PDA

View Full Version : Fuel tank rusty inside, now need a sender unit-digital dash


Gilly
08-12-2004, 08:59 PM
Hi
I joined this forum for my brother in law. I used to work on GN's and T Types when they were new, in a vehicle prep department.
He has an 85 GN, original owner. I just got to drive it today about 20 miles, it rolled 13,000 miles on this trip. He wants to sell it, BTW, but that's another story.
Up until yesterday, the car hasn't been started for 2 years. We were going to take it to a car show, that's when we discovered it's a no-start. Doing a few simple steps, i discovered it has no fuel pressure, probably due to a bad pump (pump relay clicked and I tried jumping the relay, still no pressure at the rail). SO we had it towed to the dealer I used to work for, I have a friend who still works there. Pulled the tank and the insides of the tank was all surface rust. My bro in law was informed ny "someone" that it's best to not store car with alot of fuel in it, which most people would agree is wrong. OK, so i could have had the tank cleaned and sealed for $90. I am kind of against that, i've heard stories about the selaer flaking off. Other option: well, no tank available from GM anymore, but the place who would clean and seal the tank said they could get an aftermarket tank for $155, so he decided wisely to go that route, plus a new pump of course, and disposing of the old turpentine/gas in the tank.
Got that all done and an oil change and the hood struts were shot, so replaced those too. We wanted a coolant flush, they didn't get that on the repair order though, so should get that done sometime.
So I'm driving it home, I should have had about 5 gallons in it, but I'm getting 2 dashes in the fuel gauge "- -". So I put another 5 in it before getting on the highway with it, should have 10 in it now (pretty darn sure about the amount) and was reading mostly 15, sometimes it's show 14, other times it would blink the 2 dashed lines. Got back into town and filled it, now shows the dashed lines all the time. Owners manual says this means an open circuit in the sender. According to GM sender is not available, discontinued June 1995. Part number 2509 2110. Remember this is digital dash, not analog. This digital really sucks, not one really useful gauge, just speedo, fuel gauge odometer and trip meter, what a bad option. Oh and the 2-light "boost" gauge.
I also put Sta-Bil into the gas.
The thing rides pretty floaty, will long-term storage like this ruin shocks? Seemed to get a little better later in the trip, still not like I remember when they were new.
I don't know if nayone noticed on eBay, but I'm the guy who auctioned off the "Turbo Performance Tested" decal last week, the one the PDI tech would stick in a window when the PDI was done.

Gilly

Keller
08-13-2004, 01:39 AM
Hi
He has an 85 GN, original owner. I just got to drive it today about 20 miles, it rolled 13,000 miles on this trip.
<snip>
Up until yesterday, the car hasn't been started for 2 years.
<snip>
Other option: well, no tank available from GM anymore, but the place who would clean and seal the tank said they could get an aftermarket tank for $155, so he decided wisely to go that route, plus a new pump of course, and disposing of the old turpentine/gas in the tank.
<snip>
So I put another 5 in it before getting on the highway with it, should have 10 in it now (pretty darn sure about the amount) and was reading mostly 15, sometimes it's show 14, other times it would blink the 2 dashed lines.

You're gonna wish you didn't do that...

The fuel injected TR's all have a tank with a large plastic baffle in it that keeps the fuel from sloshing around as much as the normally aspirated cars. Especially during acceleration. The aftermarket tanks do not have this. Your guage reading problems may be entirely due to fuel movement while in motion. People using these tanks find their cars starving and stalling while nearing low fuel levels much easier during turns and acceleration. Frankly, I don't know if you can 're-line' or 're-coat' with the baffle in it that easily either, but a professional shop might.

I'm not sure if the pump hanger/sender assemblies are unavailable, but I bought one not long ago. The are different numbers for digital and analog dash cars. (Different guage sender resistances.) That one could likely be repaired with a little careful work. Its probably just a bad spot on the sender.

Tanks can be stored with fuel. Just best to be stored with Sta-Bil or the like to prevent water condensation or breakdown. Not empty, I would think.

Hopefully you did not go with the stock GM pump, either.

Gilly
08-13-2004, 04:21 AM
It did make a difference to the guy ordering the tank if it were a Turbo motor or not, so hopefully it has the baffle. I'm hoping he'll keep it full enough now that sloshing won't be a problem. I did see the baffle in the original. It's a "garage queen" anyways, I don't think it'll matter, at least to him. I think it was a better option than trying to seal it. The new one was made in Canada if that means anything.
Sure, just went with a GM stock pump, this car isn't beat on very regularly, stock will work fine, sorry if we have a different mindset about this car.
I think he should have been storing it with a full tank all along, that's what caused this problem, lots of temp fluctuations, we're in Wisconsin.
Thanks for the comments.
Gilly

Keller
08-13-2004, 06:15 PM
The new one was made in Canada if that means anything.
Sure, just went with a GM stock pump, this car isn't beat on very regularly, stock will work fine, sorry if we have a different mindset about this car.

:confused: To each his own. I think the Canadian aftermarket tanks are precisely ones that have caused problems. And high flow aftermarket pumps aren't really more expensive than GM originals. Especially if you are paying list from GM. I realize thsi is a "garage queen", but when someone tries to make him prove the car can run on the way to a show... ;)

Gilly
08-14-2004, 08:45 PM
He's never had it in a show, pretty much just sits in the garage and collects dust. And rust in the fuel tank, hee hee hee.
I had to deal with what I could quickly put together for him, had to handle pretty much everything myself. I had ordered the pump about a week before we were going to get it towed. I never thought to check for a GN website. Anyways, it's running now, more than I could say a week ago.
How low does the tank have to get before sloshing causes a problem (just so I can tell him)? I still think he's better off with a new tank w/o a baffle, rather than trying to reseal a tank (coat the innards) and have that stuff flaking off in a few years. The sloshing problem can be "expected" at lower levels and you can keep the tank full, but the sealant flaking off, who knows if and when that'll happen, next thing ya know it's 10pm Saturday and your fuel pump sock is plugged with flakes of sealant. Plus if it happens 10 years from now, who's to say even an aftermarket tank will be available? I dunno, I think I did the right thing given the alternative, it'd be one thing if a GM tank was available and we would have just had to wait for it to show up.
I got the fuel pump cheap enough, I think it was about $80. Sure wish a sender was still available.
Gilly

turbofish38
08-26-2004, 03:39 PM
My books show the digital sending unit still available from GM. Use part number 25092748. BTW they also show the an*log being replaced by the digital part number. At one time many years ago I did confirm through my own testing that you could interchange sending units with out any adverse problems. The digitals were always inaccurate after a couple of years anyway. The aftermarket fuel tanks have a steel baffle spot welded in where the factory one is a plastic tray. The only problem with the aftermarket tank is the baffle isn't as tall as the factory one. I've been batting .500 with the cars I have that have in tank fuel pumps. Some can go almost a year sitting with a full tank and start and run with no problems and others I cant get a fuel pump to last a couple of months with out seizing no matter what I add to the gas. Go figure?