Gasoline meter

Need urgent support.
My XJ is at Service garage; since around 1 and a half month the needle of the gasoline became "crazy" and also the yellow warning light (no gasoline warning). Most of the time when i filled the tank gasoline needle went up ok, but after a few minutes it went full down and just at each time the yellow light turned on.
I didn't left it at the service garage as they didn`t had the spare part of the gasoline tank (meter that floats) and they said no doubt it was failing. Well, spare part arrived and was replaced today, but mechanics realized at the test that failure didn't went away. They said they will follow the electric line all along to the computer and then to the "panel". Also one of their theory, the worst, is that the computer of the XJ should be replaced.
Someone has an idea about it?
Please help!!!!
XJ classik year 2000 4.0
Thanks in advance.

Mike

Are all the rest of your guages(meters) reading correctly?

dont let them replace the computer though. usually the float wears out on the printed circuit. if they replaced it there may be a poor connection at the instrument cluster. is that the only gauge affected?

Yes they are. Even tested with the auto check system (contact + reset miles button).
Thanks

Mike from Chile said:

Yes they are. Even tested with the auto check system (contact + reset miles button).
Thanks

Click to expand...

I mean is the only gauge affected. Does anyone know what is the path of the wire between Gauge (needle?) and the gas tank? Is it true that it pass thru computer? Anyway the method they are using now is to check with an electronic tester the voltage at different points of the wire as they said they found a loss off voltage when failure appears (don`t understand too much and wonder if its true)
Tks

Mike from Chile said:

I mean is the only gauge affected. Does anyone know what is the path of the wire between Gauge (needle?) and the gas tank? Is it true that it pass thru computer? Anyway the method they are using now is to check with an electronic tester the voltage at different points of the wire as they said they found a loss off voltage when failure appears (don`t understand too much and wonder if its true)
Tks

Click to expand...

FYI the first time my float was replaced they broke the pump. Took it back to get the pump fixed they broke the new sensor and finally got it done right on the third time.

Your Gas level sensor line runs from the pump to the Computer (PCM), and the PCM communicates with the instrument cluster via the CCD Bus. This Bus carries most of the data that the Cluster uses, all through the same wires. So, if only one gauge is failing, it should be: a) because the PCM is getting the wrong reading, b) the PCM itself has gone bad or c) The gauge itself is broken.
Turn your Key to the RUN position while holding the trip-reset button in for 5 or 10 secs and watch your instruments: you'll see if your gauge is bad.
Otherwise, double check your wire between the Gas Level sensor (pin 3 at the pump connector) and PCM connector C3, pin C26. You should have a good ground from PCM connector C1, pin A4 to pin 4 at the Gas pump. Also, you can see what voltage you get between these 2 wires: it should be about the same at both ends and change according to your Gas level at the tank.
If all this is OK, then it must be your PCM.
Good Luck. Hope it's just a wire.

Thanks to all of you guys for your complete hints. Will transmit this info to the guy who is working on it, allthough he seems to be on the right way.

Will tell results after it.

Mike

if its an aftermarket float make sure that it is the right length, i had mine replaced 4 times because my gauge wasn't working before they realized that the aftermarket float was getting stuck against the tanks wall.

News Update,
I finally took my XJ from service; the guy told me he wired rirectly fron float to PCM and problem went aout; so he worked on a big conector inside the cabin below the dashboard(¿?) and suddenly realized that problem was gone. He made several ride test and was ok, even when I was driving home.....BUT.... few minutes before arriving, needle fell and recovered intermitently until it became down.

What do you think?

Mike

Probably, same under-dash connector. Have it cleaned again. I'll check the manuals & let you know over the weekend its ID and location.

Ok. By the way you must speak panish don't you?
Saludos
Miguel

I had several wiring problems on my 98. First was the big grey connector down by your left foot on the firewall. Mine was so loose it almost fell out, nobody had tightned the bolt in the middle of it that held it together. Second was the connector to the right of your right leg, black one, controls power to the radio, switches, etc, that one was also falling apart from being loose. Third was the instrument cluster going dead, removed the cluster, cleaned the connectors and put it back together again, the screws holding that panel in were also loose which I think is why it was backing out on bumps and reconnecting on bumps. That still left the fourth problem of the gas gauge being inaccurate, I have not had mine out but from others I have talked to the gas sender is painted on there and the paint/finish comes off from gas breaking it down. Now I was also told that the sender was not a seperate item that you could replace, you needed to do the whole fuel pump because it was one piece. Lately I'm hearing different so I have to wonder if Jeep/Chrylser redesigned it after 98. Be nice if someone could post a picture of the 98 fuel pump that went bad and compare it to a new replacement to see if the pumps are the same...

That's right. The connector by your left knee. Actually, in the 2000 XJ there are two twin-looking connectors with a bolt each right in the middle. Those are C100 and C200 in the diagrams. Your fuel level wire (dark blue with a light green stripe) runs through both on its way from the sensor to the PCM.

Sure speak spanish. Actually, my family is from Spain. :wave1:
Saludos.
Jose Luis Diaz.

After a second 2 days visit to an "official" service the answer is that they checked over all connections, dismounted the dash for a second time and everything is OK; they report that to Headquarters and they "would have said" that several cases of defectuos floats have been reported, so they would ask for a new one again. ¿¿?? I don`t trust at that answer, but I'll need to bring it back to the service to know the truth.

Thanks