| village grande | -- 08-25-2016 @ 5:21 PM |
|
My question is about the proper amperage I should be getting when reading from the batt. terminal on coil thru my multimeter to the wire coming from the ignition switch that was on the batt. terminal. The engine is a completely stock 8ba, including 6 volt pos. ground and the ignition system with a coil that meets the resistance numbers listed in the ford shop manual. There is no ballast resister required on the 51 ignition. Voltage to the Batt. terminal is 6.2 my amperage reading is 2 at idle and this number goes down below 1 when rpm's increase. I'm told this amperage number should be about 3 and I don't understand why it goes down to below 1 with increased rpm. The engine idles fine but stumbles or misses when pulling under load, seems to be ok at first but gets noticeable as the engine heats up.
|
|
| 40 Coupe | -- 08-26-2016 @ 4:09 AM |
|
As a guess I suspect your not inserting your ammeter in the correct location to read the amperage to the coil. Remove the wires on one side of the ignition coil and place one side of the ammeter on the wires and the other side of the ammeter to the coil where the wires were connected. It does not matter which side of the coil you select. With the distributor points closed, and the car ignition on (not running) you should read about 2.5 to 4 Amps.
|
|
| village grande | -- 08-26-2016 @ 6:42 AM |
|
Thanks for that information I was taking the reading with the engine running. The amp reading now with engine off and key on is 4.6 on both coil posts. The shop manual does call for an amp reading of 5 to 5.5 with engine off and 2.75 to 3.0 with engine running at idle. Should I be concerned with my readings and how would I get them closer to spec? I realize many things could cause the stumble under load but could these readings be the cause? I have a dwell of 27 degrees and have replaced the condenser and points. Carburetor was rebuilt with a new power valve and all plugs look grey, dry and equal, compression is in the 90's in all cylinders. The car starts and runs fine except for this annoying stumble under load. Thanks for your help and advice. Bill
|
|
| carcrazy | -- 08-26-2016 @ 7:23 AM |
|
If your "stumble" occurs during acceleration, your accelerator pump may be to blame. A stumble is caused by too much fuel being delivered while a hesitation is from too little fuel. What are the ambient and coolant temperatures when your stumble is most prevalent? Are you running the stock metal core spark plug wires?
|
|
| village grande | -- 08-26-2016 @ 8:47 AM |
|
I don't think I'm explaining the problem correctly. The problem is not a hesitation on acceleration, it's more of a miss in all gears when your holding a steady speed. The ambient temperature at this time of year in NJ ranges from 80 to 95, and the engine runs at about 180 to 190. Thanks again -Bill
|
|
| village grande | -- 08-26-2016 @ 8:54 AM |
|
Spark plug wires say (Belden EDGE Premium 7mm cable-SAE-13) from NAPA #700171. Installed about 2 years ago, the problem just started about a month ago.
|
|
| TomO | -- 08-26-2016 @ 9:09 AM |
|
A miss at steady speed can be caused by a bad plug, plug wire, fuel delivery or mechanical problem. Try to isolate the miss by running the engine at a speed where the miss occurs and shorting out 1 plug at a time. Each plug shorting should show the same drop in RPM. If you find one that does not cause a drop in speed, pull the wire and check the spark. Weak spark on 1 cylinder could be the cap or the wire. If the spark is good, do a compression check wet and dry. Weak spark on all cylinders could be caused by a bad coil or condenser. Tom
|
|
| carcrazy | -- 08-26-2016 @ 8:08 PM |
|
Since your car misses under load, I suspect that one or more of your resistance core spark plug wires is breaking down after it heats up. You can check the resistance of the suspect wire when it is cold and when it is hot. I have had resistance core wires that checked OK when cold but went to infinite resistance when hot. If you find that the wires have high resistance, the best thing is to replace the entire set with metal core spark plug wires as originally used by Ford. They are available from most of the early Ford vendors.
|
|
| village grande | -- 09-03-2016 @ 5:59 PM |
|
Carcrazy----Ign wires check normal, The installed coil meets shop manual specs (secondary ohms-4100--primary ohms 1.15) The 51 8ba uses no ballast resister. So the way I understand it the voltage to the coil on the 1951 will be the same as battery voltage which is 6.2 volts. With my amp meter connected between the coil input terminal and the disconnected input terminal wire I get a reading of 2 amps with the engine running at idle and the amperage drops to 1 amp as the rpm's increase. Shop manual call's for the engine running at idle for this test. I understand the amperage should be in the 2.75 to 3 amp range. Why would I be getting this low reading and why would the the amperage drop with increased RPM. I'm using a digital multi-meter on 20 amp scale. I don't know if this is the cause of my miss or stumble at cruising speed but I need to at least get this voltage - amperage problem cleared up first. Thanks for any advice--Bill This message was edited by village grande on 9-3-16 @ 6:04 PM
|
|
| pauls39coupe | -- 09-04-2016 @ 9:55 AM |
|
Take your condenser off and throw it as far as you can. Take a trip to the local NAPA store and pick up a new one, I believe a # IH 200 will work, but ask a good counterman.
|
|
| village grande | -- 09-04-2016 @ 6:48 PM |
|
I know the symtoms sound like a condenser problem (and might still be) but I have tried 3 different condenses, the one in there now is a Napa -ECHFA66. From what I'm reading here on the other coil thread, my voltage and amperage at the coil are wrong. I have 6.2 to 7.2 volts (battery voltage) due I guess because of no external ballast resister. The amperage is 2 at idle and goes down to 1 or less with increased RPM. It looks to me like I might need an external ballast resister even though the 51 does not call for one and the coil matches exactly the shop manual spects. Does the low and lowering amperage reading with increased RPM point to a specific problem or is this normal? Thanks for any advice--------Bill
|
|
| 40 Coupe | -- 09-05-2016 @ 4:34 AM |
|
Are the spark plug wires resistive (NAPA #700171)?? If you have an old set of wire core plug wires try them (coil wire also).
|
|
| TomO | -- 09-05-2016 @ 8:01 AM |
|
Your coil has an internal ballast resister and adding an external one, will drop the primary voltage causing a weaker spark. The amperage of the primary circuit,while running, is determined by the coil resistance, coil inductance, condenser capacitance, point resistance, point dwell and the condition of the circuit from the ignition switch to ground. This includes the condenser ground. The time (changed by RPM) that the coil has to build the voltage will also affect the current draw. That said, the amperage is not as important as the voltage developed by the ignition system. You should see around 20,000 volts at idle and it may drop as much as 10,000 volts at higher speeds. If you are getting a weak spark, I would check the grounding circuit of the distributor and engine. Check the value of the condenser (0.21 mfd - 0.25mfd), next and use a coil tester to check the coil off of the car. Tom
|
|
| trjford8 | -- 09-05-2016 @ 1:32 PM |
|
Are you using Champion spark plugs? I've known several people with similar problems and when they changed the plugs to Autolites the problem disappeared.
|
|
| village grande | -- 09-05-2016 @ 4:19 PM |
|
40coupe--plug wires are NAPA 700171 Tomo--strong spark, no problem starting or idling trjerd8--using Autolite 216 plugs car actually runs fine but noticeable miss when cruising at a steady speed. If I hold it in first gear to long it starts to stumble badly. I guess I'm hung up on the coil voltage and amperage because I keep reading on other threads that the voltage should be around 4 and the amperage around 2.75 to 3 --could my readings be different because my coil uses an internal resister? I've been told I need to add a 1.5 external resister to get the voltage down at the coil input terminal. Why would I want a lower voltage at the coil input and would this increase the amperage reading. I guess in the end could any of this be the cause of my miss at a steady speed?
|
|
| TomO | -- 09-06-2016 @ 8:27 AM |
|
The lower voltage reading is for a car that has an external ballast resister. You should see battery voltage at the input of the coil when the engine is not running and around 7 volts when the engine is above idle. Check your condenser for a solid mounting, so it has a good ground. Check the wire from the coil to the points inside the distributor, the insulation may be bad causing a short when the advance mechanism moves the mounting plate for the points. Check the point tension for 17 - 20 ounces to open them. Check the dwell at all rpms, it should not vary. If it does check the distributor bushings. Do a cylinder balance test at 1,000 rpms to find out if it is just one or two cylinders that are not firing all of the time. Tom
|
|
| pauls39coupe | -- 09-06-2016 @ 9:04 AM |
|
Do what Tom says, as most drivability problems are electrically related. However your problem occurring in 1st gear leads me to believe you may have fuel issues. Your float level may be set too low to keep the jets covered, you may have a restriction in the line or the fuel pump may be headed south
|
|
| EFV-8 Club Forum : | https://www.earlyfordv8.org/forum |
| Topic: | https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=10020 |