Thought I'd ask you guys. 74 F100 with 360. Most of the time starter engages normally and engine starts with no problem. But occasionally (getting more frequent) starter will drag (like a weak battery). If i keep trying, all of a sudden it will turn over normal and start right up.

Battery is brand new (last week) and alternator is no more than 8 months old. Both work fine. I don't think it's the starter as there's never any clicking. Starter always engages and turns motor over. It's just that occasionally it drags from (I would guess) lack of current. The starter relay (solenoid?) looks pretty old and cables could be implicated here.

Just wondering what's the best way to test and in order what would you test?

Thanks,
Dave

 

It could be a heavily worn starter, they start to get loosey goosey in the bearings and armature shaft and such and can bind up. If the starter and battery ground cables are original or, even just old, they should be replaced. Try a voltage drop test on the cables to ground one at a time while cranking the engine over. Just a tiny bit of corrosion or resistance will cut the current flow bigtime.

 

While it's possible that the starter could be "dragging" (armature rubbing the field), it's more likely something else as you suspect lack of "current". You could perform the voltage drop test suggested. It would be good to inspect the interior of the starter just to be sure all is well. Sometime worn starter brushes or weak brush springs can cause such a problem. It's a good opportunity to give the starter a "tune-up". It's amazing how a nearly invisible film on a connection can really lower the voltage available. Also molded on wire terminals have been known to create internal voltage drops. If you find that any of the cables need to be replaced, I'd suggest changing to at least one size (gauge) larger. Don't assume that "new" means "good"; while it usually is, I have had new parts that did not perform correctly.

 

Since it's intermittent I first thought a dragging starter. A corroded cable wouldn't be intermittent, though loose connections could be.

 

Agreed that would be the first suspect, a dragging starter. But it costs nothing to check all your bat cable connections to rule them out. But it is most likely a dragging starter. So be prepared to replace that.

 

Another possibility is a loose enough battery cable at the terminal clamp you cannot obvious see or feel that tends to get overlooked, or perhaps a weak ground as some vehicle owners do not upgrade their grounding on these old american rigs - various scenarios like this can also make a starter go intermittent like what is described here and what others have posted also about the starter itself actually being bad and having a mind of its own....

What I have done to all 9 of my old rigs is :

Interlinked together and coated connections with larger 0 or 2 awg ground wires from battery to block, frame, starter housing, trans housing, cowling, volt reg, body and so forth.....got rid of those previous owner battery lead clamp terminals and installed brass ones that you mount the battery cables to, not the pre-crimped to cable kind that tend to lose continuity over time....

That way I will know when a starter is actually bad for sure after confirming cranking power load at battery and if any loose connections to battery or starter are present....Installing at least a 4 gauge cable ground wire (or equivelent ground strap) to the starter mounting bolt and the other end to the frame or sufficient grounding point will do your starter a favor from a stock starter cranking of (raww raww raww) to (nee nee nee nee nee) with the extra grounding sure makes a difference.

Had a new reman starter that only lasted me 3 months earlier this winter in one of my two 70 F250 trucks as it was intermittent working similar to what is described by the OP here, as I swapped a used starter I had onhand that I knew was good and immediately worked flawless and exchanged the 3 month old new problem starter back to the parts store as they had to honor it under warranty with my receipt even though they retested it and could not find anything wrong with it on their end and were hesitant to do so until I requested the manager as she told the staff to honor it as she stated to them I do a lot of business with them and that she had the same problem with the premium starter brand in the past also.

With superior grounding that I installed in all my rigs, I can certainly eliminate bad grounding when diagnosing electrical problems or components, which is why I have much less electrical problems because of it.

 

Clean, insp, replace as needed OEM -grounds and +hot connections. Add grounds like mentioned above. Ditch the built/molded in wire to battery connections for HD put together style. FTE members way of doing it, that looks great. Clean, insp, fire wall mounted starter cylonoid and connections.

 

If possible avoid that style of aftermarket battery terminal like the plague they are nothing but trouble. Ideally, the best route to go is using Mil style battery clamps such as below with crimped and soldered terminal lugs. But just about anything is better than above.

 

Well that is the great thing about this forum, you can get all kinds of free advice. And what works just fine for some, might for others too. And then again it might not, and you can always have/find a better idea and post it on here. Nice HD connectors. Where did you get yours and how much?

Military Battery Terminals - 610825902733


Complete kit, minus the soldering iron and the lighter to heat the heat shrink.
And for the u tubers out there...
All I know for sure it that ones that come from most auto stores that have the wired made into the battery connection can become loose internally and cause some wiring/starting/instruments issues.

And an even better idea.

 

NAPA carries them
https://www.napaonline.com/en/search...h_form-allprod

I would not call the last one a better idea especially on lead-acid batteries I would not touch those unless the wire terminal was loaded with Noalox or the like. They will corrode in time if not protected and you are back in the same boat as the cheap plate clamp ones. The Mil ones with a terminal lug crimped on the cable then soldered and heat shrunk are the best solution.

With lead-acid batteries these connectors are in a corrosive environment so crimping the lug on with a proper die pressed crimp See below pic (Not the point crimp as was shown in the first video) ensures a proper mechanical electrical connection, then soldering the lug to the cable seals the connector to ensure it never ever corrodes internally, then heat shrunk with watertight heat shrink between the lug and cable jacket prevents corrosion between the conductor and insulation. A little terminal grease/Noalox/Kopr shield on the battery post and under the cable lug keeps that connection from corroding and with the use of Mil style battery clamps this is a lifetime install, I have vehicles that were done in the late 70's like this and are still in service on the same bits.

Rember your battery terminals are in a corrosive environment and potentially subject to electrolysis erosion, brass connectors are highly subject to electrolysis erosion as the Zinc eroded out of the brass and they will eventually turn to dust.
The only way to mitigate some this is by using AGM batteries that do not outgas to the same degree as lead-acid batteries or completely slather the connections in a terminal grease.
When I do a repair I want to do it once and never look at or worry about it again.

 

Any bulletproof crimp wire connectors are super reliable as mentioned and shown, however I would disagree on certain aftermarket battery terminals as trouble....

I just personally hate lead terminals as I install the brass ones for the slightly better conductivity, and I never had trouble with the brass terminals coming loose at the cable mounting points either....although I have added stop nuts on the bottom side of the mounting bolts when a terminal clamp had stripped threads (there I admitted to that)....

I also prefer coating all my power cable and ground cable ends with grease or die electric grease on other power connectors or plugs or components so that no corrosion will build up on terminal ends or within the wiring by keeping conductivity sound and in check, -grease coating mounting nuts, bolts and threads stay fresh too....

I still have the same battery cables and terminals on my 70 Thunderbird when I replaced them back in 1985 and never had to clean connectors or cables as they never built any corrosion, just kept them greased....

My days in Southern California didn't have to worry about coating this and that as much as living in the arctic long enough as I seen a lot of neglect without taking extra precautions that lead to problems because of the harsher environments and exposure, as coating terminal cable ends does wonders on preventive measures eliminating wire corrosion problems here in the arctic region.

Installed new 4 gauge power cables and brass terminal (red greased) on my newly second 70 F250 I just purchased back in 2016 :



Added a 2 awg ground cable to starter mounting area on my newly 73 F100 back in 2012 and black greased cable ends, and red greased power end connector on new starter and power cable end as well :



Wire brushed and cleaned new volt reg mounting area and installed additional interlinked 6 gauge ground wire and black greased all mounting areas and 1 awg cable end nearby as volt reg is superior grounded while not relying on that one little factory 16 gauge ground wire itself shown at lower mounting point :



Installed two large gauge cables mounted on frame, one interlinking to starter and other one mounted near volt reg in picture above, black greased all cable ends :


...and a few people that admire any of my old rigs (which ever one I am driving) that look average to mad max poor condition will mention all the marker and tail lighting are so nice and bright, or when they hear me start the vehicle they will ask if I have a hi torq starter in it.

All larger ground cables installed in my rigs didn't cost me a dime as I have access to a lot of scrap wire, old welding lead cables and such that is still good enough condition for grounding use, etc. so pretty economical for me....Power cables are always brand new when upgrading electrical for me.

 

Hey guys. Thanks for all the advise and ideas on proper rigs for cables, etc. One thing I forgot to mention, truck cranks fine when cold. No drag or slow starter! It only has this intermittent slowing of the starter (or dragging) when engine is hot. I'm wondering about heat soak? Whatever it is it's a recent development. I will be checking and testing both cables, grounds, etc.

I think I'll replace the solenoid as well. Looks like it's been on the truck since 74!

 

I wondered about that. Excessive ignition advance will cause this, have you changed the timing recently maybe? Good solid grounds and cables of sufficient size will help considerably for heat soak, and of course shielding is another remedy. The OEMs have always used the smallest gauge cable they thought they could get away with. They worked sorta OK when everything was brand new and bright though not so hot when the years go by.

 

In that case I have some advice. DON'T EVEN THINK ABOUT THROWING THE OLD ONE AWAY!!!!
Keep it as a spare for when your brand new one fails in a few weeks.

Ok, so that might be a slight exaggeration, but only slightly. Buy a good quality one for more money and you might get a good one. Find a Motorcraft or other that's made in USA and you're possibly better off still.
If your issue does turn out to be a tired old starter relay/solenoid, great you can throw the old one away. But slow hot starts are usually one of two things. Old tired starter, or too much ignition advance AND an old tired starter and/or cables.

If you do have a problem with your new relay, post up the info to a thread that's here somewhere (don't have a link at the moment) where we're posting up all of our experiences with starter relays, and what brand, model, price and source they came from.

Good luck.

Paul