Author Topic: Fuel gauge reading isn't correct, what's up? (Read 6779 times)

91 318is · « **on:** June 13, 2010, 08:25:16 PM »

Long story short, cluster was swapped out and now the fuel gauge is reading 1/2 tank when fuel tank is almost empty, and the low level light comes on. I read around and seemed like a normal problem with swapping early model clusters into late model cars. I got a working gauge and matched the part #'s with realoem's correct part # for my car, swapped it, and is still not correct. I also swapped the fuel level sender for a new unit, that obviously didn't help.

Oh and I also, I checked to make sure the little box that plugs in the front of the cluster is the correct one and it's the blue one, which is for the 318.

Anyone have any idea?

Romrog318is · « **Reply #1 on:** June 13, 2010, 08:39:12 PM »

check the level sensor in the tank
this was the problem in my other 318

carlos318is · « **Reply #2 on:** June 14, 2010, 05:03:10 PM »

The float chamber gets stuck in the tank I have never maneged to repair one yet either

91 318is · « **Reply #3 on:** June 14, 2010, 07:01:19 PM »

the fuel level sender was changed for a new VDO unit.

I'm thinking it has something to do with the cluster, the PO told me as soon as he had the cluster swapped by a shop, it hasn't been right since.

So that's why I changed the gauge out for another fuel gauge that has the correct PN for the car, and that still didn't help.

Any other way the cluster would cause this problem besides the actual gauge?

Slick92GS-R · « **Reply #4 on:** June 16, 2010, 08:10:26 PM »

you would have to change the little 'pill' from your old cluster to the new one.. its looks like a lil memory card on the front right (i think) corner

91 318is · « **Reply #5 on:** June 16, 2010, 08:16:25 PM »

Quote from: Slick92GS-R;93607

you would have to change the little 'pill' from your old cluster to the new one.. its looks like a lil memory card on the front right (i think) corner

The code plug you mean? Well from what I've read, I got the blue plug, and that's for a 318.

Slick92GS-R · « **Reply #6 on:** June 16, 2010, 08:19:48 PM »

Quote from: 91 318is;93609

The code plug you mean? Well from what I've read, I got the blue plug, and that's for a 318.

ah yes.. the code plug .. the name escaped me.. whatever code plug that came with the original cluster is what you should stay with

dvmotorsports · « **Reply #7 on:** June 18, 2010, 01:46:22 PM »

The coding plugs are not always blue. Mine is white/cream

Anyhow, this is a common problem on E30's. It is one of three things.

a. coding plug
b. grounding nut on back of the fuel gauge is loose
c. faulty connection at the the pump/level sender

DesktopDave · « **Reply #8 on:** June 18, 2010, 08:20:14 PM »

That gauge is never right anyway. It lies to me all the time.

jscribble · « **Reply #9 on:** June 18, 2010, 09:28:31 PM »

Ditto that. I give mine an accuracy range of +-20%. Mileage is a better gauge imo, doesn't change unless I run crummy (read: ethanol) gas. If the coding plug doesn't work out, at least yours sounds like it has an even discrepancy.

91 318is · « **Reply #10 on:** June 28, 2010, 07:18:19 PM »

Well I got another known good cluster out of a 318is, I had to swap my coding plug over because from what the guy told me, it wasn't the right one. Still doesn't work though.

How do I know the coding plug is a M42 coding plug? What's the part # for the correct one?

91 318is · « **Reply #11 on:** June 28, 2010, 07:19:37 PM »

Also, I checked the connection on the sender, that looks good, pumps seems to work becuase I've been driving the car with the gauge messed up.

The gauge doesn't jump or fluctuate which would indicate a bad connection.

AHHHHHHHHHHHHHHHHH!!!!!!!!!

91 318is · « **Reply #12 on:** June 29, 2010, 09:25:32 PM »

nobody?

jscribble · « **Reply #13 on:** June 29, 2010, 09:57:23 PM »

Sorry friend, I'm drawing a bit of a blank here. I don't have too much experience on this one. Will report back if I come across a pn or any other info. Good luck!

NO_CARRIER · « **Reply #14 on:** June 30, 2010, 01:40:38 PM »

I thought these cars had TWO level sensor, (e36) one on each side of the tank. And the computer averages the two out to provide the fuel level. If ONE of the senders is stuck at full, then when you are empty it would say 1/2 tank. Maybe try checking the other fuel level sensor?