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Crank (hall) sensor woes!

2K views 13 replies 5 participants last post by  Banman 
#1 · (Edited)
HELP, HELP, HELP! Victim is a '91 900s w/LH2.2.4 and EZK ignition

After nothing else could be the cause of my intermittent stalling problem I removed the crank pully to change the hall sensor. I found the sensor covered in metal dust. Anyone know if this would cause the signal to intermittently fail--I'm guessing it could but I'd like to know for sure.

I replaced the hall sensor with the generic one from e-euro parts.com. It didn't come with any instructions and the wire colors were different and of a smaller gauge... however it did screw into place correctly...

So I figured ignore the color and just match +, -, o from the new switch to the old switch. Hooked it up and nothing. No spark. Tried the wires matching the color and nothing... Finally removed the new switch and reinstalled the old switch (after removing the metal dust) and hooked it up and still nothing...

Could I have damaged some other part of the ignition system with the new sensor hooked up wrong, or if the new sensor was faulty somehow could it have caused a new problem? I'm thinking the old sensor should have worked after cleaning the metal dust away since it worked most of the time with the dust there.

I'm about ready to scrap the f---ing car! :evil:

Really hoping somebody can give me some usesful advice about what might be happening. Thanx!
 
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#2 ·
Semi-good news: The Saab has been sitting in the snow while I was deployed a month. Went to push the Saab back into the garage with my jeep. Hooked the battery back up to lower the window so my wife could hear me as I pushed. Turned the key "just to see" and it started right up! Drove it into the garage and let it run--it died after a few minutes but then restarted when I held the gas pedal to the floor. It wouldn't restart consistently though. None of the belts are connected so after it restarted and ran a bit I shut it off. I'm recharging the battery and really hoping someone out there can give me a clue about what I'm missing...
 
#3 ·
Banman said:
Semi-good news: The Saab has been sitting in the snow while I was deployed a month. Went to push the Saab back into the garage with my jeep. Hooked the battery back up to lower the window so my wife could hear me as I pushed. Turned the key "just to see" and it started right up! Drove it into the garage and let it run--it died after a few minutes but then restarted when I held the gas pedal to the floor. It wouldn't restart consistently though. None of the belts are connected so after it restarted and ran a bit I shut it off. I'm recharging the battery and really hoping someone out there can give me a clue about what I'm missing...
Be careful running it with the belts off as the water pump won't be turning. Few minutes is probably about as long as I'd want to run a cold engine without any coolant circulation. If you do have spare belts handy, just hook up the water pump and alternator ones and leave off the AC and power-steering so you can run the engine with the two most important auxilliary devices operating.

Anyway check all the ignition-related things like distributor cap, rotor, leads, and also fiddle with the electrical connections to the air-mass meter, AIC, etc. and make sure they're ok too.

Craig.
 
#4 ·
The belts are off because I've been removing/reinstalling/removing/reinstalling the crank pully so many times. I don't wanna put it all back together till I'm sure the crank sensor is right! It's below freezing here--would take several minutes just to get the car warm let alone hot--I was watching the temp. gauge the whole time. Thanks though.

Can someone answer my crank sensor questions please...
 
#5 ·
Now that the battery is recharged and the saabs been sitting in the warm
(45') garage a few hours. It started right up four times in a row! Once again I can't check for anything broken when it works so well... I guess I'll put the belts on and go for a drive--like rolling the dice... and see what happens.

Can someone please tell me about rust and metal bits and dust packing around the crank sensor and what the effects could be. I'm guessing the metal debris w/could bogger up the CS but I'd really like someone with any experience to chime in... anyone, anyone, Bueller...
 
#6 ·
Banman said:
Now that the battery is recharged and the saabs been sitting in the warm
(45') garage a few hours. It started right up four times in a row! Once again I can't check for anything broken when it works so well... I guess I'll put the belts on and go for a drive--like rolling the dice... and see what happens.

Can someone please tell me about rust and metal bits and dust packing around the crank sensor and what the effects could be. I'm guessing the metal debris w/could bogger up the CS but I'd really like someone with any experience to chime in... anyone, anyone, Bueller...
I believe that the crankshaft hall-effect sensors can be buggered up by leaks of coolant running down the back end of the engine. Are the metal bits steel or aluminium alloy fragments? Do you know where they might have come from?

I don't think dust/dirt would cause much of a problem other than allowing oil, etc. to be trapped through absorption into the muck. Unless there is a lot of metal particles (steel mostly) in the muck, it wouldn't have much in the way of a magnetic 'signature' that would have any effect on the operation of the hall sensor.

Is there any way you could capture some pics of the area around the crankshaft pulley and hall sensor that we could have a look at? It might be a good idea to de-grease the entire area (assuming there is a fair amount of grease/oil there trapping dirt and other particles), try to get the engine running, and see how things go after that.

Craig.
 
#7 ·
To late for pics--everythings been cleaned up, sprayed off and blown with compressed air.

All the bits sticking to the Hall sensor were ferrous--ie magnetic... the source I guess would be the crank pully coming apart last winter. Lots of steel from that one--sounded like train brakes! I'm guessing that because the alternator bushings were shot the alternator pulled the belts toward the firewall so the crank pulley went towards the firewall instead of into the oil pump...

Some coolent could have gone down there as I replaced the water pump when I replaced the crank pulley...
 
#8 ·
If the crakn pully comes apart its common for them to wear into the oil pump housing and also to damage the crank sensor.

When you hold the pedel to the floor the injectors don't fire, is there any reason it might have been flooded?

Perhaps you have more than one problem.
 
#9 ·
When the crank pulley broke the steel outer ring went towards the A/C pulley bracket (actually cut into it 1/8") the car never stopped running. I replaced the crank pulley 10,000 miles ago so I don't think the hall sensor was damaged at that time but that certainly was the source of the metal dust and shards that accumulated on the CS over the past year.

The one time flooding issue I think was from running after sitting in 0degree temps for weeks.

To make matters worse: After giving four clean restarts I tightened the crank pulley bolt and put the belts back on and now it won't start--back to being at wits end...
 
#10 ·
Banman said:
The belts are off because I've been removing/reinstalling/removing/reinstalling the crank pully so many times. I don't wanna put it all back together till I'm sure the crank sensor is right! It's below freezing here--would take several minutes just to get the car warm let alone hot--I was watching the temp. gauge the whole time. Thanks though.
Don't underestimate the water pump.

Without the pump running, you're not going to get any water circulation. None at all. So the heat going INTO the water at the hot bits (round the combustion chambers) won't quickly get to where the temp gauge's sensor is.

Engine bits get hot very quickly without any cooling - to demonstrate this, start the car from cold, leave it idling for a minute or so, then stick your hand on the exhaust manifold. Doesn't burning skin make a lovely smell?
<no, please don't actually try this...>

All that heat is going to be trying to dissipate into a relatively small amount of water, rather than the several litres in just the block with the 'stat closed.

Another fine demo - with the engine (any water-cooled car with a temp gauge is good) properly hot, turn the ignition off. Motorway services are good for this. Wait five minutes, then start the engine again. You'll note that the temp gauge has risen noticably, but will fall quite quickly once the engine is running and the water circulating again.
 
#11 ·
A lot of encrusted yuck can interfere with the Crankshaft Position Sensor.
Crusty coolant yuck can ruin one, oily yuck can do the same.
If it works OK on the test drive, it will probably continue to work. Let it idle for 1/2 hour before your drive. It will get hot and you'll be sure your cooling system is working right.
 
#12 ·
TooMany--your point about "hot-spots" and distance from the temp sensor is noted. Demo on how cold the mountains are--after running for more than a minute I wrapped my cold hands (carefully) around the toasty exhaust to warm them back up. Only the turbo was too hot to handle!

Got it running while all connected--died after about 7min. No spark! Swapped the EZK box and it fired back up with a smoother idle. Left idling for 1/2 hour ran like it should... test drive will wait till my wife comes home.

Jim M. Is it possible for an incorrectly installed or faulty crank sensor to fritz the EZK? I had checked this item more than once during my "intermittant stalling" (earlier post) adventures and it checked ok. Also I never got any check engine light or codes to indicate a problem with it. Also do you have any experience with the "generic" replacement hall sensors from e-europarts.com?

Thanks all !!!
 
#14 ·
Finally my pesky ignition may be fixed! I've driven ~400 miles (1 weeks commuting) since cleaning the metal debris from the CS and replacing the EZK. I guess I'll never be able to know if my (random stalling) problem was always the EZK or not. Very disconcerting to not know for sure what fixed the car and what caused the problem...
 
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