No start, no codes - Chevy Impala SS Forum
 
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post #1 of 8 (permalink) Old 04-17-2016, 02:15 PM Thread Starter
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Question No start, no codes

Okay, car died on the road yesterday, just cut out and shut down completely. Here's what I've found so far...

Engine still cranks
No fuel pressure
No spark
All fuses okay
Temp gauge pegged hot at all times, engine did not overheat
Fuel battery and oil pressure gauges seem to work
Fuel pump relay okay
No power to radio in ACC keg position
Power to radio in "on" key position
No indicator lights in "on" key position
No PCM codes from diagnostic center when jumped
All power accessories work (mirrors, windows, seats)
Thought I saw small amount of smoke from steering wheel, but no heat and the car hasn't burnt to the ground (yet)
Power at fuel pump fuse, but not ignition fuse, no power at fuel pump relay
Odometer/Speedometer display has worked intermittedly for a while, so I don't know if it's displaying mileage or not.

I've got an LTCC ignition system in there and it was working fine for a more than a year, I just put some Moroso plug wires which are (supposed to be) high resistance like the LTCC calls for. Fuse is a 25A which is 5A over what it calls for because it kept blowing the 20A I had in there but I've never had a problem before, and the fuse was not blown.

I'm thinking the PCM fried somehow or the ignition switch shorted out somehow. Any ideas or suggestions?

"I am free because I am morally responsible for everything I do. I am free no matter what rules surround me. If I find them tolerable, I tolerate them. If I find them too obnoxious, then I break them. I am free because I know I am morally responsible for everything I do."
- Robert A. Heinlein

"The United States has become a place where entertainers and professional athletes are mistaken for people of importance."
- Robert A. Heinlein
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post #2 of 8 (permalink) Old 04-17-2016, 04:28 PM Thread Starter
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Update: I pulled out the PCM and cracked it open to look at the boards. Nothing looks burnt, there's no burnt smell, and since I don't have an oscilloscope or any diagrams of the board configuration I can't really bench test it.

Gonna put it back in and look at some more things like seeing if there's even power getting to the fuel pump, and see if maybe something burnt out between the ignition ant PCM.

"I am free because I am morally responsible for everything I do. I am free no matter what rules surround me. If I find them tolerable, I tolerate them. If I find them too obnoxious, then I break them. I am free because I know I am morally responsible for everything I do."
- Robert A. Heinlein

"The United States has become a place where entertainers and professional athletes are mistaken for people of importance."
- Robert A. Heinlein
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post #3 of 8 (permalink) Old 04-17-2016, 08:38 PM Thread Starter
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So I think I've got it narrowed down to the ignition switch... the direct circuit to the starter works and that's why it cranks, but something must be fried between the switch itself and the PCM.

This explains lack of fuel pressure, because there was no signal going to the fuel pump relay, lack of spark because there was no power going to the PCM/IGN fuse, lack of codes because there's no power going to the PCM, and all the other symptoms. Now I'll just have to pull the wheel off and take a look at the ignition switch itself and see if I'm right, and it's burnt out, and then figure out why it burnt out.

If anybody is interested here are some links that were pretty helpful to me:
http://www.brianesser.com/tech/wirin...20Controls.pdf
http://www.brianesser.com/tech/wirin...ntrols%202.pdf
http://www.brianesser.com/tech/wirin...ntrols%203.pdf

As well as some pictures (They're for a 1995 F-Body PCM but the 1995 B-Body PCM is basically the same from what I saw)
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"I am free because I am morally responsible for everything I do. I am free no matter what rules surround me. If I find them tolerable, I tolerate them. If I find them too obnoxious, then I break them. I am free because I know I am morally responsible for everything I do."
- Robert A. Heinlein

"The United States has become a place where entertainers and professional athletes are mistaken for people of importance."
- Robert A. Heinlein
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post #4 of 8 (permalink) Old 04-17-2016, 08:40 PM
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I read your post with great interest and hoping I could be helpful. But when I got to the LTCC mention, I lost hope since I have no experience with that. But one thing struck me. NEVER, never, never sub a higher rated fuse than spec'd unless other upgrades - including wiring - have been done. And you may have seen smoke..................

When you first began to blow fuses, that was the time to investigate why. It may have prevented the situation you now face.

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post #5 of 8 (permalink) Old 04-17-2016, 09:13 PM Thread Starter
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The LTCC manual does tell you to start with a 20A and increase incrementally if needed. The 25A never blew out, and for a year and a half was fine with no issues whatsoever. The wiring harness that the LTCC kit comes with includes a module which would constitute the wiring upgrade you suggested, otherwise they wouldn't recommend stepping up to the 20A fuse to begin with.

LTCC Installation Manual
Quote:
Originally Posted by Page 7
Note: The LTCCs current draw is 16-amps; the existing fuse for the ignition is 10-amps, it must be upgraded to 20-amps before starting the car for the first time. If a problem occurs, move up in 5-amp increments.
Like I said in my last post, I don't think the PCM was damaged, which would have been the worst case scenario. If that's the case then it's not likely that the fuse was an issue, and the internals of the LTCC control module were fine as well. It didn't have any power going to it though so there was no way to see if it was throwing any codes.

I'm guessing the problem may either be the new spark plug wires I installed, which are supposed to be high resistance Moroso wires, so I can check the resistance on them, or the ignition switch was just ready to give out after 21 years. I can also go back down to the recommended 20A fuse and see if it blows out once I get the car running again.

"I am free because I am morally responsible for everything I do. I am free no matter what rules surround me. If I find them tolerable, I tolerate them. If I find them too obnoxious, then I break them. I am free because I know I am morally responsible for everything I do."
- Robert A. Heinlein

"The United States has become a place where entertainers and professional athletes are mistaken for people of importance."
- Robert A. Heinlein
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post #6 of 8 (permalink) Old 04-18-2016, 11:09 AM
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Quote:
Now I'll just have to pull the wheel off and take a look at the ignition switch itself and see if I'm right, and it's burnt out, and then figure out why it burnt out.
To save you some time: The Saginaw columns in the b bodys
have the "ignition switch" at the bottom of the column.

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post #7 of 8 (permalink) Old 04-18-2016, 04:51 PM Thread Starter
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Quote:
Originally Posted by Z09B4U View Post
To save you some time: The Saginaw columns in the b bodys
have the "ignition switch" at the bottom of the column.
Yeah, that'll definitely make things easier, thanks for the tip! Now hopefully if I'm right it didn't take the harness out with it.

"I am free because I am morally responsible for everything I do. I am free no matter what rules surround me. If I find them tolerable, I tolerate them. If I find them too obnoxious, then I break them. I am free because I know I am morally responsible for everything I do."
- Robert A. Heinlein

"The United States has become a place where entertainers and professional athletes are mistaken for people of importance."
- Robert A. Heinlein
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post #8 of 8 (permalink) Old 04-18-2016, 10:23 PM Thread Starter
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Update: Back up and running. It was indeed the ignition switch. One of the pins was fried. Thankfully the connector was fine

"I am free because I am morally responsible for everything I do. I am free no matter what rules surround me. If I find them tolerable, I tolerate them. If I find them too obnoxious, then I break them. I am free because I know I am morally responsible for everything I do."
- Robert A. Heinlein

"The United States has become a place where entertainers and professional athletes are mistaken for people of importance."
- Robert A. Heinlein
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