Help a Fool - Engine Revs Up When Gentle but Dies Under Load

[Crazyswede]

who are you?

[Crazyswede]

on timing marks...I find its helpful to scrub them with a wire brush to clean off the rust. Are you looking through the little window in the plastic cover when you are looking for the marks? I would go an set the timing first before doing any more fuel adjustments.

[Mars]

I'm just some guy in Seattle.

[squaab99t]

I'm just some guy in Seattle.

Folks in Seattle know classic saabs. You also may want to check that cylinder one is in fact at TDC per the timing marks. Some hot rodder might have switch flywheels on you? 9000 flywheel has different mark locations. Pull the spark plugs out and put a wooden dowel or chop stix in the hole. Turn the engine by hand and see if the piston comes to TDC matching the timing marks. Check the rotor and cap to see if it is in the window to send spark to cylinder 1. Note it might be pointing at cylinder 4 because it is on the wrong strke. Now check your timing with the vacuum advanced hose off. Like it was mentioned clean the marks, use white paint on 15 degrees and check it with the garage lights off to really see the white pop.

[Mars]

I took it for a drive (and it drove perfectly for some reason) to warm up the motor, then plugged the distributor, and cleaned off the flywheel (HUGELY helpful). Then I hit it with the timing light in the dark to see what I could see and it was showing more than 30 degrees of advance... I'm guessing that means its not a 99 flywheel as you suggested squaab? I wouldn't imagine it would run like that, would it?

[Jordan]

It will run, but it will burn very hot. You're igniting the cylinder way before the piston reaches the top of its stroke which puts a lot of undue stress on it. Was this reading with the distributor vac line plugged in or not. and at what RPM? it makes a big difference. 30 degrees at 30000 RPM is OK, 30 degrees at idle with advance unplugged=BAD

[squaab99t]

I took it for a drive (and it drove perfectly for some reason) to warm up the motor, then plugged the distributor, and cleaned off the flywheel (HUGELY helpful). Then I hit it with the timing light in the dark to see what I could see and it was showing more than 30 degrees of advance... I'm guessing that means its not a 99 flywheel as you suggested squaab? I wouldn't imagine it would run like that, would it?

Looks like you are on the right track. So you skipped step 1? Seeing if cylinder 1 is at top dead center and if the flywheel show 0 degrees?
Trouble shooting is very systematic. At least that is what we tell ourselves and is much better than shooting in the dark.

Last night, did you try to adjust the distributor to pull the timing to something like 15 degrees BTDC? If the slots did not allow enough travel it might mean the distributor cog gear is off by 1 tooth. It is a helix gear so it rotates as you put back in place. The other trick is that the driving shaft is a hex coming off the oil pump. A super long slot screwdriver (longer than the dist shaft) is the only way to clock the oil pump to get the hex shaft socket and the helix gear all synced. Takes a bit of time, and trail and error. Beer helps too.

[Mars]

It will run, but it will burn very hot. You're igniting the cylinder way before the piston reaches the top of its stroke which puts a lot of undue stress on it. Was this reading with the distributor vac line plugged in or not. and at what RPM? it makes a big difference. 30 degrees at 30000 RPM is OK, 30 degrees at idle with advance unplugged=BAD

This was done with the distributor plugged and at 850-900 RPM.

Looks like you are on the right track. So you skipped step 1? Seeing if cylinder 1 is at top dead center and if the flywheel show 0 degrees?
Trouble shooting is very systematic. At least that is what we tell ourselves and is much better than shooting in the dark.

I must admit I did skip that in the interest of just seeing if I could actually see the timing marks this time around. I will check TDC and 0 tonight!

Last night, did you try to adjust the distributor to pull the timing to something like 15 degrees BTDC? If the slots did not allow enough travel it might mean the distributor cog gear is off by 1 tooth. It is a helix gear so it rotates as you put back in place. The other trick is that the driving shaft is a hex coming off the oil pump. A super long slot screwdriver (longer than the dist shaft) is the only way to clock the oil pump to get the hex shaft socket and the helix gear all synced. Takes a bit of time, and trail and error. Beer helps too.

I have not tried to adjust the distributor yet. Thanks for the tip about the helix gear. I have pulled the distributor and reinstalled a few times while initially getting things set up and ran into that annoyance. I'll give that adjustment a shot and if I can't get it into the right range, I will pull the distributor and try that.

One more question. Would all this be in vain if this is not the right flywheel?

[Mars]

I just checked TDC. Piston 1 hits TDC at 0 deg advance. All is good there. Checked the distributor and it was firing at about 30 deg advance so I dialed it back to 17. Fired it up and it idles nice but won't rev up (how it used to run). Going to wait until its dark to verify settings with the timing light.

[sjones]

Going to wait until its dark to verify settings with the timing light.

You're blinded by that giant nuclear reactor floating in space too? It's rare, but here's summer. We ought to do a nwsoc 'fix-it day' in Seattle. The recent one was quite productive for me a couple of other folks, but it was a wash out weather wise.

[Mars]

Going to wait until its dark to verify settings with the timing light.

You're blinded by that giant nuclear reactor floating in space too? It's rare, but here's summer. We ought to do a nwsoc 'fix-it day' in Seattle. The recent one was quite productive for me a couple of other folks, but it was a wash out weather wise.

I would LOVE that. I'm STILL waiting for the sun to go down. I can't pull the car into the garage - it's full of motorcycles! But, I put in a starter button to bypass the spotty ignition cylinder, pulled out the headliner unit in an attempt to address its sag, and cleaned up some wiring and switches.

[Mars]

Alright, got it set to 17 degrees. The manual said 15 deg for N American and 17 for other, since I don't have emissions stuff installed I went with 17. Tomorrow I'll play with it a bit more. Thanks for the tips guys.

[Mars]

Got a chance to fiddle more and what I'm experiencing is richness at idle and lean at greater than about 30% throttle opening. As far as my tests show, everything else checks out (fuel pressure, fuel dist, fuel pump, warm up regulator, air regulator thingie mounted up by valve cover). To fix this I've customized the mounting plate for the switch that actuates the 5th injector (normally at WOT) to activate much sooner. It has a fine method of adjustment so I'm going to have to play with it a bit to get things set just right, but now the car screams!

[SwedeSport]

Does the 99 CIS system use an " accelerator pump " like the 900 does? sounds similar to what my 900 8v did a while back. Once I made sure this thingamajiggy was working and it ran fine.


The way I understand it, it fires the cold start injector when it senses the vacuum drops off, (ie opening of the throttle plate) to compensate for the instant lean condition.

[Mezzanine]

Does the 99 CIS system use an " accelerator pump " like the 900 does? sounds similar to what my 900 8v did a while back. Once I made sure this thingamajiggy was working and it ran fine.


The way I understand it, it fires the cold start injector when it senses the vacuum drops off, (ie opening of the throttle plate) to compensate for the instant lean condition.

Those things typically fail when the diaphragm inside fails, allowing a vacuum leak too. Pull the vacuum hose off and suck on it- you should only be able to draw a little air. If it passes that test, you can then check resistance across the contacts.

Mars, have you hooked up a CIS fuel pressure gauge to this thing yet? You're welcome to come by my place and use mine. Bonus: I have lots of CIS spares to fiddle with if necessary.