Hello all,
My 85 K5 has developed a nasty habit of not always starting. She has always been extremely reliable. Regardless of altitude, weather conditions or temperature she always fired up immediately. Now I can’t use her as my daily driver much less for road trips. Sorry for the length but I think it will help with the diagnosis.
Mechanicals:
350 w/700R4, computer controlled carburetor with all of the CA smog.
Symptoms:
If she doesn’t fire on the first attempt one of the following happens.
1. Tries to run while sounding like she is firing on 4 or 5 cylinders then either
a. Idle eventually smoothes out and she runs fine or
b. Sputters and dies. (If this happens see 2 below)
2. Engine turns over fine, seems like she is trying to catch occasionally or just as I release the key.
I have spark (I pulled plug wires and arced to the headers) and fuel is entering the carburetor throat.
Background:
This issue started 2 years ago after driving through an extremely heavy rain storm (which was never a problem before) to the airport. She sat for two days in the parking structure and when I returned she tried but wouldn’t start. During the attempts I heard what sounded like arcing around the starter area. When my wife arrived to pick me up I had her try to start the Blazer while I looked for the source of the arcing sound without success. She sat in the parking structure for a week until I could return and she fired right up (the arcing sound remained). I figured that something just needed to dry out and since there were no additional failures to start, I forgot about it.
Last winter her new trick was occasionally not starting in the morning if it was cold, foggy or raining. However, she would immediately start later in the day or that night even if the conditions were exactly the same. This winter she has become progressively less willing to start even during our 70 degree days.
Attempted repairs:
I changed out the starter last year (arcing sound remained though it has not been noticeable for several months). Replaced the cap, rotor, plug wires, plugs, ignition module, and fuel filters (both inline and at the carburetor). I have checked for vacuum leaks and now I am out of ideas.
I reviewed the "won't start" posts without success. Hopefully I have provided enough information in my mini novel that someone will be able to figure out the problem.
Thanks
My 85 K5 has developed a nasty habit of not always starting. She has always been extremely reliable. Regardless of altitude, weather conditions or temperature she always fired up immediately. Now I can’t use her as my daily driver much less for road trips. Sorry for the length but I think it will help with the diagnosis.
Mechanicals:
350 w/700R4, computer controlled carburetor with all of the CA smog.
Symptoms:
If she doesn’t fire on the first attempt one of the following happens.
1. Tries to run while sounding like she is firing on 4 or 5 cylinders then either
a. Idle eventually smoothes out and she runs fine or
b. Sputters and dies. (If this happens see 2 below)
2. Engine turns over fine, seems like she is trying to catch occasionally or just as I release the key.
I have spark (I pulled plug wires and arced to the headers) and fuel is entering the carburetor throat.
Background:
This issue started 2 years ago after driving through an extremely heavy rain storm (which was never a problem before) to the airport. She sat for two days in the parking structure and when I returned she tried but wouldn’t start. During the attempts I heard what sounded like arcing around the starter area. When my wife arrived to pick me up I had her try to start the Blazer while I looked for the source of the arcing sound without success. She sat in the parking structure for a week until I could return and she fired right up (the arcing sound remained). I figured that something just needed to dry out and since there were no additional failures to start, I forgot about it.
Last winter her new trick was occasionally not starting in the morning if it was cold, foggy or raining. However, she would immediately start later in the day or that night even if the conditions were exactly the same. This winter she has become progressively less willing to start even during our 70 degree days.
Attempted repairs:
I changed out the starter last year (arcing sound remained though it has not been noticeable for several months). Replaced the cap, rotor, plug wires, plugs, ignition module, and fuel filters (both inline and at the carburetor). I have checked for vacuum leaks and now I am out of ideas.
I reviewed the "won't start" posts without success. Hopefully I have provided enough information in my mini novel that someone will be able to figure out the problem.
Thanks
