LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Fuel pressure question

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Old May 31, 2014 | 10:01 AM
  #16  
Injuneer's Avatar
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Re: Fuel pressure question

I was under the impression that a bad ign switch was just dead car, no turn over, etc.
Not sure exactly what you are getting at, but.....

The ignition switch has multiple positions. One ("start") sends power to the starter to start the engine. Another ("run") sends power to the components that need power to operated the engine. An intermittent problem with the contacts/terminals/wires connected to the "run" circuit can cause the engine to stop running intermittently. Isn't that the problem you are trying to solve, based on the info you added in post #8?

everything was fine until I hit the train tracks "bump" and down she went and that's where I'm at today
Old May 31, 2014 | 10:15 AM
  #17  
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Re: Fuel pressure question

Originally Posted by Injuneer
Not sure exactly what you are getting at, but.....

The ignition switch has multiple positions. One ("start") sends power to the starter to start the engine. Another ("run") sends power to the components that need power to operated the engine. An intermittent problem with the contacts/terminals/wires connected to the "run" circuit can cause the engine to stop running intermittently. Isn't that the problem you are trying to solve, based on the info you added in post #8?
AH! Gotcha.....well shoot. I knew the ignition switch had multiple functions, but I didn't know that the two different positions were separate. I thought the starter, and other components were synchronous on the same contact. I guess I will go to the shbox and try to find an ignition switch testing document and go from there.

Thanks for all the help guys, and sorry for the "around the bush" conversations, but this is a bit of a different animal for me and I get less and less motivated since i've been borrowing a friends car for 2 weeks now.

I guess I'll get started today and provide feedback when I find a definitive problem.

Thanks again!
Old May 31, 2014 | 10:32 AM
  #18  
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Re: Fuel pressure question

So far, all we can do is SUGGEST POSSIBLE causes of the problem. You've got to follow through and check these possibilities. You've got to check the fuel pressure, you've got to scan it for codes. Without a logical diagnostic approach, you are just wasting time and money, and may never solve the problem. I wouldn't jump on the ignition switch until going through the other steps.
Old Jun 3, 2014 | 11:24 AM
  #19  
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Re: Fuel pressure question

OK guys, so heres a breakdown...
I've installed the new ignition switch to no luck. Sounded like a good plan at the time, but it was cheap so what the heck. No burn marks on the old one or anything.

SO....I went through the troubleshooting tech pages on shbox.com and have come to the conclusion that I am not getting any spark....

Coil tested good, icm tested good, ignition fuses were good, switch is now good, and fuel pressure at turn over is around 44psi

I did see the test for the injectors for checking the pink wire for pulse or something along those lines, but I don't have a test light at the moment so I skipped that.
I also skipped pulling the injectors simply because I wanted to go through the document step by step which I believe only leaves my opti. Thats the last part of the document I have to go through. Havent' actually tested it yet, but I have my suspicions that it will be the bad guy in this horror movie.

I guess that only really leaves one culprit huh? I decided to play a little trick on the car and gave it a little dab of ether but she didn't even burp.......

Last edited by awcforever; Jun 3, 2014 at 11:27 AM.
Old Jun 3, 2014 | 12:04 PM
  #20  
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From: Hell was full so they sent me to NJ
Re: Fuel pressure question

Originally Posted by Injuneer
...... I wouldn't jump on the ignition switch until going through the other steps.
Originally Posted by awcforever
OK guys, so heres a breakdown...
I've installed the new ignition switch to no luck. Sounded like a good plan at the time, but it was cheap so what the heck. No burn marks on the old one or anything.

.....
I give up. You win.
Old Jun 3, 2014 | 12:54 PM
  #21  
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Re: Fuel pressure question

Originally Posted by Injuneer
I give up. You win.
LOL! I have been going through the steps. I heard so much bad about the switch that I just figured heck spend the $60 on a new icm, coil, and switch cuz im sure it needed it anyway.

Hopefully I can get the opti finished up tonight and find out if it is in fact bad. AHHH! Sorry for the bouncing around guys.......I was hoping the initial cheap investment of some cheap parts would have proven to be lucky.........guess not
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