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Dan
Dan, Technician
Category: Chevy
Satisfied Customers: 23981
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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The engine cranks but no spark, 242k automatic, 1997 Chevy

Customer Question

the engine cranks but no spark
JA: How many miles are on the car? Is it an automatic or a manual transmission?
Customer: 242k automatic
JA: What is the model/year of your Chevy?
Customer: 1997 Chevy Silverado C1500 2wd 305ci 5.0L
JA: Are you fixing your Silverado yourself? What have you tried so far?
Customer: I've tried changing ignition coil, icm, cam sensor, crank senor distributor cap and rotor
JA: Anything else you want the mechanic to know before I connect you?
Customer: no there's not
Submitted: 6 months ago.
Category: Chevy
Expert:  Dan replied 6 months ago.

Hello, my name is ***** ***** I'm here to help get your problem solved.

Expert:  Dan replied 6 months ago.

This usually means the distributor has failed and appears to be the one part you haven't replaced. Here are testing instructions, let me know if you have questions. Thanks.

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https://www.dropbox.com/s/2of3ro6p84mxyui/nospark.PNG?dl=0

Customer: replied 6 months ago.
hey Dan, I have a 1997 Chevy Silverado 2wd 305ci 5.0 liter. the engine cranks but I'm not getting any spark to my spark plugs
The ignition coil is giving spark to the cap but somewhere in between
Expert:  Dan replied 6 months ago.

Sounds like the distributor still, you will want to connect a Digital Volt Ohm Meter (DVOM) set to AC volts to the Green and White wire of the pickup coil and crank the engine. If voltage is less than 0.7 V AC, replace the distributor shaft and pickup coil. Let me know how it goes or if you have questions, thanks.

Customer: replied 6 months ago.
I have replaced the Ignition coil in case of weak spark, the ICM, crankshaft positioning censor, Camshaft postioning sensor, and cap and rotor
Expert:  Dan replied 6 months ago.

Only thing left pretty much is the distributor.

Customer: replied 6 months ago.
its mfi engine and how can we get to the pickup coil
Expert:  Dan replied 6 months ago.

You need to access green/white wire going into distributor and use that to test.

Customer: replied 6 months ago.
I thought only the carb, HEI distributor have the pickup coil, do the fuel injected ones have one also? or is it a cam sensor on MFI
Expert:  Dan replied 6 months ago.

You are correct, sorry about confusion. Does check engine light come on for bulb check when first turning key to on position?

Customer: replied 6 months ago.
I will have to check.. the trucks is at my mothers'
Customer: replied 6 months ago.
it should take 10-15 minutes, I will let you know
Expert:  Dan replied 6 months ago.

Sounds good, thanks.

Expert:  Dan replied 6 months ago.

If so, check to see if pink wire going to coil has good power while trying to start.

Customer: replied 6 months ago.
the ignition coil?
Expert:  Dan replied 6 months ago.

correct.

Customer: replied 6 months ago.
I replaced the ignition coil and icm in case of weak spark, would that solve the problem, or would low voltage to the ignition coil be a problem somewhere else
Expert:  Dan replied 6 months ago.

Low voltage on pink wire would be wiring or ignition switch.

Customer: replied 6 months ago.
alright i pierced the pink wire, the had key in on position and it read 12.5V, then as i was cranking it dropped to 8-9V. is the ignition switch and harness the problem
Expert:  Dan replied 6 months ago.

It could even be a weak battery. Monitor battery voltage while trying to start. If battery voltage drops below 11v then it sounds like a weak battery. Let me know, thanks.

Customer: replied 6 months ago.
i was charging the battery with another vehicle at the moment.
Expert:  Dan replied 6 months ago.

That isn't always enough and a actual charger works much better then trying to charge with jumpers

Customer: replied 6 months ago.
i was testing voltage of pink wire, while i was jumping the truck with another vehicle
Expert:  Dan replied 6 months ago.

Monitor battery voltage while trying to start, let me know what voltage drops to. We need to figure out if battery is weak or if poor contact in circuit is causing excessive voltage drop.

Customer: replied 6 months ago.
also what i found strange was when i was driving the truck at a steady 30mph the truck turned off completely, and wouldn't turn on again. what could cause that
Expert:  Dan replied 6 months ago.

A weak battery could cause that.

Customer: replied 6 months ago.
low voltage in pink wire for ignition coil would cause no spark to the spark plugs
Expert:  Dan replied 6 months ago.

That is correct so now we need to figure out what is causing the low voltage.