Question about 1994 Chevrolet S-10 Blazer

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HEI Coil is burning out

I have a hot rod which I had to make up the entire wiring harness myself. I keep burning out HEI coils....Do I need to install a resistor or diode in the 12V power feed to the distrutor of some type to keep this happening? The engine is a 1980 Chevy Truck engine (350)

Rick

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If the Electrical system is grounding out, particularly the hot lead to the coil. then you will fry coils. Check your Positive leads at the fuse box for continuity to ground. 1st check the ignition wire i.e. red wire going to your coil. Disconnect the ignition wire from the coil or distributor (depending where your coil is located). If it has continuity to ground, then go to your fuse box and pull out all your fuses and test each terminal for continuity to ground until you find which circuit is grounding out and polluting the rest of the positive circuitry. If it is only the ignition hot wire then you know that is where the problem is. If it is coming into the fuse block from another positive source, isolate that source by not allowing it to come into contact with + current.

Posted on Oct 31, 2008

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Did this car used to have a points distributor? I have seen problems if you dont run new wire for the distributor because the old wire wasnt 12 volts because it had a ballast resistor in it. When you pt the coil in are you makeing sure you are checking the button that it sits on? That could be what is burning the coil out. Try and test the power wire and make sure you are getting a full 12 volts fro it. Good luck and if you found this helpful please rate this solution when you get a chance.

Thanks - Tech101

Posted on Jun 25, 2008

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1 Answer

How do I wire a 4-terminal solenoid for this truck? I do not understand what goes on the I and S terminals?



It depends on whether you are running a points or an HEI setup.

The ballast resistor is tied into the coil on a POINTS system, so that it supplies 9 volts to the coil when the motor is running. This lower voltage lengthens the life of the points. During starting however, the coil is fed a full 12 volts to make starting easier.

An HEI system has a full 12 volts fed to it when starting or running, because the switching transistors inside the HEI won't burn out like points will. This is why the two systems are wired differently.

The two small terminals on the starter solenoid are marked as R and S - which stand for Relay and Solenoid, which probably doesn't mean anything to you. SO, think of the two terminals this way - S stands for Start, R stands for Run.

The S terminal is for engaging the starter. The R terminal is for supplying high current battery voltage - to the coil and to the fuse panel. The R terminal is ONLY USED IN POINTS SYSTEMS - the HEI system has no need for it.

A diagram that might help you:

6_30_2015_2_55_02_am.jpg

Jun 30, 2015 | 1987 Ford Ranger

1 Answer

Original Engine wiring conv. to hei schematic?


Dead simple. Old system used a resistor wire between ign. switch and coil. HEI does not need this so you need to run a 10 or 12 guage wire from the ignition switch "ON" position to the new coil with no resistor in between. This also means you no longer need the extra wire from the starter to the coil which was used to bypass the resistor wire in the old system to provide full 12 volts for starting car. The reason for the resistor wire in the circuit was to reduce the voltage to the coil once running so the amps in the spark would be higher to burn more thoughly and increase fuel mileage.

Apr 23, 2015 | Cars & Trucks

1 Answer

INSTALLING HEI IGNITION AND NEED HELP


i have no issues WITH CAPS, used to have a home computer in 70s with ASR33 printing terminal that did all caps..... all the time.
Is this a 1990 jeep? and what engine? you never stated the engine
4.2 L AMC straight-6 engine?

what distributor are you running off what engine, and what year.
is it with full mech, advance and vacuum advance , pre 1986?
the nutter bypass, 4.2L
it cuts the ECU out of spark controls.

this means ECU advance is killed, on now only the dumb
module runs advance.
the stock system had a ballast resistance wire. and the
start wire to the the coil bypasses this wire. for full coil power.
this is not used in HEI.
infact there are many HEI setups. which one. 7wire. ?

here is 7
http://www.msextra.com/doc/ms1extra/MS_Extra_Hardware_Manual_files/ew7hei.gif


if i had your rig, it upgrade it to MSD. sure would. done many.
by doing that , all the mystery of parts, that works ends.
if you need help, spec out your set up, including, schematic
and BOM, parts used, p/n of parts used.

here are 3 HEI ( 4,5,7 pin)

http://brianesser.com/tech/wiring/msd/WDTN_pn9615_Page_030.jpg

The biggest issues is spark timing curves.
getting them right for those Webers.
and standalone spark controls win here.

the right way
http://www.jegs.com/p/MSD-Ignition/MSD-Ignition-Controller-for-GM-EFI-Carbureted-LS-Engines/758329/10002/-1

You tune the spark advance for YOUR engine and setup.
not that funky stock spark box and nutter mod.

my guess, is you burned up the ballast when it hit the real
inside distributor coil primary, that is totally the wrong coil
for a ballast. I hope it dont burn up a good coil,,,,,,,
The coil and all wiring for EFI must be correct
and the bypass for starting , is useless. for that distrubutor
because it runs 12v all the time, so if the ballast did stay good
the HEI would be running way too low , at 8v. running.
and would fail.
here is a great HEI page, under dev. but is good.

http://www.crankshaftcoalition.com/wiki/Hot_rodding_the_HEI_distributor

this link above shows how to get HEI right on a carb car
but fails to show the benefits of true spark advance tuning.
Great fuel economy can be attained under light loads
with large spark advance. and then less under full load.
(no pinging too)
The spark advance , allows the flame front to start at the correct time
to take advantage of piston rod angles.... and not send unburned fuel out the exhaust.
Id put an MSD in there and tune it carefully, I would. (webers a given)_

Feb 03, 2014 | 1990 Jeep Wrangler

1 Answer

How to replace gmc1990 pickup coil


I assume this is the HEI coil. If not let me know and I can help further.
Instructions
    • 1 Put your safety first. Engage your emergency or parking brake. Also, disconnect the negative battery cable from the Chevy Corvette's battery.
    • 2 Make the ignition system visible. On older models, you may need to remove the plenum extension for the intake manifold using a screwdriver or wrench. For newer models, remove the cover for the fuel rail.
    • 3 Look for additional parts that you need to remove. For HEI systems, you need to access the distributor through the cap. Other systems use an ignition coil harness connector.
    • 4 Disconnect the secondary wires, or spark plug wires, from the ignition coil. Tag each wire with masking tape, so you know which terminal to reconnect the wire to. If you connect the wrong wires to the terminals, your Chevy Corvette won't start.
    • 5 Detach the ignition coil mounting bolts and remove the ignition coil. The amount and type of bolts vary depending on the part number for the Corvette ignition coil. You may also need to remove the ignition coil arc seal.
    • 6 Clean the distributor cap with a soft cloth. Now is a good time to replace the seal, if needed. Insert your new ignition coil and secure it in place. As you reassemble, use a Torque wrench to tighten the mounting bolts or screws to 13 inch pounds (1.5 Nm) of torque.
    • 7 Reassemble the rest of the parts and reconnect your battery. Start the Chevy Corvette to ensure the repair worked.

Oct 18, 2012 | 1990 GMC Sierra

1 Answer

Need hei distributor wiring diagram


That distributor is an easy one. You need to connect the harness attached to the distributor housing to the cap. There is a marking on the cap that says "Batt" Connect that to the hot lead from the ignition switch that is on (with 12V present) and off with switch off. Likely the connector and wire are still in the engine compartment somewhere near the distributor. The other lead connection is marked "tach" you don't need to connect it anywhere but can attach a hand held or on dash tachometer to it.
If you get no spark from the distributor, either the module inside it is bad (no test for that. they are either good or bad) or one of the wires coming from the pickup coil that attach to the module has broken (common on those). (assuming good or new cap, rotor and coil).
It's a very simple and reliable distributor. In fact I'm using one on a 305 Monte Carlo racemobile right now. (with MSD coil, cap and rotor)!!!

May 26, 2011 | 1978 Chevrolet Caprice

1 Answer

I have a 84 camaro with hei distributor motor is a 69 camaro 350 i keep melting the wires on the coil put new coil in car runs good for an hour or so then gets warm and melts wires and stall also did new...


HEI distributor and burning coils,it in you connection first make sure you install primary and secondary prorperly as it comes out of the cap , and inside the cap wire from modules dont make contact if you are burning its from primary circuit, this is the (B+) or (battery most likely), your secondary is your tach and that need to switch from postitive to negative for it to create spark obvously if tach was grounded or applied power you wont start,but there are times the condensor in the distributor does stays fixed and shorts out the coil (replace that condensor its for suppression) when the condensor is replaced run a fused direct wire at B+ (from ignition) run the vehicle and monitor the tach wire and check to see if that get hot

May 08, 2011 | 1984 Chevrolet Camaro

1 Answer

Wiring for a small block 350


need to know if its a HEI cap and rotor or not. HEI caps have the coil built into them , an all in one ignition as compared to a external cylindrical coil.
you need to know that. either the distributor cap is a huge hurken thing (HEI) or it has an external coil somewhere or the cap has a ninth distributor hole in the middle of the cap to put a coil. wire.
after you figure out which one it is then you have to either go to www.autozone.com and study chevy wiring or buy a haynes manual for the similar vintage engine. for the external coil I would try a chilton manual for a chev truck before 1972. for HEI anytime thereafter. I may be off by a few years on the age of the engine. but hopefully you got an idea of what to do, or just google chev engine wiring? and study away.
good luck

jm

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1 Answer

Hei distributor on old L6 engiune won't fire coil


'56 engine was likely a "blue flame" engine that had a points type ignition system. If someone installed a HEI setup in there, you need to know what year vehicle it came from. The old system used a hot wire from the ignition switch to the (+) side of an external coil...the (-) lead went to the points. The most common conversion uses the same (+) wire but it then connects to the "batt" terminal on the distributor cap.(coil is inside) There are no other wires involved except for the short harness that goes directly into the distributor that connects the coil, pickup coil and control module to each other..

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2 Answers

Coil


please make shure that you have the hot wire on a switch this is the wire that goes to the side if the distributer if the wire that you have in place right now is hot al the time it will overheat the coil and burn it out ok good luck

Jul 12, 2008 | Chevrolet Chevy Cars & Trucks

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