97 900SE Turbo - Fuel pump? Alternator? Spark Plugs? WORSE?? Help! - Saab Forums - Saab Enthusiast Forum

97 900SE Turbo - Fuel pump? Alternator? Spark Plugs? WORSE?? Help!

BadBetty666's Avatar
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Join Date: Aug 2010
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Pawtucket, RI

08-27-2010, 09:58 AM   #1  
97 900SE Turbo - Fuel pump? Alternator? Spark Plugs? WORSE?? Help!

I have a 1997 SAAB 900 SE Turbo that I’ve had for almost 2 years. My problem started on Tuesday when I was sitting in traffic. While stopped at a red light, the car “hiccupped” – it sounded like the car was going to die for like a second and then it was fine. Later that night, it happened 4 other times, twice while stopped dropping a friend off at home and twice when accelerating from a complete stop (which when this happened, the car was jerking as well). On Wednesday, it didn’t happen at all, but I had a friend just check the engine – he said it sounded fine, that it might’ve been because we had so much rain for the past few days that some water got in a wire or something. On Thursday during my lunch break, I was driving and it started “hiccupping” and jerking very hard and then just died, jolted to an abrupt stop and made a lot of weird clicking noises under the hood. I wasn’t out of gas and the car has oil in it, however I was flipping out thinking the worst. I had it towed to my house, upon where the tow truck driver attempted to start it and it started. He said it could be the fuel pump, but I don’t have or make the kind of money to just start replacing parts and paying for all that labor. I know it’s slightly overdue for an oil change, it hasn’t had a tune up (spark plugs, etc) in at least 10 months, & the fuel filter hasn’t been changed since I’ve owned it. Can anyone give me some ideas of what could be going wrong?

flynnternet's Avatar
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09-26-2010, 04:11 AM   #2  
Booster Pump?

That sounds like the Booster (Primer? Pre-Load? Feed?) Pump that is located on the Primary Pump assembly in the gas tank. It pressurizes the gas to ~2 PSI for the primary pump. $40 or so for the part.
It died in my '91 900T and she behaved in a similar manner.
Sputter, jerking, feels like the gas has been shut off, maybe stalls; certainly not drivable.
Stopped or at highway speeds.
Then a couple minutes later: All Happy Again!
[#!%*! I hate an intermittent failure.]
Worse when it was hot outside and/or the gas tank was not full.

The pump assembly can be removed through the access holes under the board in front of the spare tire storage.
Unscrew the rubber 'hinges' form the spare-tire storage lid and removed the board.
Then pull (toward the rear!) on the board behind the rear seats.
(Not up, or you will be bending the clips back into shape. Ask me how I know...;-)
This is in a 3-door; YMMV.
If you need to remove the assembly, it looks like a flexible driver shaft and nut-driver bit will be required to get the clamp removed.
(I took the car in and let my guy do pump since I had most of the disassembling work done already. So I dunno!)

Before you start pulling the pump assembly!

There is a trouble-shooting procedure for the booster pump, now that you have access to the primary pump electrical connections.

Start the car (give it a minute or two for the alternator to level out the system voltage) and measure the voltage (with a DVM) where the primary pump is connected to the harness. (On top of the pump are two connections that are retained by nuts, it's pretty obvious.)

There is another set of wires in the access hole that lead to the booster pump, IIRC they enter the tank via a white plug-looking item which is seated in a rubber grommet.
These wires need to be disconnected [see below] and the voltage measured again at the PP.

--There should be a slight increase in the voltage (0.3V IIRC, hence the DVM and not an analog meter) at the PP, if the booster pump is running.
So keep looking elsewhere. Bummer. ;-\

--If the voltage remains the same (+/- ~0.02-0.03V): the booster pump is dead. (Not taking any current, which will lower the voltage at PP = not running!)

Some units have some sort of connector for the wires feeding the BP in the access hole.
Mine did not, so I pulled the white thing out of the grommet and pulled the in-tank connection. PITA getting it back in, almost FUBARed the grommet.
(I was later informed there is a work-around for this situation, although I forgot to ask what it is. There might be a connector farther up the harness that I did seek out. Or you can always cut one of the wires and butt-splice it back together I suppose.)

I must credit my Source:
Ken Morrison
Saab Master Mechanic
Old Town Import Auto
Fort Collins CO

flynnternet's Avatar
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Join Date: Sep 2010
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09-26-2010, 04:31 AM   #3  
Booster Pump Function?

I think it might be Feed Pump.

I had unscrewed the gas cap during one the '91 900Ts fits and did not get the pressure release (and stall) that my beloved '81 would present.

Per the Saab Guru in Fort Collins:
Trollhatten changed the system (at a year I do not recall) so that the tank is not pressurized. I assume that this FP makes up for the 'low' pressure in the newer systems.

Good to know for us Older Skool 900 Nuts

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