Hot starting issues

-
Joel Chapman

Joel Chapman

Well-Known Member
Joined
Jul 28, 2019
Messages
286
Reaction score
42
Location
Mountain Home, ID/ Hughson, CA
So I have a 71 Dodge Dart with a 360 and mopar electronic ignition conversion kit. After I installed the headers I have been having issues starting the car when it has any sort of temperature left in it from driving where I was going. I’ve swapped the coil and ballast resistor today and I’m still getting no spark when the i try and start the car but get a spark when I turn the key back to what I assume is the accessory position (the last position before it locks up and you can remove the key). I’m getting fuel to the carb and the car starts right up first thing in the morning, just not when it has anything close to operating temp left on the gauge. What am I missing? Any help would be greatly appreciated!
 
The key circuit has two ignition power outputs. With key in the "run" position the "run" or IGN1 contact feeds power out through the bulkhead, (normally dark blue) to the VR, to the alternator field on 70/ later, electric choke if used, and some smog doo dads on later models AND THE ballast resistor. THIS POWER GOES COLD IN START position

In "start" the bypass IGN2 circuit (normally brown) is now active as is the (normally yellow) "start" wire. The brown goes to the coil+ side of the ballast resistor, and is the ONLY power to the ignition during "start." The box gets power during this time "backfeeding" through the coil resistor to the ECU box.

Hook a light or preferably a meter to the coil + and ground. Turn key to run. You should have somewhere between 6--10V because of the drop through the resistor. Now crank the engine, and while doing so, read the meter, and you should now have "same voltage as battery" at coil + because the brown should now be feeding "full battery" power to the coil

If not, check at the ignition switch connector at the column, at the brown and blue through the bulkhead connector.
 
as 67 said and also the 'KITS' are notorious for bad orange ecu's and are not USA made. Most are authorised MP. and it can also be a pickup in the coil. They both get weird with heat and fine when cool.
 
halifaxhops said:
as 67 said and also the 'KITS' are notorious for bad orange ecu's and are not USA made. Most are authorised MP. and it can also be a pickup in the coil. They both get weird with heat and fine when cool.
Click to expand...
It’s not even the original orange ecu from the kit. I’m running the autozone box right now. The only reason I would say it shouldn’t be the coil is I just put a new one on yesterday. Moved it a little bit further away from the valve cover even. I’m just stumped as to why it’s only when the car is hot that I’m having issues.
 
Joel Chapman said:
It’s not even the original orange ecu from the kit. I’m running the autozone box right now. The only reason I would say it shouldn’t be the coil is I just put a new one on yesterday. Moved it a little bit further away from the valve cover even. I’m just stumped as to why it’s only when the car is hot that I’m having issues.
Click to expand...
Really sounds like one or the other, they both act that way when they fail.
 
67Dart273 said:
The key circuit has two ignition power outputs. With key in the "run" position the "run" or IGN1 contact feeds power out through the bulkhead, (normally dark blue) to the VR, to the alternator field on 70/ later, electric choke if used, and some smog doo dads on later models AND THE ballast resistor. THIS POWER GOES COLD IN START position

In "start" the bypass IGN2 circuit (normally brown) is now active as is the (normally yellow) "start" wire. The brown goes to the coil+ side of the ballast resistor, and is the ONLY power to the ignition during "start." The box gets power during this time "backfeeding" through the coil resistor to the ECU box.

Hook a light or preferably a meter to the coil + and ground. Turn key to run. You should have somewhere between 6--10V because of the drop through the resistor. Now crank the engine, and while doing so, read the meter, and you should now have "same voltage as battery" at coil + because the brown should now be feeding "full battery" power to the coil

If not, check at the ignition switch connector at the column, at the brown and blue through the bulkhead connector.
Click to expand...
I found this at the connector from the steering column. If I am reading the wire diagram right I believe it is my wire for ign1. Any ideas what could cause the metal connector to seep into the plastic?

A89CD79B-984C-4EF4-9B72-F293A3A6C8E0.jpeg


E92EBBD8-105B-4BF7-9EBD-DA5765B0BEE2.jpeg
 
My guess is bad connection causing heat. That looks scary. Hope your Battery is disconnected. Hopefully you can cut them back and solder them correctly. There was a thread where someone found a plug that worked out well for a replacement.
 
Kendog 170 said:
My guess is bad connection causing heat. That looks scary. Hope your Battery is disconnected. Hopefully you can cut them back and solder them correctly. There was a thread where someone found a plug that worked out well for a replacement.
Click to expand...
From what I can see the wire about the cuts are fine. So I should be able to get in there and solder them up right. Just curious if this is all from just the wire going bad and then been fixed poorly or if I need to be looking for a big problem some where in the circuit.
 
Joel Chapman said:
when I turn the key back to what I assume is the accessory position (the last position before it locks up and you can remove the key).
Click to expand...
That's run. Accessory is on the other side of the locked position.
upload_2022-7-20_9-6-54.png

upload_2022-7-20_9-7-18.png

1975 Plymouth Valiant Operators Manual

Joel Chapman said:
I found this at the connector from the steering column. If I am reading the wire diagram right I believe it is my wire for ign1. Any ideas what could cause the metal connector to seep into the plastic?
Click to expand...
Heat.
According to the FSM, yes you read the diagram correctly, J2 wires are Ignition 1 which is Run.
The one side should be 16 ga dark blue with a stripe and the switch side has no stripe.
upload_2022-7-20_9-18-49.png


Kendog 170 said:
Maybe this can help ?
Repop steering column electrical connector. | For A Bodies Only Mopar Forum
Click to expand...
Looks like they were throwing darts in that thread, but yea there are some threads about the steering column connectors and terminals.
Try scrolling through this thread for those molex-like bullet terminals.
Sources for Chrysler type wire terminals
Its critical the barb's hold ther metal terminal in the connector or the terminals will back out when the two halves are assembled.

Since it starts when cold, it seems less likely to be cross wire issue but maybe a loose or poor connection in the J3 wires Ignition 2 (Start).
Heat issues will be from drawing lots of current. Everything that requires the key to be on or in accessory draws power through the J1 wire (heavy red) going into the key switch.
The Run circuit should not draw a lot of current. But if the terminals are not will connected that can cause heat.
Possible causes of excess current could have been a short or high draw in the alternator field circuit, accidental grounding of the run circuit, aftermarket items added to the run circuit.

In 1971, at least with the standard Valiant cluster, the Gage IVR and warning lights also get power from J2 (run) circuit. The diamond represents a factory splice.
upload_2022-7-9_14-4-15-png.png
 
Mattax said:
Since it starts when cold, it seems less likely to be cross wire issue but maybe a loose or poor connection in the J3 wires Ignition 2 (Start).
Click to expand...
If its sparking when the key is released from start, then check J3 connections and hte key switch itself.
You check for major faults using resistance or continuity. One probe connected to the feed into the key switch (battery disconnected). and the other probe at J3 circuit.
upload_2022-7-20_9-42-49.png
 
Mattax said:
If its sparking when the key is released from start, then check J3 connections and hte key switch itself.
You check for major faults using resistance or continuity. One probe connected to the feed into the key switch (battery disconnected). and the other probe at J3 circuit.
View attachment 1715958478
Click to expand...
J3 connection is the yellow wire at the end of the connector correct?
 
When your ECU sends ONE spark during the shut-down, this proves that your entire ignition system is working; except the magnetic trigger, you have to test that separately.

Since you have already stated that your system is doing this, when hot, you can safely assume that your coil, ECU, ballast, and ignition switch are all working properly.
So to me this is an easy diagnoses; the next time it craps out, pull the coil wire out of the DISTRIBUTOR and near-ground it about .25 inch . Then crank the engine. If everything is working right, there will be a stream of sparks issuing from the wire. and you can move on.
If no spark-stream is visible, check the the case-ground of your ECU. If that is good, AND your ECU still passes the ONE-spark test at shut-down, AND your Ballast resistor is known to be good, then go after the pick-up and or reluctor-gap.
In my experience, the reluctor gap works from ZERO gap to .030, but the spec is .008 to .011.
The pick-up has a resistance spec of something like 300 to 400 ohms depending on it's temperature, but I have measured good working ones as high as 900 ohms. And I have measured non-working ones at 350 ohms.
My pick-up test is this;
I pull the still-connected D out of the engine, and with the Ignition in "run", I spin the driveshaft. A stream of sparks should issue from the near-grounded coil wire.
The thing with the pick-up is this;
the wires are multi-stranded something like 11 of them each, and the constant flexing of the reluctor-plate by the Vacuum advance tends to break them over time. Even just one connecting wire will still measure a Correct resistance..... but that one wire may not provide enough signal for the ECU. So I go to the manual-test as above.
Besides, it's so much fun to spin that shaft and see the spark-stream..... lol.
 
Last edited:
But my guess is that your problem is gonna end up being a fuel issue.
Usually a hot-start issue can be traced to the engine being rich..... and your fine cold-start sorta points to that..... but we don't know a thing about how your choke is set.
But since you say your carb has fuel, it could just as easily be lean.
Next time she's hot, before you shut it down, increase the idle speed to ~1000/1200 with the speed-screw and stall it out. How does it hot-start now?

My guess is that your tuner gave your engine too much idle-timing, which caused the idle-speed to be too high, and so he closed the throttle, which partially shut off the transfers, which then go lean at idle. To get the idle fuel back, he opened the mixture screws. So then it idles ok. But with the transfers as good as dried up at idle, she won't start. That's a guess.
To get your transfers working again, you will have to take the carb off and reset the speed screw such that the exposure underneath the blades is about square. Then reset the mixture screws to in the middle of their adjustment range. With a Holley this is about 1/2 to 3/4 turn out. All others are about 2.0/2.5 turns out . If your idle-speed ends up being too high, you will need to retard the timing. After this, it should, if the wet fuel-level is correct, jump to life.
BTW
With stock-compression and cam, and the factory-type distributor; it is impossible to give your engine the cranking and idle-timing it wants, and still have the power-timing not get her into detonation ....... so I wouldn't even try. Some to most SBMs will like idle-timing as high as 30 or more degrees. The only way to get this is to use the Vacuum advance running full-time on manifold vacuum. But with a stock-type engine, she is almost sure to rattle upon throttle tip in. If you set it this way, the only way to slow the engine down at idle, is with the speed screw, which shuts off the transfers. So then you get a big hesitation or stumble every time you go from idle to off-idle, as the transfers switch from passing air, to pulling up fuel. The transfers are your primary low-speed fuel supply, so they gotta be working. The mixture screws are just trimmers, and used mostly just at idle. If your "trimmers" are rich, she will be a pig on gas and sluggish at tip-in. and she often starts to give hot-idle issues.
Don't underestimate the wet fuel-level which not only has to be correct, but it also has to be consistently so. If you have a solid-lifter cam, the lash will make a big difference too.
 
AJ/FormS said:
But my guess is that your problem is gonna end up being a fuel issue.
Usually a hot-start issue can be traced to the engine being rich..... and your fine cold-start sorta points to that..... but we don't know a thing about how your choke is set.
But since you say your carb has fuel, it could just as easily be lean.
Next time she's hot, before you shut it down, increase the idle speed to ~1000/1200 with the speed-screw and stall it out. How does it hot-start now?

My guess is that your tuner gave your engine too much idle-timing, which caused the idle-speed to be too high, and so he closed the throttle, which partially shut off the transfers, which then go lean at idle. To get the idle fuel back, he opened the mixture screws. So then it idles ok. But with the transfers as good as dried up at idle, she won't start. That's a guess.
To get your transfers working again, you will have to take the carb off and reset the speed screw such that the exposure underneath the blades is about square. Then reset the mixture screws to in the middle of their adjustment range. With a Holley this is about 1/2 to 3/4 turn out. All others are about 2.0/2.5 turns out . If your idle-speed ends up being too high, you will need to retard the timing. After this, it should, if the wet fuel-level is correct, jump to life.
BTW
With stock-compression and cam, and the factory-type distributor; it is impossible to give your engine the cranking and idle-timing it wants, and still have the power-timing not get her into detonation ....... so I wouldn't even try. Some to most SBMs will like idle-timing as high as 30 or more degrees. The only way to get this is to use the Vacuum advance running full-time on manifold vacuum. But with a stock-type engine, she is almost sure to rattle upon throttle tip in. If you set it this way, the only way to slow the engine down at idle, is with the speed screw, which shuts off the transfers. So then you get a big hesitation or stumble every time you go from idle to off-idle, as the transfers switch from passing air, to pulling up fuel. The transfers are your primary low-speed fuel supply, so they gotta be working. The mixture screws are just trimmers, and used mostly just at idle. If your "trimmers" are rich, she will be a pig on gas and sluggish at tip-in. and she often starts to give hot-idle issues.
Don't underestimate the wet fuel-level which not only has to be correct, but it also has to be consistently so. If you have a solid-lifter cam, the lash will make a big difference too.
Click to expand...
So right now the only tuning was done by me…and the idle mixture screws are all 1/2 way out. That’s what the vacuum gauge wanted to be in the green at idle. She definitely smells rich. So from what I am gathering your saying I would mess with the curb idle speed screw on the throttle? Also if it’s lean why would the spark go away?
 
Last edited:
AJ/FormS said:
But my guess is that your problem is gonna end up being a fuel issue.
Usually a hot-start issue can be traced to the engine being rich..... and your fine cold-start sorta points to that..... but we don't know a thing about how your choke is set.
But since you say your carb has fuel, it could just as easily be lean.
Next time she's hot, before you shut it down, increase the idle speed to ~1000/1200 with the speed-screw and stall it out. How does it hot-start now?

My guess is that your tuner gave your engine too much idle-timing, which caused the idle-speed to be too high, and so he closed the throttle, which partially shut off the transfers, which then go lean at idle. To get the idle fuel back, he opened the mixture screws. So then it idles ok. But with the transfers as good as dried up at idle, she won't start. That's a guess.
To get your transfers working again, you will have to take the carb off and reset the speed screw such that the exposure underneath the blades is about square. Then reset the mixture screws to in the middle of their adjustment range. With a Holley this is about 1/2 to 3/4 turn out. All others are about 2.0/2.5 turns out . If your idle-speed ends up being too high, you will need to retard the timing. After this, it should, if the wet fuel-level is correct, jump to life.
BTW
With stock-compression and cam, and the factory-type distributor; it is impossible to give your engine the cranking and idle-timing it wants, and still have the power-timing not get her into detonation ....... so I wouldn't even try. Some to most SBMs will like idle-timing as high as 30 or more degrees. The only way to get this is to use the Vacuum advance running full-time on manifold vacuum. But with a stock-type engine, she is almost sure to rattle upon throttle tip in. If you set it this way, the only way to slow the engine down at idle, is with the speed screw, which shuts off the transfers. So then you get a big hesitation or stumble every time you go from idle to off-idle, as the transfers switch from passing air, to pulling up fuel. The transfers are your primary low-speed fuel supply, so they gotta be working. The mixture screws are just trimmers, and used mostly just at idle. If your "trimmers" are rich, she will be a pig on gas and sluggish at tip-in. and she often starts to give hot-idle issues.
Don't underestimate the wet fuel-level which not only has to be correct, but it also has to be consistently so. If you have a solid-lifter cam, the lash will make a big difference too.
Click to expand...
Also I have about 10 degree of timing in at idle
 
I can only answer from the information given.
There are only TWO reasons that you can, on a MOPAR, have spark in crank but not in run. The first is the ballast and the second is the ignition switch. The ballast has been replaced and Dell showed you all about the wiring. If you follow his advice, you will no longer have a spark-issue.
My second post#21 is pure speculation on my part, assuming that you don't/didn't/nor ever did have, a spark issue, lol, and based on my experiences.
However, with just 10* of idle-timing and the mixture screws "half-way out" what ever that means..... you should be ok.
My question is this;
If you set the mixture screws with a vacuum gauge, when does it smell rich, lol, and where are you smelling, and when.
As for me, I don't use a vacuum gauge for this...... cuz most of the time it just never lines up to what the book says it should.
But fix your spark first, and then we all can deal with the carb later.
 
Joel Chapman said:
J3 connection is the yellow wire at the end of the connector correct?
Click to expand...
upload_2022-7-22_14-16-9.png

^^^This is a functional schematic.^^^
It shows the relationship between the wires and the components of interest.
These are useful to follow or learn the path electricity flows from the power source to the items needing power.

Chrysler wires are labled on the diagram with a letter and number (and sometimes a segment letter). The first letter indicates function or connection.
A Battery
R Alternator
J Ignition (I is not used probably to avoid confusion with 1 and l)
L Lights
H Horn
G Gages
Q Accessory (Everying not needed to run the engine)

This followed by a - and the SAE wire gage size and a letter code indicating the insulation color. There is a key with the diagrams explaining the color coding.
upload_2022-7-22_14-13-20.png

^^^This is the wiring diagram illustration of the column connector^^^
J3 is a 14 ga wire covered in brown insulation.
It is shown in the 4th position in on the side with the larger terminals. Also the connector is illustrated with some bumps which when compared with the one in hand should correspond.
It's always worth checking the real one to see if it matches the drawing because sometimes the drawing has a mistake and even if not its a good way to understand which half and direction the illustration represents.
 
You must log in or register to reply here.
-

Back
Top