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First, check to see if you have spark at the plugs Posted by RS [Email]  (#15)  [Profile/Gallery]
(more from RS) on Sat, 26 Aug 2006 09:45:35
In Reply to: Re: 91 saab 900T fuel pump???? HELP!! HELP!!! HELP!!!!, chuck kusiak, Sat, 26 Aug 2006 05:57:45 Members do not see ads below this line. - Help Keep This Site Online - Signup |
A couple fo comments and then a few other things to look at:
It's possible that the fuel system cleaner loosened up a lot of crud in the tank and plugged up the filter. I had similar symptoms in an '88 900S and replacing the fuel filter solved the issue.
Look closely at the cap and rotor to make sure that the carbon button in the cap hasn't disintegrated and check the resistance between the middle of the rotor and the end to make sure that it's not more than 1000 ohms.
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If you have spark -
Narrow it down see whether there is power at the fuel pump when a helper is cranking the car. You'll need to remove the plywood spare tire cover (2 small torx screws) and pry up the fuel pump cover (the large round cover) to access the fuel pump. Use a multitester to measure the voltage. If there isn't power at the fuel pump when you crank it, then it might be an ECU problem. My bet is that it isn't.
Also, try putting a jumper between fuses 27 and 30. 27 is the fuse for the emergency flashers (which is always hot regardless of the position of the key) and 30 (which is the fuse for the fuel pump.) If the fuel pump runs, when you do that, and the car starts, then it's probably OK.
IF you measure voltage at the pump and it doesn't do anything (including not making a buzzing sound as it runs), it's a gonner. I just helped a friend replace the fuel pump in his '89.
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On the other hand, if you don't have spark at the plugs when a helper cranks it, then there are other issues preventing it from running.
The fuel injection computer (ECU) won't let the fuel pump run when you turn the key until it receives an RPM signal from the ignition module. IF it doesn't receive that signal, it usually means that either the hall effect sensor (or associated connector) went bad or the ignition module went bad. Ignition modules do spontaneously give up the ghost or they'll let the car cough a few times until they heat up.
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Here's a link to a more detailed discussion of how to diagnose a no-start problem
http://townsendimports.com/Web/engine_folder/nostart24.htm
, Sat, 26 Aug 2006 09:45:35 <-- Viewing This Message
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