gas guage problem

[gary pichon]

I have recently purchased a used 97 Z3 1.9 that has a gas guage problem. When I first fill up the needle swings back and forth between empty and full then settles to read accurately. The swinging seems to be related to car movement. The sending unit was replaced about 10,000 miles ago. The carpet is cut. How and where do I check the connections to make sure they are tight? Is this likely a connection, computer, or sending unit problem.

Thanks Gary

 

[wileycoyote]

This is a really common problem. I had the sending unit replaced a couple times, under warranty, but now I just live with it.

Check this page out, it has all the details on why this happens.

http://www.waycoolinc.com/z3/essentials/fixit/index.html

 

[Z3_Ant]

i have this problem, my car is the same year as yours but it's a 2.8, at first i was a bit concerned but now it's a case of watching it, it makes me laugh!! hehe.... it's a case of dealing with it or spending money to sort it out, i know what my choice is..... lol

 

[Big Daddy]

Mine too did that and I tried all the fixes, except replacement. When I began using Redline SI-1 Injector Cleaner in the car it stopped acting weird. One day I just noticed that the gauge was no longer bouncing around, or not going to 3/4 instead of full. It has been over two years and has not done it again....yet?

 

[wileycoyote]

Is Redline SI-1 available in stores? I am going to run some injector cleaner today, was planning on using the Chevron Techron stuff.

 

[Z3_Ant]

yet...........touch wood!!! lol

 

[Big Daddy]

Is Redline SI-1 available in stores? I am going to run some injector cleaner today, was planning on using the Chevron Techron stuff.

No it is not that I know of. Some specialized dealers have it, race shops, etc.

 

[Bear6360]

I would bet that most of you top off your gas tanks. I topped mine off and experienced a similar problem. They had to cut the carpet in the back to fix the problem.

See here for more details:

 

[grc]

bear, it sounds like they did yours worse than mine! after the dealer did my sending unit the gauge compared to the miles traveled/left in tank were considerably different than before. i attribute this to the float arm being bent differently. yours could be going"beyond range" at full and the rheostat or whatever is going above itself to an area that doesn't make contact. just a guess?

 

[Bear6360]

I wondered why it smelled like gas in my car for days after they fixed it.

 

[Big Daddy]

I used the SI-1 Injector cleaner and still top off my tank. No problems in the last year.

 

[wileycoyote]

I got really worked up and posted a few flames on Roadfly regarding the SRS and gas guage problems. BMW NA just sent me an email and offered to help. Not sure what they can do, guess I'll find out next week.

 

[grc]

i've read somewhere that it is believed to be deposits/residue from the fuel that builds up on the contact area of the sender. injector cleaner may help if this theory has any merit. i use injector cleaner regularly and don't have the dancing gauge. the injectors seem to need to be lubed to keep top performance.

 

[Bear6360]

Glen, what do you use?

 

[grc]

i get the cheap fuel injector cleaner at the local dollar store. i notice a difference in the way the engine runs if i haven't poured one in for a while. the BMW parts counter has a product that surprisingly isn't too expensive. but it's the same stuff for a buck. i wouldn't be surprised if it turned out to be kerosene or deisel! look on the bottle for a CAS number and research it on the web. i found that the $15/qt octane boost is kerosene.