850 cuts out when more than %50 throttle is applied

salts850 · Post by **salts850** » 02 Nov 2009, 22:07

This past weekend i noticed a vacuum line(black hard plastic) underneath the car where the pass seat would be that was disconnected. I think it goes to the gas tank.I repaired the line and didn't drive the car until today. The car pulls like never before, but it cuts out until you back out of it a little. I don't have any silicone lines, all are standard. Could it be a hose or line sucking shut? No cel light so far. I've replaced every hose so far, but not all at the same time. I don't want to hurt anything so i don't get on it as I'd like to. When it cuts out, it really throws me forward.

Post by **jblackburn** » 03 Nov 2009, 07:31

It sounds like one of your turbo hoses is collapsing under boost to me. I'd check out the pipes going from the airbox to the turbo, and from the intercooler back to the turbo. Is it really cold up there? Older Saab's have a problem with the intercooler and lines icing up in the winter before the car is allowed to warm up all the way; I'm not sure if this was ever a problem with these cars or not.

Rich · Post by **Rich** » 03 Nov 2009, 08:24

I have the same problem with mine. Finding it hard to get accross intersections. I was told it could be:
1. Mass air sensor
2. Fuel pressure regulator
3. Fuel pump relay
4. Fuel pump
If i hook a pressure gauge and go for a drive, what do the pressure changes mean if there are any?
Rich

OK
Went for a 5mile drive with a pressure gauge hooked up.
@idle I have 30 psi. When I accelerate hard, it goes to 38 back to 30.
@ 2400 rpm and 60 mph its at about 24psi. Are these pressures in range?
I also discovered the mass air sensor wires are not suposed to be wrapped in black tape. I will look at it when the wife brings the car home.

Post by **Ozark Lee** » 03 Nov 2009, 20:58

Are these pressures in range?

They are all very low but it may simply be the gauge. There are Snap On gauges and then there are Harbor Freight gauges - it gets kinda relative. The norm is around 44 psi.

That said, the variation in pressure bothers me and I would start by pulling the vacuum line off of the fuel pressure regulator and see if you have residual fuel in the vacuum line. If so, the FPR is dead and it is sucking raw fuel back into the intake manifold.

As far as the fuel pump itself goes, if you have positive pressure the fuel pump is working.

The MAF clue is also telling as to a potentially poorly done repair and that will cause similar problems to the drive-ability problems that you describe.

...Lee

salts850 · Post by **salts850** » 03 Nov 2009, 21:49

I will take a closer look this weekend at the hoses and pipes. It's probably about time i buck up for the better hoses. It is getting colder here, but not below freezing yet. lol all in time. I always let my car warm up before i take off. I'll let you know what i find or come up with.

salts850 · Post by **salts850** » 18 Dec 2009, 00:05

As the weather here got colder i found out that my thermostat wasn't doing it's job. I also found the lower vacuum line to the turbo(red i believe) was disconnected. Heat swelled the rubber and it fell off. I've since replaced the line and installed a clamp. I also turned the regulator arm out for the winter. It doesn't fall on it's face. The intercooler hoses are very old. Before summer i will installed all new ones at the same time instead of one here and there. Sorry i couldn't nail down the culprit. IF your car had about 190,000 on it, would it be fair to say the flame trap is probably filled or slightly plugged if never replaced? I have oil in my intercooler lines and i know it softens them up and they colapse or suck shut.

Post by **jblackburn** » 18 Dec 2009, 06:35

A Turbo doesn't have a flame trap; it has an overly complicated PVC system instead which probably is clogged at this point.

Everybody's thermostat has failed as winter has approached this year - I don't remember seeing half as many problems last year. But that turbo line that fell off sounds like your culprit to me. New hoses will make your car happy

salts850 · Post by **salts850** » 26 Dec 2009, 13:32

OK, thanks jack. Hope your holidays were a good one.

squiggy · Post by **squiggy** » 26 Dec 2009, 15:30

I had a problem after installing a new fuel pump where the car would start and run great until about 3,000 rpm. Then it would lose all power and die if I did not take my foot off of the gas pedal. Turns out it was a problem with the way I installed the new fuel pump. I took it out, took it apart, put it back together, reinstalled the pump and everything worked great.

Rich · Post by **Rich** » 27 Dec 2009, 09:11

What did you do incorrectly the first time with the fuel pump?
Ours seems to have the problem at 3000 rpm or higher as well. I have not replaced the mass air sensor as the problem "went away" after using better gas. But its more likely because we have been under the 3000 rpm around town.