The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1969 - 1972 Blazers and Jimmys Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-13-2018, 11:20 AM   #1
ochre1971
Registered User
 
ochre1971's Avatar
 
Join Date: Apr 2016
Location: Charlotte, NC
Posts: 59
HEI Questions

I have what I believe to be HEI in my 71, see picture to confirm. I really know very little about these except for the basic function.

While on a moderate road trip over the 4th she failed to start one morning. Cranked over just fine, but sounded like she wasn't getting any fire. I removed the air cleaner and started wiggling wires around at the HEI connection while my wife was cranking, to see if I had just lost contact somewhere. She fired right up at that point.

So, my question is, is there any maintenance I should consider doing to this thing? Are there common problems I should look out for? Anything from the crowd with more knowledge than me, which is an admittedly low bar, that I should be aware of?

Thanks for any input and education.
BP
Attached Images
  
ochre1971 is offline   Reply With Quote
Old 07-14-2018, 12:13 AM   #2
1967GTO
Registered User
 
Join Date: Nov 2017
Location: Riverside, Utah
Posts: 28
Re: HEI Questions

That is an HEI distributor. I just got one to put in my 72. I wonder if the ignition module was hot and just happened to cool down enough to start. I always had a spare module in my 71 c10. I never had to use it though.
1967GTO is offline   Reply With Quote
Old 07-14-2018, 12:46 AM   #3
truckster
Senior Member
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,760
Re: HEI Questions

HEI is about as trouble-free as they get. It sounds like you just had a loose connection at the terminal.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson
truckster is offline   Reply With Quote
Old 07-14-2018, 06:32 PM   #4
simicrintz
Registered User
 
Join Date: Dec 2017
Location: Escondido
Posts: 305
Re: HEI Questions

I have an HEI in my Jeepster and lost the module as well (same symptoms as you describe) but yours does sound more like a loose wire. That said, the ignition module is pretty cheap and probably worth having a spare in the truck.
__________________
-Bruce
1971 K5 Blazer 4WD
simicrintz is offline   Reply With Quote
Old 07-14-2018, 09:37 PM   #5
paul mora
Senior Member
 
Join Date: Jan 2009
Location: huntington beach california
Posts: 975
Re: HEI Questions

I have been running a hei with a tuned port injection system for over 15 years. I never use any module except for delco. Believe me I have been through many of them. I continue to have a problem staring my Blazer occasionally. This happens once every three more or every six months over sometimes more often. I found that I have good fuel pressure but it won’t Fire. So just keep a can of staring fluid give a two second blast in the air filter and it start right up. I have replaced parts cleaned injectors and I have found the starting fluid solves my problems and I stopped replaceing parts
__________________
Pulatoy
paul mora is offline   Reply With Quote
Old 07-14-2018, 09:52 PM   #6
truckster
Senior Member
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,760
Re: HEI Questions

Quote:
Originally Posted by paul mora View Post
I have been running a hei with a tuned port injection system for over 15 years. I never use any module except for delco. Believe me I have been through many of them. I continue to have a problem staring my Blazer occasionally. This happens once every three more or every six months over sometimes more often. I found that I have good fuel pressure but it won’t Fire. So just keep a can of staring fluid give a two second blast in the air filter and it start right up. I have replaced parts cleaned injectors and I have found the starting fluid solves my problems and I stopped replaceing parts
If starting fluid gets it going the problem isn't with the HEI. Starting fluid only provides fuel; the spark and timing have to be there for it to do any good.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson
truckster is offline   Reply With Quote
Old 07-15-2018, 10:45 AM   #7
paul mora
Senior Member
 
Join Date: Jan 2009
Location: huntington beach california
Posts: 975
Re: HEI Questions

I have always that spark was not the problem and it was fuel. But gone thr throughout the fuel system and all is right. Iwill crank alld ay lone with spark at the plugs. Maybe iit is a weak spark
__________________
Pulatoy
paul mora is offline   Reply With Quote
Old 07-15-2018, 09:30 PM   #8
Walter White
Registered User
 
Walter White's Avatar
 
Join Date: Oct 2015
Location: Charlotte, NC
Posts: 113
Re: HEI Questions

That is a nice looking rig you have. I blocked a drive thru line for a few minutes a while back when my coil wire decided to go. HEI wouldn't have that coil wire but same concept. Hopefully you just had a wire that disconnected. If it happens again, I would replace the wires
Walter White is offline   Reply With Quote
Old 07-16-2018, 05:54 PM   #9
ochre1971
Registered User
 
ochre1971's Avatar
 
Join Date: Apr 2016
Location: Charlotte, NC
Posts: 59
Re: HEI Questions

Thanks fellas for the responses and input. Doesn't sound like I should worry about this too much at this point. I'll do some more research and probably go ahead and get a new module to have on-hand. Also, sounds like a good excuse to look into some premium spark plug wires, something I've had somewhere on my list for awhile now anyways.
BP
ochre1971 is offline   Reply With Quote
Old 07-29-2018, 05:24 PM   #10
ochre1971
Registered User
 
ochre1971's Avatar
 
Join Date: Apr 2016
Location: Charlotte, NC
Posts: 59
Re: HEI Questions

So, an update. Last week couldn't get her to start at all. My low budget fix of wiggling wires seems to no longer be adequate...
Removed cap and distributor today, replaced the module and coil out of desperation. Scuffed and cleaned all contact points. Got everything put back together and no joy.
I have 12v to the distributor when key is on. Pulled a plug wire and used an old plug to check for spark while being cranked. Nothing.

Any ideas? Is there something else in the hei that I should look at replacing? Anyone had similar experience?
Thanks for any help.

BP
ochre1971 is offline   Reply With Quote
Old 07-29-2018, 10:37 PM   #11
truckster
Senior Member
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,760
Re: HEI Questions

Make sure the center button is in the cap. They sometimes drop out.

And this isn't meant as an insult, but make sure your 12v is going to the BAT terminal.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson
truckster is offline   Reply With Quote
Old 07-30-2018, 12:16 AM   #12
RustyBucket
Registered User
 
RustyBucket's Avatar
 
Join Date: Jul 2009
Location: Space Coast, Fl.
Posts: 1,050
Re: HEI Questions

I had an H.E.I. in my '72 Jimmy that quit working. Changed the module, read about it, cussed it, disassembled, reassembled, still no fire. A friend had a new chineez one in the box, dropped it in and away it went. I paid him $50 & I think they're still pretty cheap on ebay & amazon. Might be an easy fix. Sometimes I can't figure out exactly why electrical stuff won't work & I can live with that.
__________________
Dad always said, "Son, WISH IN ONE HAND, and ......."
--------------------------------------
--------------------------------------
Current toy trucks:
'71 GMC 1500 SUPER CUSTOM short/step, orig. dk. blue, 350/700r, ps,pb, A/C
'72 Blazer 2wd, ochre & white, 454, tremecTKO 500 5spd. ps, pb, A/C, tilt

Last 10yrs of hobby vehicles, had a FEW more in the 50yrs. before these:
'66 Plymouth Belvedere City of Miami cop car clone.
'70 Nova 406"sb, 13.5-1, solid roller, Brodix, p.glide/t.brake, back halved, 9" Ford, spool 4.88, cage,ladder bar/coilover, 10.5 tire....... SOLD!!
'67 C10 short/step side mount spare -- SOLD!!
'72 Jimmy 2wd, 350/350, ps, pb, fun driver, lots of bondo & a shiny red paint job..... SOLD!!
'69 Nova 350, 4spd, A/C, ps, p.b, ...SOLD!!
RustyBucket is offline   Reply With Quote
Old 07-30-2018, 10:04 AM   #13
ochre1971
Registered User
 
ochre1971's Avatar
 
Join Date: Apr 2016
Location: Charlotte, NC
Posts: 59
Re: HEI Questions

Thanks, not insulted Truckster. Been doing a lot of reading and watching videos, trying to learn myself up to speed on this thing...
I pulled the red battery wire and hooked a voltmeter to it, showed ~14v with key in ON position.
Rusty, good point. And a frustrating one. With all the reading I've done it seems it isn't uncommon for people to say they had one or multiple dead modules out of the box. So, was that my problem but I fixed it with a bad part? Do I go buy more and keep trying until I definitively mark it off the list? Still trying to figure that out.

Question: The center button / brush, is it supposed to contact the flat metal conductor that is on top of the rotor? Or is the electricity supposed to arc across a gap between the two? You can't see the connection once they are in place, but it doesn't appear they are going to be able to touch each other. The brush is slightly recessed into the rubber grommet that goes under the coil.

Will probably take it all apart again tonight and go through it again. At least stare at it for awhile and have a beer or two. Maybe something will come to me...

For the good news, at least it's conveniently located.
ochre1971 is offline   Reply With Quote
Old 07-30-2018, 10:14 AM   #14
simicrintz
Registered User
 
Join Date: Dec 2017
Location: Escondido
Posts: 305
Re: HEI Questions

Quote:
Originally Posted by ochre1971 View Post
Question: The center button / brush, is it supposed to contact the flat metal conductor that is on top of the rotor? Or is the electricity supposed to arc across a gap between the two? You can't see the connection once they are in place, but it doesn't appear they are going to be able to touch each other. The brush is slightly recessed into the rubber grommet that goes under the coil.
Pretty sure it touches; don't believe there is supposed to be any gap.
__________________
-Bruce
1971 K5 Blazer 4WD
simicrintz is offline   Reply With Quote
Old 07-30-2018, 12:58 PM   #15
truckster
Senior Member
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,760
Re: HEI Questions

There should be no gap there. You should have a spring under the button.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson
truckster is offline   Reply With Quote
Old 08-05-2018, 02:37 PM   #16
ochre1971
Registered User
 
ochre1971's Avatar
 
Join Date: Apr 2016
Location: Charlotte, NC
Posts: 59
Re: HEI Questions

Another update. I have officially proclaimed myself a hei distributor expert. That, and a dollar should get me a cup of coffee...
Hard to put into words the time, effort, frustration, number of times I've crushed my plums hanging over the front end trying to reach the distributor. Etc.
I bought a new coil. New rotor. New cap. Disassembled the shaft and removed the pickup coil and tested. I can't very well think of any component I haven't removed, tested, held in my hand and wished really hard.
Pondered all night about just buying a whole new distributor assembly. While it should have certainly fixed my issue, I couldn't stand the thought of not knowing what was wrong and ultimately being beaten by this #(+@ thing.
That being said, I went to AutoZone and bought a module. Then went to advanced Auto and bought a module. Then went to pep boys, they had 2 options, a $30 one and a $12 one. I bought both.
All except for the cheapo were BWD brand, made in good ol 'merica. The cheapo was Chinese. You probably know where this is going. The Chinese was the only one to work in my bench test and ultimately in the Blazer.
I wish I could send BWD a bill.
I bought this Blazer several years ago for as much of a hobby as I did too drive it. Guess I got what I wished for, but man is it frustrating to spend so much blood sweat and tears on parts that are rotten out of the box.

I've read about this problem here and elsewhere over the past week or so. Ultimately, I was struggling to believe the problem was really that widespread and continued to test, inspect and retest and reinspect everything multiple times instead of trying multiple modules.

Hopefully someone with the same issue will read this and be quicker than I was to buy multiple modules and multiple brands. Thanks for everyone's help. Going to go drink now.

Tomorrow I'll start researching setting timing, as for all the times I pulled the distributor my timing is now off. Be careful what you wish for.
Attached Images
 
ochre1971 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 08:23 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com