|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
12-11-2020, 07:04 PM | #1 |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Could a bad tachometer make a Model A hard to start?
I’m still learning about the Model A ignition system (and tachometers, for that matter), and I’m wondering if a bad tachometer could make a Model A hard to start. Here is some background information.
Around the beginning of November, I noticed that my tachometer (https://www.westach.com/product-page/2ct32-6v), purchased new in May of 2020, was acting flakey from time to time. (From May to October, the tachometer worked fine.) While idling at a stop light, sometimes the needle would “float” high, but there was no corresponding change in the engine sound, and then the needle would eventually drift back to 500-700 RPM or so, again without any change in the engine sound, meaning that the RPM sounded constant, but the tachometer erroneously indicated a change in RPM. Also, while driving at what was likely to be 1500 to 1800 RPM, the needle would sometimes waft up to 2200 to 2500 RPM, with no perceptible change in the engine sound. Apparently, the tachometer sometimes has a mind of its own and displays whatever it wants to display. The unit appears to be under warranty; so, I need to call about it. However, I’m curious. For the last couple of weeks, the car has been uncharacteristically hard to start. (https://www.fordbarn.com/forum/showthread.php?t=289945) I’ve jumpered the junction box posts together to take the ammeter out of the equation as a potential problem. I’ve tried a number of different coils (two oil filled coils and one Ford script coil) and two condensers. I’ve thought I had the problem solved a number of times, but the car would continually “backslide” into hard starting over the course of a couple of days. I have observed the following while working through this issue.
Yesterday, I installed a Pertronix 40111 epoxy coil (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1), and the car began to start reliably again (hot and cold), even with the tachometer connected to both sides of the coil. Installing the Pertronix coil was the final change I made. So, it's higher output appears to be allowing the engine to start reliably again. So, I’m wondering if a bad tachometer could make a Model A hard to start. Could the tachometer be robbing the other coils of enough of their power so that the points do not get enough spark to fire the engine? |
12-11-2020, 10:14 PM | #2 |
Senior Member
Join Date: May 2010
Location: Portland OR
Posts: 6,340
|
Re: Could a bad tachometer make a Model A hard to start?
With all this missing around, did you consider checking the Battery? Does not matter if new or not, still could be bad. If battery load test good, then check all the grounds. Set the points at .020-.021. If the car is still positive ground, are you connecting the leads to the correct terminals? How many volts are you getting to the points cold, if 6 volts, that is what the cold reading should be.
__________________
I know the voices aren't real but damn they have some good ideas! |
Sponsored Links (Register now to hide all advertisements) |
|
12-11-2020, 10:29 PM | #3 |
Senior Member
Join Date: Jun 2017
Location: Walla Walla, WA
Posts: 1,045
|
Re: Could a bad tachometer make a Model A hard to start?
Unless it's defective and shorting stuff out, then I really doubt it. Disconnect it and see if it helps. I think your issue lies elsewhere. Colder weather will make it harder, and require a little more choke on a cold start than summer.
|
12-11-2020, 11:00 PM | #4 | |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
Quote:
I keep the battery on a trickle charger, so the battery has good charge (6.3 volts or so, according to my test meter) every time I try the starter. The starter turns freely when engaged. I can try setting the points wider to .020-.021, maybe tomorrow. The car is positive ground. The leads are connected to the correct terminals. With the points open, the movable arm gets 6.3 volts. Sent from my iPhone using Tapatalk |
|
12-11-2020, 11:03 PM | #5 | |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
Quote:
It’s disconnected from the Pertronix coil at the moment. (It didn’t seem to make any difference with the tachometer connected or not with the Pertronix coil. I didn’t think to question the tachometer until after I installed the Pertronix coil.) I was thinking about putting one of the other coils back in the car with the tachometer disconnected to see if it made any difference. Sent from my iPhone using Tapatalk |
|
12-11-2020, 11:06 PM | #6 |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
|
12-12-2020, 01:21 AM | #7 |
Senior Member
Join Date: May 2010
Location: Portland OR
Posts: 6,340
|
Re: Could a bad tachometer make a Model A hard to start?
Yes because it increases the dwell time.
__________________
I know the voices aren't real but damn they have some good ideas! Last edited by redmodelt; 12-13-2020 at 09:41 AM. Reason: Made correction. Removed part of statement. |
12-12-2020, 07:48 AM | #8 | |
Senior Member
Join Date: Jun 2014
Location: Land of Lincoln
Posts: 3,127
|
Re: Could a bad tachometer make a Model A hard to start?
Quote:
__________________
Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done |
|
12-12-2020, 08:07 AM | #9 |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
|
12-12-2020, 08:09 AM | #10 | |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
Quote:
I recently checked the battery. The water level is good. I recently cleaned the points (several times). I plan to try widening the gap. Sent from my iPhone using Tapatalk |
|
12-13-2020, 02:02 AM | #11 |
Senior Member
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 2,354
|
Re: Could a bad tachometer make a Model A hard to start?
Dwell is the time the coil is energized and saturating, meaning the points are closed. The reason the spark is “hotter” with a wider gap, is because the coil is putting out more voltage(up to its maximum design). If the gap is too wide, you’ll over work the coil and it will fail.
|
12-13-2020, 08:34 AM | #12 | |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
Quote:
The higher output from the new Pertronix coil “fixed” the hard starting for the moment, and my wife and I were out in the car yesterday because it turned out to be a warm day. The car has fired up on first crank multiple times all day yesterday and the day before on the Pertronix coil. I plan to put one of the other coils back in the car and adjust the points wider to see if that makes a difference with either of those coils. I'd like to determine what caused the issue in the first place. |
|
12-21-2020, 04:55 AM | #13 | |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Could a bad tachometer make a Model A hard to start?
Quote:
Sent from my iPhone using Tapatalk Last edited by shew01; 12-21-2020 at 05:15 AM. |
|
12-25-2020, 12:12 PM | #14 |
Senior Member
Join Date: Jun 2010
Location: (Old)Shasta (Redding) CA
Posts: 385
|
Re: Could a bad tachometer make a Model A hard to start?
I would use a battery maintainer in place of a charger, Less apt to damage the battery
__________________
Connoisseur of Rust |
12-25-2020, 12:30 PM | #15 |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
I received the repaired tachometer from Pete Cornelius yesterday. (Wow, that was a quick turnaround. Shipping was probably 3 days each way. So, he must have repaired it on the same day that he received it. He seems to be a great guy, and he was very helpful on the phone.)
I plan to reinstall the tachometer as soon as I can. The car has been starting consistently on the first crank without the tachometer installed. Sent from my iPhone using Tapatalk Last edited by shew01; 12-29-2020 at 07:30 PM. |
12-25-2020, 12:32 PM | #16 |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
|
12-26-2020, 07:26 PM | #17 |
Senior Member
Join Date: Sep 2016
Location: Roanoke, VA USA
Posts: 1,908
|
Re: Could a bad tachometer make a Model A hard to start?
I just wanted to report back on this issue.
I got the repaired tachometer installed today. The car starts on first crank with it connected now. I’m now using the same coil and condenser that I was installed prior to starting becoming an issue. I’m glad to put this issue to bed. Thanks, everyone, for your feedback. Sent from my iPhone using Tapatalk |
|
|
Sponsored Links (Register now to hide all advertisements) |
|