How to Tune an Eight Valve Saab 900

this will dramatically increase efficiency and performance on your eight valve saab.(some methods apply to 16 valve also)

Difficulty: Easy

Instructions

1. Replace spark plugs: the swedes recommend this every 12,000 miles or once a year. Use NGK plugs available at almost any automotive store.

2. when disconnecting spark plug wires be very carefull, grasp the connection as close to the sparkplug as possible.

3. (easiest when engine is cold)

4. pull plug wire briskly and unscrew plug.

5. i have had bosch wires brake when i pulled them becausei did not grip them close to the plug.

6. i recommend Beck Arnelly wires if yours are shot.

7. any wire that shows visual wear should be replaced(cracking or fraying)

8. REPLACE DISTRIBUTOR CAP AND ROTOR

9. first pry the clamps off the distributor cap

10. (its the round cylindrical thing sticking out of the front of your engine)

11. with a plastic cover and five wires coming out of it)

12. now on the inside rim or the plastic cap,

13. you'll see a square nub that

14. fits into a square bay in the distributor

15. now hold your new distributor cap(Beck Arnelly are best)

16. next to the connected one looking into the inside of it

17. now turn them so the little square nubs are both in the same relative location... i.e. both at twelve o'clock.

18. and take one wire at a time from the old cap pulling briskly and pushing it firmly into the new caps corresponding hole

19. do all five wires. one at a time making certain they are in their proper hole. and pushing again to make sure you have an excellent connection.

20. now now on top of the distibutor there is a little plastic propeller looking thing ...

21. pull that off and put the new one on.

22. now put the new cap back on , lining up the little square nub.

23. and fasten the clamps by pressing in at the apex of their arcs with one hand while holding the new cap in place

24. with the other hand.

25. .

26. CHECK O2 SENSOR FUNCTION.

27. this is easy if you have a volt meter.

28. first lets identify the 02 sensor.

29. on the passengers side inside the engine you'll see

30. a big iron pipe coming off the engine.

31. this is your exhaust header.

32. on this there is a little gizmo with a wire coming out of it.

33. this is the o2 sensor( some have 2 wires)

34. follow the wire to a connector on the wheel well.

35. its connected? GOOD, now disconnect it, set your volt meter to DC VOLTS

36. touch your black wire to the engine and your red wire to our o2 sensor wire

37. oh the engine has to be running at this point...don't worry the o2 sensor only generates about a half a volt

38. about enough to tickle a butterfly

39. if your o2 sensor doesn't put out any volts at all,

40. test the volt meter on your battery. should gget 12.6 volts or so.

41. if your oxygen sensor is dead replace it.

42. itunscrews with a pipe wrench and screws back in... but its in there so twist hard.

43. the swedish engineers recomend this unit be replaced every other year.

44. don't forget to plug the wire back in now.

45. if you get any voltage at all your o2 sensor works and you can move on... shut the engine off.

46. Check and Adjust IGNITION TIMING

47. *NEED STROBOSCOPIC TIMING LIGHT

48. OK start by hooking the timing light to the battery black to neg. red to + .

49. then take the inductive pick up and clip it around spark plug wire #1 the one that is closest to the cockpit of the car.

50. they are also labeled on the valve cover.

51. now find the distributor.and it has three 10mm nuts

52. so get the opened end 10mm wrench ready.

53. okthere is a hose coming out of the distributor going to the intake manifold

54. unhook this hose at the distributor end and plug it with a pencil.

55. now you need a friend.

56. but first lets find the timing window.

57. between the distribtor and the intake manifold there is a black plastic sheath, deep below hoses and wires

58. its prety much in the front of the engine

59. not to the radiator though. and centered . now there is a small plasic circle cut out

60. this is your timin window.( remember there are only a few square feet this could hide in so LOOK.

61. YOU'LL FIND IT.

62. this little window will display

63. numbers as the strobe flashes inside the hole

64. ok

65. now have your girl friend start the car and bring the tach up to 2000 rpm's

66. shine your timing light in the hole and see what the number lined up is.

67. it should be 20

68. if it is anything else you must lossen the distributor.

69. and turn it slightly one way and then the other to see

70. where twenty is working with the person in the car to find that magic spot where the engine

71. is at 2 on the tachometer and the timing mark reads twenty on the line.

72. when you finally find that sweet spot . crank those 10mm bolts down but not too hard , they might break.

73. now reconect the hose to the distributor and un hook the timing light.

74. SET THE IDLE

75. the idle is set at the intake manifold which is the

76. tube that is connected to either the big black rubber bellows or the aluminum turbo tube.

77. now here you'll find a cable connected to a lever ...this is the throttle.

78. first make sure the screw under the lever that acts as a backstop for the throttle is completely backed off until it doesn't touch the nub on the throttle lever, and then just turn it in one half a turn so they just touch.

79. will your car idle now?

80. if not or if it oscilates,

81. take the rubber boot of the tube and get in there with an old tooth brush and some carb cleaner and open the throttle and clean all around inside of there. be thorough i've had more luck smoothing out rough idles this way than any other.

82. all clean now reattach the boot and run the engine to normal operating temp.

83. on the top of the throttle there is a bolt with a lock nut that appears to be holding "nothing " in place . this bolt holds your idle speed in place. lossen the lock nut , turn it and you will see.

84. now turn it slowly and in small increments reving the engine and letting it idle down between increments until you land at about 900 rpms. just below the one on the tach.

85. now tighten the lock nut and your set.

86. FOR BONUS PERFORMANCE

87. CHANGE AIR OIL AND FUEL FILTER

88. AND CHANGE ALL FLUIDS AND BELTS.

89. THE AIR FILTER IS UNDER THE BIG BLACK RUBBER BELLOWS.

90. THE BELTS ARN'T AS HARD AS THEY LOOK, WITH BELTS I SAY DON'T THINK JUST "DO"

91. AND WITH THE COOLANT YOU DRAIN THAT AT THE BOOTOM OF THE PASSENGERS SIDE OF THE RADIATOR.

92. DO THIS ONCE A YEAR AND YOUR SAAB WILL SHINE LIKE A STAR.

93. a guy in rochester n.y. has 400,000 miles on his 900 and a careless owner can expect 250,000 mi. if they tune up.

94. a meticulous owner may expect 3-4 hundred thousand miles out of there saab 900 if they love there car care for it and take care of it .

95. a guy up in nova scotia got over 500,000 on his old 76 saab 99 with the eight valve .

Tips & Warnings

• saab dealers also have excellent parts for a little extra dough.
• THE ENGINEERS RECOMMEND THIS ONCE A YEAR OR 12,000 MILES TOO.
• if you cannot read the marks in the timing window: make sure the
• light is clean , the lens and all. if that doesn't work
• hold a wire brush in the hole to clean the surface of the wheel
• for a while with the engine running.
• beck arnelly parts all the way for long life and dependability
• many of these parts are made in america: surprisingly and are of great quaility, and have good dependibility.
• i've never had anything they make fail.
• keep loose clothing long hair and pony tails and rings and jewelery ouyt of the engine compartment and for pete's sake wear old clothes. your gonna get greasy. ...
• saabs are notorious for seeping oil. they don't really leak but when working on one expct to get greasy.they just seep.slowly /they all do/

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on 1/16/2006 Don't disconnect your 02 sensor while testing it. The oxygen sensor is a device that is used to trim the air/fuel mixture as close to stoichiometric as possible. With the 02 sensor disconnected the controller will not receive the correct inputs, and depending on the air fuel mixture being too lean, you may not get a voltage signal from it. With the sensor connected, put your voltmeter ground side on the battery and your positive lead on the voltage signal from the 02. While the engine is running in closed loop operation (feedback mode), if your vehicle is running properly, you should see a voltage fluctuation of .2V-.8V.
.5V is the mean value indicating a perfect fuel mixture. Above .5 is rich and below .5v is lean. The only way to verify if the 02 is calibrated correctly is to have a gas machine measuring the actual 02 emissions from the tailpipe.

on 12/9/2005 Go for nothing less than a Bosch distributor and rotor arm, they're original equipment and best quality.
Same with spark plugs and leads, NGK and Bougicord.
Don't let the people at Eurocarparts or GSF fob you off with other makes of spark plug, my 900's have always run best with NGK's.
Once, at Eurocarparts upon checking the paper work, I'd noticed my Saab had been typed in as a 9000. I insisted that a 900 be typed in to check the codes of the bits that I had ordered. The guy didn't want to do it, another more helpful body behind the counter did it and sure enough, all the codes changed.