A picture is worth a thousand words or close to it anywayā¦ Thanksā¦
I am going to assume that you have the vacuum advance hooked up and did not lock the dist outā¦ I think I can see vacuum going to itā¦
So the MSD does not run through any ballast resistor, very basic straight forward wiringā¦
Red to coil + (and 12V keyed)
Orange to coil -
Black to engine ground and Gray to tackā¦
But as Tester pointed out, looks like your accelerator pump is leakingā¦
So to eliminate the ignition switch being bad (EDIT: and bypassed the ballast resistor wire), with the key off (on the floor) you can run a B+ wire to the coil + and jump the starter solenoid and see if it starts any better once the choke is setā¦ To turn engine off, simply remove the B+ going to the coil +ā¦ Obviously keep all body parts and loose wiring away from anything rotating around the front of the engine since it is a front mount dist and coilā¦
Quig:
Hereās one thing you can check.
The Holley troubleshooting page for this distributor (at [1]) states:
To check the Ready-to-Run Distributor, confirm that there are 12 volts on the Red wire when the key is On and while cranking. It is important to confirm 12-volts during cranking as many older vehicles may have resistor wiring or ballast resistors inline which could affect the voltage needed to fire the ignition.
I would make sure that whatever voltage is available at the battery during cranking (likely 12v), that you have that same voltage on the Red wire. If youāre below that (like 9v or so), you probably havenāt bypassed your ballast resistor wire correctly, or something isnāt wired correctly.
[1] MSD Tech: Distributor Troubleshooting - Holley Motor Life
The stain near the accelerator pump is dry.
The battery is 12.4V before cranking.
9.5V during cranking.
There is no ballast resiator in this configuration.
Informative photo above, thanks for posting. I notice the rubber vacuum port cover (unused apparently in this configuration) near the accel pump appears to have a small tear in it. The stain around the accel pump (mentioned above) seems suspicious, given thereās no gasoline coming out of that port. Resolving why seems like the number one priority. Similar to figuring out why a kidās water pistol isnāt working. Possibilities are (1) No water in the gun; (2) piston seal is leaking; (3) nozzle or tubing to it clogged.
12.4 volts is a little low for a fully charged battery, but probably not related to your stubborn start problem. 9.5 v at the battery posts during cranking however does seem a little too low. Where did you probe to make those voltage measurements? Directly on the battery posts?
Just curious about your MSD distributor ā¦ what is the purpose of that circular lid with the small holes on top? The part with the āMSDā written on it?
Hi Quig:
Was that ā9.5v during crankingā taken at the battery or at the Red wire on the MSD distributor?
The reading must be taken during cranking at the Red wire at the distributor. I had asked for both readings, as the reading at the battery during cranking is a reference that can help us better help you.
Iām trying to determine if your ballast resister wire is mis-routed and not being bypassed during cranking. If that happens, thatās a problem. (And very likely the problem youāre chasing.)
9.4V measured at the battery
The MSD cap prevents a plug wire from accidentally coming off. However i think it is just a place for branding.
Quig:
No one is talking about voltage readings at the plug wires.
Look at the picture on the MSD site:
MSD 8352 Ford 289/302 Ready-To-Run Distributor
The voltage during cranking needs to be taken from the Red wire that feeds the distributor. If itās not in the range of 9.4v, then itās likely your ballast resistor wire is not being bypassed during cranking. Not bypassing the resistor wire during cranking would definitely cause your problem.
Please read the voltage at the red wire (that feeds the distributor) during cranking.
The battery voltage is too low, should be at least 10 volts and ideally 10.5 volts or higher.
Given the normal resistance in the ignition wiring, the voltage delivered to the distributer will be less than battery voltage and your battery voltage is too low.
Itās more for higher vibration engines that are using solid engine mounts (no rubber) or motor plates, big rowdy cams w/tight LSAās etc etc causes a lot of vibration that can/could cause the wires to come loose from the cap which could be badā¦
The red wire Joe is referring to is the coil+ wire and needs to be checked at the ignition coil+ā¦
An MSD Ready-to-Run Distributor requires a solid 12 volts to perform at its full potential.
9.4V is NOT 12 Vā¦
The voltage at the red wire is much lower than 12V. Between 6 and 7V. Since the battery voltage during cranking is only 9.5V this voltage will never be 12V. I talked to a tech support guy at MSD(Holley) yesterday. He suggested the battery. Maybe that the issue but the battery was purchased in April '23. That would be disappointing.
Quig:
During cranking, if your battery voltage is 9.5v and the voltage at the Red wire is between 6-7v, it means you have a ballast resistor wire that is not being bypassed, or corrosion in the circuit between the battery and the red wire feeding the MSD.
During cranking, the āstarter solenoidā up on the firewall will make a direct connection between the āSā terminal on the solenoid and the +screw on the coil. This makes full battery voltage available to the ignition circuit during cranking, (even though that voltage is lower due to the amps drawn by the starter). I recall that voltage used to be in the 9-10v range. All this happens when the ignition switch is in the āstartā position.
Once the car starts and you let your key rest in the ārunā position, the āstarter solenoidā up on the firewall is no longer engaged. The ignition coil now gets its voltage from a path that goes through the ballast resistor wire, (which drops the normal runtime voltage at the coil from the 13v battery voltage to a 9-10v range).
Ignition circuits on cars of those decades were designed to run on 9-10v, because thatās the only voltage that was available during cranking.
However, after cranking is done and the system voltage rises into the 13v range, there needed to be a way to keep the ignition voltage suppressed to the 9-10v range. Thatās where the ballast resistor wire comes in. Once you let your key go from the āstartā to the ārunā position, the circuit that feeds the coil now includes the ballast resistor wire, which correctly drops the voltage to the coil.
Ignition systems with points required a ballast resistor, otherwise the life of the coil and points would be shortened. I understood that many electronic distributors did not need them, but I canāt vouch for that.
In your reply, when you stated that during cranking your battery voltage was 9.5v and the āred wireā voltage was lower, in the 6-7v range, it could mean the following:
- The ballast resistor wire is incorrectly in the circuit during cranking.
- Or there are corroded connections in the circuit during cranking between your battery and your ignition coil (red wire).
To triage #2 above, I would start testing the voltage during cranking at various points along that circuit. You want to find the point along the circuit where full available battery voltage (during cranking) drops. If you find a low 6-7v reading on the āSā terminal coming out of the starter solenoid, itās possible that the copper plate inside of that has gotten corroded over the years. Even though we used to take those apart and clean those disks, if thatās where your voltage drop is happening, it may be easier to just buy a new solenoid.
Triaging #1 above will be a little trickier. (First, you should check with MSD if their distributor needs a ballast resistor.) You would need to verify that voltage to the coid red wire is not just coming through a circuit that includes the ballast resistor wire.
If new parts never failed there would be no need for warrantyāsā¦ Yes your new battery could be junkā¦
With all due respect I have a feeling you are letting your engineering back ground over think all thisā¦ Go back to the basics (K.I.S.S. it)ā¦ If your battery voltage is to low then test it and replace if it fails, then check voltage again to make sure it is not dropping much/very little, then check your voltage at the coil for B+ not reduced voltageā¦ This should have been diagnosed in short amount of time, I mean it is a 1966 vehicle with a little upgrade, itās not the space shuttleā¦
Again, it only takes a few minutes to straight wire the vehicle to start it as I explained earlier in a post, that bypasses the entire vehicle wiring harnessā¦
If the vehicle runs great once started, then you should have good compression, the ONLY other things that will keep it from starting is the ignition system or fuel systemā¦
I think my MSD stops working at about 10.5 voltsā¦
You have been told multiple times your voltage is too lowā¦
But if you just want to drag this out, then have funā¦ lol
BTW If you donāt know what KISS it means, someone or myself will be glad to explain it, and my wife has told me this many times when I have been over thinking an issueā¦ lol
NO it does notā¦ I have posted the link a few times as well as you have, for wiring up a MSD ready to run distā¦
Why is everyone here so focused on the red wire when @quig_at_home_187298 hasnāt even checked to see if there is a spark during the start cycle? You all are just wasting your time until he tests for a spark. If no spark, then we can concentrate on why there is no spark. But if there is a spark, then we can start looking elsewhere.
Basic troubleshooting back in the 60ās. fuel, spark, timing and compression in that order. Didnāt need computers to get us lost in the troubleshooting tree.
Because Quig stated that during cranking his voltage at the distributor (red wire) was 2.5 to 3.5v lower than the available 9.5v at the battery. That alone could cause a no-spark situation.