Strange M20 no-start condition

[arecks]

This usually happens after I've driven the car a bit, parked, and came back.

It's an M20 late-model. Not 100% sure of the ECU last 3 digits - haven't pulled it.

It first started about two months ago. I had driven the car to a shopping center and parked - facing uphill - on a steep incline. It was a very nice day - cool and not hot (I mention this because of my later observations). After about an hour, I came out and it would not start - no cranking. I checked all the connections and nothing. Popped the rear seat horizontal section and banged on the fuel pump cover. It started and I was on my way. I never could hear the pump running because I'm under the impression that the pump doesn't start on an M20 until the key is turned to START.

It happened again a couple weeks ago. I drove about five minutes, parked, got something to eat and ran an errand, and came back to no crank/start. It was pretty warm - maybe 85 degrees. All connections were good. Battery connection was tight. Banged on the starter with a ratchet extension. Nothing. Banged on the fuel pump cover with my hand. Nothing. Came back in the middle of the night when it was cool out and it started right up.

Over the following two weeks, I drove the car a few times with no issues. It was progressively getting warmer here in MD.

This past Sunday, it was in the low 80s and I had driven it about 25 minutes, parked it, and started it within five minutes and left it idling. I drove back about 15 minutes, parked it, and came back after about 15 minutes and it didn't crank. I popped the hood and let it cool down. After another 30 minutes, it started.

Each and every time, I turn the key to START and the gauges function and I don't get any repeated clicking as if the battery is dying. If I have the hood open, I do hear one faint click. No battery light and no cranking.

I can't imagine it's the fuel pump or a relay (??) because it usually starts the first time when I go to drive the car after it's been sitting for a while. Could it be the starter solenoid overheating? The starter ground is pretty shady-looking with some black putty connecting the strap to the starter and the strap has aqua-colored copper patina on it. It's not particularly dirty, but it's not clean. I do NOT have the facilities to do the starter right now.

The other ground straps could be the culprits, too. The one on the left side of the oil pan is not really clean, esp. after I made a mess with the p/s delete. The covering on the cable is mostly cracked and coming off. The hood strap is in OK shape. The ground at the right shock tower is OK. The positive block on the right side of the firewall is sketchy - there's a cable that has a small square block that looks like there was a small "combustion event" there. Not sure.

Ideas?? I don't know how to diagnose this because it's so intermittent.

[ScottSneed]

Replacing those grounds would be a good start, then the relay, then I'd consider the starter. My car acted like this, and eventually wouldn't start anymore. Replaced the starter, and it started right up, every time.

Also, does your car smell of fuel when first starting? Have you changed your soft fuel lines? Fuel Filter?

[arecks]

Thanks. I replaced the fuel filter about six weeks ago. The soft lines were all good. No leaks. The top of the fuel tank DOES leak, however. Been meaning to replace those hoses and clamps.

BTW. ran into this old BavAuto article coincidentally while looking for an article on why my signals no longer cancel after I installed an MT2 wheel and took it off (put an MT1 on and now I have a Renown wheel mounted). https://blog.bavauto.com/3562/no-start-1989-325i-e30/

BOOM: Step 10
"10: If you do hear a “click” at the starter, when the key is turned to START, this means that the circuit from the ignition switch to the starter solenoid is OK. The “clicking” is indicating that the solenoid is, at least, attempting to energize the starter. Either the solenoid or starter is faulty or there is not enough battery power getting to the main starter motor input terminal. We will now test the solenoid, the starter motor and the battery power to the motor."

[arecks]

Sticky

I don't know, but that BavAuto article from 2010 should be a sticky in every forum. It's a super-easy-to-understand guide to understanding why your E30 doesn't run (and likely will get you figuring out the same on 90% of other vehicles from the same period and before, too). I'd delete my original question, but I think it'll be helpful.