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Discussion Starter #1
Hello all!

So the other day I pulled the fuel tank on my '91 C900 and removed the sender unit that was separate from the fuel pump assembly. Curiosity got the better of me while I was looking at the sending unit, and I ended up pulling the top off and breaking 2 connections inside the unit. Greeeat.

So far I have been unsuccessful in trying to find wiring diagrams and instructions on how to fix it. Has anyone fixed a sending unit before? I would love to save the money and not buy a whole new one.

Also, I noticed that the fuel pump assembly has a float arm, assuming that is a sender as well, can I move power to the float arm sender, and bypass the other sender unit?

Any help would be much appreciated!


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You cannot use the sender on the pump - totally different characteristics. That sender is for a 9000/9-3/9-5.

I'm not aware of anyone who has done a successful long-term repair on a sender. It probably has been done - they aren't complex - but I've never seen it.
 

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As mentioned it';s a 9000 pump and the sender uses a different power to the 900 sender unit, I'm no sparkie, but think I heard it was resistance levels in the 9k where the 900 nis direct? but may be wrong about details but can't be used.
The sender can be repaired but I haven't got any details but if one wire was off it's easy which one goes where, but not sure which goes where, I have a spare one like yours in the garage, I took out of one I owned as had a good one to replace it.
 

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You can repair the sender. It's not rocket science. There are only two wires; difficult to get wrong and a wiring diagram exists in the manual in the stickies. I've repaired several and they keep working, even years later. I believe there is a post on repair of the sender in this forum if you do a search. The sender in the pump assy is for a 9000 and not compatible with the 900 gauge. If in doubt source another on eBay, http://www.ebay.co.uk/itm/Genuine-SAAB-900-Fuel-Gauge-Sender-Transmitter-9361957-/263222612039?hash=item3d494a5047:g:i2oAAOSw5FpZmwaa
 

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Discussion Starter #5
I was able to fix the sender, it wasn't hard once we got going. I'll post another thread with a write-up on how we did it when we get the OHM readings.

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I would appreciate that. I see the long rod is attached with one wire.

In my car the long rod has fallen off, just two loose wires.

Not sure where to connect them.
The fuel guage still reads full, but no doubt is faulty.

Previously when the level got down to about 1/2, the gauge would flciker wildly.

And does anyone know where I can get the rubber seal that goes here.
Mine had been put in upside down, I think, hence the smell in the car when it had been refueled! Been like this since I got the car, and I had been blaming a leaky overflow!

This is the reason I took it out and found the sender had fallen apart.
 

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Discussion Starter #8
So the 2 wires in the outer tube are for the low fuel light. One connects to the Ground terminal, and the other connects to the center terminal marked "L". Doesn't matter which is ground because it acts like a switch - either on or off. The third connector, on the center tube, goes to the terminal marked "S". This would be your signal/sensor. To make the re-soldering easier, we removed the push nut from the bottom, and pulled everything out of the cylinder. When you're all done making repairs, there are slots that each tube go into to make sure they're parallel and don't restrict the float. Hope this helps.


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Sorry about putting up no photos.
It is now back in the tank. Should have taken some.
Wasn't thinking straight!

Redarmleader, brilliant, you are my hero.
Your photos are so helpful, many many thanks.

I have no outer cylinder, or bottom nut, bottom fitting, and strainer, they must be in the bottom of the tank.
However, they might be missing completely as someone has had it out before, and put the seal in upside down, hence smell in the car when filled!
What is the outer cylinder made of, maybe I will have to make another one.

Once I have run it down to empty, I will have another try.

Again many thanks.
Maybe it will now work properly once I have repaired it, first time since I owned it!

Robin

Oh, at least I have eliminated the smell, I filled it absolutely to overflow, no smell in a 15km drive around the block!
 

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Discussion Starter #10
Sorry about putting up no photos.
It is now back in the tank. Should have taken some.
Wasn't thinking straight!

Redarmleader, brilliant, you are my hero.
Your photos are so helpful, many many thanks.

I have no outer cylinder, or bottom nut, bottom fitting, and strainer, they must be in the bottom of the tank.
However, they might be missing completely as someone has had it out before, and put the seal in upside down, hence smell in the car when filled!
What is the outer cylinder made of, maybe I will have to make another one.

Once I have run it down to empty, I will have another try.

Again many thanks.
Maybe it will now work properly once I have repaired it, first time since I owned it!

Robin

Oh, at least I have eliminated the smell, I filled it absolutely to overflow, no smell in a 15km drive around the block!
The cylinder seems to just be aluminum.

If you happen to make another one, make sure the two tubes stay parallel so that the float moves up and down with ease. I would also recommend making sure there is a strainer on the bottom just to make sure contaminants don't mess with the electronics.

Good luck!

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Many thanks.
In that case I don't imagine it matters much what the outer cylinder is made of.
Could be plastic I guess as it is only there to protect the float. As it is now, all I have is the float on its slide, the low level light tube has fallen off. Gauge works better than it used to, if fluctuates a bit, but not as wildly as it used to.

Many thanks for your photos.
 

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The cylinder seems to just be aluminum.

If you happen to make another one, make sure the two tubes stay parallel so that the float moves up and down with ease. I would also recommend making sure there is a strainer on the bottom just to make sure contaminants don't mess with the electronics.

Good luck!

Sent from my LG-H900 using Tapatalk
strainer is mainly to stop the rush of fuel into the tube, so that your sender isn't making your dash needle go mental every time you go round a corner, as I had a 900 I bought with the strainer already dropped off, so fuel level was always bouncing around, just fished it out the tank refitted perfect
 

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strainer is mainly to stop the rush of fuel into the tube, so that your sender isn't making your dash needle go mental every time you go round a corner, as I had a 900 I bought with the strainer already dropped off, so fuel level was always bouncing around, just fished it out the tank refitted perfect
Damping of the float and therefore the fuel gauge needle is controlled by the flow of fuel into the sender assembly via the small (2mm) metering hole in the plastic bottom plate, as seen in the 4th photo above, and not the strainer. This is the only way that fuel can get in when the sender is fully assembled. The strainer is there to stop small particles entering and jamming the float mechanism and also potentially blocking the small fuel metering aperture (hole). Without an outer tube the float and gauge will bounce around all over the place.
 

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Hello all!

So the other day I pulled the fuel tank on my '91 C900 and removed the sender unit that was separate from the fuel pump assembly. Curiosity got the better of me while I was looking at the sending unit, and I ended up pulling the top off and breaking 2 connections inside the unit. Greeeat.

So far I have been unsuccessful in trying to find wiring diagrams and instructions on how to fix it. Has anyone fixed a sending unit before? I would love to save the money and not buy a whole new one.

Also, I noticed that the fuel pump assembly has a float arm, assuming that is a sender as well, can I move power to the float arm sender, and bypass the other sender unit?

Any help would be much appreciated!


Sent from my LG-H900 using Tapatalk
Hi,
I have a 1990 8 valve classic 900i and the Veglia fuel level sender is if not working. I confirmed it was not a problem beyond the sender by disconnecting the plug from the sender grounding the level and warning cables to the earth pin in the cable and the fuel gauge and warning light worked fine.
I cannot find a replacement Saab sender on the Internet. I see that VDO do a range of senders with matching ohm features, however my first problem is finding the length of the sender in the ca I discovering how to remove the “castellated “ cover nut, but if anyone can tell me the length of the Saab sender that would enable me to continue searching for a replacement ( which will be no easy job).
Once I confirm a VDU unit will work, my next task is to see how I can overcome the fact that VDO units have 5 or 6 hole flanges using screws to secure the sender to the tank.
Regards, Mark
 

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use the later unit and get a wiring connector out of a scrap car and join existing wires to your own
 

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use the later unit and get a wiring connector out of a scrap car and join existing wires to your own
Hi,
I have the Veglia unit with 3 male pins. Can you give me the car details or part number of the later unit to which you refer please. If you can and it works your idea will put my beautiful car back on the road!
Regards, Mark
 

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If yours has the 3 'pin'(3mm diam) connection you are OK, the earlier ones had three small flat connectors. Saab nbr is 8980393.
 

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If yours has the 3 'pin'(3mm diam) connection you are OK, the earlier ones had three small flat connectors. Saab nbr is 8980393.
Hi,
Thanks for your speedy replies.
You suggest I get the later sender. However your last reply suggests the later sender ( now defective it seems) is already on the car. After hours on the Internet I cannot locate a use sender. There appear to be 3 options. First, try to repair the current unit. Second, keep looking. Third, try to locate another model and adapt this, which was the idea I was pursuing. For this I needed the length of the Veglia sender on the Saab 900. Any idea?
Mark
 

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I have 6 in the garage but UK> If you go onto face book and search ''Saab 900 (1979-1993)'' , it's a USA based site, but has people from other parts of the world, ask if anyone has one, as there are lots of C900 owners IN USA etc, as that's all the sites about> I'm sure you will soon get one (y)
 
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