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89 Gmc Sierra 5.7 Won't Start, No Spark


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3 replies to this topic

#1 jambo726

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Posted 22 August 2008 - 04:06 PM

89 GMC Sierra 2WD, 5.7 AT
Newly installed GM crate OEM motor 2 mos ago
New Optima yellow top battery
Alternator and starter are new
New plugs, Taylor 8.5 wires, new cap and rotor
All was well after install

Recently engine began stumbling and then just quit running


Engine will crank but will not fire
I can hear the fuel pump when the key is switched on. When the fuel line is disconnected from the the throttle body and the engine is cranked, fuel spurts out of the line.

Fuel filter changed->cranks but will not start, no spark

Coil changed to MSD OEM->cranks but will not start, no spark

Hooked up a spark tester between spark plug and plug wire to see if the light comes indicating a spark->still cranks but not start and no spark

So, It gets fuel, there is gas in the tank(1/2 tank), fuel delivery is OK, coil is OK, new plugs, cap, rotor, battery.

Since it cranks but will not start and there is no spark, could it be the IGNITION CONTROL MODULE or NEUTRAL SAFETY SWITCH?

Thanks for your help

#2 ziptow

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Posted 22 August 2008 - 05:41 PM

89 GMC Sierra 2WD, 5.7 AT
Newly installed GM crate OEM motor 2 mos ago
New Optima yellow top battery
Alternator and starter are new
New plugs, Taylor 8.5 wires, new cap and rotor
All was well after install

Recently engine began stumbling and then just quit running


Engine will crank but will not fire
I can hear the fuel pump when the key is switched on. When the fuel line is disconnected from the the throttle body and the engine is cranked, fuel spurts out of the line.

Fuel filter changed->cranks but will not start, no spark

Coil changed to MSD OEM->cranks but will not start, no spark

Hooked up a spark tester between spark plug and plug wire to see if the light comes indicating a spark->still cranks but not start and no spark

So, It gets fuel, there is gas in the tank(1/2 tank), fuel delivery is OK, coil is OK, new plugs, cap, rotor, battery.

Since it cranks but will not start and there is no spark, could it be the IGNITION CONTROL MODULE or NEUTRAL SAFETY SWITCH?

Thanks for your help



Sounds like the ignition module in the dsitributor...run it down to Autozone..they'll test it free.
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#3 jambo726

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Posted 22 August 2008 - 07:00 PM

Sounds like the ignition module in the dsitributor...run it down to Autozone..they'll test it free.


Hey ziptow,
I think I will pick up an ignition module and a OBD-1 code reader to see what codes it has thrown. I am assuming the code reader should pick up a failed ignition module vs a bad neutral safety switch. Will let you guys know what it was.

#4 jambo726

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Posted 23 August 2008 - 12:02 AM

Well, just got done. I removed the old ignition module and replaced it with the new one. Buttoned everything back up. It fired up on the first try. Did not have to install the neutral safety switch. OBD-1 code reader had no codes afterwards. All is good tonight. It did need a new fuel filter and the MSD coil although not the problem made the truck start better. I think the cause may have been that one of the ignition wires on the distributor was not seated fully causing there to be a gap that need additional juice to jump across. Maybe not but it runs great now. Thanks ziptow!!!! You were spot on...... This forum rocks!!!!!!

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Sounds like the ignition module in the dsitributor...run it down to Autozone..they'll test it free.


Hey ziptow,
I think I will pick up an ignition module and a OBD-1 code reader to see what codes it has thrown. I am assuming the code reader should pick up a failed ignition module vs a bad neutral safety switch. Will let you guys know what it was.