stereo is more important than some metal cylinder that is never seen and can be bypassed without significant effect on engine performance.

To Discretesignals: From what I have read, it's biggest function is to prevent vapor lock when the engine is warm. Well, I think it is letting the fuel leak out of the lines anyways, and it doesn't have an issue, other than when its been sitting for a bit and it takes a very long time to start the engine. I think it is because the fuel may have leaked out of the lines. As for the distributor, several people have said (I would link if i could) that they have bypassed it without a noticeable effect on anything.


Hammer Time
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Jan 15, 2014, 8:25 AM

Post #12 of 21 (1170 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In


Quote
From what I have read, it's biggest function is to prevent vapor lock when the engine is warm.


There is no such thing as vapor lock on a fuel injected, return type system.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
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Jan 15, 2014, 8:45 AM

Post #13 of 21 (1169 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

OK - Now you are cracking me up some! "Of course stereo is more important" - well not if you like some stage fireCrazy

Whatever you even tried to rig up to by-pass this dang thing doing so such that it doesn't become its own problem or leak still will be a challenge. Fuel will leak where other things will not so no room for faking it.

I doubt it's vapor lock as that is so old I remember it for real! That happened at the engine end when fuel was boiling unseen in the lines under low pressure, hot days and engine heat. Forget that one.

Now post from DS is out of view but thought there was more to this silly thing. I figured it had to have more going on than just an empty can. It seems as I guessed it holds fuel under pressure for when pump isn't operating and thought it might also be able to cover a sudden fuel need when pump couldn't be fast enough and it seems so, so there's more going on in there than you think.

I know it's old but since long before this car makers just don't put extra things out of new car buyer's sight especially that don't have a reason as it cost something to design and put it there new. As I said it isn't there for its good looks.

If you don't have the tools have it done. Those flare nuts look good for this age but just wait and see how fussy those are and easily twist up the lines or worse leak or really worse send on shards of metal that shouldn't make it thru fuel filter but would or could be in the system - not cool.

Flare nut wrenches or flare nut crow foot sockets along with PB as those nuts will like to stick to line not so much the threads stuck. Can take an assortment of them to get in tight places with the correct grab so you don't mess it up and really ruin your day. Well I guess you could just sit in the thing and listen to tunes till the battery croaked - laugh.

That band that holds it could be a real problem by itself? That's where the body of such things would rust under that band. You can't use torches to get this out and I'm not being funny this time so rely on PB especially. You already broke one at the junkyard so you get the idea.

Screw the cost for this which is nothing as cars go. I need more fuel in my own vehicle just to top off my gas tank than this will cost!

It's fuel dammit. Fine if you don't care but it could blow up, catch fire and be a real disaster and a hazard to others. It's your responsibility to make this right or dump the vehicle if you can't keep it safe.

Enough badgering from me, you get the scoop,

Tom



Hammer Time
Ultimate Carjunky / Moderator
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Jan 15, 2014, 8:54 AM

Post #14 of 21 (1165 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

With all the weight and cost issues in manufacturing a car now, do you really think they would install unnecessary parts?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



nickwarner
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Jan 15, 2014, 10:55 AM

Post #15 of 21 (1154 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

You drive a VW and think $75 is an expensive part? Wow. This thing holds fuel. It is there for a reason. It is leaking fuel and that creates a hazard. Fix it once, fix it right and drive the car. Your car needs to be safe to be around all the rest of us who have to share the road with you. It isn't a stereo holder with four tires. If you can afford subs, amp and a deck you can pull out $75 and fix the thing they are in.

I wouldn't brag up the stereo too much anyhow. If you only spent $75 you don't exactly have a lot. The amp in my truck was a bit over $600 and the subs ran me $130 each without a box, and it is by no means a competition stereo.


Tom Greenleaf
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Jan 15, 2014, 11:13 AM

Post #16 of 21 (1153 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

Nick - That much stereo in your truck is totally important and useful. You blast it and shake all the snow and ice off of it without having to really clear it off, LOL,

Tom



nickwarner
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Jan 15, 2014, 12:06 PM

Post #17 of 21 (1146 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

It gives me great gas mileage. Every time I turn it up the subs rattle at least 25 pounds of rust off my frame that I no longer have to burn gas to move around.


Hammer Time
Ultimate Carjunky / Moderator
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Jan 15, 2014, 12:27 PM

Post #18 of 21 (1145 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

Yep, I see them all the time. $900 stereo in a 10 cent car. The wheels are falling off and it barely runs but it's got a $1000 stereo.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



nickwarner
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Jan 15, 2014, 12:47 PM

Post #19 of 21 (1143 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

You mean the 22" rims are falling off of that? What a shame.


Discretesignals
Ultimate Carjunky / Moderator
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Jan 15, 2014, 6:10 PM

Post #20 of 21 (1134 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

Don't think I would get another accumulator from the salvage yard. Who knows how long rotted gas has been sitting in it eating up the diaphragm.

I wonder if the replacement accumulators are more tolerant to ethanol??





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


RoboDisko
User

Feb 8, 2014, 5:54 PM

Post #21 of 21 (1058 views)
Re: Unkown fuel system component leaking fuel 84 Jetta Sign In

Hey stop describing my car :)

But really, I'm not that bad. My stereo in it sounded good, except for an utter lack on the low end. And I had a little extra $ at that time. It was only $100, I built the box myself to save money.

As for the car, it runs, but it needs maintenance. It's been 0F here for a while, if i go out there again I'll probably freeze. I hope to get it running very well over the summer.

Anyways, for the problem. I went back to the junkyard, equipped with more tools, and managed to pull it. But yea, its cold here, and do you have any idea how hard it is to take a bolt off when you can't feel the bolt, or your fingers? Although I had thought I broke it, I didn't, and it doesn't leak. However, if i put it under a faucet going in one side, it freely comes out the other, on either side, so it obviously doesn't perform it's intended function. My old accumulator does the same thing, so it has probably been broken for a while. Installed it - no leaking fuel - :).

Anyways, I'm pretty happy with the broken bypass I put in, and I plan on leaving it as is. My car is far from running well, so I started a new thread looking for suggestions to make it run better. It's called "Old Car Performance/Efficiency Suggestions" (Why no link? Because it's against the forum rules to make your life easier in that manner) And we should move further talk about my stereo, rust, and 22" rims there.


(This post was edited by RoboDisko on Feb 8, 2014, 5:54 PM)






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