Chrysler electronic ignition issues

[junkyardjeff]

It gets no spark while cranking but will spark once when the ignition is turned off,the truck got a motor swap with the original motor still running and the motor from the other truck running too but now the no spark situation. The truck in question is a 84 Ramcharger and the motor came from a 79 Ramcharger that is getting a bigblock swap,everything on both trucks look identical so what should I look at. The 84 has a MSD box with the original mopar distributor and was doing the same so I hooked it up back to the factory electronic ignition and the same,the only thing that was not changed is the 84 has the 79 distributor that looks the same as what the 84 motor had on it.

[38HAULR]

Hi Jeff.
Is the 79 unit the Chrysler box with a 5 pin plug and dual ballast resistors and conventional coil? These were used on our Chrysler Valiants from 74-79
I would double check the wiring . A "Google"  on that system under "Valiant electronic ignition" should give you the right connections  if you do not have a manual . Sometimes when stumped. Start from the beginning. Looks like a simple wiring fault from the description of not getting any voltage when in cranking cycle.

I have converted one of those  set ups to real HEI .   Chucked the box and coil as well as the ballast.
Used the two wires from the distributor pick up coil to trigger a 4 pin Bosch module used commonly on many 80,s vehicles here in OZ with HEI . The module then connects to a HEI version of a conventional coil  . Only snag was getting the pick up coil polarity right to the module. Will not harm it, just throws the timing way out.

[junkyardjeff]

5 pin plug and single ballast resistor.

[38HAULR]

I have done a "Google" search on the net under "Chrysler valiant electronic ignition"   and some wiring images come up .  Single ballast is there if this helps.

Frank.

[Beck]

Just a thought, and I may be way off on years.

There were lean burn and regular distributors back in the day. I know the pickups are different, but cannot figure out why. The lean burn was a problem. I know the dealer fix for them was to install a Mopar high performance distributor. It was non lean burn.

Just a side note on the HEI conversions. I tried both pickups for a HEI conversion. Both seemed to work. A GM 7 pin module will flow more current than a 4 pin. Some of the pins are not needed.

[38HAULR]

Hi Beck.   We got the lean burn units here with the last model Valiants produced around 1980 . Thinking back I think the distributor had no vac advance fitted  .    In Australia the distributors were made by Bosch as were the points versions made for Chrysler until 74 when they went electronic with the Chrysler box,  and GM and Ford until the eary 80,s until they changed  to the 4 pin module HEI .  The beauty of this was that parts interchanged . The Chrysler version had the pick up coil as a bolt in unit like points and the cam assy had the reluctor sleeve .  So any earlier points version of the three makes  would take the Chrysler bits for conversion to trigger the module ,and by a simple coil swap you had HEI . This worked well for our Valiants  from 70-74 with the "hemi 6" . And indeed for the latter 74 onwards where the pick up coil replaced points  where you could simply ditch the Chrysler box which in reality was just transistor switching of a conventional coil and replace it with a module and coil swap to get HEI .

[kb426]

Is the start wire hooked up to the starter? You might want to check continuity to the ballast resistor from that post.

[38HAULR]

It does sound like  lack of voltage supply to ignition during crank cycle from the initial description

[Arnold]

My .02..motor swap I am heading to the grounding circuits. I have been beaten a few times with rotted wire/ends inside factory cables that can barely be seen. They were probably hanging on by a thread anyway. And could not tolerate any movement.

[38HAULR]

One quick test .   Use a voltmeter or a test lamp and  check the volts between engine block  and the +ve coil terminal with ign "on" . Then  check whilst cranking .

[wayne petty]

some testing..

ohm meter set to 2K ohms... measure pickup coil... usually around 980 ohms..   500 to 1500 OHM accepted..


before disconnecting.. flip the meter over to 2 volts AC or 20 Volts AC or 200 Volts AC..  have somebody crank the engine.. you need to see really close to 1.0 volts AC from the pickup coil or it won't be enough to close the power transistor in the ignition module..  if it cannot be closed with the AC signal.. it cannot open to discharge the magnetic field in the coil and no spark will be generated..

why the heck do this stupid test..  the reluctors can fail.. yes.. a piece of sintered metal can fail.. when it gets soaked in solvents.. sand blasted..rusty..  or just dirty.. it won't retain enough magnetic field to create enough voltage as it spins past the pickup coil pole piece..

don't forget that the reluctors have 2 offset keyways.. one for clockwise distributors.. one for counter clockwise..

the power transistor in the module needs 3/10s of a volt above ZERO.. to close and connect the coil negative to ground.. this sends electrons thru and builds a magnetic field in the primary..  as the reluctor tips align with the pickup coil.. the AC voltage drops to ZERO and the power transitor opens causing the magnetic field in the coil primary to collapse thru the secondary creating a high voltage spark..

so 3/10s above ZERO is needed.. that is 0.6 volts AC..   +0.3 Plus -0.6 = .06 VAC but that is the minimum..

so +0.5 and -0.5 make a volt and that is enough.  over 0.98 AC  is what i expect.

sorry for the complications... this is something i know too well after 35 years of working on cars for a living.

you can check at the distributor connector and at the module connector..

be sure to squeeze the module connector tubular terminals slightly so they grip the pins in the module better.


i usually hook a test light clamp to the coil positive connector.. and stick the probe end into something grounded...  have a friend slowly turn the key from OFF to RUN, Cranking.. RUN.. then slowly off..

in RUN you should have a medium bright light.

in CRANKING you should have a full bright light..

back in run.. back to the medium light..

on 2 pin resistor models..  the resistor bypass voltage comes from the BAL terminal on the starter relay...  that is BAL for ballast resistor not BAT.. for battery..

with chrysler electronic ignition... you MUST have a braided ground strap from the head.. and USUALLY to the mounting bolts of the ignition module.. or close to it and make sure the module housing is grounded to the body properly...

why... to complete the high voltage spark path.. where does it go when the spark goes into the block. it actually comes from the block.. but that complicates things.  electrons flow from negative to positive.

this high voltage needs to complete its path back to the coil... right thru the module..  if you are missing the ground connection between the engine and the firewall or where ever the module is mounted.. you will have a fairly short life span on the ignition module..

i usually if i can get the engine to run.. i perform the voltage drop test..

http://i.imgur.com/WMDprhm.jpg




do some additional testing on 3 and 4..

test 3B negative battery post to the ignition module housing..

test 4B  engine block to the ignition module housing..

post results by number..

test 5 goes to either the stud on the starter relay.. or somewhere there is a threaded stud with ring terminals for the power distribution..  

test 6 is really important also...  

most mopars have a LONG LONG distance between the alternator output and the battery..

on many.. the alternator output wire goes thru the bulk head connector.. to the AMP meter.. from the other side of the amp meter back thru the bulk head connector to the starter relay and the positive battery post from there.  that can be 8 to 10 maybe 12 feet of wire.. so a voltage drop reading of 0.7 volts is expected... and mopar manuals even describe that as an accepted voltage drop all the way back into the manuals in the late 60s..  burned bulk head connectors... loose or burned connectors at the amp meter terminals..

even bad ignition switches..   that is why i had you hook up a test light backwards to the coil positive..

sorry for the wall of text.. and the delay in getting you an answer..so many other forums out there to read and annoy people on..

[38HAULR]

Did this get fixed?

[junkyardjeff]

I have not had a chance to go back and look at it and i lost the guys phone number.