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Discussion Starter #1
Hi, all seemed to be going will towards recommissioning car after coolant change plus c&m so I expected it to fire up happily…but oh no.

When last run it all ran perfectly, it has no 'history'.
Well, at first it did fire but only to idle at 2000 rpm which dipped 'sharply' to say 1700 rpm and then 'curve' back (quickly) to 2000. It would cycle through this in a consistent way (complete cycle say 5 secs peak-to-bottom-to-peak) with a gap of a couple of secs. Dissconnecting the AIC had no significant effect.
Inspecting the distributor cap I saw it was not on 'square'…the plug leads were on as before I did the service and the dis. cap contacts were good. After this idling issue they showed signs of 'wear'.
I then checked the leads and re-installed them to dis. cap… then it would mis-fire/not fire……I had got in a stupid tangle with them and seemingly got the order wrong.
Am confident now that they are all correct re firing order and cap is square but it will not fire though I sense there is a tiny spark.
I take it that the plug leads are not assigned to a specific distributor cap connection/pole.
Battery cranks starter OK.
Do not have access to multitester at the moment.
I had various electrical connectors off during the service including vacuum lines (which I pluged).

My mind has seized over this…help very much appreciated!

…its an N/A C900 auto with LH 2.4
 

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finbarr said:
I take it that the plug leads are not assigned to a specific distributor cap connection/pole.
Nope, they have to be in the right order and on the right pole.
 

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Bring your engine around to TDC (static) based on the timing marks on the flywheel - remove your distributor cap - note the "pole" on the cap that the rotor is pointing to - if you're on the compression stroke the pole (where the high tension lead attaches) nearest the rotor arm contact should be #1 - if you've really muffed the position of the leads on the cap - this might get you going again. Once you've established #1 the rest just go on in normal sequence -

Best of luck

Steve
 

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Discussion Starter #4
Thanks so much !
So its the leads…a relief, given that I have damaged 4 items during this lengthy coolant overhaul (including the ignition coil, not that I should admit that) ;oops: :nono; .

So, how best to turn the engine over, re TDC? I guess~it has to be by one of the pulleys…which is best.
The engine rotation is anti-clockwise when viewing the engine from the radiator which is clockwise when looking at the pulleys from the firewall?
Did look through Bentleys but did not clock that detail (re TDC/pole/lead|).
 

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you can turn the engine over with a prybar or big flathead screwdriver on the flywheel through the timing hole on top of the clutch housing
 

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yfs87 said:
you can turn the engine over with a prybar or big flathead screwdriver on the flywheel through the timing hole on top of the clutch housing
and remove the sparkplugs when rotating the engine by hand - that way you're just fighting friction (piston rings dragging on cylinder bores, main bearings, crank bearings) and not fighting compression at the same time!
 

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Discussion Starter #7
That's really great, many thanks…I should be on my way now.
Now of course it is obvious there is a relationship between firing order and camshaft~cylinder position.
Does to stand back and think of the overview sometimes, at least. I'll learn one day.
 

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finbarr said:
That's really great, many thanks…I should be on my way now.
Now of course it is obvious there is a relationship between firing order and camshaft~cylinder position.
Does to stand back and think of the overview sometimes, at least. I'll learn one day.
heh .. the only engines it's "easy" on are thumpers (single cylinders) - especially 2 strokes!;)
 

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It needs to be re-iterated that....

changing the distributor position on the 900's with crank pulse sensors does not alter the timing but, the relationship of the rotor to the electrodes in the distributor cap. That is, the centre of the rotor being direct adjacent to an electrode or as close as possible. Thankfully, the shape of the rotor tip gives you a fair margin to play with.

You could turn the distributor 90 degrees, and, as long as you change the spark lead positions accordingly, you would or should not see any ill effects of performance.

Timing on LH 2.4 and above is set only by the crank pulse setup. Not adjustable.
 

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Discussion Starter #11
not firing still...

Hi,
Have been working on this and still not firing :x .
First step was to follow instructions re. set up TDC and noting the nearest distributor pole to the rotor contact.
At that stage...
1. I set the flywheel position to 0 degrees (is this correct?...perhaps 14 degrees BTDC ? as in Bentleys re. ignition timing)
2. The rotor arm was pointing down to bottom left (say the 7 o'clock position, when viewed from the drivers seat) so accordingly I set lead/cylinder 1 to that pole and set the others in order from there.
Does that position sound right?
3. The engine did not fire, it vaguely 'spat' once.

Just to say, before this service the engine ran perfectly.

Following this failure I checked a number of electrics armed with my new multimeter and Bentleys.

1. Battery at full charge; spark at plug visible but not familiar enough to gauge stength; fuses OK.
2. Coolant sensor, throttle sensor, AIC, ign. coil, rotor arm impedance all OK
3. Re ignition amplifer there are 2 tests. One test was fine but the one that tests (I think) power to coil from amp that involves connecting the meter to Ign. Coil Terms. 1 & 15 the test failed. The reading with ign ON was to be 6V initailly and meant to fade to 0V in 2~3 seconds, it did not, the actual reading was 3.2mV which was continuous.
So, in some respects this could point to the ign. amp but I am confused the the presence of a spark at plug. Also, surprised that it would fail so abruptly.
Having said that would the high and oscillating idle (behaviour when last firing) be indicative of a failing amp?

Next and latest move...
1. I set the flywheel to 14 degrees, just to give a try though it naturally did not effect postion of rotor to pole from before.
2. Just a vague spit, akin to mis-fire but not continuous, cranking over healthily.

At this stage to do anything more seems pointless, (almost damaging!) and prefer not to rush out to buy replacement amp without greater certainity about what is really the cause of all this...the mind is fused...HELPPP!
 
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