Ok guys, please help me out! It suddenly died, won't start, ran great juste before. I get a 42 code. I unplugged my msd to try and don't have spark. What could it be!?

 

replace the ign module first, if no bueno swap the pick up coil also or just do both at the same time. The module is easy to replace with just pulling the cap.

 

By ignition module you mean? The coil is rather new... You know tests i can do to verify components? I replaced thethe cap and rotor a week before. Had to pull out the distributer to repair a broken screw of the old cap. Retimed it afterwards and nothing moved it ran perfectly just before it died......

 

Like Twin_Turbo said, it's likely a bad ign module under the dist cap. http://www.chevythunder.com/est_code_42.htm

 

I have the same code also I've been trying to figure out what the problem is, I've already replaced my distributor, computer, prom, so I think that the est or bypass is frayed somewhere, is it possible to just place a new white and tan/black wire from the distributor to the ecm rather than taking apart the wire harness

 

Cool thx, I'm trying to find one...

 

Well... Still no fuego after replacing the ignition module, i have spark from the coil up to the tip of the wire of the center of the cap but nothing at the end of the wires to the plugs... Any ideas?

 

If you have an MSD control box it is probably the problem.Go back to the factory ignition system and I bet it will start right up.I bought both The MSD and Crane spark boxes and both went out within 6 months.I put the factory stuff back in problem solved.

 

Check the ground wire on the ESC box by the firewall. Check the whole connector for that matter and make sure none of the wires are corroded or pulled back.

 

I disconnected the msd and same thing

 

Thx

 

If you have spark at the coil wire going to the distributor then the only parts in between the coil wire and spark plugs is the rotor and the cap itself and of course the spark plug wires. Check your rotor for a broken tip and check the cap for broken terminals inside the cap. HTH!

 

Yes I do but not to the plugs...and between also I guess there is the ignition module so might it be the ecm that cuts off supply to the plugs because of a problem with something?

 

No, the ignition system and ecm control the primary side of the coil. If you have spark at the coil going to the distributor cap then the primary circuit is fine. The secondary side of the coil produces the spark that fires the plugs. If you have spark coming from the coil then the problem is with the cap, rotor or wires as stated earlier.

 

Ok cool, the thing is that I have spark going to the coil yes, but the spark is very low and barely lights up one cylinder... I would think the coil but we tried and old coil I have that I know works and same thing... Very low spark... Any ideas? Like I said msd is disconnected and wires hooked up stock.