97 Jetta, yes again, fuel gauge oscilating...

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Alrighty,

I haven't had a change to get my jetta to the shop (have been waiting for the new grille parts to arrive and so I can get this all done at once) to check on the misfire issue. Am going to check the o-rings and the coil pack next.

Today's story: First, the car has been starting rough for the last week, but no 'check engine' light. It's a good thing, right? Second, I started the car tonight, and it was rough. I stepped on the gas then then the fuel gauge went all the way to empty. It oscilated a bit. I drove it two miles to town and in that time it only got as high at 3/4 (it is a full tank). But it sounds as smoothe as ever. When I parked the car the gauge went back down to 1/4. I need to drive to Philadelphia and back tomorrow (3 hours each way). Should I be worried at all about this?

vwecodiesel


The car's stats: 97 jetta, gas engine, 99900 miles, 5 speed

posted by  vwecodiesel

The fuel guage issue sounds to me like a 'sender unit', basically it just opperates the guage itself, it shouldn't be anything to worry about though, just make sure you keep a close eye on the fuel and dont run out, if in doubt, top it up, it cant hurt lol! :thumbs:

posted by  Cliffy

Should I be concerned that the gauge went up when I stepped on the gas to get up a hill?

posted by  vwecodiesel

Not really...what were you thinking the problem could have been?...there's only so much trouble this can cause you :thumbs:

posted by  Cliffy

Not sure, injector issue or voltage regulator? This car is still new to me. Is this gauge regulated by a a microprocessor instead of sending the current from the sending unit to the gauge? Could my misfire problem and the gauge problem stem from the microprocessor?

I need to get the computer-free ecodiesel back on the road....

posted by  vwecodiesel

To tell you the truth, the sender unit was the first thing that came into my head lol. I'm not sure how it's regulated on your particular car, but I'd say the faults you describe are unrelated myself! :thumbs:

posted by  Cliffy

My husband insists there is a gremlin living in my car lol

posted by  vwecodiesel

Yes...or it's posessed by Satin lol....If you are concerned about it (not the devil...the problems your car is giving you lol), I'd highly recomend you take it to a Mechanic, afteral, you know your car better than we do! :thumbs:

posted by  Cliffy

The fuel sending unit on fuel injection is located with the pump inside the tank on most cars. (Some German cars use Bosch Jetronic/K-tronic systems). The sender, as said before, reads separate from the pump itself. A bad ground at the sender usually casues a fluctuating needle in the dash guage. Have you checked the car for recalls or tech bulletins regarding the miss? I have sent several to the dealership for ECM resets. Especially if you get a loping idle with the miss. (Also, those material looking vaccum lines are tricky to see if they are leaking air, there is one going from the fuel pressure regulator, check it for dry rot). That line is $11 a foot at the dealership. Get the local dealership to tell you which two wires at the harness plug by the gas tank are for the sending unit and what their resistance/voltage input/output should be, and check it. If they pass, odds are pretty good you have a bad ground. I believe the sending unit and the pump share a common ground on that vehicle. If it is 5 wire plug, I know they do. If you have more then 5 then they have their own grounds. The microprocessor processes what is sent to it, it usually does not act up on one single item like the gas gauge since the circuit would transfer both the fuel delivery and gas content on the same board. I would check the resistance on the coil and plug wires. The coil on that car is VERY expensive, especially if it is located in the back near the firewall on the drivers side. CHA-CHING! They usually dont go bad this early on.

posted by  MsSnapon

MsSnapon

Thanks for the ├╝ber reply. Will check on all those things. My mechanic in Philly suspected the coil pack back in February, but I haven't been able to leave the car with him over night since I don't live there anymore.

vwecodiesel

posted by  vwecodiesel

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