1991 intermittent starting problems
snoopybear
03-10-2005, 01:29 PM
This question is about a 1991 Bravada 4.3 since it's very similar to a
Blazer. When I need it to start at critical times, I can never be sure that it will. It cranks OK. I've replaced all of the ignition parts that should affect starting. At the times it won't start, if I leave it alone for 20 minutes or so, it fires right up!! During cranking, the injectors are firing OK. Also, starting fluid does no good. No codes are being set. I put in a new coolant sensor (the one the commper reads). I would certainly appreciate any other ways to diagnose this problem. Also, does the computer read the throttle position sensor at cold startup (warm startup too)?
Blazer. When I need it to start at critical times, I can never be sure that it will. It cranks OK. I've replaced all of the ignition parts that should affect starting. At the times it won't start, if I leave it alone for 20 minutes or so, it fires right up!! During cranking, the injectors are firing OK. Also, starting fluid does no good. No codes are being set. I put in a new coolant sensor (the one the commper reads). I would certainly appreciate any other ways to diagnose this problem. Also, does the computer read the throttle position sensor at cold startup (warm startup too)?
BlazerLT
03-10-2005, 04:29 PM
What ignition parts did you replace?
Did you check the battery voltage?
Ever replaced the fuel filter?
Ever check the timing with the timing wire unattached?
Did you check the battery voltage?
Ever replaced the fuel filter?
Ever check the timing with the timing wire unattached?
snoopybear
03-10-2005, 04:51 PM
Replaced the ign module, pickup assy, dist rotor and cap along with ign coil. Replaced fuel filter. Batt voltage checks ok along with timing (wire not attached). Thanks for your time on the message. Any other things I might check will be appreciated.
Regards.
Regards.
BlazerLT
03-10-2005, 05:15 PM
Replaced the ign module, pickup assy, dist rotor and cap along with ign coil. Replaced fuel filter. Batt voltage checks ok along with timing (wire not attached). Thanks for your time on the message. Any other things I might check will be appreciated.
Regards.
What is the battery voltage?
Regards.
What is the battery voltage?
snoopybear
03-10-2005, 05:54 PM
The battery voltage is 12.92v. Regards
BlazerLT
03-10-2005, 06:04 PM
The battery voltage is 12.92v. Regards
Check fuel pressure.
Check fuel pressure.
snoopybear
03-10-2005, 10:13 PM
I'll acquire a gauge and get back to you
Cam1959
03-11-2005, 06:00 PM
This question is about a 1991 Bravada 4.3 since it's very similar to a
Blazer. When I need it to start at critical times, I can never be sure that it will. It cranks OK. I've replaced all of the ignition parts that should affect starting. At the times it won't start, if I leave it alone for 20 minutes or so, it fires right up!! During cranking, the injectors are firing OK. Also, starting fluid does no good. No codes are being set. I put in a new coolant sensor (the one the commper reads). I would certainly appreciate any other ways to diagnose this problem. Also, does the computer read the throttle position sensor at cold startup (warm startup too)?
so cold starting = yes, hot starting = no. what could be effected so much by temp ? choke adjustment ? vacuum drops after while too, vacuum timing advance adjustment ? air-lock in fuel line ?
Blazer. When I need it to start at critical times, I can never be sure that it will. It cranks OK. I've replaced all of the ignition parts that should affect starting. At the times it won't start, if I leave it alone for 20 minutes or so, it fires right up!! During cranking, the injectors are firing OK. Also, starting fluid does no good. No codes are being set. I put in a new coolant sensor (the one the commper reads). I would certainly appreciate any other ways to diagnose this problem. Also, does the computer read the throttle position sensor at cold startup (warm startup too)?
so cold starting = yes, hot starting = no. what could be effected so much by temp ? choke adjustment ? vacuum drops after while too, vacuum timing advance adjustment ? air-lock in fuel line ?
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