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Would the starter relay be activated if the switch were bad?
Originally Posted by jetson8859
My starter went out on the 87 S4 about a year ago. Same symptoms, turn key and nothing, everything else worked. My confirmation was whacking starter with a hammer while someone tried to start. I tapped it twice and car started right up.
I charged the battery (it wasn't down, but it couldn't hurt), got under the car and cleaned/reseated the connections and it did start.
But when it kicks and cranks, the starter sounds fine, but there's a weird thing going on with the ignition circuit(?). When I turn the key to the start position, there's a brief, silent delay between the turn of the key and when the starter turns. No ticking, clicking or whirring but silence during that 1 or 2 second delay. I repeated the startup a few times and got this 1 second delay each time. Almost as though a relay or the solenoid was "waking up".
Sound familiar to anyone?
You can test eliminate the car side at the 14 pin connector by touching pin 14 to the jump post to see if it will spin over. I recommend doing this with the car out of gear for you own safety. If you don't get anything then most likely it's the starter or wiring between the 14 pin and the starter.
I charged the battery (it wasn't down, but it couldn't hurt), got under the car and cleaned/reseated the connections and it did start.
But when it kicks and cranks, the starter sounds fine, but there's a weird thing going on with the ignition circuit(?). When I turn the key to the start position, there's a brief, silent delay between the turn of the key and when the starter turns. No ticking, clicking or whirring but silence during that 1 or 2 second delay. I repeated the startup a few times and got this 1 second delay each time. Almost as though a relay or the solenoid was "waking up".
Sound familiar to anyone?
Mine was acting similar to yours when hot. I solved it by putting a relay for the starter solenoid close to the 14-pin connector getting power for the starter solenoid direct from the jump post. I don't know if it's the ignition switch that's the problem or if I'm loosing power in the Fuse panel. After all it's 36 years old wires in there. Works fine with the relay with strong cranking when hot.
You can test eliminate the car side at the 14 pin connector by touching pin 14 to the jump post to see if it will spin over. I recommend doing this with the car out of gear for you own safety. If you don't get anything then most likely it's the starter or wiring between the 14 pin and the starter.
Thanks Sean, I'll take your advice. I need to get in there and check the 14 pin anyway...
Originally Posted by SwedeInSiam
Mine was acting similar to yours when hot. I solved it by putting a relay for the starter solenoid close to the 14-pin connector getting power for the starter solenoid direct from the jump post. I don't know if it's the ignition switch that's the problem or if I'm loosing power in the Fuse panel. After all it's 36 years old wires in there. Works fine with the relay with strong cranking when hot.
If a connector cleanup at the 14 pin doesn't do the trick, I think I'll try your relay idea. I take it there's some kind of a universal in-line relay base that I'd use..
There's no starter relay in the MT cars, only a jumper that functionally connect the ignition switch "50" terminal directly to the "50" terminal on the starter solenoid. The click you heard is likely the X-bus relay dropping out when the key is turned to "start" position. You can use a test light or DMM to check for voltage at that relay socket jumper with key in "start" position. The solenoid probably needs at least 9 volts or so to engage the drive gear and close the electrical contact battery to motor. Should be plenty if the starter motor isn't actually running.
Some will recommend a few love-taps with a hammer to get the starter motor to turn. In my experience, that impact will allow a too-short brush to slide enough to meet the commutator and buy you a little time to get home. Once. Directly.
For those considering the DIY bushing-and-brushes refurb, be aware that there are mica slices separating the contacts on the commutator. They typically wear evenly with the copper. If you use sandpaper or emery cloth to "polish" the copper commutator much at all, you risk leaving the mica slices high enough to keep the brushes from making proper contact. Use a fingernail or a razor blade to check there are no protruding pieces. You may find that a little delicate Dremel surgery is needed to ever-so-slightly undercut the mica in the slots between the contacts.
And a Public Service Notice that the emery cloth strips that seem perfect for cleaning the commutator are made with a very conductive aluminum oxide abrasive. Not the bext choice for detailing a multi-element contact array. Use sandpaper.
Cleaning the pieces: Use detergent and hot water rather than solvents. And for sure no brake cleaner, as it can damage wire insulation especially the enamel used on the windings. Once cleaned to your satisfaction, blow the water out with compressed air and plunk it in the garage toaster oven overnight at a nice comfortable 150º to bake out any remaining moisture. Add fresh grease to the bushings, and reassemble.
My Favorite Method: Buy a Bosch rebuilt unit from one of our favorite parts purveyors.
Cleaned the 14 pin and the delay seems to be gone. Starter was engaging after a battery charge and a clean & reseat of the connections at the starter, but I had that delay. After the pin clean/reseat, the delay seems to be gone and hopefully I'm back to a reliable starter.
Bob, your favorite method is certainly good advice and for the cost, not a bad idea to have a spare sitting around if/when the starter does take a dump.
Your detailed explanation is being saved in the archives (actually Evernote)....you can never have too much info. on hand relating to the components of these cars - especially those that can leave you on the side of the road.
So I'm now back to a no-start situation. I jumpered #14 to the jump terminal and just heard a click at the starter, so I'm ruling out wiring between the ignition and 14 pin connector.
I'm noticing a common symptom: no-start when the engine is hot. At the track (hot engine is an understatement) then the next time after a 20 drive around town. It'll probably start fine tomorrow morning.
I'm seeing some discussion about adding a relay to the starter wiring as you mention, Anders, and as is discussed on Greg Nichols' site and diagrammed here:
^ Is this yours Randy?
If it's the combination of a tired starter, internal contacts, and old wiring to the starter, I'm starting to wonder if a "fresh" starter will only work for a while before it starts to need a bit more juice to kick...then I'm back to the same problem. Is this relay fix a common alternative to replacing wires and/or the harness?
The relay you are thinking about adding exactly duplicates jumping the 50 lead in the 14-pin to the jump-start post. Adding a relay won't do anything for you except add another future potential failure point.
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The solenoid on the starter motor does a couple things. It actuates a fork that pushes the bendix drive out via pivot fork so the little gear on the end engages the teeth on the flywheel. Once the gear is in position, a copper disk connects the battery terminal to the motor terminal, allowing current to flow from battery to starter motor windings. How heat affects these operations can vary. Can be a problem engaging the solenoid to the point where the copper disk passes current to the motor, .or. can be a problem in the motor where current isn't making it to the rotor (via the brushes and commutator). Put a test light on the motor side of the solenoid so you can see the solenoid work. If the light goes on and no starter motor run, problem is in the starter motor.
Meanwhile, all this is more than a little esoteric. The aggravation of testing and headscratching is way more than the aggravation and cost of just putting a rebuilt starter in and calling it a day. Just one fail-to-start exceeds cost-to-repair, in my opinion. I hate getting stranded by stoooopid stuff.
...
My Favorite Method: Buy a Bosch rebuilt unit from one of our favorite parts purveyors.
^^^ This. The 928 has some things that are prone to fail, the starter isn't one of them. And some starters are failure-prone, but the 928's isn't one of those, either. But starters do wear out, and wiring can get funky. Check especially the bus-50 wire (4.0 yellow) that connects to the starter solenoid, that part of the harness is heat-sleeved but does run close to the exhaust.
I ordered a reman starter from Roger and it's out for delivery today. While I'm pulling the old starter, I figured I'd go over the wiring.
When doing a search for "starter ground" I came across a post on Greg Nichols' site (http://www.nichols.nu/tip624.htm) where "Kevin" says that the starter ground point is located in the spare wheel well.
I'm not seeing any grounds aside from the battery ground strap. Anyone know what ground he's referring to and where it might be in an S4?
Also, he mentions a "boundy speedy" which my car has developed recently.
UPDATE: This reman starter turns 2x as fast as the original that it replaced - same wiring, same battery, same conditions. I guess I was dealing with a really tired starter. I did find a chassis ground cluster behind the little black cover inside the spare tire recess. Cleaned them up and shot some contact cleaner for good measure.
Also, thanks Roger for getting me the starter so quickly! From TX to my doorstep in MD in 2 days! I certainly didn't think I'd have this starter in before Frenzy. Now I have 2 cars to choose from
09-12-2016, 09:54 AM
