Fuel Sender/Gauge E30

[_ethrty-Andy_ 2122]

The gauge drops smoothly from Full to 0 in the time it takes the fuel tank to fall to about half way. ie half full tank indicates empty on the gauge, full tank = full on gauge. I have replaced the Sender twice, and the gauge cluster was rebuilt and then replaced and none of these fixed it. im out of ideas.. they are the only two possible issues i can think of. The Sender is VDO and my gauge cluster is MotoMeter (though i have tried a VDO cluster) does that cause any compatibility issues? I went to the yard and all three E30s with Motometer clusters had VDO senders.

Any Ideas?

Edited January 5, 2010 by ethrty320

[e30ftw 394]

Whats the issue? I don't get the first line at all.

[_ethrty-Andy_ 2122]

sorry should have proof read. Edited

[e30ftw 394]

Do you have the fuel level sender from a facelift car?

The fuel tanks on pre-F/L are different as the fuel tank is seperated into 2 sections, as it goes over the driveshaft, on a pre-fl e30 the 2 sides are joined by a pipe at the bottem, joining them. On a facelift car they are not, they are just joined from a transfer pump which pumps fuel to the other side IIRC, So the fuel level sender will indicate different level overall I think.

Sorry if it don't make sense, But I am sure that must have something to do with it, I've read someone having a similar issue before.

[_ethrty-Andy_ 2122]

Do you have the fuel level sender from a facelift car?

The fuel tanks on pre-F/L are different as the fuel tank is seperated into 2 sections, as it goes over the driveshaft, on a pre-fl e30 the 2 sides are joined by a pipe at the bottem, joining them. On a facelift car they are not, they are just joined from a transfer pump which pumps fuel to the other side IIRC, So the fuel level sender will indicate different level overall I think.

Sorry if it don't make sense, But I am sure that must have something to do with it, I've read someone having a similar issue before.

I know what you mean.. my 90' 320i doesnt have that but my '89 316i does. Never noticed that difference before. Would you mind finding me the link to this person if possible? im going away on a road trip next week and would rather like it fixed. its never bothered me before but handy to know now

[e30ftw 394]

I remember reading it on bimmerforums or e30tech or something, Not sure.. Might be completely wrong, wait til someone else chimes in. But I'm pretty sure the level sensors are different between the tanks. The 89 should have a facelift tank, only pre facelifts (pre 88) had a pipe connecting them at the bottem.

[hotwire 352]

Do you have the fuel level sender from a facelift car?

The fuel tanks on pre-F/L are different as the fuel tank is seperated into 2 sections, as it goes over the driveshaft, on a pre-fl e30 the 2 sides are joined by a pipe at the bottem, joining them. On a facelift car they are not, they are just joined from a transfer pump which pumps fuel to the other side IIRC, So the fuel level sender will indicate different level overall I think.

Sorry if it don't make sense, But I am sure that must have something to do with it, I've read someone having a similar issue before.

Partly correct ^^^^^^ Yes to the tanks as physically described but incorrect as to fuel transfer in the F/L tank.

This is infact done via a syphon type tube (on fuel return) mounted inside the tank where it runs along bottom of L/H side up & across the bridge & down into the swirl pot by the fuel pickup on the drivers side.

There is a sender on each side.

If yours is F/L- I recommend removing both senders (under cover each side of car) & checking fuel level in each side is the same.

I had a case in my race car when I first got it where unknown to me - the syphon tube inside the tank had a hole in it up near the top at the bridge, this caused the tank to empty from the drivers side (as usual) but fuel return was simply dumping into L/H side & not transferring due to the loss of prime in the pipe.

Net result - car running out of fuel & L/H side still full.

Remedy - replace the tank.

Motometer/VDO - not a compatibility issue - they interchange

Edit: If fuel levels correct - Check L/H sender

Edited January 6, 2010 by hotwire

[_ethrty-Andy_ 2122]

Partly correct ^^^^^^ Yes to the tanks as physically described but incorrect as to fuel transfer in the F/L tank.

This is infact done via a syphon type tube (on fuel return) mounted inside the tank where it runs along bottom of L/H side up & across the bridge & down into the swirl pot by the fuel pickup on the drivers side.

There is a sender on each side.

If yours is F/L- I recommend removing both senders (under cover each side of car) & checking fuel level in each side is the same.

I had a case in my race car when I first got it where unknown to me - the syphon tube inside the tank had a hole in it up near the top at the bridge, this caused the tank to empty from the drivers side (as usual) but fuel return was simply dumping into L/H side & not transferring due to the loss of prime in the pipe.

Net result - car running out of fuel & L/H side still full.

Remedy - replace the tank.

Motometer/VDO - not a compatibility issue - they interchange

Edit: If fuel levels correct - Check L/H sender

So your saying something is ment to be under that round panel under the seat? ive wrecked a couple E30s and have had that cover go to nothing so didnt even bother to check it on the 320i. so there is a sender there i should replace? ill have a look if i have a sender there or not

[e30ftw 394]

I thought thst was the one you were talking about. Yes on facelift cars there should be a level sender under that circle cover, on the left side.

[_ethrty-Andy_ 2122]

I thought thst was the one you were talking about. Yes on facelift cars there should be a level sender under that circle cover, on the left side.

okay sweet ill have a look tomorrow

[hybrid 1039]

Do you still have this issue ?

[_ethrty-Andy_ 2122]

i did before the car got taken to pieces yeh

edit: which means as far as i know yes. i havent done anything further to try fix it

edit2: (after reading the thread) I replaced both left and right senders and still had the same issue. Did not check to see if the level in each side was the same, but the car doesnt run out of fuel.. it must get fuel from the LHside as well.. no way i can do 500-600+ kms on one side of the tank in town driving. So i doubt that syphon tube is the issue. hmm

Edited May 16, 2010 by ethrty320

[hybrid 1039]

I beleive the problem isn't with the gauge or the sender.

I think you possible have a FL cluster electronics on a Pre-FL senders.

Here is what I found last night as Im using a pre-fl tank( pre-fl car) with a FL cluster.

I ran out of gas when the gauge read half way (FL cluster / pre-fl tank/senders) When I put some gas in the tank I got 40liters of gas however its been very slowly going down on its way to half way (real empty)

So, I removed the FL cluster and added my pre-fl fuel gauge and pre-fl front bezel cover electronics to make a hybrid.

result = gas gauge 20 liters (1/3rd full) and tacho / speed / fun meter stopped working and I guess temp too but car was cold

I then made the following

pre fl fuel gauge + fl front bezel electronics + fl gauges

result = 20 liters (1/3rd full) with everything else working.

My conclusion however is that I still have an issue that, I think mytank is probably really half full but only showing 1/3rd full .. so full tank = full tank on gauge however empty gauge = half full tank. (not sure yet will test later when I can legally waste petrol )

I think the only way around this is going back to pre-fl cluster and working some magic on the loom adapter. As changing the tank to FL is a major as I have already spend the $$$ on fuel pumps / surge tanks.

Trick: You only find this sh*t out when your try this wierd stuff for yourself as most people just leave their clusters alone! haha

[_ethrty-Andy_ 2122]

When i got the car it was bone stock save for an alarm so everything thats been done to it i have done. All senders that i have used have been from facelift cars and same as the clusters (have only ever wrecked facelift cars). Keep at it thought mate its appreciated!

[huff3r 347]

I beleive the problem isn't with the gauge or the sender.

I think you possible have a FL cluster electronics on a Pre-FL senders.

Here is what I found last night as Im using a pre-fl tank( pre-fl car) with a FL cluster.

I ran out of gas when the gauge read half way (FL cluster / pre-fl tank/senders) When I put some gas in the tank I got 40liters of gas however its been very slowly going down on its way to half way (real empty)

So, I removed the FL cluster and added my pre-fl fuel gauge and pre-fl front bezel cover electronics to make a hybrid.

result = gas gauge 20 liters (1/3rd full) and tacho / speed / fun meter stopped working and I guess temp too but car was cold

I then made the following

pre fl fuel gauge + fl front bezel electronics + fl gauges

result = 20 liters (1/3rd full) with everything else working.

My conclusion however is that I still have an issue that, I think mytank is probably really half full but only showing 1/3rd full .. so full tank = full tank on gauge however empty gauge = half full tank. (not sure yet will test later when I can legally waste petrol )

I think the only way around this is going back to pre-fl cluster and working some magic on the loom adapter. As changing the tank to FL is a major as I have already spend the $$$ on fuel pumps / surge tanks.

Trick: You only find this sh*t out when your try this wierd stuff for yourself as most people just leave their clusters alone! haha

Dunno if it helps, but my PFL hits R with at least 15L to go most the time. Normally hits the 20L mark after about 200-250kms, when really it shouldnt hit that till at least 350kms... so maybe its just a PFL E30 thing? Or maybe something in mine is stuffed too haha

[_ethrty-Andy_ 2122]

I just drive around till ive done around 500kms and then refill and reset the gauge. i end up putting around 35-40 liters in, dont want to let it go any lower than that in case i get stranded some where hah