No Start Vortec - Intermittent/Weak spark?

[dirtridinz71]

I got a call from a coworker today who has a 98 GMC 1/2 ton with a 350 Vortec. The other day while driving it just quit on him and wouldnt restart. No codes are showing with a scanner and the fuel pressure is good.

He is saying that it has spark but it is weak after the intitial spark and then randomly has a good spark and will 'cough' a little, never enough to start it. According to him they are getting this from a test light reading.

My first thought was ICM but he has replaced that along with , coil, cap, rotor and wires.

Any idea's? Could it have possibly jumped timing? Bad distrubutor? Symtoms of a bad spider?

 

[1997chevydriver]

When my truck just "up and quit" on me it was the gear at the bottom of the distributor. It completly stripped out.

 

[Vortec Lover]

is there any oil on the plugs?

bad distributor could do it

I don't know much about spiders, so I don't know that

 

[dirtridinz71]

When my truck just "up and quit" on me it was the gear at the bottom of the distributor. It completly stripped out.

That would be an option if there was no spark, but there is spark just seems weak?

 

[The Arctic Fox]

When my 1990 5.7 TBI quit running going down the road my dad replaced the icm distributor cap and rotor and it started right up. But I would try the cheap route first by buying cap and rotor first. My problem was it would just sit there and crank all day and would catch any spark.

 

[dirtridinz71]

Anyone ever have the ignition switch in the coloum go bad? I've read a couple cases of that causing a no start but the engine will turn over, could be reason for no SES codes? I have an extra coloum and couple ignitions, if it sounds like a possible solution it would be worth swapping?

 

[trailer-trash]

If the spark isnt blue....swap the ICM or coil with known good ones...I had an ICM give me a fit. It wont throw a code or tell you a thing.

 

[CrustyJunker]

I had an AutoZone coil do that to me once on my Vortec. Control was fine and showing consistent signal to the coil, but coil was throwing weak (dim orange) sparks if any. Replaced and success.

If you wanna troubleshoot the key switch anyway...You can jump it out at the starter relay in the under-hood fuse block. Should be a gray relay next to the A/C relay (if I remember correctly, middle socket when facing the driver side fender). Good luck!

 

[dirtridinz71]

Good info, I'll pass it on to him and hopefully get it running again.

 

[TomCoppola]

Any result? I have a similar problem



Sent from my Vortec powered iPhone