Weak spark?

[sebenfitty]

So...is it a 2 wire or 3 wire?? Either way the ground should be 0v if meter is properly grounded. You would have to have a meter with a LOW HOLD function while cranking to see if ground is being supplied. If you are seeing something like 3 or 4 v on the ground side thats also a bad ground.

Sorry about the low voltage guess earlier. Forgot you said it died on the water. Following both threads.

Mike, I don't know as much about PCMs strategy but AFAIK the CKP is looking for # 1 and providing tach signal. CKP is priority and with other brands Im used too CPS can be lost and still run. ECM just goes back to open loop and runs base timing. Im just guessing tho. We are technically still a PCM dealer from those years pre 12-13, but dont talk to those guys often.

The coil? I believe it is 2 wire.

4 on the ignition module.


Sent from my iPhone using Tapatalk

[freeheel4life]

I cant remeber from your rebuild, are you a 343ex or a 330 ??

[sebenfitty]

330.
Looks like the center wire is for the tach if I had the 3 wire. FYI- tach is currently unplugged, as it seems to be bad. Was alarming constantly


Sent from my iPhone using Tapatalk

[sebenfitty]

So I dropped it off at the shop. Timing was off. Said they turned the distributor and it fired right up....

How TF does this happen? Wasn't like this was a gradual thing. Happened while driving around.
This was one of the first things I checked. I made sure distributor was tight and could not have turned. After that I ruled out timing. The tech agreed that the distributor was tight and could not have moved.

Anyone experienced this? Not seeing it in any discussions.

[boatwakes]

Verify timing is correct at idle and 3300rpm. The latter being most important. Doesn't need to be under load but the total timing at 3300 should be no more than 34 degrees. Crab cap distributors ( flat cap with pretty spark plug wire orientation to each side of the engine) use the ECM to control timing once they're "close" to where it should be. I dunno if the 330 has that distributor but if it does...check for oil in the rotor area. If it's there, REPLACE the distributor, shaft seals went bad and you'll lose the engine to misfiring, cross spark, timing etc. ask me how I know. I have a recollection I helped you with the motor earlier this year, correct? Timing doesn't just change so check the above and let me know.

[sebenfitty]

boatwakes All correct. Vortec engine. You helped me quite a bit at beginning of summer with the rebuild.

I changed out the rotor and cap twice while troubleshooting this time. Never saw any evidence of oil. From the sound of it, the shop pulled it apart also.
Still, that's what I was going to ask, is if I should just go ahead and change the distributor and if an auto parts store distributor would be fine?

Mefi scanner/program I bought is no longer working, or I probably would have noticed the timing issue. Gotta grab a new laptop when I get a day off, check that timing. I assume the shop verified everything was in spec, but I will definitely be keeping an eye on it. We went out on a short midnight cruise this weekend. Everything went fine, but made me nervous.

[boatwakes]

As for the distributor, yes on the automotive for the crab cap only. However, they do not utilize brass or gold plated terminals so longevity is compromised. Get the MSD and call it good.

Use a timing light to check timing. What you see on the computer needs to be referenced against base timing setting. i.e., if base timing is 10 degrees at idle with timing light, you should see 34 at 3300rpm. If it's retarded or advanced from that, rotate the distributor (only capable of about 30 degrees) to compensate and if that fails, pull the distributor and jump a tooth. Check total timing again with a light at 3400 and adjust accordingly. Make sense?

[sebenfitty]

Makes sense. I’ll check it when I get a day off


Sent from my iPhone using Tapatalk