Trouble staring after winter slumber

[mark houghton]

Today, for the first time in probably 4 months, the weather is nice and I decided it's time to ring in the new year. Ordinarily she will light up in less than a second of cranking even after sitting for a couple months. This time, no bueno. Cranked and cranked...and cranked... no fire. Weird, not normal. Checked both pump relays and yes, pumps were running. So I'm thinking "sheet, do I have spark?" Decided to crank her one more time and she finally lit. Drove for 50 miles, several stops and starts, no problem.
So wtf, surely the fuel accumulator was bone dry and took a while to fill the Iines with fuel but again I've never had this happen in years past. I probably cranked her over for a total of 20 seconds or so until she finally fired up. Full tank of ethanol free gas and Stabil back in November.
Other than that and a little paranoia/what if on the road....damn, felt good to be back behind the wheel!

[stownsen914]

So you commented on the priming of the fuel system. That's the first thing that comes to mind. Unclear why it's different this year though. It could take a few sec to prime the system and pressure to build. 20 sec is kind of a lot though.

[Alan L]

Could have been something stuck - like the CSV - which finally fired. They do seize - rust in the solenoid bore. So it could have been temporarily stuck shut.
Alan

[mark houghton]

Originally Posted by stownsen914

So you commented on the priming of the fuel system. That's the first thing that comes to mind. Unclear why it's different this year though. It could take a few sec to prime the system and pressure to build. 20 sec is kind of a lot though.

Yeah, not normal at all. Went down several hours later and she started up in less than a 1/4 second of cranking, as usual. Could be my fuel metering arm was stuck and not opening up the delivery ports in the fuel head to feed the injectors. Or the thermal time switch/injector which should be squirting fuel but maybe not if the distributor ports aren't opened. I run without the plug installed for the metering arm safety feature: i.e., the pumps run as soon as I turn on the key. Just some sort of gremlin to remind me that this is an old machine requiring me to get my hands dirty on occasion. Not my first rodeo.

[mark houghton]

Originally Posted by Alan L

Could have been something stuck - like the CSV - which finally fired. They do seize - rust in the solenoid bore. So it could have been temporarily stuck shut.
Alan

Yepper, something like that most likely. This thing has always been faithful, fires right up no matter how long she sits. Climate controlled storage all winter as usual. I think she was just pissed off being left alone all winter, a good kick in the ass end might have fixed things.

[Bucketlist]

Against some popular opinions I start mine monthly in the garage and run it a few minutes to circulate the fluids and stay on top of future problems. I also run pumps with ignition on. I cycle pumps twice and she starts on the first turn. Yesterday it was nice enough to blast out to Cars & Coffee, nice turnout for March.

[mark houghton]

This morning, stone cold, lit right up with less than a half second on the starter. Back to normal. I suspect Alan is correct, stuck solenoid in the CSV for whatever reason. I fully understand the function of this gizzmo, tied in with the thermo time switch, but have never had to mess with either.

Just for kicks, let's dissect the function: the TTS gets its power from the starter circuit (I think) and will power the CSV until the bimetalic strip in the switch heats up and interrupts the circuit. Something like that anyway.

But....but, one would think that even if malfunctioning as mine did, after prolonged cranking the injectors would eventually provide enough fuel to start the engine. Or...or...perhaps air flow across the metering arm when cranking is only sufficient enough to trip the switch for the fuel pumps to energize (mine's unplugged, pumps run without cranking), perhaps not enough deflection to open up the fuel delivery ports in the fuel distributor. Thus the need for a cold start mechanism to get the engine running and draw enough air to pull the metering arm down and open the fuel ports.

What say you?

[Alan L]

The cranking has to open the airplate enough to fire pumps - thats how the hot start works - no CSV function.
I just suspect on a cold engine that has sat for a while the squirt of fuel down the throat gives it what it needs to fire. Bit like squirting something down the carb body on a hard start. Voila - the engine that didn't want to go fires in to life.
The CSVs do fail because of rust accumulating in the solenoid bore. I opened a failed one up and that was the issue. You can imagine that slowly accumulating if not used, and finally it can't move the solenoid. It is just a fine surface coating of rust deposit - but the bore tolerance is pretty tight.
Alan

[mark houghton]

Originally Posted by Alan L

The cranking has to open the airplate enough to fire pumps - thats how the hot start works - no CSV function.
I just suspect on a cold engine that has sat for a while the squirt of fuel down the throat gives it what it needs to fire. Bit like squirting something down the carb body on a hard start. Voila - the engine that didn't want to go fires in to life.
The CSVs do fail because of rust accumulating in the solenoid bore. I opened a failed one up and that was the issue. You can imagine that slowly accumulating if not used, and finally it can't move the solenoid. It is just a fine surface coating of rust deposit - but the bore tolerance is pretty tight.
Alan

Thanks Alan. Yeah, for hot starts the TTS is heat soaked and won't energize the CSV...thus depending on the injectors for fuel once the metering arm deflects enough to run the pumps and open the fuel ports. Still weird though in my recent episode, considering the extended engine cranking I did and still apparently not injecting any fuel. Even if the CSV wasn't working, she should have fired up eventually though more sluggishly than a warm start. Both pumps were running and no strong gas smell as one might expect if flooded due to a no ignition spark problem....so I kinda ruled that out.
I hate to say it, but this needs to happen again so I can trouble shoot it...preferably at home!

[Alan L]

It will only happen again at the most inconvenient time. Murphys Law.
Alan

[McGalliard]

Can I ask a few questions about the thermo-time switch? Mine is a ‘75 US 911S. My reading of the wiring diagram suggests that the power comes to the thermo-time switch THROUGH the starter. So how does it continue to operate for up to ~8 sec after the engine has started and the starter is released from duty? Furthermore, in my ‘75 system, the power to the TTS from the starter goes through the throttle valve switch. By my electrical testing, power to the TTS is only given when the throttle switch is closed, which means the throttle pedal is depressed? My understanding is that one should never (have to) touch the pedal to start the car. What am I missing?

[McGalliard]

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