Help ignition..here we go again,,,

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highflyer

highflyer

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Yesterday I spent 3 hours putting in another switch..today I went to harbor freight and the motor kkkkked all the way there ..you know pinged but only while giving it gas..cruising was ok...when I got out of HF it would crank but not fire..till I realized it wanted to fire if I cranked then let go of the switch..then it would catch..the old switch did it on occasion also..maybe the run wire [brown maybe]isn't getting power???till I let go of the switch in crank position...still having a light pulse bright ...dim...on the headlights..another switch didn't help that...also put in new tumbler..keyswitch...halppppppp,please...j
 
Same ol 360 ..milled the block to even it out..same with the j heads small valves basically stock pistons and 340 cam.,edelbrock carb and manifold...in a 73 duster with a 74 wire harness,stock ign and charging system..everything new or rebuilt..orange box ign... mopar regulator..what in the system would keep it from starting while cranking but let it start just as the switch comes back to the run position...j
 
had similar problem with old motorhome...crank no start...let go of key..try to start...had a bad pick up coil in distributor...had another electronic distributor..swapped it out...bingo...old MH runs great ..
 
highflyer said:
Same ol 360 ..milled the block to even it out..same with the j heads small valves basically stock pistons and 340 cam.,edelbrock carb and manifold...in a 73 duster with a 74 wire harness,stock ign and charging system..everything new or rebuilt..orange box ign... mopar regulator..what in the system would keep it from starting while cranking but let it start just as the switch comes back to the run position...j
Click to expand...

The ignition has a wire that goes ONE place. This is the wire which gives you ignition power in "start" and Ma calls it "IGN2" It's traditionally brown, and goes from a contact on the ignition switch, through the SWITCH CONNECTOR, through the BULKHEAD CONNECTOR, and ends at the coil + side of the ballast connector

If this wire has lost connection or is not hooked up you won't get ignition power in "start."

What do you have for a shop manual/ wiring diagrams?



73, 74 diagrams

http://www.mymopar.com/downloads/1973/73ValiantA.jpg

http://www.mymopar.com/downloads/1973/73ValiantB.jpg

http://www.mymopar.com/downloads/1974/74ValiantA.jpg

http://www.mymopar.com/downloads/1974/74ValiantB.jpg

Look at socket "Q" on the bulkhead connector on either diagram "A" above. "Q" is brown wire, goes up to the coil resistor

Now follow that off the page to "B" and find the brown going to the ignition switch

(Fourth wire from the top of the connector)

Check both those points with your meter. To keep the starter from cranking, just disconnect either of the "push on" terminals at the starter relay.

Now first probe the coil PLUS terminal, turn the key to start and confirm you have no power.

Next access the ignition switch connector and check there at the brown in crank. If you have power there on the dash harness side of the connector then the trouble just about has to be in the bulkhead connector

THIS IS ONE WIRE. This IS the dictionary definition of "electrical 101"
 
My Challenger was doing the same thing. It would crank for ever and when I let off the key, it would fire. I tested the brown "start" wire and I had power at the coil. After that test, I tried starting the car again and if fired right off.

Fast forward a few weeks and I was in the middle of a car cruise. The car just shut off. This time, it fired right back up while cranking, but as soon as I let off the key, it died. After sitting awhile it fired right back up and ran. On a hunch, I got out and wiggled the connector at the base of the steering column. The engine started running rough. I wiggled it some more and the engine shut off.

The first issue I was having was due to the brown wire in that connector not making contact. When I stabbed it with a test light, it made contact again. Then, a few weeks later, the blue wire in the connector lost contact and the car died while driving.

Check your lower steering column connector and make sure all the wires are tight.
 
ok.....seems all arrows are pointing at connectors....... firewall and switch connector.the mag pickup is new and recently installed and did the same thing with the one I took out so im now after reading going to look at the brownwire connection all the way thru and ALL connector connections...thanks for all of your input ill be back after I investigate...j
 
The connectors on the ballast resistor are suspect also.
It is also possible that during starter operation the majority of current is being used leaving less than enough to power the ignition. The ignition module needs a full 12 volts at all times to function properly. Even those 5 pin modules that operate on less than 12 need to first have 12 volts supplied to one side of the resistor so the correct voltage comes from the other side.
The wire that carries 12 volts to the starter is huge while the wire that supplies 12 volts to the rest of the car is undersized, especially where aftermarket additions are present.
Those later model wiring harnesses had more points of failure than most. I've found melted connections at rear of right valve cover, base of steering column, and behind the left kick panel.
 
This same problem for me turned out to be a bad pick up coil as well, so either proper voltage not getting to p.u.coil or its bad. To replicate, take a running mopar w/elect ign and unhook the p.u.coil wires, crank and let off key. Good luck
 
The lastest ....today I spent a couple hours on wiring issues...I did the "electrical 101'thing today.after I watched the niniers get their butts handed to em.i checked for power at the switch connector. red and brown wire both had power...the red had 12 +volts coming in and the brown had 5.09 volts in run position.. ..at thee outside of the firewall conn there was 5.09 volts at the brown..checked the + at coil and it had 5 volts also...checked the 4 prong resistor and there was 5.0 volts there also...I did some continuity and resistance checking also..i didn't find any wires that were remarkable..except one..very difficult to tell ,but checking the Ign module wire plug one wire caught me ..the yellow and black stripe wire right at the connectorI thot [bit difficult to tell] or I think has a break...I couldn't tell definitively with an ohm meter so I used my meter as a checker with sound..it beeped as I moved it[connector] around it sometimes would stop making beep and as I moved it around it would be very loud and sometimes hardly noticeable ..and sometimes very light sound...the other thing,the schematic shows a four position resistor with a blue jumper on the end that has an open slot for the wire connector to slide into...my schematic says right end brown wire on top..mine is actually brown on bottom..drk green red on bottom mine is actually on top..the same on other end..they are reversed according to schematic...now I checked the resistor...1,5 ohms bottom and 5.8 at the top...is this right or wrong...and which ...thanks for the help ..j
 
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highflyer said:
So iv had time to get onto the wiring the last few days,,,brown wire connects at the switch connector same volt both sides..5.3..firewall connector both sides 5.3...at the ballast resistor 5.3 at the coil 5.1..blue wires at the both connectors ..11.8 resistor... 11.8 ign mod plug same...my resistor is 4 prong with the 1.4 value on the bottom and the 6.0 value at the top..the brown wire is plugged in at the bottom down stream from the blue..the schenmatic shows the brown wire p[lugged in at the top yet mine is plugged at thwe bottom...ideas and help...please.still havnt figured why it wont start whiule cranking but trys while you let go of the switch..the other thing is the blue wire has 10.3 at the alt but if you disconnect it and recheck,it has 12.3..j
Click to expand...
 
Without knowing "under what conditions" these measurements are made, or what you are looking for, at least some of it is meaningless

The brown wire WILL LIKELY have a low value (you posted 5.3) with key on/ engine off. This is because you are not reading the brown wire, really you are reading the coil+ terminal voltage.

This circuit path is..........

Battery........harness........ign switch.........bulkhead..........coil resistor..........coil + ................. through the coil, and the coil is grounded out by the ECU causing the coil to DRAW CURRENT

So what you are measuring in this manner is the coil "loading down" the resistor, perfectly
normal

It is simply that the brown is hooked to the coil + just as your probe is

One thing you want to check, is "what is" coil + voltage with the key in "start?" This should be close to battery voltage, and in no case below 10.5V

++++++++++++++++++++++++++++++++++++++++

11.8..... this sounds like ignition "run" voltage coming out of the bulkhead and feeding the coil resistor, the ECU, the alternator field, and the voltage regulator.

This is LOW. Either the battery is low, or you have some voltage drop in that circuit.

A better way of checking this is to post battery voltage so you know whether the battery is low or not.

Then measure voltage drop directly by sticking one probe on the switch side of the ballast and the other probe on the battery positive post. This will give you the voltage drop (loss) from the battery........through the harness and connectors ...........and to the ballast 'high side.'

++++++++++++++++++++++++++++++++++++

When you disconnect the blue field wire you are relieving the ignition run line of some current, because the alternator field and the regulator are drawing current with key in "run." The 12.3, by the way, indicates the battery is probably "up" and that you DO have a harness voltage drop problem

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When hooking up the resistor, you need to examine the resistor for the "U" shaped cutout in the ceramic. This "indexes" the resistor so that you can tell which half is which. This is actually two resistors in one ceramic block, and they are different resistances.

See this diagram:

See the upside down "U" in the resistor block at the bottom? In this photo, the right side of the resistor supplies the coil, the left side supplies the 5th pin of the ECU. The right side of the resistor is the SAME as the 2 pin resistor

Ignition_System_5pin.jpg


Now look at this diagram:

All they have done here, for a "4 pin" ECU is to eliminate the left side of the resistor that was in the drawing above

Ignition_System_4pin.jpg


You cannot always tell a 4 pin ECU from a 5, as many replacement 4 pin boxes actually have 5 physical pins. It's just that it's not connected to anything.

A 5 pin ECU must use a 4 pin resistor

A 4 pin ECU CAN use EITHER a 2 or 4 pin resistor, it's simply that the second resistor does nothing and is connected to nothing with a 4 pin box.
 
Make sure the connectors on the flux capacitor are tight. And clean.
 
I agree with RustyRatRod, the "still having light pulse ...dim... on the headlights", that has to be the flux capacitor connectors.
 
Not much more I can add. Pulsing and/or dim headlights screams low system voltage throughout the car and not limited to the ignition alone. All blue wires need to have 12 volts. This includes not only ignition but, voltage regulator, alt' field, etc..
I suspect your orange box module has only 4 pins so one half of the ballast resistor isn't being used. If the keys on those connectors are still present so they can only be properly placed on the resistor... upside down from printed schematic would be as simple as loosen the bolt in center of resistor and rotate it 180 degrees.
If the keys are broken out of the connectors and you suspect they are placed wrong... switch them around.
If it was mine, I would confirm the 4 pin module, then probably replace the dual resistor with a single resistor but... only after I found and fixed the low system voltage problem.
 
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