HEI help

[bigbadchev72]

Ok here goes, A couple years ago I replaced the points dizzy in my bosses 72. He has a 327 in it and we installed an HEI we bought from the local parts house. I ran a new power 10ga power wire from the fusebox (key on) to the HEI.

Well a couple months later I remember him calling me to help him at a friends house, he was visiting and went to leave-no start. It ended up being a bad module.

He came up to me yesterday and asked me to look at it again, The truck sits all year until hunting season comes around. He was trying to start it and it just cranked, He pulled the cap off and inspected it and saw nothing wrong. He re-installed it and it fired right up.

Then he moved it into the shop to get it cleaned out. When he went to start it no fire again, it just cranked. Said he checked all connections and still nothing.

I am suppossed to go over there sunday to check it out. BAd module again? something else to look for?

[crazy longhorn]

Check to see if the ign wire is tight on the cap....I know that sounds too simple, but I have had a bad clip that let the wire shake loose & leave me playin on the side of the road! When you stated, that he took the cap off & put it back on"then it ran".... you know that he had to remove the wires to remove the cap. Worth a shot crazyL

[68gmsee]

Yeah, it does sound like a loose or bad connection of some sort.

Of course the best thing is to have a known good spare HEI with you but if that's not available, double check all the voltages and make sure there's a good ground connection to the engine and to the cab.

[Wrenchbender Ret]

You didn't say wheather it was a new or used unit. If it had been used the pickup coil on those are known to give intermitant failure. The wires from the pickup coil to the module flex every time the vacuum advance moves. They sometimes break inside the insulation & are hard to detect.

[GASoline71]

Make sure there is a dedicated 12v wire to the HEI.

With aftermarket HEI's... you get what ya pay for. So be careful with those 50 dollar parts store HEI's.

Gary

[ChevLoRay]

My truck came with an HEI, but I have no idea where it came from. When it took a dump on me, I replaced it with an ACCEL HEI, that is essentially a reman unit. It was about $10 more than a reman from the Zone, or Advance or O'Reilly's......and all three of those store had the same part number.

I added a hotter coil and life was good.

Make sure you use the dielectric compound when you install the new module. It carries the heat away from the module. Heat kills electronic components.