96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
10-18-2014, 04:30 PM
#1
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96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
Ok so, here's the deal, I was having issues with hard starting so, I hooked up a fuel pressure gauge to the valve behind the plenum, went to turn the key to "run" and got nothing. My radio and lights work, my ScanGauge II turns on (but won't connect to the computer) but the gauges don't perk up, the pump doesn't prime and the starter won't turn over. The battery has 12 volts of charge, the battery terminals are good, the ECM fuse in the fuse block under the hood isn't getting power, and my VATS is bypassed.
10-18-2014, 05:14 PM
#2
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Re: 96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
Seems me and you both are experiencing issues from the computer. I think the best way for us to understand this is understand the different communications in a tuner and how the computer operates all together. I am in the same boat chasing down the issue. Anybody got a good guide to understanding the PCM and its controls.
94 Z28 A4- ported heads/intake long tube headers. Egr/smog delete.
94 Z28 A4- ported heads/intake long tube headers. Egr/smog delete.
10-18-2014, 05:18 PM
#3
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Re: 96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
I'll post from what I know. Maybe check the wiring to the fuel pump to make sure your getting power to it. This is similar of the problems Im having but the outcome of the problem could be from multiple sources.
94 Z28 A4- ported heads/intake long tube headers. Egr/smog delete.
94 Z28 A4- ported heads/intake long tube headers. Egr/smog delete.
10-18-2014, 06:12 PM
#4
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Re: 96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
Might need to check the ignition switch. See if you are getting power to fuses that are energized when the switch is turned to ON.
10-18-2014, 07:24 PM
#5
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Re: 96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
I wouldn't jump to the conclusion that it's a PCM problem. The dash gauges (fuel, oil, coolant, volts) don't interface with the PCM.
10-18-2014, 08:57 PM
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Re: 96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
10-19-2014, 08:37 AM
#7
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10-19-2014, 08:50 AM
#8
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Re: 96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
As shbox suggested, the ignition switch may be defective. Check the voltage at these fuses with the ignition switch on: Injector, engine sensor, ignition, ac/cruise which are all in the underhood box. Also air bag, pcm ign, gages which are all in the I/P (inside) panel. If all have no power, the problem is most likely a defective ignition switch. To further confirm that, check the voltage at the HVAC fuse inside, It should have power if the ignition switch is the fault. If not, the problem is upstream.
10-22-2014, 05:05 PM
#9
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Re: 96 LT1 Won't Turn Over, Gauges Don't Turn On, ECM Not Getting Power
Thanks guys! It turned out to be my switch. The new one I installed is surprisingly stiff and has this thing called feedback that I had never experienced in my car before lol
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