Aftermarket HEI question???
Thread Starter
Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Aftermarket HEI question???
I have a $139.00 aftermarket (GM copy) HEI tach drive distributor in my 74 - 454. It is about a year old. Just recently it started missing and now has gotton even worse. It will not start. Using a timing light, I have determined that it only FIRES "occasionally" at best. It has a good 12 volt power supply.
Would I start with replacing the module(s) in the distributor base ... OR ... the coil in the topcap ????
Thanks for suggestions....
Would I start with replacing the module(s) in the distributor base ... OR ... the coil in the topcap ????
Thanks for suggestions....
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Check the pickup (reluctor) coil also in your debugging. The wires have to flex everytime the vacuum advance moves, and a crappy coil connection might have finally let go. (If you disconnect the vacuum advance while debugging the system, it might make it easier to test.)
When you find the problem, put in an OEM replacement part. A lot of the aftermarket stuff is not very robust.
When you find the problem, put in an OEM replacement part. A lot of the aftermarket stuff is not very robust.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
HEI - normally the module or pickup coil leads.
Check the pickup coil for continuity. The movement of the vac. advance can cause the leads to break internally- may not be noticeable looking at them. Move the vac. advance while checking.
Typical HEI pickup coil ohms about 800.
It's possible to disassemble the pickup coil & repair the leads.
Module - AutoZone has Wells (OEM supplier).
I bought a "new in the box" HEI, checked it out before install & found the pickup coil "bad". I disassembled including the pickup coil & found a lead was not soldered to a pickup coil wire. Soldered to fix.
Check the pickup coil for continuity. The movement of the vac. advance can cause the leads to break internally- may not be noticeable looking at them. Move the vac. advance while checking.
Typical HEI pickup coil ohms about 800.
It's possible to disassemble the pickup coil & repair the leads.
Module - AutoZone has Wells (OEM supplier).
I bought a "new in the box" HEI, checked it out before install & found the pickup coil "bad". I disassembled including the pickup coil & found a lead was not soldered to a pickup coil wire. Soldered to fix.
