Went from love to hate.

[Jims86]

All I could find was the dizzy connector. I thought I had the coil to dizzy harness but I might have used it on the Blazer. I can grab one when I go to the junkyard next time though.

Thats cool....the dizzy connector would be the hard one to come by, would be cool if I could get that.
I think I saw the coil to dizzy pigtails in the electrical isels at the parts store.

 

[Jims86]

The HEI system needs a minimum of 10 volts on the primary side in order to produce the 20,000 volts required on the secondary side.

As you noted above, there is sufficient power (12 volts) available at the coil input with the key in the "RUN" position.

But, from what I gather while looking at the previous posts, this is specifically a "non start" condtion as opposed to a loss of ignition while running.

While a voltage check at the coil input with the key in RUN is a helpful diagnostic, it tells you nothing about coil supply voltage while the engine is being cranked over by the starter.

Get a realtime voltage value while the starting circuit is energized. Use a couple of jumpers attached to your test leads - long enough to allow you to read the meter while reaching in and turning the key. Or have a helper crank the engine while you monitor the voltage at the coil input.

Note whether the supplied voltage at the coil remains above 10.5 VDC while cranking or drops under the 10 volt minimum.

If voltage is stable and above 10.5 while in the static condition, but suddenly drops dramatically when the key is moved to the start position, you have a short to ground in the ignition switch/solenoid wiring circuit or within the starter/solenoid itself.

Inspect the purple wire that runs from the ignition switch to the S terminal on the solenoid. Pay extra attention to where it enters/leaves the L shaped conduit.

It is rare, but occasionally, the starter and solenoid with develop internal shorts to their casings (which are grounded). Buy a new one or, if you have a spare, change it out and see what happens.


One way to determine if the starting is causing a system wide voltage drop (one that is severe enough to prevent ignition) without pulling anything apart or buying anything, is to provide an external 12 volt supply to the coil.

This is easy enough; use a battery charger or a seperate, independent battery and run a jumper from the positive to the coil (be sure to disco the installed wire or the independent supply may be pulled own as well) and grond the negative to the frame.

Ya beat me to it!
Good Catch Jerry, I did notice that we kinda forgot the No start condition, in favor of the drivability issue.

 

[chengny]

I'm always sympathetic to this scenario - it happened to me 3-4 years ago, and figuring it out just about killed me.

New complete distributors (3), gear engagement with the cam verified, new plugs, new wires, new rotor and cap, timing checked again and again, valve binding and preload checked. Always got 12.4 volts at the B+/pink wire terminal. This was all checked by many people, all of whom know stuff about stuff. Never got more than the weakest little yellow spark that could barely jump across the electrodes.

Went so far as to clamp a distributor by the shaft housing in a vise, attached one plug wire and a plug to a post, applied 12VDC to the B+ and spun the shaft with a 1/2" drill motor.

That made a spark - OH BOY did it make a spark! I had my hand near enough to the posts that didn't have wires and when I pulled the trigger on the drill - I lit up like a Christmas tree. Took about a week for my heart to return to it's normal rhythm.

But put that same distributor back in the truck, crank it over - NOTHING!


One night after about 50 tries I started to notice that the only time the engine seemed to fire (and only for a brief moment) was at that instant when I would give up and let the key snap back to the run position from start.


Long story short: Went to the corner of the gargage found a beat up old starter. Wired it up, bolted it on and turned the key. Not only did the test plug that was laying on the engine make a big, bright blue spark , but the engine fired up before it had made 2 revolutions!

 

[Kapdin]

HOLY ****, my head just spun a bit after reading that ill proceed to re read that a few times. But to late on talking me out of a new dizzy since its on its way as we speek. Even tho im broke now ill have a piece of mind of new parts lol. But if i hear you right even tho ur starter was grounding out it still spun the engine just fine? The only reason i would pick my dizzy over the starter or igintion to be shot is becuse every time it decideds to not spark all i do is open the dizzy move/touch a few things put it back to gether and boom not even a full revolution and the truck fires.

 

[Jims86]

HOLY ****, my head just spun a bit after reading that ill proceed to re read that a few times. But to late on talking me out of a new dizzy since its on its way as we speek. Even tho im broke now ill have a piece of mind of new parts lol. But if i hear you right even tho ur starter was grounding out it still spun the engine just fine? The only reason i would pick my dizzy over the starter or igintion to be shot is becuse every time it decideds to not spark all i do is open the dizzy move/touch a few things put it back to gether and boom not even a full revolution and the truck fires.

Well, if you think about it, you still may need the dizzy, as the bushing in your current one may be worn and causing your miss...a cause of 85% of rough idle miss problems.

 

[Kapdin]

WOOOOP WOOOOOP! dizzy was the problem, replaced my first one and they aint bad at all. So i do have a few questions. I do believe my idle is a little high but not sure how high, when i unplug the vac advance and the motor is warm it drops to 900-750???? i m just guessing here, so i went ahead and set my timing. tell me if im wrong. So i took whiteout to the blancer where it had a perfect slit and highlighted it, then cleaned the timing marks \/\/\/0\/ and my book and jim says stock was 4-8 BTDC and my dizzy instructions told me to advance my timing a few degrees from stock. So i set it down two 4 and it sounded pretty good, it did idel down a tish so then i tightened it all up and took it out, seemed pretty good and smooth but then i tried launching it hard and (this has always happend since ive owned it) when i put it to the floor it starts for a split second to pull then it goes into 2-3 seconds of no pull just like spuddering and when it get rollin a bit comes out of it. Maybe to big of jets in the carb? But then i started thinking if my idel is high then maybe i set my timing to low, so then i went back and set it to the first \/ which i asume is 8 and the idel went up a tish and then took it out, actualy felt like it pulled maybe a bit harder but still from a stop and to the floor just sdudders... wat you guys thinking?

 

[Jims86]

WOOOOP WOOOOOP! dizzy was the problem, replaced my first one and they aint bad at all. So i do have a few questions. I do believe my idle is a little high but not sure how high, when i unplug the vac advance and the motor is warm it drops to 900-750???? i m just guessing here, so i went ahead and set my timing. tell me if im wrong. So i took whiteout to the blancer where it had a perfect slit and highlighted it, then cleaned the timing marks \/\/\/0\/ and my book and jim says stock was 4-8 BTDC and my dizzy instructions told me to advance my timing a few degrees from stock. So i set it down two 4 and it sounded pretty good, it did idel down a tish so then i tightened it all up and took it out, seemed pretty good and smooth but then i tried launching it hard and (this has always happend since ive owned it) when i put it to the floor it starts for a split second to pull then it goes into 2-3 seconds of no pull just like spuddering and when it get rollin a bit comes out of it. Maybe to big of jets in the carb? But then i started thinking if my idel is high then maybe i set my timing to low, so then i went back and set it to the first \/ which i asume is 8 and the idel went up a tish and then took it out, actualy felt like it pulled maybe a bit harder but still from a stop and to the floor just sdudders... wat you guys thinking?

Was it in drive when you set base, vac unplugged, and vac line plugged? The video link I posted is about what you want to hear for an in gear idle....maybe just a slight tad more. You want it to throb like an Idling diesel locomotive.
Make sure you didnt cross 5 and 7 on the plug wires. Maybe post up some video of whats going on?
I wonder if your secondaries may be coming in late.

 

[Kapdin]

awww **** forgot about the drive part... ill try that and forgot to listen to your vid ill do that now.

 

[Kapdin]

huh, thats pretty low, but my truck in drive with brake might be close and yea i pluged the vac. quick info on turning the idel down? i see two screws one on each side of the carb.

 

[towjoe]

Leave those 2 adjusting screws alone, the one you want is on the linkage on side of carb where throttle cable hooks. Should be facing rearward and towards the bottom on front of drivers side of carburetor. The two in front side are idle air adjustments. Another thing check for a vacuum leak if it's still running fast at idle first to make sure it's not drawing a vacum

 

[Jims86]

Leave those 2 adjusting screws alone, the one you want is on the linkage on side of carb where throttle cable hooks. Should be facing rearward and towards the bottom on front of drivers side of carburetor. The two in front side are idle air adjustments. Another thing check for a vacuum leak if it's still running fast at idle first to make sure it's not drawing a vacum

x2^^^

 

[Kapdin]

Hey so sittin at work, will get to retiming my truck when i get home but just thinking, do you suppose that miss/pop at idel is detenation? cus when i put the new dizzy in i check the timing and it was wayyy advanced and still had that studder at idel till i cranked it back to 4 and it went away now this moring it did it a few times at idel now its set at 8ish? but remember its set at prolli high idel so dunno wat its realy set at.

 

[bucket]

If the distributor bolt is not tightened enough, the timing can change on it's. It really doesn't matter though, you need to set it again anyway. Engine warm and at idle (I never set mine in drive, it's not needed IMHO), set to the desired idle. Then set timing and reset the idle again if it went up or down. After resetting the idle, set the timing again and make sure the dizzy bolt is good and snug.

 

[Kapdin]

Ight guys i broke down a picked up a vacuum gauge after work. So i re-timed it plugged the vac advance again and had the gf hold brake in park and boom deff was low enough rpm's checked it and it was off so i just put it dead on 6 BTDC, then tightened it all up and then hooked up the vac gauge, i have limited options on were to put it so i put it on the vac addvance with a T connector and stone solid at 20 on the gauge. I rly have to try to hear the idle hic up now, very un notice able but still bothers me cus i know its there. Afew other things i was thinking about, my POS. batt cable is spliced and my starter is covered in oil from a leak i fixed, and that charcoal canister isn''t plugged, any of that a big problem?