Author Topic: Help. Loss of all power after a double tap ign.  (Read 580 times)

duffinatur

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Help. Loss of all power after a double tap ign.
« on: May 17, 2018, 01:02:55 AM »
My car has been running great and I finally have it plated for short test drives. I've put about
60 miles on it in about 4 trips. never an issue.
Yesterday I cranked the key - and after engaging but before firing up, my thumb slipped and the key
released a little off of "start" and I cranked it over right away to start again and everything died.
Not even courtesy lights or brake lights.  Like the car didn't even have a battery.
I've checked and replaced every relay, fuse and maxi-fuse for the power to the ECM and checked
every ground except what's on the starter.
I also disconnected the battery overnight hoping for a "reset" on the ECM. (?)
My battery has 12v (didn't kill a cell), there's 12v power going to the relay, switch and
interior connections...until I turn the key, then everything dies.

Today, I pulled the column, starter switch and again checkd every fuse. I have all power, even radio, dome, etc
until I engage the key, then it all turns off until I release the key. That's better than yesterday but still no joy.
I don't hear the fuel pump priming.

I thought about a new ignition switch, or new battery, or even key switch
(I just rebuilt my column and am not pleased so I ordered a new column that will come with a new ignition switch).

Does anyone have any suggestions?
Thanks,
Duff

After numerous internet searched for possible causes I'm stumped.
Could it be a fried ECM? a shorted wire somewhere, a ground I missed?
Has anyone with an LS swap ran into this issue?
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

aussieta

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Re: Help. Loss of all power after a double tap ign.
« Reply #1 on: May 17, 2018, 04:08:26 AM »
measure the battery whilst a helper holds the key in the start position
then measure fuses and relays under same conditions
testing for "failing under load" conditions
dont forget to test the body of car still has negative under load
1978 Y84 W72 WS6

Jack

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Re: Help. Loss of all power after a double tap ign.
« Reply #2 on: May 17, 2018, 05:37:41 AM »
If I had to guess I would say that your battery terminals and main ground connection to the block (and possibly the wire itself) is corroded. 




Regards, Jack

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #3 on: May 17, 2018, 12:25:08 PM »
Thanks
I'll get a friend to come over and be a 2nd pair of hands.
I also dug out of my spare parts box a NIB ignition switch that I'll
install just to eliminate one other possibility.
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #4 on: May 17, 2018, 08:40:44 PM »
Cleaned both ends of the battery ground cable and also checked for voltage drop at the battery
during cranking (minimal @ 1.2v). I still need to check for drop at the fuses, but some are under the console.
Battery stayed on a charger overnight and is holding at 100%.

The next two things I'm trying are replacing the ignition switch on the column and the starter solenoid.
After that I'm out of ideas.

It does seem the longer I wait the better the system recovers. At first EVERYTHING died out during cranking,
but today the dome even stayed on during cranking, and the fuel pump activates with the key "on".
It's very confusing.
« Last Edit: May 17, 2018, 08:44:45 PM by duffinatur »
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

Re: Help. Loss of all power after a double tap ign.
« Reply #4 on: May 17, 2018, 08:40:44 PM »

Jack

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Re: Help. Loss of all power after a double tap ign.
« Reply #5 on: May 17, 2018, 09:08:02 PM »
Did you check the battery main ground to the block? I would remove the wire, strip back and make sure the wire in not corroded  from the inside, also remove the bolt and sand around the stud. You don't want any rust or paint between the termination and block.




Regards, Jack

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #6 on: May 17, 2018, 10:15:11 PM »
I did. cleaned both ends and mating surfaces with 100 grit paper.. It's possible it's corroded
inside the insulation?
I have a spare new one in my stash of parts...I'll swap it out and see what happens when I
put in the new ign switch tomorrow.

The one thing I haven't tried, and have never been a fan of doing, is jumping the terminals
on the starter with a screwdriver (neighbors suggestion) to see if it will turn over.
With my headers there's no way to reach it from above...
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

aussieta

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Re: Help. Loss of all power after a double tap ign.
« Reply #7 on: May 18, 2018, 12:41:39 AM »
the dome light would seem to prove it is not ignition switch
still leaning to battery, main power/ground fault very early in the circuit
1978 Y84 W72 WS6

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #8 on: May 18, 2018, 10:14:50 PM »
I think you're right AussieTA, but I can't find any.

So far:
Checked starter: OK
New ign switch: OK
all new relays/fuses
battery good: will check level again tomorrow
ground good: batt to block, block to frame, frame to body. (so far)

I'm worried my ECM has an issue, or crank position sensor?, or there's a mouse eaten wire
up under the dash, or something more serious. My nice organized wiring under the dash is now all pulled
out of of the loom. I can't remember if or where there's a fusible link other than the firewall maxi-fuse
I think I'll be pulling more wire loom tomorrow and checking every circuit for continuity.

I'm still seeking advice...until it cranks over I'm also still stumped. Things were fine until the double tap on starter.
« Last Edit: May 18, 2018, 10:36:28 PM by duffinatur »
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

aussieta

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Re: Help. Loss of all power after a double tap ign.
« Reply #9 on: May 19, 2018, 01:47:39 AM »
where is the fusible link/s on your car
ecu would not take out dome light
test under load
turn headlights on, they probably wont work, but pull switch out and redo your tests
1978 Y84 W72 WS6

Jack

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Re: Help. Loss of all power after a double tap ign.
« Reply #10 on: May 19, 2018, 04:22:25 AM »
I don't think it's the fusible link and still think your battery is shorting out. Test the battery while it's in the car connected and take it out and test again, you should not get any leakage across the terminals. Take a volt meter and see if you are getting zero volts when you measure across the (-) and other parts of the car.




Regards, Jack

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #11 on: May 19, 2018, 01:11:42 PM »
Jack, AussieTA,
Thanks for the tips, I'm getting juice from the negative side.
I just have to find the cause. I swapped out or checked all the usual culprits:
ign switch, starter, grounds (engine bay), and relays/fuses.
I'm going to work my way backward from the battery and try to trace it down.
I'll be unplugging all the unnecessary points one at a time (radio, lights, door locks,
seats, windows, etc.)
One thing I neglected to check is when I replaced the ignition relay
I may have installed a normally open relay in place of a normally closed relay.

What's puzzling is this is something sudden that happened, not an intermittent
issue. I feel like I broke something during the starter double tap.

I'm weak with electronics, I can barely read either one of my multi-meters.
I really appreciate all the help.
Thanks
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

aussieta

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Re: Help. Loss of all power after a double tap ign.
« Reply #12 on: May 19, 2018, 05:27:40 PM »
place your multimeter on dc volts
place black lead on batttery negative, place red lead on battery positive
measure approximately 12 volts
have someone hold key in cranking position, do you still have 12 volts
place black lead on engine block on a clean bolt, have someone hold key in cranking position, do you still have 12 volts
place red lead on ignition relay supply side, have someone hold key in cranking position, do you still have 12 volts
place red lead on starter motor heavy wire, have someone hold key in cranking position, do you still have 12 volts
place red lead on starter motor thin wire, have someone hold key in cranking position, do you still have 12 volts
do the same with any and all fuses you can find, measuring both sides of all fuses
work your way along until you dont have 12 volts
please list your test results as "measured battery positive post to negative post at 12.3 volts(whatever reading you get)" not just "checked fine" and whether you tested static (car just sitting there) or under load (headlight on or starter in crank position)
checking under load catches many mechanics out
1978 Y84 W72 WS6

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #13 on: May 19, 2018, 08:31:04 PM »
Thanks AussieTA,
Part of my issue was I was using a pocket size (cheap) multi meter, and a metered test light. I thought
I could get by with what I had, but they're not so good for diagnostics. I borrowed a better unit from
my neighbor and will get back at it next week.  I'm also working solo and need a 2nd pair of hands
for testing under load. Maybe I can get one of the neighbor kids to crank the key.

I really do appreciate the tips and will post up my results, I just haven't had any good ones yet.

As I posted at LS1tech:
Thanks, gents,
I bought a new battery and I still have the same problem.
I'm going to walk away from it for a few days (family and work responsibilities).
I'm on a mini vacation next week (I WAS going to final wet sand and buff the car but now??) so I'll come
back at it with a fresh pair of eyes. I've swapped out everything for new parts and added grounds but still no joy.
Some of the more unusual things I've tried:
-cleaning the mounts to the starter/block (Wasn't sure if starter housing is grounded..it didn't hurt)
-Tried hot wiring the ignition switch - did the same as before
-swapped for a new battery - didn't do anything
-unplugged everything not connected to the LS harness except the gauges so far, even the trunk release
-added extra grounds from the block to frame, (I still need to add an extra permanent frame to body ground)
-pulled the seats to be able to better look up under the dash (I'm 6' 2", I needed the room, )
-Pulled the console to check the neutral safety, back up light switch and a few grounds.t

Next time I work on it I'll pull out the LS swap harness instructions to make sure it's connected correctly.
I'll jog the starter to make sure the car will turn over manually
I'll look at Holley HP EFI if I get angry enough. I'm close now.

A few questions for anyone willing to answer:
Could I have fried my ECM? (I don't get any error codes on my reader, but the car's not running.
Could I have fried my alternator? would a bad alternator cause this kind of prob?
(I have a spare going on with an alternator relocation kit)
Could something mechanical cause this kind of issue, or a sensor? Like I wrote before,
it feels like something broke/happened/occurred that had never happened before.
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

aussieta

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Re: Help. Loss of all power after a double tap ign.
« Reply #14 on: May 19, 2018, 10:10:06 PM »
i doubt it is your ecu or alternator
working alone use your headlights to load the circuit
if your meter reads 12 v at the battery that is accurate enough
1978 Y84 W72 WS6

Re: Help. Loss of all power after a double tap ign.
« Reply #14 on: May 19, 2018, 10:10:06 PM »

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #15 on: May 22, 2018, 01:17:22 PM »
Just a quick update:
I only had a few minutes before work this morning so I quickly ran a remote
switch between the bat and start wire post on the starter and she fired right up,
no hesitation. It turned off with the key.

SO: no mechanical damage or any of the other things I was worried about.

Now I just have to find the cause...At least I know what circuit to check when I get back at it tonight.
I may just remove and replace the starter wires.
Thanks for the advice, gents.
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

duffinatur

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Re: Help. Loss of all power after a double tap ign.
« Reply #16 on: May 24, 2018, 12:03:22 PM »
I ended up replacing the wire from the ignition switch to the starter and it seems to have fixed the problem.
Originally I had this wire going through a starter relay (as instructed by my engine harness mfg), but realized
there was no need for a relay as I updated to a new Painless fuse and body harness last year.  The old wire
that I removed was the most likely issue but doesn't seem to visually have anything wrong with it, but
I haven't check continuity on it yet. It's probably corroded or broken inside the insulation and it's shrink wrapped
so I'm just going to toss it and move on. Plus I need to re-loom most of my harness and I added a few upgrades
while I had it apart.
Bypassing the relay, replacing the wire and adding a few grounds for good measure and I'm good to go.

Thank you for all the advice and help, I used it all and it helped me to narrow down the problem.
76 Pontiac TA (long gone, first car)
69 Cadillac Eldorado (long gone)
00 HD Road King Classic
65 Pontiac GTO (gone, not forgotten)
67 Shelby AC Cobra replica (gone, winning shows still)
76 Trans Am LS1/4A TA (a recreation of my very first car)
74 Olds Cutlass Supr (status: on hold)
69 Pontiac Grand Prix (frame-off beginning soon)
Build: http://transamcountry.com/community/index.php?topic=57079.0

ryeguy2006a

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Re: Help. Loss of all power after a double tap ign.
« Reply #17 on: June 05, 2018, 11:10:20 AM »
Glad you figured it out! I didn't reply as I didn't have anything to add that someone else didn't already mention.

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Re: Help. Loss of all power after a double tap ign.
« Reply #17 on: June 05, 2018, 11:10:20 AM »
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