[jlillie]

c900 1990 cabrio turbo
Hi guys,
been few weeks since i last posted and thats because my 900 has been running really good as my dd.
Lately though, every now and then she'll start stumbling on acceleration. At first i thought it was just due to not paying attention to what gear i was in and how fast i was going (rpm's to low).
But this morning it happened and she was definitely stumbling to the point i was going to turn around and take her home when it just cleared up. And this seams to be what happens - she'll stumble a bit and within few seconds it clears up and no issues.
I'm thinking fuel pump is about to go out.
What do you guys think?

 

[jvanabra]

Does indeed sound like a fuel pump. On the 3-doors failing pumps are often easy to hear, but the convertibles not so much.

 

[jlillie]

Since i reported this issue on Wednesday, the problem didn't re-occur until way home from work on Friday. This time the stumbling/bogging down, lasted for few minutes. Then it slowly went away and no problems rest of way home.
Is the fuel pump known to have intermittent issues like this or would it be possible?
These are the worst kinds of problems - not broke when your trying to fix them.
My worst nightmare would be having her leave me dead on the bridge between Cape Coral and Ft. Myers during rush hour. I've seen that guy and trust me you don't want to be that guy ?.
Hey thanks for the reply jvanabra!

 

[Jim Mesthene]

Persistent fuel issues that cause problems such as you describe almost always generate a Check Engine light.
A Hall effect sender, or other ignition component that is failing when it gets hot, doesn't.

 

[06aeroSS]

Since i reported this issue on Wednesday, the problem didn't re-occur until way home from work on Friday. This time the stumbling/bogging down, lasted for few minutes. Then it slowly went away and no problems rest of way home.
Is the fuel pump known to have intermittent issues like this or would it be possible?
These are the worst kinds of problems - not broke when your trying to fix them.
My worst nightmare would be having her leave me dead on the bridge between Cape Coral and Ft. Myers during rush hour. I've seen that guy and trust me you don't want to be that guy ?.
Hey thanks for the reply jvanabra!

When my fuel pump was failing it would cause hesitation issues (but I didn't know it was the fuel pump at the time). Luckily in all Saabs that we've ever had the fuel pumps failed the same way. Not while being driven. They all created a no-start issue after having been parked. Beat on the bottom of the fuel tank while jumping the fuse and that got us a couple more starts to get back to home/repair shop before total failure.

 

[jvanabra]

The only fuel pump failure in a c900 I ever had gave an intermittent bogging issue, but I kept pushing it. For weeks. Eventually it died after I'd driven about a 1/2 mile from the house one afternoon. I whacked it with the tire iron and it started up again, so I drove immediately home and ordered a new one.

In the end, it's a electric motor.... they can definitely fail in a variety of ways.

Edit: That's lies! The second time I had one fail it was more or less without warning. I was coming home from work and could hear it struggling in the trunk..... louder, quieter, louder, quieter. It died two blocks from my house and I ended up changing it in a burger joint's parking lot.

 

[jlillie]

Well, after my last post on this issue i decided to take care of a known issue that may/or may not be the problem; I knew the muffler had fallen apart internally, although it looked perfect from the outside. I could here stuff rattling around inside every time i started the car. I thought it might be possible something inside the muffler was occasionally blocking flow. I installed a new exhaust system this past weekend and drover her to work yesterday with a single slight stumble going into work;however, on the way home she started stumbling, hesitating almost immediately. Made it over the bridge ok (thank God, and i did pray. It got a little better during the 12 mile drive home and was almost gone by time i got there.
I've decided to leave her sit until this weekend when i can roll in a new timing chain. I bought one a while back but got lazy cuz she was running so good. While i do this i'll do a complete check of the ignition system which i agree with Jim, is most likely the issue.
I really appreciate all the replies. Thank you.
Will update after the timing chain roll in.
btw, this car (1990 c900t mt cabrio) had 275k on the dial when i got her and the speedo was broke for who knows how long. I have no clue as to how many miles are on this timing chain or what else may or may not have been done to this motor. But i do know this. When she runs good she runs great and she burns little to no oil at all.

 

[jlillie]

Inspecting the distributor I find oil leaking out from cap. I've noticed oil under the distributor cap on the Turbo heat shield before but didn't pay much attention to it.
Is there an internal seal in the distributor that has gone bad? Could this be affecting the Hall sensor?

 

[jvanabra]

It's unlikely to affect the Hall sensor since that's just a magnet, but it could affect the contacts in the cap.

 

[jlillie]

It's unlikely to affect the Hall sensor since that's just a magnet, but it could affect the contacts in the cap.

Inside of the cap was dry. The oil appears to leak through the distributor base some how all the way out to the cap then leaks out to the turbo shield.
I happen to have a dist from my parts motor. I"m going to take it apart see how it works and what seals it.
Thanks jvan

 

[jvanabra]

There are seals on the distributor shaft that can fail and let oil by. There was a thread recently about fixing that... it's not all that difficult. A small leak/dribble isn't uncommon - you just need to be sure it doesn't turn into something serious that fills the cap with oil.

 

[jlillie]

There are seals on the distributor shaft that can fail and let oil by. There was a thread recently about fixing that... it's not all that difficult. A small leak/dribble isn't uncommon - you just need to be sure it doesn't turn into something serious that fills the cap with oil.

Its a slight dribble right now so i dont think its causing any issues yet. I disassembled my spare dist and found that there are only bronze races at top and bottom of the distributor housing. No seals. So the races must act as seals as they are quiete close tolerance.