Spinning starter no start

[Chris Utter]

1987 944S starter just spins, won't engage flywheel. Stranded at gas station. Worked fine all day at track. Towed to garage, pulled starter, new by the way, bench test good. Replaced anyway still same, spins , no start???

[wwdwgs]

wiring to the solenoid?

[kdjones2000]

Push start it to get home... Check teeth on flywheel / replace starter.

[Chris Utter]

Wiring is good, starter spins.
Second starter.
Actually recently replaced clutch, pressure plate, new ring bolts.
To check that ring gear got to pull transaxle and torque tube???

[944 Ecology]

Originally Posted by Chris Utter

Wiring is good, starter spins.
Second starter.
Actually recently replaced clutch, pressure plate, new ring bolts.
To check that ring gear got to pull transaxle and torque tube???

Just remove starter and use a prybar to rotate the engine using the ring gear teeth.

It might help to take out the spark plugs.

[Chris Utter]

Ok, I'll try that. Not till Sunday. I'll check back then.

[Chris Utter]

Well after cleaning out oil leak into spark plug holes... twin cam valve cover.
flywheel spins easy. So going to reassemble and try again.

Teeth look perfect.

[Chris Utter]

Still just spins...
Reinstalled sparkplugs and gave flywheel prybar, nice and tight but will rotate.
Baffled

[Jfrahm]

If it never worked I'd wonder if you installed a Turbo bellhousing but... does an S only have 1 crank sensor? That bracket might not even fit the Turbo bellhousing.

I suppose if you did put in a Turbo bellhousing it could have just barley engaged the ring gear a few times but wore down the teeth until it couldn't.

...'s all I got.
-Joel.

[kdjones2000]

Just because the starter spins doesn't mean that the gear is moving out to engage with the teeth on the flywheel. When you tested it (you say it is "new", what exactly does that mean?), did the starter drive (the teeth) move out while it was spinning?

Nothing else makes sense, based upon what you have described so far...

[Chris Utter]

The starter is new. Worked just fine for several weeks. Then, turn the key to leave gas station, it just whines, much like it's not ingaging the flywheel teeth. Pulled the starter and bench tested it , reinstalled it , just spins... removed and returned it , got replacement new out of box installed second one , just spins...
Pulled it out again and turned flywheel with prybar , no damage to teeth, spins as it should, reinstalled again and it still just spins.
Two bad starters in a row?
I'm pulling a known working starter out of another car and try that.

[Chris Utter]

BYW, bell housing is stock, and yes it only has one position sensor. Everything worked great after clutch job, full day at Sonoma. 5 run sessions, So yes, it doesn't make sense.

[Jfrahm]

Can you measure and/or get a pic of the flywheel teeth?
A gummy starter can fail to extend the bendix and just spin, but otherwise the starter gear at least clashes with the flywheel teeth and makes noise. Noise other than the whirr of the starter spinning.

Given another starter has been tried my next guess is that the flywheel teeth are actually worn down and no longer engaging, perhaps from a starter problem while driving that went unnoticed.

I have an S2 flywheel I can measure, I think it's the same as an S flywheel.

[Monkey Wrench]

in most cars Ive owned you can flip the ring gear for a new face but I'm not wishing that job upon you.

some starters use a bendix some use a solenoid.. if it uses a solenoid, I'd disassemble the motor and lube the bushings it slides upon, if the armature moves. those one ones usually have an armature that can slide in and out.

if the teeth are rounded out and that's the issue at least it would make grinding noises. if you aren't even hearing that, just spinning it seems like its not popping out.

you are sure the battery is ok right? I know its the obvious. I think if its a bendix it requires some inertia, thats what drives it..

if it has a solenoid than the solenoid pulls in and also simultaneously closes the contacts for the starter to crank, that's a better system. i've had some, where I found I could flip over the contacts.. some and probably most modern ones are sealed up with no easy access. a bad contact can cause pull in, and no cranking.

if you think its burrs on the teeth , Id take a small file and go around , not reshaping but knock any rough bits you can find off, just dress it up.. if the teeth are all rounded then maybe flip it over but that's a lot of work. you'd need to pay attention to that timing pin.. mark its orientation with respect to TDC

dont muck that up or you'll pull it TWICE. your car will not love you if you put the pin in some other location. I did that once only it was a flex plate.. but same thing,, well it wouldn't run over 3000 RPM
i think that was the one and only time I got so frustrated I called a tow truck and sent it to a mechanic. lol he called me in 2 hrs, done ! he said..
money well spent, for me ;-)

the old trick of having one guy turn the key while another simultaneously bumps the starter with a shovel handle or similar does help, you might try that..

just because its new doesn't mean its still lubed up properly. in fact it probably has a nice snug new bushing involved, maybe a tad too tight.

if you take it apart mark the orientation then pull it open to inspect. you might find you need to extract the brushes too.

if it has a little metal cap on the end opposite the gear, Id open that cap maybe lube that bushing if this makes sense. some starters have a little cap there with 2 screws to lube it.

volvos were great for starters, sturdy things, for a very long time it was unchanged or a interchangeable.

I hate those bendex things, the best you can do is replace them, I dont think there is anything you can fix if they are bad. maybe boil it in oil or try to get it working to free its own parts up..

if you turn on your headlights and crank you might see if they go dim. the power from the key to the starter might go through a shifter switch or some cars have a brake pedal switch.

you might use a meter on that wire and see if it's actually getting 12 V and not some lower voltage. you could put some sort of load on that wire to test if it only has voltage or if it has voltage AND potential ( amperage)

check your battery cables, sometimes it is the obvious, hate to pull the transaxle to find you just had a loose battery post .. got an old headlight or something that would draw some degree of amps? try loading it to make sure it is not just 12 V and almost no amps .. if you connect something else to that circuit( eg old headlight) then crank you can see if the thing you plugged in to the same 12 V circuit seems to be starving of power when you are trying to crank. If you sense a "brown out" when cranking it then that may lead you to an electrical direction.


you can check if this makes sense but in a volvo I;d put a good heavy lead on battery post positive, MAE SURE IT IS NOT IN GEAR, then stab the terminal on the starter, this elliminates the key and car wiring, any safety switches, as a test.

I just had one of my volvos it was an automatic, it would start in neutral, it would no longer start in park, Problem was bad park neutral safety switch contacts. in that car the power from the key to starter runs through that switch, they get dirty. a thing like that could cause a brown out, Im not sure if it has a switch on the brake, maybe?

some cars make you step on the brake before they will start.

it sounds like you do have energy at the starter, you said it is spinning. that proves you have some current there. is it sufficient current?

[djnolan]

A trick you can try is to loosen the starter mounting bolts a little so it engages more gently. This works on chevy's.

[Monkey Wrench]

so he checked the ring gear and it looks ok and he has power , it spins

the new bendix may be bad. the inertia makes it oppose it's internal spring and then it pops out when turning , once no longer pushing, engine over-runs the gear , the small gear is no longer driving, its being driven, then it should pop back in.

when you replace a gear and throw in a new gear, they are not worn in. you now have a new gear in mesh with an old gear.

the gears need a tiny bit of backlash or clearance so the bendix can travel in and out freely , yes it may be binding.

first Id try slackening the bolts pull the starter as far away as the looseness allows and re-torque it this may get it over just that thou or two it needs to provide clearance in the mesh, for free sliding.

you could do things like file the holes ( slightly) or neck in the bolt slightly reduce its diameter slightly.

another approach to fit a new gear and an old gear is to apply grinding compound mixed with grease and run them together, then you need to run them for a while in mesh, then carefully remove any remaining grinding compound and Do not let that grinding compound get into any other parts.

you can do this when you have one of those stubborn bolts that you need to fight all the way in and out.. Apply it to the bolt, run the bolt in and out a few times, then just be careful not to wreck stuff with stray grinding compound. remove every trace of it.. now you can turn the bolt in with two fingers. the grinding compound works upon the locations that are in contact.

it may be hard to see or access but if you could touch the gears with them engaged you should be able to rock that little gear just slightly, if its too close it is bound up, it needs a tiny bit of backlash.

Because you can't see the two gears , you might need to just imagine whats happening there instead.

you can also check the mesh contact with bluing, bluing is hard to see, white paint may work better.

I remember a guy in a rear end shop had a special white compound he liked, when you set up gears in a rear end you need to look at how the gears contact, with this its not that critical , they just can't be binding up.

I used to fix printing presses, with those those you have a lot of gears and extremely tight tolerances. the machines are extremely sensitive to any roughness of the gear train, it can cause shock lines through the image and thus produce work that can't be sold.

I'd sometimes need to change all the gears i a gear train, that's often a whole lot of disassembly of parts.. a trick is to replace the one bad gear and try to run them in, to try to avoid more disassembly. they can't run with vibration or the machine cant produce saleable work. as soon as you stick anew gear in mesh with old gears you have some misfit in the mesh

any amount of run-out (bend) in the shaft holding the gear, will l make it tighter , looser, tighter , looser, like that.