[Mimmi]

Try to tap starter when you start it. Does this help?
If yes, you have bad starter (or worn out brushes/carbon dust).

 

[jvanabra]

My thoughts exactly. I carried a hammer in the Suburban for nearly a year because I was too lazy to replace it.

 

[Cornbinder89]

Now that I am more or less retired, I do my own starters and such. I had one "rebuild" that was so bad, that I have sworn off having a so called specialist do them. I just did two 80 year old Delco's and I have an early 6 volt gear reduction Delco from the 30's on my bench at the moment. It took a lot to crank 450 CID on 6 volt in the dead of winter! I also have a somewhat rare L/N 100 amp bar wound alternator from the early 50's on the bench also.
I used to send out because time was a problem. now I can afford the time to source what they need and do the job right.
I am not saying it does or does not need a starter, but having two starter that act identically and both have the exact same fault is not as likely as there being another single cause that makes both starters not work.

 

[jvanabra]

Can't argue the point, but two old starters does not mean one good one, and the symptoms suggest Mimmi's diagnosis, at least to me.

 

[OregonSaab900s]

two bad starters? he already change the original to his "spare" starter. At this point I think he needs someone wo understands the system to be helping in person.
DC motors with bad fields, bad armatures etc don't work "fine" some of the time and not others.
A bad solenoid is a possibility, but having two starters with the exact same fault is unlikely. It isn't impossible, which is why I think someone who knows what they are working with needs to look things over.
It is very hard to diagnose electrical over the internet, esp when the person at the problem isn't well versed on the system.
Before we send a person changing parts on what one "thinks" the problem is, we need to test and prove it. Otherwise you end up chasing your tail.
A armature with a shorted coil or bad bars, high mica etc, doesn't work fine one time and not another. Field coils don't short then un short, same for opens.
The way the solenoid works, it has to get the pinion into the ring gear before it will make electrical contact to the motor. It is possible that the contact in the solenoid is defective and it is possible that both his starters are defective in this manor, but not likely, and less so when it worked fine on a "bench test".
It is possible that the mounting plate on the back of the block is broken or bent, and there are many more "possibilities"
Before I would say change the starter yet again, I would want to be sure of the cause.

I want to let you know, I am well versed on electronic components. My dad, who has been my second hand, is an electrician btw. And yes, it is very odd that both motors worked when I bench tested them. Mounting plate isn’t bent, this is my 8th Saab, (3rd c900). Just to establish a bit of credibility

it is also very weird that this same test had similar results with another person. But I’m not going to dive into a wiring diagram to try to figure it out or anything and just live with it. Hopefully this thread hopes people with the same issue.

 

[OregonSaab900s]

Try to tap starter when you start it. Does this help?
If yes, you have bad starter (or worn out brushes/carbon dust).

I did try the starter tap before, no luck on that test.

 

[Cornbinder89]

Its not a matter of credibility but what you see and how it is releyed in words that can get things muddled. We can only react to what you write, not what you see and do under the hood.
You can chase your on tail by replacing stuff and not confirming that it is 100% the problem. Laws of probability are such that two different items with the same problem, when exchanged, are less likely to be at fault than something else that is effecting both units to not function. It isn't 100% that they both don't have the same problem, but neither is it 100% that they are the problem.
You can spend the coin on a "rebuild" and still be where you are now. If that is a gamble you are willing to take, then go for it. At least you have one "core" off and ready to turn in.
If it fixes it, great! If it does not are you going to put yet a 4th starter on?
If the motors spin well "on the bench" but have trouble in the car, that brings the question why? It can't be that he motor suddenly has a bad armature in the car but repairs itself when removed. It could be that the solenoid can't get the drive pinion into the flywheel far enough so the contacts on the back close, but then you need to find out why? and new starter and new solenoid are unlikely to change that. May need a new ring gear. It may have nothing to do with any of this and the problem is further up the line.
YOU need to test, we can't from this end of the keyboard.

 

[99Super]

I've chased a similar problem several times and it was cured by replacing one or both of the battery cable terminals. They get corroded internally and won't conduct enough current to turn the starter but still show good voltage. I get the copper ones from my local battery shop and solder them on after giving the cable end a good acid cleaning.

 

[srpphx]

Here's a link to the townsend site which may help diagnose the issue Intermittent Starter Problems

 

[900power]

Clean the negative battery connection at the transmission (passenger side, lower front corner of the trans). Also clean the connection below the radiator on the passenger side (there's several grounds going there). If that doesn't fix it, I would take the positive battery cable out of the good 900 and put it in this car. Those cables are quick and easy to remove or install (especially on a NA), and would tell you if the positive cable is the problem.

I've had to wrap the positive battery cables in electrical tape on all of my 900s because the insulation crumbles off. I wrap the entire cable in a few layers.

 

[Cornbinder89]

Wondering if you ever got this solved and what the problem turned out to be?

 

[OregonSaab900s]

Wondering if you ever got this solved and what the problem turned out to be?

I did not solve the problem. It still could be the cables, or the starter. It is not the grounds as I already cleaned those. The issue did occur again and i used the wire jumper at the TSI socket and I engaged it on and off a few times and the starter then cranked the engine and again, it was back to normal until I parked it. So it is still an intermittent issue.

 

[Cornbinder89]

So it is still an intermittent issue.

Worse kind to find, as you can never be sure it is solved, or just hiding!