No start - Starter doesn't engage

[tcheb]

I went through a lot of previous posts on no start conditions but the vast majority is about no fuel or no spark conditions. Mine is different.

When I turn the key, I can hear the click and the fuel pump activate but the starter does not engage. The issue started a couple of months ago, then resolved itself after a few days. Then a few days later the car refused to start again and the car has been sitting for a month and won't start anymore.

What I eliminated so far:
- it's not the ignition switch - I tried jumping the connectors in the diagnostic port and same thing happens
- it's not the starter - I replaced the starter and it didn't help
- it's not the battery - I connected it to an external jump starter and same thing

What else could it be???

[reelizmpro]

I'd be looking at the starter solenoid and the connections. Sometimes the fragile wiring breaks when you remove/install. Typically new starters, come with new solenoids though. So does the starter motor spin at all?

[tcheb]

The previous starter was fairly new but I replaced it with a brand new one to eliminate the possibility it broke prematurely.

The starter motor does not engage and does not spin.

[e30austin]

does the engine turn over by hand?

if you bought a remanufactured unit, i'd be skeptical of the solenoid. they are usually junk, right out of the box. what i've also seen, is folks tightening the 5mm nut (8mm head) down too tight, pulling the stud out of the solenoid, resulting in a starter that should work well, but has no internal connection.

also, look at your ground strap at the engine block, as well as the battery connections in the trunk.

[tcheb]

The car starts when pushed and runs perfectly fine. The starter doesn't even engage. If the engine was seized, I assume it would engage but not turn. Also, I'd see lights dim or something from the current draw.

I really doubt I have two defective starters, one brand new, one three years old. Both are Bosch units from Pelican Parts.

I'll check the ground strap. Is there a way I can test voltage drop or resistance using a voltmeter? I can fix anything mechanical, but I'm worthless with electronics.

[iansane]

Is it a little 'click' like a relay or a big click/thunk like the solenoid engaging? It sounds like an issue with power getting to the starter. Firstly, when you swapped the starter you put the little wires on the correct terminals of the solenoid, right? Easy to do on rebuilt starters that might have rotated the solenoid on rebuild. Secondly, I would hit everything with a meter to make sure you're getting power. 12v+ on the big lug of the solenoid, 12v+ on the little terminal when cranking, 12v+ on the big output lug of the solenoid on cracking, etc...

I'll check the ground strap. Is there a way I can test voltage drop or resistance using a voltmeter? I can fix anything mechanical, but I'm worthless with electronics.

You could put a single side of a set of jumper cables from the block to the strut tower bolt or similar ground location.

[tcheb]

Is it a little 'click' like a relay or a big click/thunk like the solenoid engaging?

definitely a relay click

[It's Soda Not Pop]

My starter will spin but not engage at times when it's hot. Did you car start life as a automatic? If so it's probably your ignition switch. The starter isn't getting a good 12 volts at times. You can bypass it just to get it to start by jumping pin 11 and 14 in the Diag plug.

[tcheb]

My starter will spin but not engage at times when it's hot. Did you car start life as a automatic? If so it's probably your ignition switch. The starter isn't getting a good 12 volts at times. You can bypass it just to get it to start by jumping pin 11 and 14 in the Diag plug.

It doesn't spin nor engage. It's always been a manual and I already ruled out the ignition switch by jumping the pins.

Thank you all for the responses so far!

[It's Soda Not Pop]

How are your grounds?

[tcheb]

How are your grounds?

When I inspected them visually, they looked ok, Not corroded or shredded like some others I've seen, for example this one : https://farm8.staticflickr.com/7407/...07e01a34_h.jpg

Other than that, I don't know how to test it.

[ForcedFirebird]

Early/late model? m20/m42?

Was the car auto before?

Take the car out of gear. Use a piece of wire or other metallic object to jump the starter. The bottom lug (10mm nut on late model, 3/8" spade connector on early) and jump to the big red wire. If the starter engages, then you have a problem upstream. You can also do this at the diagnostic plug if you jump the correct wires. The black/yellow needs to go to red. Make sure you are out of gear if manual!

My guess is the ignition switch itself. It's an orange plastic casing with white innards. The orange surround has little clips to "snap" the two halves together. That clip tends to break off and allow the actual switch inside to disconnect. To test, remove bottom wire from starter (black/yellow), turn key and look for battery voltage.

[tcheb]

Early/late model? m20/m42?

Was the car auto before?

Take the car out of gear. Use a piece of wire or other metallic object to jump the starter. The bottom lug (10mm nut on late model, 3/8" spade connector on early) and jump to the big red wire. If the starter engages, then you have a problem upstream. You can also do this at the diagnostic plug if you jump the correct wires. The black/yellow needs to go to red. Make sure you are out of gear if manual!

My guess is the ignition switch itself. It's an orange plastic casing with white innards. The orange surround has little clips to "snap" the two halves together. That clip tends to break off and allow the actual switch inside to disconnect. To test, remove bottom wire from starter (black/yellow), turn key and look for battery voltage.

it's a 1986 325es that's always been a manual.

I know it's not the ignition switch. I already tried to jump the pins on the diagnostic port that bypasses the ignition switch and nothing happened.

[ForcedFirebird]

Ok, so you have isolated it to the starter. The diag port Y's right into the starter wire well before it gets back into the car.

Being an 86, you will NOT have the top wire for the k5 relay going to the starter, and you "should" have the spade connector. Many aftermarket starters will cause you to convert to the eyelet, but either way, let's move on.

Try bumping the starter right at the solenoid. Big red wire to the bottom lug should bump the starter. If not, then check for power at the big red wire to the other large lug - 13mm hex nut, it has short ground strap to starter case.

To easily eliminate ground as a problem, use a jumper cable and attach to the engine and chassis using the black grips.

[tcheb]

well finally figured it out. It was the starter after all... The old starter gave up but when I installed the new one, I connected the smallest wire to the wrong prong. I don't know what the other one does, but when I connected the wire to the right prong, it started right up.

I bench tested the old one just to be sure and indeed, it doesn't do anything when I short the positive with the prong at the bottom. It draws current, but doesn't do anything.