trouble shooting & rebuilding HEI ignitions

if your ignition is working correctly your getting a hot blue spark, thats got a noticeable audible snap to it if you test an ignition wire by removing it from a plug temporarily and holding it about a 1/3" from a ground like the block,a quick check of your shop manual for the correct advance and procedures for setting the timing and your timing light will be very useful in setting the ignition timing.
if you don,t have that snappy blue spark,, but only a dull yellow or red spark, chances are decent that the coil or the battery voltage or possibly a ground strap are defective, so check those possibilities , and don,t forget youll need both a timing light and a v.o.m. meter to check out your ignition.

WATCH THE VIDEO


If your chasing an intermittent, engine miss or stumble, youll need to logically isolate and test each potential source, and while it might be related to fuel pressure, carburetor float levels or crud in the carburetor fuel bowls, or a vacuum leak, on a hose or the brake booster, or fuel pressure or volume of fuel delivery or the carb fuel level, you might also be dealing with a loose electrical connection , on the battery , other wiring or system ground in the cars ignition system or sensors, or something simple like water in the fuel, or a clogged fuel filter, the point here is LOGICALLY ISOLATE AND TEST THE POTENTIAL OPTIONS, AND IT HELPS TO HAVE A FACTORY SHOP MANUAL< A MULTI METER A VACUUM GAUGE AND TAKING NOTES WON,T HURT EITHER

DON,T SKIP READING THE LINKS AND SUB LINKED INFO
AND IF AQ LINKS STATES...CLICK TO EXPAND...CLICK THE LINK AND READ IT!
http://www.4secondsflat.com/HEI_Distributors.html

viewtopic.php?f=36&t=10946&start=16

https://www.customwiresets.com/product.php?productid=16162&cat=0&page=1&featured

http://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/distributor-mounted-icm-tests-1

http://garage.grumpysperformance.co...-auto-elecrtrical-connectors.3105/#post-68805

Ive found its a whole lot faster to use a quality IR temp gun, to locate a individual cylinder that's mis-firing as it tends to run significantly cooler than adjacent cylinders, or hotter if its a vacuum leak at times, as lean F/A mixes tend to run hotter
(Ive used this one for years)

http://www.professionalequipment.com/ex ... ermometer/
Wide temperature range from -58 to 1832°F (-50 to 1000°C)

many temp guns don,t read high enough or accurately enough
http://www.professionalequipment.com/ex ... ermometer/
that you can use on the engine to check ALL 8 exhaust temps, individually, this quickly locates plugged injectors or vacuum leaks ETC
Wide temperature range from -58 to 1832°F

when selecting an IR gun for automotive use, you really want to be able to read from 0 F deg-about 1400F deg. to cover most conditions you'll test for

http://easyautodiagnostics.com/gm/4.3L- ... cm-tests-3

below youll find some helpful links

http://www.megamanual.com/ms2/GM_7pinHEI.htm

http://rmcavoy.freeshell.org/HEI.html

http://www.performancedistributors.com/faqs.htm

http://www.chevelles.com/techref/ftecref5.html

viewtopic.php?f=50&t=3110&p=8302#p8302

summit racing and a few other places sell clear distributor caps which can be useful
http://www.summitracing.com/parts/sum-g5236

http://documents.msdperformance.com/5520.pdf




The ignition control module in the distributor is another item that normally fails when hot, that needs to be replaced is you suspect its defective



https://www.competitionproducts.com...ail&utm_term=0_dccdcdc641-e5856f3f6b-34475433
I have yet too try it personally yet, but this modual above SHOULD BE a noticeable improvement










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

http://static.summitracing.com/global/i ... m30247.pdf

http://www.summitracing.com/parts/msd-8 ... structions

http://prestoliteweb.com/Portals/0/down ... e_0006.pdf

http://www.chevelles.com/techref/ftecref5.html

http://www.kendrick-auto.com/ignition.htm

http://www.pontiacstreetperformance.com ... curve.html

http://www.73-87.com/7387garage/drivetrain/hei.htm

http://rmcavoy.freeshell.org/HEI.html

http://www.enginebuildermag.com/2009/07/properly-matching-your-camshaft-and-distributor-gear/

http://www.pontiacstreetperformance.com ... curve.html

http://www.corvette-restoration.com/res ... v_Spec.pdf

http://www.chevelles.com/techref/ftecref5.html

http://www.circletrack.com/howto/1842_i ... index.html

http://www.chevelles.com/techref/ftecref5.html

http://www.superchevy.com/how-to/97438/ ... m#cxrecs_s

http://www.hotrod.com/techarticles/sett ... index.html

http://www.chevyhiperformance.com/howto ... index.html

viewtopic.php?f=70&t=251&p=6437&hilit=+shiming#p6437

http://www.ehow.com/how-does_4809570_tr ... butor.html

be sure you inspect the distributor gear for excessive wear
especially if you changed from a flat tappet to a roller cam.

http://www.summitracing.com/parts/CCA-12200/

http://www.summitracing.com/parts/CCA-12140/

viewtopic.php?f=70&t=251

videos
http://streetmuscleaction.com/engines/hei/

http://www.73-87.com/7387garage/drivetrain/hei.htm

http://www.enginefactory.com/high_perfo ... ibutor.htm

http://www.summitracing.com/parts/MRG-6011/?rtype=10

http://cranecams.com/pdf/90001700c.pdf

http://www.customclassictrucks.com/howt ... index.html

http://corp.advanceautoparts.com/englis ... 1001he.asp

http://reviews.ebay.com/HEI-Ignitions-A ... 0002053885

http://www.ehow.com/how_5453767_rebuild ... butor.html

http://www.circletrack.com/techarticles ... index.html

http://www.davessmallbodyheis.com/

viewtopic.php?f=70&t=270

http://temp.corvetteforum.net/c3/joevet ... urve.shtml

http://arrc.epnet.com/autoapp/9110/9110 ... System.htm

http://www.rodandcustommagazine.com/tec ... index.html

http://www.hotrod.com/techarticles/sett ... index.html

viewtopic.php?f=36&t=2412&p=6369&hilit=+alternator#p6369

viewtopic.php?f=36&t=1169&hilit=+alternator

viewtopic.php?f=70&t=840&p=1696&hilit=taylor#p1696

 

AS a general starting point for tuning your SBC or BBC engine your HEI MSD,or similar distributor timing should be at about 8-12 btdc at idle, and all in by about 3100rpm at about 36 degrees total advance, naturally youll want to make some adjustments in the timing or fuel/air ratio as needed, and reading plugs and verifying your TDC, and timing tab and use of timing tape on the damper , use of a vacuum gauge and timing light are a good place to start.
you can normally change the total advance and rate of advance by changes in the distributors weights, springs, etc.

IF your tach is not reading correctly on a 1984-90 corvette check the electrical connections and replace the tach filter

www.grumpysperformance.com/46137b.jpg

viewtopic.php?f=70&t=202

viewtopic.php?f=70&t=875

http://www.angelfire.com/realm2/84camar ... tm#hd1-1-4

viewtopic.php?f=70&t=1809&p=7228&hilit=timing+curve#p7228

viewtopic.php?f=50&t=383&p=2301&hilit=+vacuum+gauge#p2301

viewtopic.php?f=70&t=1135&p=2289&hilit=+distributor+curve#p2289

Troubleshooting the GM HEI Distributor
By Don Bowman, eHow Contributor

updated April 05, 2011
Troubleshooting the GM HEI Distributor thumbnail The GM HEI distributor affects the power in your vehicle's engine.

GM HEI Distributor Basics

The GM HEI distributor uses a hall effect for the triggering and sensing the No.1 cylinder location and the rpm of the engine. It uses an ignition module within the distributor to regulate the timing curve as well. It will automatically advance the timing on acceleration a specific amount and retard the spark when decelerating and starting.

It uses a standard rotor, under which is located a centrifugal set of weights and springs that act as the final mechanical advance. The GM HEI distributor's springs can be replaced with three different weights of springs that, in effect, allow the advance at lower rpm. The ignition coil is housed in the distributor cap, which makes the GM HEI distributor a very efficient, self-contained unit. It can be used with many ignition-enhancing-after-market capacitor discharge units such as MSD or Jacobs (multiple spark distribution).

This system creates a multitude of sparks rather than one spark, and it lasts over many degrees of stroke. Some of the early units also had a vacuum advance that mechanically retarded the spark for start and deceleration and increased the spark approximately 10 degrees on start-up. The combination of the vacuum and the mechanical weights did all of the controlling of the spark in the early units. The module in these units primarily acted as a switch.
Testing the GM HEI Distributor

A no-spark condition is checked by checking the distributor for power at the connector on the side of the cap. If there is power, disconnect the electrical connector and remove the cap. Check the rotor and the cap for excessive wear. Check the coil tower for excessive wear. Remove the top plastic cap on the distributor cap. Use an ohmmeter and check the coil positive terminal to the metal case of the coil. The reading should be infinity. Check the coil tower and the negative terminal. The reading should be 900 ohms. Check the positive terminal to the negative terminal. The reading should be around 700 ohms. If any of these tests show drastically different readings, the coil is bad. If the coil is good, the cap and rotor are not cracked or worn significantly and there is no spark at any wire, replace the ignition module.
Engine Runs But Has no Power

Hook up an advance timing light by hooking the carbon connection over the No. 1 cylinder wire and hook the positive and negative clips to the battery. If there is a vacuum advance, pull the hose off the vacuum source and plug the leak. Start the engine, pull the trigger and shine the light on the right side of the harmonic balancer. Turn the knob on the timing light until the straight 0-degree line on the harmonic balancer is lined up with the 0-degree mark on the timing chain cover. Read the degrees of advance by the mark on the timing light advance knob. For instance, if it is 8 degrees before top dead center, check the label under the hood for the timing specifications. Adjust the distributor, if necessary, by loosening the hold-down nut on the distributor base and turning the distributor and rechecking until it meets specifications. Turn the distributor counter-clockwise to advance and the clockwise to retard the spark.

Once set, reconnect the vacuum hose and see how much the distributor advances. If the advance rises about 10 degrees, the vacuum advance mechanism is operational; if not, replace it. Raise the rpm to 2,500 and recheck the timing. It should be around 32 degrees plus or minus one degree. If the timing does not rise, the centrifugal advance mechanism isn't working. If it rises but is less than 32 degrees, adjust the distributor to achieve this number.


DOC posted this bit of info
"First be sure the 12 volts doesn't drop out when cranking..If it does you may need a secondary Ignition wire or a better source of power for the HEI.

The Module can be tested for free, at any Auto Zone, store and if it is bad...youll need it replaced, so be sure YOU HAVE the new one checked.before you leave the store because once you leave the store..It's your problem.. DO NOT forget the heat sink grease compound..or you will be replacing the module again real soon!

On the coil, Remove and invert the cap, Measure between the tach and BATT terminals , using a DVOM, Set to OHMS scale, RX1 and calibrated to 000. It should read less than an ohm, but more than 000, If not it's bad.
lightly used distributor cap




floating carbon button that contacts rotor top spring

rotor shows carbon arcing, which can be caused by placing the spring loaded button above the insulated washer rather than under it with only the spring poking thru (see assembly diagram)

IF YOU FIND THE CAP AND ROTOR MELTING DUE TO EXCESSIVE HEAT! DROP THE PLUG GAP FROM THE RATHER STANDARD .045 to, the CLOSER GAP OF .023 THAT REDUCES THE RESISTANCE, AND USE THE LOW RESISTANCE BUTTON. PART #MSD-8412

The carbon rotor button in a stock HEI distributor cap has very high resistance. When the high voltage of an MSD 6, 7, or 8 Series ignition is added, this resistance builds up heat and can actually melt the distributor cap.
To solve this problem,
(1) install one of these MSD low-resistance HEI bushings, which will pass the secondary voltage from the distributor cap to the rotor with out the excessive heat buildup.
(2) verify the grounds on the car and battery to frame show less than 3-t0-4 ohms at the MOST
(3) drop the plug gap to .023-.025 rather than the more common .043-.045
http://www.summitracing.com/parts/MSD-8412/

while admittedly this picture, below, is an extreme case ,
any corrosion in the frame ground to battery cable connections, causes heat and lower ignition current


I've seen the rubber washer installed incorrectly, too. Put the button in the cap, spring end toward the coil. THEN install the rubber washer, then the coil. Once in awhile, I see that someone has installed the rubber washer, then the button, then the coil.
http://www.superchevy.com/how-to/67498-hei-coils-modules/




I figured Id point out a few basics
that I find it hard to believe are commonly over-looked
and
that's the fact that you'll want to
check the condition of the batteries and electrical connections in any meter you use.
before you go doing any testing.
I can remember several times that I've found
9 volt and AA batteries inside multi meters that were corroded and leaking acid,
and remember guys telling me injectors were defective, only to find later that the meter they used to test with was defective or the internal fuses or battery was dead, or 90% dead and internal connections in the multi meter were corroded.
and as a result, connections internally were damaged so badly that the connections were turned to white metallic salts.
Ive also watched and seen guys try to check for good grounds , or ohms resistance or voltage and spend a lot of wasted time ,
because the multi-meter had a blown internal fuse , or the connector probes & leads, that did not fit,
and were not designed to be used with that particular multi-meter.



having a wide assortment of different multi meter test leads available is a huge benefit while testing
the clip test leads that test thru a wires insulation without much damage are a big help






most internal fuses will have the voltage/amps stamped on them,
any mechanic should have an assortment in his tool box, as your constantly going to need replacements while testing auto related issues




always make a point of flipping the multi meter too low range OHMS and touching the leads from common (BLACK) to (RED) test lead tips,
to watch the display or needle bounce to verify the multi meters functioning,
then place the black ground or common lead on a cars grounded chassis,
and touch the red probe to a fuse and verify it reads 12-14 volts current


https://media.distributordatasoluti.../4133557fb8456fa5ec26aff60729042350758d52.pdf















Next measure the secondary, set your DVOM scale to RX10k or higher..put the probes between the BATT and the carbon pickup for the COIL..it should read between 6000 and 30,000 OHMS..Outside of that range toss the coil and get a new one.

Check the Carbon pickup and spring follower, it may not be reaching the rotor pickup..or be worn or snapped past runout.

If that won't bring it to life, check the Magnetic pickup, by measuring the resistance across it. (you'll have to lookup the spec's for that year HEI..GM made a year divider on the pickups, and from a certain year Down were one resistance and a different resistance for that year and up..) If it is bad, you'll have to pull the distributor, and disassemble it to replace it."



this APPEARS TO BE A SMALL CAP DIAM HEI replacement

but its simple enough to tell with a caliper or even a ruler

small cap distributors measure approximately 4" in diam.

LARGE cap distributors measure approximately 5.25" in diam.
and theres both male and female ignition wire connection style caps







http://www.ehow.com/how_6153213_install-hei-distributor-cap.html

http://www.pertronix.com/support/manuals/pdf/hei.pdf

http://garage.grumpysperformance.co...cting-a-distributor-for-your-application.855/

http://www.pontiacstreetperformance.com/psp/HEIconversion.html

http://www.superchevy.com/how-to/67498-hei-coils-modules/

http://apps.msdignition.com/pdf_catalog/2008_catalog_65-68.pdf

http://www.setyourtiming.com/pdf/8365_frm28975.pdf

http://www.rustynutscarclub.com/HEI.htm





http://www.summitracing.com/parts/CRN-1 ... |Year|1985


Both the large & small cap ccc distributors can be swapped, the wiring is the same color. Thay make a conversion harness or you can make one, go to a junkyard & get the est harness from each type, then splice in the middle. but remember the small cap totally dependent on the computer for ignition advance curve in A FEW APPLICATIONS

you can buy harness connectors
http://www.eficonnection.com/eficonnect ... eType.aspx

viewtopic.php?f=36&t=3439&p=14806#p14806

http://www.davessmallbodyheis.com/


btw this is a rather cool custom touch, (VIDEO LINK BELOW ) you can swap to an HEI cap with wire routing that doesn,t look like crap

http://www.accel-ignition.com/Products/ ... edCap.aspx

I have near zero desire to run any hei,ignition.
or similar coil in distributor cap chevy ignition,
but from a reasonable comparison , based on cost vs performance and durability,
well you and I are forced to make choices based on both cost and performance.
Id swap to a vertex magneto in LESS than a 1/2 nano second if I had that option on most BBC and SBC engine builds,
but finding one in pristine condition ,at a decent price is not very likely.
crank trigger, individual, coil per cylinder ignitions and computer controlled ignitions have some advantages over the vertex ignitions
after all that magneto technology is almost 70-100 years old, and the better individual coil per cylinder ignitions that can adjust individual cylinder timing,
with the computer control speed to detect detonation, and in some models, that,
work with injection controls and sensor out-puts ,
too change injector pulse duration, or adjust the advance or retard curve, as required,
thousands of times per second if that were required are far newer than the magneto ignition.


related info

http://garage.grumpysperformance.com/index.php?threads/vertex-ignitions.1320/#post-64168

http://garage.grumpysperformance.co...il-per-cylinder-application.10741/#post-46899

http://garage.grumpysperformance.co...ouble-shooting-rebuilding-hei-ignitions.2798/

http://garage.grumpysperformance.com/index.php?threads/distributorless-ignition.5916/#post-18181

http://garage.grumpysperformance.co...es-and-trouble-shooting-guide.1179/#post-5875

http://garage.grumpysperformance.co...ition-wires-getting-the-header-clearance.840/

http://garage.grumpysperformance.co...ing-a-stand-alone-ignition-coil.275/#post-337

http://garage.grumpysperformance.com/index.php?threads/shiming-a-distributor.251/

http://garage.grumpysperformance.co...grated-multi-spark-digital-rev-limiter.13948/

http://garage.grumpysperformance.co...stributor-for-your-application.855/#post-8931

 

replacing HEI distributor advance weights & springs









http://www.pontiacstreetperformance.com ... curve.html








there are weight and spring kits available from Accel also

the answer to how much coil voltage is required depends on the compression ratio, plug gap, rpm levels fuel/air ratio and the coils design, more volts won,t hurt but they won,t generally improve much either, its maintaining a precise and predictable timing of the ignition arc across the plug gap thats important 40K-45k volts is fine in most application, where most ignitions fail is that as rpms increase the delivered voltage drops but 40K-45k volt capacity in a coil and a plug gap in the .045 thousands range is certainly able to function correctly on most muscle cars with less than 11:1 compression ratio , and typical 12.7-14.7:1 f/a ratios running with out power adders , once you start adding things like nitrous, superchargers and alcohol or nitro it will require more amps and volts,
keep in mind as rpms increase the time required for a coil to recharge to full capacity remains constant but the time between sparks drops rapidly





read these
http://en.wikipedia.org/wiki/Capacitor_ ... e_ignition

http://www.tonyfoale.com/Articles/Ignition/Ignition.htm

http://www.sentex.net/~mwandel/cannon/sparky.html

heres some info for the MSD advance curve kit


Helpful part numbers for HEI distributors:


GM part numbers

01894379 ZZ4 distributor mainshaft assy.

12167658 Connector used to connect TACH and B+ to distributor .

10456413 Melonized distributor gear (supplied on distributor 93440806)

1950569 Distributor shaft/bushing plastic grease seal

1837617 Distributor shaft washers (pack of five)

Delco D1906 4-pin module



NAPA part numbers

DP109 HEI weight pins for distributors that use plastic bushings on weights

DP112 HEI weight plastic bushings

DP114 HEI weight "stamped 106"

DP115 HEI weight "stamped 139"

DP126 HEI weight "stamped 105"

MP100 (GP Sorensen EL315) HEI yellow color code (Chevy, Caddy except Seville, Olds Toronado) V-8 pickup coil

MP101 (GP Sorensen EL310) HEI Blue (or black) color code (Olds except Toro, Buick, Caddy Seville) V-8 pickup coil

MP102 (GP Sorensen EL359) HEI clear color code (Pontiac) V-8 pickup coil

(My source for the GP Sorensen pickup coils sells them for about $16 instead of NAPA's $40. The GP-S ones I bought are even made in the USA!)

RR230 HEI Capacitor and Harness from module to side of cap 6 ½”

RR231 HEI Capacitor and Harness from module to side of cap 10 ¾

RR233 HEI module to cap Harness 3 ½

RR234 HEI Capacitor and Harness from module to side of cap 8 ¾

TPL45 Heat sink compound for HEI modules—10 small tubes

RR201 Coil frame ground—wire style

RR204 Coil frame ground—Stamped steel strap

RR202 Plug wire retainer ring—8 cyl.
https://www.competitionproducts.com...ail&utm_term=0_dccdcdc641-e5856f3f6b-34475433
I have yet too try it personally yet, but this modual above SHOULD BE a noticeable improvement

GM part numbers
01894379 ZZ4 distributor mainshaft assy.
12167658 Connector used to connect TACH and B+ to distributor .
10456413 Melonized distributor gear (supplied on distributor 93440806)
1950569 Distributor shaft/bushing plastic grease seal
1837617 Distributor shaft washers (pack of five)
Delco D1906 4-pin module


NAPA part numbers
DP109 HEI weight pins for distributors that use plastic bushings on weights
DP112 HEI weight plastic bushings
DP114 HEI weight "stamped 106"
DP115 HEI weight "stamped 139"
DP126 HEI weight "stamped 105"
MP100 (GP Sorensen EL315) HEI yellow color code (Chevy, Caddy except Seville, Olds
Toronado) V-8 pickup coil
MP101 (GP Sorensen EL310) HEI Blue (or black) color code (Olds except Toro, Buick,
Caddy Seville) V-8 pickup coil
MP102 (GP Sorensen EL359) HEI clear color code (Pontiac) V-8 pickup coil
(My source for the GP Sorensen pickup coils sells them for about $16 instead of
NAPA's $40. The GP-S ones I bought are even made in the USA!)


RR230 HEI Capacitor and Harness from module to side of cap 6 ½”
RR231 HEI Capacitor and Harness from module to side of cap 10 ¾
RR233 HEI module to cap Harness 3 ½
RR234 HEI Capacitor and Harness from module to side of cap 8 ¾
TPL45 Heat sink compound for HEI modules—10 small tubes
RR201 Coil frame ground—wire style
RR204 Coil frame ground—Stamped steel strap
RR202 Plug wire retainer ring—8 cyl.

 

http://www.mrgasket.com/Portals/0/downl ... _29050.pdf

 

multi spark ignition works in a very similar manor to the standard HEI,its not the multi strike capability but the higher voltage , and better timing control thats usually the bigger benefit
you might want to read these links
http://auto.howstuffworks.com/ignition-system.htm

http://www.chevyhiperformance.com/techa ... ns_basics/

http://www.autos.com/aftermarket-parts/ ... ion-systemspark generating capability of a stock HEI site:http://garage.grumpysperformance.com



except the lower rpm range allows time for the coil to build and discharge a second or even three successive ignition sparks per compression stroke to insure the compressed charge of fuel air mix will ignite, this tends to increase low rpm efficiency, as occasionally that 2nd or third ignition electrical arc does help ignite a reluctant to burn cylinder, but in the vast majority of cases the first strike is still the one igniting the cylinder so no change in timing is required

 

viewtopic.php?f=50&t=3110&p=8302#p8302

http://easyautodiagnostics.com/gm_icm_d ... dule_1.php

http://easyautodiagnostics.com/gm_icm_d ... dule_2.php

http://easyautodiagnostics.com/gm_icm_d ... dule_3.php

http://easyautodiagnostics.com/gm_icm_d ... dule_4.php

http://easyautodiagnostics.com/gm_icm_d ... dule_5.php

http://easyautodiagnostics.com/gm_icm_d ... dule_6.php

 

http://chevythunder.com/hei_troubleshooting_page_2_coil_.htm

CHEVYTHUNDER.COM

HEI and ELECTRONIC SPARK CONTROL FUNDAMENTALS AND TROUBLESHOOTING

Troubleshooting the HEI coil in cap ignition

Troubleshooting a faulty or inoperative ignition should always use a logical approach. Overlooking the basics will leave to frustration and unnecessary time and expense. The first thing to remember that the system needs to have power. Make sure the power connection to the distributor cap or the coil is good, no blown fuses, no broken, loose or corroded connections. A good 12V powered test light should always be one of the basic troubleshooting tools you need, along with a reasonable priced digital-volt-ohmmeter.



A 12V test lamp and Digital Volt-Ohmmeter should be your basic troubleshooting tools for HEI-EST systems. Use a DVOM for testing, calibrate meter scale (some do automatically) to read zero when the leads are touching each other. Do this before testing coil to insure greatest accuracy. If meter will not calibrate to read less than 0.2 ohms, check leads or replace battery.



This is the terminal for the coil-in-cap HEI ignition power. With the key turned on (engine off), there should be full battery power here. If not, you will need to check for loose connections by tracing back the wire as far as you can. Also check the fuse that protects the circuit from overload. If the fuse is blown, you will need to do further troubleshooting to find and correct the reason why the fuse blew. Short to ground is the most common cause. The connection (TACH) to the left is the tachometer output.

Connect the one side of your test lamp to the battery POSITIVE cable. Probe the TACH terminal on the dist. cap while an assistance cranks the engine. The test lamp should blink repeatedly as the engine cranks. No blink will mean either a bad module or pickup coil. If the light blinks but there is no spark points to a bad ignition coil. Further testing is required to pinpoint the problem.



As you pull the coil cover off, these are the connections you are looking at and how they are identified. Besides the Tachometer and Power connectors, the next important connector is the three-way that is marked on the coil cover as "C-", "GRD" and "B+".

In the picture on the right, see how this correlates with the ignition module. Study the picture below of the full diagram with the ignition coil.



Now with the diagram broken down to just the ignition coil, we can get an idea of the connections on how to troubleshoot for a faulty coil.



The first thing to remember that there is no physical connection between the coil windings. The "B+" and "C" winding is separate from the ground/sparkplug wire coil. The resulting turning on and off the voltage on the "B+", "C" coil windings, causes a magnetic field to be generated. When the voltage is turned off through the trigger signal, the collapsing magnetic field induces a very large voltage and current into the primary winding which is the feed for the sparkplug. This cycle is repeated as long as there is a functioning ignition module and coil, and a good ground connection, which means it is imperative that the engine grounds are solid and clean.

It must be noted that the secondary (battery/trigger coil) windings will have considerable less turns of wire on the core than the primary (sparkplug) windings. The voltage and current is inversely proportional to the number of windings on the core. So a small voltage/large current on the secondary windings will translate into a large voltage/small current at the sparkplug.



TEST 1:Remove and invert the cap, Measure between the "TACH" and "BAT" terminals , using your DVOM, Set to OHMS scale, RX1 and be sure the scale reads zero ( 0.00) It should read less than an ohm, typically around 0.5 to 0.6 ohms. Anything less or more, replace the coil.

TEST 2: Set your DVOM scale to RX10k or higher. Touch the probes between the "BAT" and the carbon pickup for the coil. This reading should read between 6000 and 30,000 OHMS. Outside of that range the coil is bad, replace.

Also using test 2 as a reference, check for shorted to ground connections, by probing the "BAT" connection and the center terminal with your DVOM leads. There should be infinity resistance or OL on your meter. You can also check the "TACH" connection as well. Either way, if the reading is anything less than OL, replace the coil.

Testing the Pick Up Coil

If the ignition coil checks out good but you were not getting a "blink" with your test light as described at the top of the page, then the pick up coil needs to be checked. This test should be done before moving on to the ignition module.



With your DVOM set on the highest scale, touch one lead of your meter to the distributor body and the other lead to one of the terminals for the pick up coil (either the green or white lead. Your reading should be infinity or OL. Test the other terminal. Any reading less than infinity means the pick up coil is junk.

With your DVOM set on RX10K scale or equivalent, touch each terminal with your leads from your meter. The reading you see here should be around 500 to 1500 ohms and the reading should be steady as the wires are wiggled.

If the coil fails either test, replace the pick up coil.

Testing the Ignition Module

If the pick up coil and the ignition coil checks good, the next thing to move on to is the ignition module. There are two ways to do this. One is with a module tester, such as shown in the picture below. This is also handy to check the pick up coil as well, using the reluctance mode. If you don't have a tester, you can use the method below.



IGNITION MODULE TEST FLOW CHART

The method below will work for both styles of the 7 pin module. Terminal identification is identical.



You may be asking, "if the ignition coil and pick up coil checks okay, why waste time, testing the module?". You're right, but this will get you familiar with the procedures, if this is the only thing you have to work with. It is best not leave anything to chance and work in a logical, methodical approach.

NOTE REGARDING IGNITION MODULES

When re-installing your old one, do not remove the white pasty substance from the bottom of the module or from your distributor. If you are installing a new module, you may clean the old paste from the distributor but, ALWAYS, use the paste when installing the module, and follow the instructions for application.

Failure to use the paste, which is a thermal transfer that allows heat to be conducted away from the module to the larger surface area of the distributor to dissipate heat, will mean almost instant destruction of the ignition module.



Thermal transfer paste must be used.

 

http://chevythunder.com/hei_remote_coil_ignition_system.htm

http://www.superchevy.com/how-to/67498-hei-coils-modules/

CHEVYTHUNDER.COM

HEI and ELECTRONIC SPARK CONTROL FUNDAMENTALS AND TROUBLESHOOTING

Troubleshooting the HEI remote coil ignition w/o Hall effect



The HEI system, using the remote coil was used starting around 1987 and used up to around the mid 1990's. This system uses the same basic electrical troubleshooting procedures as the coil in cap system, so use that page as a reference and guide for troubleshooting and repair. The difference is that the coil is mounted remotely and there is some slight difference in identifying the connections and terminals.

Troubleshooting Ignition Coil 4 pin 2 connector type

The basic test for the coil is in the illustration below. Use a DVOM for testing, calibrate meter scale (some do automatically) to read zero when the leads are touching each other. Do this before testing coil to insure greatest accuracy. If meter will not calibrate to read less than 0.2 ohms, check leads or replace battery.





Troubleshooting Ignition Coil 3 pin single connector type



Test 1: With ohmmeter set on highest scale, touch one probe to the 12V power pin and the other probe to the coil case. The reading should not be anything less than infinity. Any reading is a cause to reject the coil.

Test 2: With the ohmmeter set on the lowest scale, reading should be around 0.35 to 1.5 ohms. Anything outside this range, replace coil.





Troubleshooting the Hall effect switch

There are two styles of Hall effect switches used, but the procedures are the same for both.



4 cylinder Hall effect switch testing. NOTE: Check polarity connections carefully before making any connections.

1) Connect a 12V power supply as shown, noting proper polarity before connecting. Hook up voltmeter as well.

2) Insert a small metal blade between the notches of the switch (see second picture) and note voltmeter reading. With voltage should be with 0.5V of battery voltage. If the reading is higher, switch is faulty and must be replaced.

3) Remove blade from switch and note reading on meter. It should read less than 0.5V. If it reads a higher reading, switch is faulty and must be replaced.

V6 and V8 Hall effect switch in distributor. NOTE: Check polarity connections carefully before making any connections.





Page 1: HEI-EST basic Fundamentals