Intermittent starting problem!

 
Old 05-04-2009, 01:55 PM
  #1  
Junior Member
Thread Starter
 
Join Date: May 2009
Posts: 7
Default Intermittent starting problem!

My 2001 Saab 9-3 runs perfectly except occasionally it won't start. Turning over the key turns on all the electrical components (radio, lights, etc) but there is no sound otherwise - no clicking of ignition or huffing of engine.

After we let the car sit for a while - it can be 5, 10, 15, or 45 minutes - it starts up again and runs just fine.

The problem is intermittent. We can go for months without it happening, then it will happen twice in a week. The mechanics can't diagnose it because it doesn't happen when we bring the car in. My mechanic suggested it could be the starter, the ignition switch or the relays (a total of over $1100 of repairs) but wouldn't guarantee that that would solve the problem.

We can't see a pattern, but we think it might be happening after short drives, but we're not positive.

Can you help? Thank you in advance.

Willyffej
willyffej is offline  
Old 05-06-2009, 06:05 PM
  #2  
Super Moderator
 
Join Date: Dec 2006
Location: Kiev, UA
Posts: 2,030
Default

Replace the crankshaft position sensor. I am pretty sure that this is your problem since the car start fine when cold.
Roto is offline  
Old 05-11-2009, 12:50 PM
  #3  
Junior Member
Thread Starter
 
Join Date: May 2009
Posts: 7
Default how does crankshaft position sensor work?

Thank you Roto for your reply. Another mechanic suggested it was possibly the starter motor and, if it should happen again, i should tap the starter motor to jar it into position - that would seal the diagnosis for sure.

But I'm curious about the crankshaft position sensor. Can you explain in brief lay terms how this works and why this would be causing the problem?

Thank you again,
willyffej
willyffej is offline  
Old 05-11-2009, 02:52 PM
  #4  
Super Moderator
 
Join Date: Dec 2006
Location: Kiev, UA
Posts: 2,030
Default

Could be the starter, but it isn't likely...after all this isn't a dodge we're talking about. The reason I suggest CPS is because this is a very common failure on this type of an engine. You see, the CPS tells the engine what angle the crank is at and the signal from it determines when the DIC (ignition module) will fire the spark plugs. Now the DIC fires both plugs of the cylinders that are at TDC since at that point the car still doesn't know which piston is in the compression cycle and which one just finished the exhaust. The cylinder that is in the compression will fire and the DIC will sense this through the spark plug using ionic detection at which point the ECU knows exactly what to fire and when. It's pretty key that that signal from the CPS is good, otherwise your car won't start. These sensors just degrade over time and need to be replaced...
Roto is offline  
Old 05-12-2009, 04:52 PM
  #5  
Junior Member
Thread Starter
 
Join Date: May 2009
Posts: 7
Default

Roto
Thanks for detailed explanation, i even understand most of it. I took that info to the mechanic (the one that suggested the starter might be the problem) and he plugged in his diagnostic machine into the 'black box' and saw no record of engine errors. he said that a crankshaft position sensor problem would show up as a 'check engine' error. He again brought up starter or even ignition switch. when i asked how it could be that it always fixes itself, he told me that electronics are so snaky, it's just how it is.

he told me to leave the car for a day and they would check 'voltage irregularities' to diagnose the problem. does that even sound right?

i wish i knew a genius mechanic her in venice or anywhere in la, because again my limited knowledge of such things makes me feel uncertain.

anyway, thanks for your help. i appreciate your responses.
willyffej is offline  
Old 05-13-2009, 03:19 PM
  #6  
Super Moderator
 
Join Date: Dec 2006
Location: Kiev, UA
Posts: 2,030
Default

Unfortunately he's not entirely correct. My money is still on the CPS since most times it only shows up as a check engine code when it fails completely..and even than it might not. He's diagnosing it as ignition components because this is what it would be on most cars... I don't know what test he wants to do by leaving your car there, I'm just guessing that he'll test the car for no-start condition when it's cold and when it's warmed up and if it does a no-start he'll than tap the starter to see if it'll start than.
Roto is offline  
Old 05-29-2009, 12:42 AM
  #7  
Junior Member
 
Join Date: May 2009
Posts: 1
Default Some times won't start

I have had an ongoing probem with not having the engine start exacty as you described. Have you had any luck in finding a solution? I have my car in for repair and they can not recreate the problem. HelP!
carolmorrisey is offline  
Old 05-29-2009, 10:07 AM
  #8  
Junior Member
Thread Starter
 
Join Date: May 2009
Posts: 7
Default Still unsolved

Carolmorrisey:
We haven't yet solved the problem. On this forum, Roto has eloquently argued for the Crankshaft Position Sensor being the culprit, but my new mechanic here in LA tells me that if the CPS wasn't functioning I'd still be hearing starting or turnover noises, which I'm not. Hard to know who to believe.

This new mechanic is pretty certain (though not 100% so) that the Neutral Safety Switch is to blame. He cleaned mine (basically unhooking the connection, spraying it with WD40, and blowing it off with compressed air) but he claims there's a low probability a simple cleaning will fix the problem.

If the problem persists the next fix is to replace the Neutral Safety Switch altogether, about a $500 deal. We're on an expensive hunt.

willyffej
willyffej is offline  
Old 06-07-2009, 09:38 PM
  #9  
Junior Member
 
Join Date: Jun 2009
Posts: 2
Default Ignition Problems

Well...I'm glad I'm not the only one with this problem but I wish there was a clear cut answer. I have a 2001 9-5 and have the same ignition problem intermittently. Out of the blue I'll turn the ignition and the lights and radio...and everything except the engine comes on. No sound from under the hood. If I wait 5 minutes it will usually start. I'm going to try taking it to the mechanic this week. I may print out this thread for him to read. He owns a couple of Saabs himself so I'm optimistic!
Haystack is offline  
Old 06-07-2009, 10:06 PM
  #10  
Super Moderator
 
Join Date: Dec 2006
Location: Kiev, UA
Posts: 2,030
Default

Could be neutral safety switch. That never comes to my mind since I'm not exposed to automatics...
Roto is offline  

Thread Tools
Search this Thread
Quick Reply: Intermittent starting problem!


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.