Finishing 350 swap. No spark

[350runner]

Anything is possible. Pull a plug out and attach the wire. Then connect it to a good ground. have someone turn the engine over and watch for a spark. What color of spark do you get if any.

Sent from the dust in front of you!

 

[MadOgre]

If you have swapped out the ESC module for a non ESC module be sure to plug the connector hole otherwise crap and moisture will get into the distributor cap and you will be dead again. That's why its better to just swap distributors.

 

[PrairieDrifter]

I recently bought an 84 suburban with a 400 swapped into it with all of the emissions junk and vacuum hoses everywhere, and I believe the carb setup is probably similar to yours, but It had a miss so I changed spark plugs found one bad plug, and I decided to put a distributor from my c10 which was for a 350 and was vacuum advanced and In theory the distributor should have worked Like the stock one and all the connections were right fine but I had the same problem, once you got into the throttle it would bog down and have no power but it would idle and Rev just fine.

Long story short I put the old distributor back in and it ran perfect again. I would check if your distributor is compatible. If that's any help to you haha

 

[MrMarty51]

If You remove the spark plug wires from the distributor cap, then have someone crank the engine over, there should be a bright blue spark jumping from the plug wire terminals to the metal frame around the coil.

 

[chengny]

2X what Mr. 350runner says:

Anything is possible. Pull a plug out and attach the wire. Then connect it to a good ground. have someone turn the engine over and watch for a spark. What color of spark do you get if any.

As a corollary to that, check the voltage to the coil while cranking the engine.

I see where you have confirmed a good 12 VDC supply to the coil primary - but I am assuming that you got that reading with the ignition switch in the RUN position.

Pull a plug (and do a check of spark appearance). You should observe a bright blue arc that makes an audible snap across the electrodes. A silent, weak orange (or red, yellow) arc indicates low voltage in the secondary circuit of the ignition.

Pull the harness connector off the coil and once again - this time while cranking the engine - check the pink wire for battery voltage. If it shows 12 volts before you engage the starter but then drops significantly (say below 10.5 volts) when you crank the engine - take a look at the starter.

A starter with an internal short or ground - when cranking - can pull the entire electrical system down. And, if equipped with an HEI ignition system, it is critical that the voltage available to the coil primary be at least 10 volts.

Without that 10 volts (actually GM specs minimum as 10.5 volts) the coil will be unable to develop the 40K volts required to produce a robust spark at the plugs.

 

[chengny]

Just had a chance to read the back story on this issue and I have to ask;

Was the starter - the one that you currently have installed - involved in this...underwater adventure?

You must be registered for see images attach

If so, how long was it submerged and when did it happen?

 

[guitarfreak235]

Just had a chance to read the back story on this issue and I have to ask;

Was the starter - the one that you currently have installed - involved in this...underwater adventure?

You must be registered for see images attach

If so, how long was it submerged and when did it happen?

no no no. it was toast. replaced it on the 305 actually to see if itd turn over.

the starter is brand new.


anyways i caved and just bought a new dizzy. im getting spark now.

tomorrow ill adjust the timing and see if this thing'll work

crossing my fingers

 

[guitarfreak235]

well its all resolved now. turns out my plugs were fouled and had some bad wires too. plugs mustve went bad when the accel pump wasnt functioning. the new dizzy seems to be an improvement so im keeping it regardless.

getting the carb to work properly was pretty simple. just needed to reinstall the thermostat housing with the temp switch on it which is the ground for the accel pump solenoid

 

[89Suburban]

Thanks for the update. Good job figuring it out.