Date: Wed, 16 Aug 2000 17:47:10 GMT From: "Keith Grider" <bettynopsamam.columbus.rr.com> Subject: Re: overheating fuelpump ?!
Group, My Saab ('89 900 16V) has the single pump solution. It is an interesting design (aircraft/racing inspired) in that it has a ~6" tall bucket ~5" in diameter in the fuel tank within which the walbro fuel injection pump sits. This way the pump is almost always submerged in fuel. The bucket is kept full by what Saab calls an 'ejector'. It is a venturi which is fed with the return fuel (from the engine) the venturi action picks up fuel off the bottom of the tank and keeps the bucket full until there is no more fuel in the main tank. I just thought I would comment on this here as most fuel pumps I have seen are just laying in the tank with a sock over the inlet. Saab actually has an expensive design here which was justified by the premature failure of the old pump system (2 pumps) as well as keeps the sole remaining pump cooler (and prolonging its life) as it is always submerged. Pretty clever! I wrote this as one response slammed Saab for ignoring the problem. Actually, it was a similar problem for all bosch injection systems as well as the Japanese knock offs. I do not know what Saab currently uses in their tanks, but this was cool (for an engineer). just My 0.02 Keith Grider <nedeljkovicnopsameja.com> wrote in message news:8negjc$51p$1nopsam1.deja.com... > Robin, I had a similar thing happen to me about a year ago (not the part > about being stalled in a tunnel :-) > I have a '86 900 with 200,000 miles. My 900 model actually has *two* > pumps---a main pump and a feed pump. > > I had exactly the same symptoms as you---when I filled the tank up, the > fuel pump worked again. I think you'll find that when you get below > about a 1/2 tank that your pump will not work again. > > My main pump was at fault and I had it replaced with a brand new Bosch > unit. I also had the feeder pump replaced with a new unit. I figure if > the old pumps lasted 180,000 miles then the new pumps should last that > long as well. (And I plan to keep my Saab for a long time!) > > You mentioned that you had the pump replaced recently. If you have the > same two-pump setup as I have, then maybe your other pump has died. > (That's what my mechanic warned against---If one pump is close to a > failure point, then the other pump has to work harder and will fail more > quickly.) > > Months before my pump died, I did hear an audible buzzing noise from the > pumps when driving with the tank about 1/4 full. With the new pumps I > don't hear anything no matter how full or empty the tank is---so a loud > buzzing noise *may* indicate an impending pump failure. > > BTW, it is true that the fuel pump is cooled by the fuel it pumps. I > guess running on a close to empty tank could cause it to overheat. If > your pump has overheated (as the guy in the garage told you), your pump > may have been damaged and may need to be replaced soon anyway. > > Dusan. > > > In article <39985854.5224267nopsam.wxs.nl>, > XXXdasguptaXXXnopsamnl wrote: > > Dear fellow Saabers, > > > > During my holidaytrip to Italy I encountered an strange problem with > > the fuel pump. Or at least that is what I expect it to be. > > > > After I had driven for about 500 km, I had to drive throught the St. > > Gotthard tunnel (17 km) in Switzerland. Maximum speed inside the > > tunnel is 80 km/h. In the middle of the tunnel I felt that the car > > ('87 9000i, 350.000km, manual) lost power, and I could not keep up > > with the other cars, even as hard as I tried to step on the gas. The > > car just slowed down and came to a standstill in the middle of this > > tunnel. About 7 km from one end of the tunnel and 10 km from the other > > end..... > > > > After the Police had towed me away, out of the tunnel, the guy in the > > garage told me that it happens more often, especially with Saab cars. > > Whenever the fueltank is nearly empty (20 liters left in the tank), > > and the weather is quite hot, the fuelpump will overheat and just stop > > working....... This is due to the fact that the fuelpump needs the > > fuel in the tank to cool itself down. After i had filled the tank up > > with some nice, cool fuel, the problem vanished and since then the car > > has been driving like normal. > > > > Has any of you encountered the same kind of problem with the fuelpump? > > Is it really overheating of the fuelpump that caused the problem or > > could it be something else. The fuelpump has been changed about 25.000 > > km ago. Can somebody give some feedback on this problem? Have I > > overlooked some other possibilities? > > > > Thanks in advance, > > > > Robin > > '87 9000i 350.000km manual > > > > (remove XXX from emailaddress) > > > > > Sent via Deja.com http://www.deja.com/ > Before you buy.
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