[mrbluesuit]

Hi everyone,
I'm glad I found this sight.
I have a problem with my 1986 Saab 900 Turbo. She has been running fine, until this morning.
I went to start her, like I do every day, and she wouldn't start. I checked the fuel pump, and it was fine. I just did a fresh tune-up 3 weeks ago. At 240,000 miles, I watch her very close.
Well after checking the fuel. I checked the spark, and she had none. There is also no power from the positive wire at all.
The local dealer says (bring her in), but we are a paycheck to paycheck family, and I just cannot afford to take her in.

Can you folks please help us?

 

[cdaly]

Check for damaged connectors at the distributor. Apparently these get brittle over time leading to no spark failures.

 

[mrbluesuit]

No power to the coil

Thanks Cdaly. But maybe I didn't explain it quite right.
The positive wire running to the coil has no power.
I was wondering if it might be something to do with the (brain box). not sure of the technical term.:suprised;

 

[PHAT_joe]

do you mean the computer inside the car?

i'm not sure if the '86 has a diagnostic port on it but if it does you can get your mechanic (a local guy should be able to do this for a few bucks) to just plug in this computer into that port and it will give some problem codes, from there he might be able to diagnose the problem.

good luck, and if makes you feel any better, your not alone with having your car mysteriously die on you; mine died this afternoon and i dont even have anything close to 240k on my 900.

 

[PHAT_joe]

found this off one of the links here

http://www.thesaabsite.com/900old/Saab900ignitionhardstart.htm


check it out, it sounds daunting but it might give you a direction

 

[Raub]

Are you checking voltage at the coil terminals by going positive to terminal and negative to ground?

You need to look for this thing in your left fender well.

Between terminal 4 and 2 there should be at least 10 volts. If not then you have a wiring problem someplace. After that, disconnect the Hall sensor connector from the distributor. Check voltage betwen coil terminals. Turn ignition on. Voltage should rise to 5 then drop to 0 volts in a second or two. If it doesn't then that doo-hickey in the picture is bad (ignition control unit).

 

[Skip]

Thanks Cdaly. But maybe I didn't explain it quite right.
The positive wire running to the coil has no power.
I was wondering if it might be something to do with the (brain box). not sure of the technical term.:suprised;

First of all, welcome to SaabCentral. You found the right place!

Your 86 Turbo is the same kind of car I have, so I am too familiar with the ignition system. Tracking down and fixing your problem should be very possible.

+ to the coil (green/white wire) comes straight from the ignition switch.

The black wire from the coil goes to the Ignition Control Unit, which interrupts the coil's connection to ground to cause the spark.

The Bentley Service Manual has very detailed troubleshooting steps for ignition - and many other - problems. It is about $40, but worth every nickel if you want to DIY. Available from several online vendors - highly recommended!

FYI, pin 4 of the TSI Socket (the round 6-pin socket in the fuse box) is fed from the same source as coil positive; see if you get +12 there with the ignition on. If not, you have a problem with the ignition switch or the wiring. Pin 5 should pulse 0 and 12 V when starting (or running) if the Ignition Control Unit (and +12 coil supply) is working. TSI pins are numbered clockwise, with pin 6 empty.

The TSI pin positions are:
1) +12 always (straight from battery)
2) Ground
3) +12 when starting
4) +12 with ignition switched on
5) Alternating 0 and +12 - spark on low to high transition
6) (Empty)

 

[mrbluesuit]

Hooray!!!!

That was it!!!! The ICU was gone. I bought a new one and it runs fine. Thanks for all your great help!!!!!

 

[Raub]

Hmm....wonder how I knew that Been down that road. Glad you got it sorted out! Enjoy her!