4.3 ignition module multiple failures

[Jkjones2709]

2005 4.3 SX Drive Problem: replace ignition module take it out runs good, play in the water for couple hours take off engine gets to 2000 rpm and shuts off will not start back. Replace ignition module fires up runs good for a little while. No addition of any electronics this year, radio and amp is hooked up to acc side of key switch, alternator is putting out 13.5-13.7 volts at 1500 rpm checking by meter not gage. Have 3.12 ohms resistance on coil wire Problems found: Distributer to battery had 6.7 ohms of resistance. Removed dist clamp, and ground cable removed all paint wire brushed ran wire from ground stud to dist hold down bolt. Now have 0.1 ohms of resistance. Thought this was the problem!! Replaced: before the last ignition module blew after 2.1 hrs I replaced coil, pickup coil, dist cap, and rotor button. Ran pos wire to ignition module set timing to 6deg removed wire. Yes did clean the old grease off, sanded top of dist, cleaned with rubbing alcohol, let dry, put white heat grease on new module. Wire from coil to module look and test good, have full battery voltage going to main coil with key in run position Does anybody have any idea what I am overlooking.

 

[glenn property of pam]

you said that the coil was already replaced so that should rule that out. Check the battery again while running but set the voltmeter to ac volts. It should be a very small reading (can not remember the limit for the alternator) if its high like 12v or more then suspect a alternator problem.

 

[Lyle29464]

What Glenn said. You might check the meter on your car to see what it will show in A/C volts. Some times a cheap meter will give crazy results.

 

[Jkjones2709]

Thanks for the reply, will run to the lake this weekend to pick it up. The alternator is suspect now that you say it. When I checked it last Friday it did have a black powder showing up the front cover under the alt. never heard of alt putting out an ac voltage. Thanks again will let you know after it is checked out!!!

 

[Jkjones2709]

Finally had a morning off and ran down picked the boat up. No load running off water hose, 1500 rpm ac voltage is holding at 0.08 recorded for a minute max did jump to 1.67 adverage of 0.06. This was at a constant rpm. Went and did the same on chevy truck with 350 in it max was 0.024 adverage was 0.019. Do you think the alternator is the problem.

 

[Fun Times]

Voltage spikes and heat are the two most common things to take out an ignition module. Loose battery cables would do it as well.

Leaking spark plugs, plug wires or cracked cap could have an effect on the ignition system/module as well. Should that be the case, running the engine at night may help find a loose spark.

You may find post #11 interesting. http://forums.iboats.com/forum/engi...-won’t-run-on-high-rpms-3000-3400-rpm-maximum

Hope you find it soon, good luck.

 

[Saline Marina]

Hopefully...when you replace the ign module you are applying the dielectric grease (clear silicone paste you can get at auto parts store sold as dielectric grease). The aluminum flat base of the distributor underneath the rotating pole is the heat sink for the ignition module, and the dielectric grease creates the thermal "bridge". Without the dielectric grease you will put in a new module, it will last for awhile, could be hours or 10 minutes, and then die again due to overheating.

I see you mention "white heat grease" but it should be clear-ish and not white like lithium grease.

The pole piece which sends a form of the crank angle signal (via the cam) can give some weird readings if it gets too rusty. I had this problem in a truck engine, got by with wire brushing it and reseating the connectors. However I was selling it at that point and if I intended long term fix I would have replaced the pole piece and/or the distributor base..

 

[Jkjones2709]

When you buy the ignition control module it come with the grease. First time I cleaned the top of Distributer put grease on module bolted up. Second time took a scotch brite bad and lightly sanded the distributer put grease on bolted up. Last two cleans with alcohol greased and reassembled. Have remove all plug wires visual inspected measured length and checked ohms by lenght. All checks out. Did remove alternator this weekend took it to local rebuild shop they are going to run in test machine with a load to see what a/c voltage is under max load.

 

[Jkjones2709]

It has taken a year but finally found the smoking gun! Fuel tank vent blockage. Would run for 2-2 1/2 hrs stop for a period and tank would suck fuel out of pump start fine and run fuel out of bowl and die. Move fuel cable fuel would come out of secondary. Replaced fuel vent and she will run for extended period Ya I fill like a jack wagon on this one!!!! One thing about I know have all new electronic parts on the engine