The driver said it some times he would have to turn the key several times before the starter would work. The dealer shop said the batters were bad and replaced them. I replaced the starter and switch. Then the driver ask me to install a push button. I did this wireing it directly to the starter like you would a remote test starter switch. The day i did this i found it had a starter relay in the fuse box so i replaced it. For about a month it was fine i thought it was the relay but this morning it wouldnt turnover after several trys with the key then he tryed the button and it didnt work but after several more trys it started. When he got back I tryed it several times and it would not turn over sometimes after starting it several times with the key but the next time it would turn over. I found 1 battery nut that was worm after all the test starts. I cleaned all the terminals and load tested the batterys today. The cable ends and battery bolt posts had a film on them. The truck has 350.000 miles. It has 2 hot and 2 grounds from the bats to the starter.
Next time it does this [jump the starter solenoid] and see if it cranks. Make sure brakes are set and out of gear. I don't trust starter solenoids, even one with few hours can go bad. What starter is it? --MT39?
Bad solenoid, they like to play tricks when warm/hot and half function when cooled down.
If it didnt go with your switch I would feel prety good about starter replacement
Bought a volvo on auction that wouldnt crank over wasnt to worried about it and kinda liked that it didnt start for the sale Bring the service truck over a few days later cranks right up, then no crank again in a few days It turns out to have a firewall mounted plastic box type starter relay that was filled with water and freezing everything was nice a freshly powerwashed
Check for power at the small solenoid on the starter. If no power there, bypass the start enable relay in the dash. If there is power there, replace the starter or the small solenoid on it. Should be a 39mt starter, has a large and small solenoid on it.
One solenoid is mounted over the top of the other, and those small solenoids do take a dump on a regular basis.
how about the engine to frame ground and the cab to frame ground?
I replaced the starter and it did it agin i think the next week. I put a EXTRA STARTER button on it. The hot side of the button is wired on the big hot cable on the starter and the other wire is hooked to the big solenoid on the starter. Just like if the starter was being tested off the truck. It will act up then maybe go a week before it happens agin. After i wired the button on it witch is in the cab easy for the driver to get to it started with no problems for over a month. This week early in the morning it wouldnt start he tryed it several times then he rememberd the extra starter button but it wouldnt work ether so he went to the shop and got the new junp box. He hooked it up and it started but as he unhook the jump box that he never used before he saw he hadnt turned it on.
Could it be a bad battery cable connection or a bad ground on the negative cable to the battery? Or is there any chance that the cables have corrosion inside of them?
wouldn't be the first new starter to fail Brand new delco ?
I pulled the cables off the bats and cleaned them yesterday. I sanded them on the starter when i replaced it. I have thought about the cables being bad or corroded inside. It has 2 sets of cables from the bats to the starter. Replaceing the cables would be $500.00 to $1000.00 dollar deal but it maybe the next steep. The way it has worked on and off makes me think its not the starter but i have seen alot of bad new parts. This wouldnt be a big deal but what the truck is used for it has to be shut off to load and then when loaded it cant be worked on until it is towed off site because off fire hazard.
If you can catch it when it will not start voltage drop test the cables and such. Had a fuel hauler here doing the same thing. Also installed another push button. It was connected from the battery to the starter solenoid. Problem ended up being the starter. It was about the same year Pete with a Paccar engine. Could not get to heat sensor wire on back of starter for testing.
So it has 2 pos and 2 neg cables direct to starter ? it would be hard to believe a 2017 would corrode though both sets under the insulation With your swtiches everything else is eliminated it would be best to be under the hood testing when it doesnt start barring that I would throw another starter at it in a second a new delco not a napa ect, Starters are cheap trucks not running cost money Intermittent troubles like that are never fun
Interesting, would almost think that there are disconnect switches between the batteries and starter that are acting up. I know we had issues with no start on KW and Pete's due to the start circuit goes through the CECU computer in the dash, we would disable the over crank protection, start in gear, and one other starter parameter, then had no trouble with starting, but you have by-passed all this with the extra button makes it ...interesting.
I would remove that starter and have it tested on a bench torque load machine. IMO.
If the battery cables have the rubberized ends with copper washers there is a chance they are stacked wrong. I usually cut the rubber end off and get rid of the washers so its a clean visible connection.
I don't have any truck that new. Is there any kind of safety switches for park or neutral? clutch? I have had lots of trouble with other equipment in that way.
2 days starting ok. It will be alot simpler when it quits all together. When i was marred i bought my wife a crownvic. One day we were garage selling and we met my brother at are last sell. We had stopped at a dozen places but the last place the car wouldnt turn over. My brother jumped it and it acted like the battery was completely dead. Once it started i shut it off and restarted it several times. This was in the spring that fall we were grage selling agin and met my brother at the last place we were going to he left and the car wouldnt start i called him and he came back and jumped it . Then i drove it to his shop and restarted it several times. We drove that car another 100.000 and it took her to another state far far away thank God and never failed to start agin. That kind of sounded like a fairy tell.
If the shoe fits it came true.
Was the pinion gear teeth meshing well ?
Gear mesh on ours was fine.
We had a fleet of WesternStars with DD16's and Ultrashift transmissions. When the first truck started acting up we just had a riot trying to figure it out. It would start fine for days, then quit, we would go try to troubleshoot and could find nothing. Finally after fighting with the stupid thing for about a month, it quit, no start. Turned out to be the starter. Cheap crap, forget how much they cost but the labor to install was way more then the starter and they were throw away. I'm serious, these were the cheapest POS starters I have ever dealt with. After the second truck started acting up the same way and we jumped through all the hoops, it became standard practice to just change out the starter. We had a pretty decent success rate doing that, IIRC there was only one truck that had a wiring issue. But by just changing the starter out, we cut down on the down time and also freed up mechanic time. Not the best diagnosing but it worked for us.
One big problem with the MT 39 being expensive but cheaply built-is the housing screws get loose, some you can rotate the field housing by hand. We have had I don't know how many of those on DD15 and 16 take a dump priming the fuel system on short cranking intervals. It's a 200,000 mile starter at best. The only good thing is it's about 1/3 less in weight than the 42. Every service the starter is checked to make sure the housings are tight.