Hello all,
I have a couple issues, I replaced speedo cable, not a fun job on a big block 4 speed car, I drove around the block, the speedo is now working but the needle bounces around, does anyone know what causes this?
I also went to start the car, the starter drive engaged and was cranking the engine over and would not stop cranking even after I turned the ignition off, had to jump out of the car and pull the battery cable. I tapped on the solenoid a couple of times and the car started with no issues, should I just replace the solenoid ?
Yes, replace the solenoid. Your speedo cable bounces due to lack of lubrication or a bend sharp enough to bind it. Most people use lithium grease in the cable housing. To do this, you need to remove the cable from the car, remove the actual cable for the sheath, and lubricate it well, and then re-install in in its sheath. I hope I got this right…
The solenoid sticking is indicative of excessive resistance in the starter circuit - usually a missing or poor connection to ground. It causes the contacts to weld internally. Clean the ground cable connections to shiny bare metal. Ensure your cylinder head to firewall ground strap is also connected to clean bare metal and is not missing. Make sure the solenoid is well grounded to the fender apron.
Also, if you know someone with a DC amp probe, check how much amps the battery when cranking. That will eliminate a lot of guessing. Starters can take a lot of crap, as evidenced by my '72’s original one that still functions properly today. Proper power system distribution should isolate the starter. Most solenoids on the market are only good for 30-40 amps DC. If you buy a Cole Hersee 100 amp, it will be a plug and play answer.
Even 100A rating on the solenoid would fall way short. Our starters are rated at 150-200A under normal load, and 460-670A at max load. That’s why batteries are typically rated at over 500 cold cranking amps.
Thanks for the advice, the bolt for the ground strap to the firewall was stripped, and the other end to the back of the cylinder head needed sanding down to bare metal. Went to the Ford dealer for a new solenoid $89.00 Wow did not see that coming and made sure the solenoid was well grounded.
Thanks so much!!
I pulled the speedo cable, greased the inner cable and installed it back on the car, did not notice any kinks in the cable, tested the speedo while still on jack stands, the needle bounces a little at low speed and smooths out at higher speeds.
Thanks for the advice!!
Price shopping is part of the hobby for me as I have five classics that I maintain or am restoring. You can get genuine Motorcraft solenoids from Rock Auto and save yourself both the trip and a bunch of cash. I typically use the Standard SS581 solenoids on vehicles that aren’t mine. For my cars, I dig a Made in the USA one out of my used pile.
