GM HEI

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Zachary Sandberg - 28 Dec 2005 04:57 GMT

This is a followup to a post I made yeasterday, which was that I was
unable to correct a miss for a 350 which has new plugs (.045), wires,
cap rotor, carb and a host of other non ignition related upgrades.
Anyways I replaced the 2 month old plugs with new Bosch Platinums
tonight, and replaced the wires again. two plugs looked to be oil
fouled with lots of deposits. So when I get everything in and set, it
runs great in the 2000+ rpm range, but wont idle barely at all. It has
a horrible miss on multiple cylinders, but it all smooths out at higher
RPM. Am I correct that this sounds like a coil, or is there something
that i might Have ovverlooked somehow. The engine has 140xxx miles on
it, and runs strong yet.

Thanks in advance
Zach

Reply to this Message

Nate Nagel - 28 Dec 2005 10:50 GMT

> This is a followup to a post I made yeasterday, which was that I was
> unable to correct a miss for a 350 which has new plugs (.045), wires,
[quoted text clipped - 10 lines]
> Thanks in advance
> Zach

check your firing order. 1-8-4-3-6-5-7-2

nate

Signature

replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

Reply to this Message

Zachary Sandberg - 28 Dec 2005 11:38 GMT

while I havnt checked the firing order the engine runs extremely smooth
above 2k rpm. Keep in mind this is a problem that just all of a sudden
started after i was already drving down the road for 2+ hours. I will
check the firing order this morning, but unless wires switch themselves
around on the fly, I dont think this will be the answer.

thanks, Zack

Reply to this Message

Al Bundy - 28 Dec 2005 14:12 GMT

> while I havnt checked the firing order the engine runs extremely smooth
> above 2k rpm. Keep in mind this is a problem that just all of a sudden
[quoted text clipped - 3 lines]
>
> thanks, Zack

Why assume automatically that it's an ignition problem? You said you
had two badly fouled plugs from oil. That sounds more like a cylinder
problem. Check those plugs again if you remember which cylinders.
Otherwise pull all plugs and inspect.

Reply to this Message

NickySantoro - 28 Dec 2005 15:40 GMT

>This is a followup to a post I made yeasterday, which was that I was
>unable to correct a miss for a 350 which has new plugs (.045), wires,
[quoted text clipped - 10 lines]
>Thanks in advance
>Zach

I'd check for a vacuum leak next.

Reply to this Message

HLS@nospam.nix - 28 Dec 2005 21:07 GMT

I made a sort of foolish post some months ago about the HEI system (not
my first error, and probably wont be my last either). The earlier
GM HEI systems had the coil built into the distributor cap, as I remember
it.
Later versions were, I am told, different.

If yours is of this earlier type, you need to be aware that internal arcing
around the coil and even inside the cap itself is something you need to
keep in mind.

Reply to this Message