breaks up @ 3000 rpm's

[saabfan9]

...i did the test on the position sensor and it seems to fail i'm going home tonight and give it another look...i found out the other night when i had her out i'm i'm very easy with the throttle while cruising she actually behaves nothing i could do on accell still breaks up bad under load but in the garage nice and clean throttle response and that makes me question if the throttle switch is really bad ..you would think if the contacts are bad (internally) it shouldn't matter if i'm in neutral or in gear under load right?

[DougM]

The TPS adjustment with an ohm meter in the service manual makes my brain hurt, though that's not uncommon with me and electrical systems. I'm more the nut and bolt guy. Here's a bit from a friend of mines post on saabnet for confirming a correct TPS adjustment

"Refer to your servive manual for adjustment with a meter, however you also need to confirm it after as well. Turn your ignition switch on without starting the motor. Slowly turn the throttle...you will hear little clicks. You must have exactly twenty clicks. The meter method actually can give you a wrong positioned switch, but gets you close. Twenty clicks is a guaranteed correct position. Be carefull to not leave the ignition on without running it too long or you may burn out your ignition resistor mounted on the coil."

I personally have never had to confirm the 20 click method.

Remember that the fuel injection system also relies on the ignition system and engine timing for it to work up to specs.

[saabfan9]

i sat down and adjusted the throttle switch i was reading it wrong the other day so now i know it is dead on....as far as timing i feel i may never get that dailed in..if the idler shaft was out of time will i be able to properly set timing?...i have it now where the car starts easy and no spark knock although in my eyes the car should not run ....i'm halfway between number 1 & 3 on the cap and with a timing light on the car i read 30 btdc ...my adjustment on the dist is maxed and i pulled the dist to rotate the shaft 1 tooth.....also should i set the pertronix gap at factory specs .35 (right now it's about .53)?

[saabfan9]

you can see the line on the housing for tdc...at tdc my rotor points at the clamp that is halfway between 1 & 3 at this setting the timing light reads 30 btdc vac advance unplugged

[saabfan9]

at #1 on the cap and at tdc the car will not start, not even a backfire...i have no way to know if the idler is timed correctly but i did pull the valve cover and both the cam and crank are in time and the chain is tight

[DougM]

There is no timing involved with the idler, because it's only an idler gear - one end drives a water pump, which doesn't really care where the gears are timed. The other end drives the distributor, but if you set the cam on mark and the crank on zero, then drop the distributor in and line the rotor pointing to the hash mark on the distributor, you ARE in time @ zero(your one picture clearly shows your distributor is not in time - move it one more tooth). At this point the car will/should run at idle - if not, then we seem to be narrowing it down to ignition issues < pertronix? (or points gap). If you still had points and they were way off in adjustment, it wouldn't start. If you got them close to specs, it would possibly start, but not run very well. I don't know what the relationship is between points gap and moving the distributor timing to make it even fire. Some things in life(electrical) have never really been explained to me, so my mind can't grasp what is what sometimes).

[DougM]

This is where mine is at with the flywheel at zero(I did not pull the valve cover at 3am to verify where that mark is. Yours should look like this.

[DougM]

I just read an article on pertronix and dwell angles. From what I gather, just like points, the larger the gap, the larger the dwell angle. The specs for your car still should be dwell - 50 degrees plus or minus one. Dwell angles change when using points as engines are revved up, so pertronix is better because it removes that variable and keeps the dwell constant. Points gap is a mechanical adjustment, and dwell angle is an electrical measurement. To be 100% certain you are still within specs with you gap adjustment, verifying it with a dwell meter is highly recommended.

[DougM]

While I'm thinking about it, there is one more timing mark to consider. I'm going to assume you are referencing zero on the flywheel with the line in the window of the plastic clutch cover? There is actually a line cast into the block at zero, but you'd have to remove the plastic clutch cover to see it.

[saabfan9]

hard to see but i have been going off the mark on the block (after having that cover and the dist. off soo many times i think i'm starting to dream about them)...with the rotor at that mark it just cranks (no stumble or backfire nothing) if i move it 1 tooth it starts rough, max out the adjustment now reads 30 btdc and the car starts easy no backfires no overheating...but now the rotor is between 1 & 3, to me seems like 100 atdc ....i adjusted the throttle switch the points gap and adjusted the timing a bit (to with the cover on now reads 15 btdc...rotor nowhere close to mark on housing) did not take it out for a ride too late but will this morning

[saabfan9]

i see the wiring on the distributor is not the same (green-blue-red) not sure if it means anything.....mine is a 1973 ems build date of 12-1972

[Jordan]

I feel like I'm saying the same thing and nobody is paying attention but here is how you can tell your "actual" timing as things in the pertonix might be off or something else is askew:

1. Bring engine to TDC . #1 valves should be closed, Cam should be lined up with mark.
2. Hook up the timing light to pick up cylinder 1 plug ( you know the engine is in "backwards", right? )
3. Loosen the distributor body so you can rotate it and make sure you don't electrocute yourself with the soon to be live leads.
4. Turn ignition on (don't start it), hold timing light trigger down and slowly rotate the distributor body until the light flashes.

At that point, the rotor should be pointing to the hash mark on the dist. body. If it is not, you can try to re-clock the body by removing and resetting it, but over all it is not critical. The critical part is that is wherever the rotor is THAT is when cylinder 1 fires at the cap. So lock it down and check the wires and the correct sequence 1342 (in the correct direction)

You can't set the flywheel at 8º and pretend it is TDC to get timing at 8º. There probably is already going to be some mechanical advance when the car is running at idle. I'm not saying it isn't a good place to start, I'm just saying it probably won't equate to your final timing once you get the car going. You'll need to recheck it again with the vac line unplugged to make any final adjustments.

[DrewP]

The way the Pertronix works is there is a magnetic sensor (called a pickup), it's that little black plastic jobber with the black and red wire running into it.

There is also a magnet installed on the distributor shaft. It's a little collar that slides onto the distributor shaft underneath the ignition rotor. If the magnetic collar is installed crooked or upside down or something it will throw things off. It should index onto the little cam lobe that would open and close the points if you still had breaker points installed.

It sounds like either the pickup or the magnet is installed in the wrong position, since it's firing the ignition when the rotor is still way too far away from the contacts for the plug wires, making for a very long way the arc has to travel to get to the wire poles.

Also are you sure the rotor is seated all the way down onto it's little keyway, and that the indexing key isn't like broken off of the rotor?

[saabfan9]

i tried to set the rotor at the alignment mark but the car would not start the only way the car runs is to have it at that set up (doesnt make sense to me seems like it should be soo far out of time it shouldn't start) but with the car running and the rotor 1 tooth up the timing window appears with the light and if i wanted i could set the car at 8 but it backfires bad....i looked at all the pertronix stuff and the rotor is on properly and indexed on the notch...i didnt think about it being upside down but i'll take a look

[DrewP]

It also looks like it might be possible to install the pertronix trigger 180* degrees from where it is now? On Doug's car the trigger plate is on the other side of the distributor from where yours is.

I'll be at my shop this evening and I'll take a look at how mine is installed, because mine seems to be lined up correctly.