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318 hard start when cold

Franky318

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Hey guys,

I've got a question relating to cold start of my 318 (distri with hall sensor). I try to figure it out since I own the car and it is more a comfort thing than a real problem.

What happens?
If I try to cold start the engine there is a 50/50 chance that it fires up directly and dies a few seconds later or that I have to crank it for 15-20 seconds until it starts, then I need to babysit it for a moment and after that everything is fine.
The "problem" occurs when I choke it or when I use just the throttle. The chance the enginge fires up quicker is higher with the choke but then I too need to babysit the engine using to push and pull the choke.

When the engine finally runs there is anoher thing that happens quite often:
When I switch from Park to Gear (reverse or drive) the engine starts to slow down and dies. I figured out that everything is fine when I push the throttle while switching to gear or let the engine alone for a few minutes. I need to proceed this just one time. When I close the garage door I switch to park and when I switch to gear there is no problem anymore.

All this just occurs in the first few minutes after cold start. As soon as the engine heats up a little bit, everything is fine. It is also possible to drive 2km's to the next gas station, shut it down and fire it up again - no problem.

When the engine stood for a few hours (especially in the sun) the start is a bit heavy but there is also no problem (fuel evaporation I think). No problem with gear.

I mean, that's not a real problem, it's a comfort thing but perhaps something isn't set correctly and it can lead to long time faults.

Following parts were changed in summer 21: Distri cap, rotor, plugs, ignition cables, ballast resistor, coil, capacitor - nearly everything that has to do with ignition expect distributor and ICM. It didn't get better but also didn't get worse - it's something ;)

I've read a lot about this and came to following points:

1) Wrong carb spacer
When I bought the car there was a 650 Edel carb installed - with stock intake manifold. In winter 2021 I bought a smaller carb and an Edel intake. While putting everything togehter I used the spacer that was used for the carb and the stock intake manifold. Now I have seen that Edelbrock sells a spacer only for Edel intakes. It has just a square in it, no holes like the ones for stock intakes.
Could this lead to a problem. Not even related to cold start but in general?

2) Vacuum
I honestly can't remeber anymore how the old carb was installed. Afaik I installed it just like the old one. A hose to the valve cover and every other line outs on the carb were closed. When I pull the line to the valve cover the engine starts to rumble and slowly dies. I've read that this must happen if there is no vacuum leak.
Are there any other methods to test for leaks or is this test-result good enough to say there is no leak?

3) Low fuel pressure
I haven't tested it, yet but if the pressure would be too low the engine would shut down completely after some time or am I wrong at this point? I haven't touched the screw on the Edel fuel line to set the pressure. It's set from the previous owner.

4) Distributor and settings
I'm pretty sure the previous points aren't the reason for the symptoms. So I took a look at the distributor. The impulser-"wheel" of the hall sensor is pretty worn-out. I don't know how this can happen since the wheel isn't in contact with the sensor (or should it be in contact?). I also noticed that the rotor can be twisted pretty easy to left and right - and stays in this position. It can be twisted for about 5 millimeters. I'm also able to move it up and down for a few millimeters.
Could it be the vacuum advance or is it "normal" that the rotor twists and moves up and down or is it a knocked-down shaft? I don't want to pull the distri if it isn't necessary.
When my brother is in town we want to check initial timing. Perhaps something is messed there.

Perhaps you have other points to let me check which I haven't thought about. I took a few pics of the vac-lines, perhaps this will help. Since every case is individual I still want to ask you although there are a few threads about it and I don't want to spam a thread of another user with my questions.

Thank you in advance
Frank


BTW: I tried to fire it up after lunch, it went pretty good, car was ready to go after 2 minutes. But I had to play with the choke and throttle the first 25-30 seconds.

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I think much of what you describe is just due to the limitations of a manual choke. (Flying blind)

An automatic choke adjusted properly would allow full choke until it starts and then open to about 1/4" with a fast idle cam holding the idle speed enough to run higher while the engine and intake warm up.

Hopefully someone else can comment on the heat characteristics of your intake.

It sounds like it's tuned fairly well when warm.

Note idle mixture adjustments should be done warm with the air cleaner on.
 
If there is a heat riser valve, is it working correctly? Also, the crossover runner in the intake could be plugged with carbon, which hurts the cold running. When the engine is warm, you can touch the crossover passage with your hand, it should be extremely hot. If it's cold, the crossover is plugged.
 
When it’s cranking and doesn’t want to restart after stalling out from a cold restart this could be a lean or no fuel condition. When it’s in this long restart state, stop trying to start and take the air cleaner off and see if your accelerator pump squirts fuel when you move the throttle by hand. If it doesn’t squirt fuel, you could have a bad/weak accelerator diaphragm or the carburetor fuel bowl could be empty. It’s possible the short run time before it stalls is the carburetor emptying the fuel bowl before the fuel pump begins delivering fuel.

Another thing to check is where is your idle speed set? When an engine is cold they like a higher idle through either a choke high idle or manual throttle application.

I have a stock 1970 satellite with a 318. I usually give it 30 seconds or so to warm up before I try to drive from a cold start. If it’s cold I give it even longer. On a hot restart, I have challenges with all my old stuff with the fuel evaporating/boiling from a hot carburetor.
 
Hello guys,

thanks for your input.

"I think much of what you describe is just due to the limitations of a manual choke. (Flying blind)"
I bought the smaller carb with an electric choke but I honestly didn't know where I could wire the red cable (don't know the english term for "Zündungsplus" - sorry!).
So I installed the manual choke which was also installed with the bigger carb.
Perhaps you can tell me where to connect the red cable and I try it out.

"It sounds like it's tuned fairly well when warm."
Yes, I love it. There aren't any "problems" when the engine has a bit of temperature. Like I said, a few minutes are enough and everything is great.

"If there is a heat riser valve, is it working correctly? ", "When the engine is warm, you can touch the crossover passage with your hand"
I bought the car with headers installed, so they deleted the heat riser valve. I also can't touch the crossover runner. Intake gets warm after minutes and after a long drive it is pretty hot.

"see if your accelerator pump squirts fuel", "thing to check is where is your idle speed set"
The accelerator pump squirts fuel but it's quite possible that the first start will empty the bowls. Idle speed is at 880-900 - set when engine was warm.

OK, it sounds like it could have something to do with the choke and that it isn't abnormal that the engine will die when I'm too fast with switching in gear.
Will take a closer look how I need to set the choke and will report.
 
It's very easy with an AFR gauge to figure out what's happening.

I'd venture to say it's running very lean at idle. Slightly richen up the idle circuit and see if that clears up your cold start issues.

On a Holley, I know it would be a combination of pump-shot (accelerator pump discharge nozzle) & idle-mixture screws.

Think about what your choke is effectively doing, richening up the air-to-fuel ratio at idle.

Take notes of your adjustments so you can reverse if required.

It was 50* this morning, two pumps of the pedal, manual choke, feather throttle for 1-3 seconds until oil pressure builds to 60 PSI, and run at 1,500 RPM - 1,200 RPM for 30 seconds. It's ready to go. Same sequence everywhere. This is with a very mild, 318 LA.
 
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OP - sounds like what used to happen with my 360 that had a manual choke. In the end, I determined the 100% reliable way to start it was as follows:

- Pull choke cable all the way out to fully close choke on carb
- 4 pumps of the Go pedal to the floor, then wait 10 seconds (the delay allows nice fuel atomization in carb before igniting it)
- turn key to fire the motor and then IMMEDIATELY after motor fires, quick push tap on the choke cable to slightly open the choke. This slight opening of the choke lets a bit of air in the carb to keep it running. This was with an Edelbrock 600 carb - YMMV
- after motor warms a bit (3-5 minutes) you can drive
- after extended warm up (10-15 minutes) you can push choke cable all the way in for full open choke
 
With a manual choke you have to do everything the automatic choke does, well, automatically. It's a lot of fiddling around. The choke system is quite simple but you must understand how it works.
 
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Lots of good things mentioned in posts above. Yep, often a hard cold start can be choke related. There are cold, warm-up, and hot idle adjustments (I have an eddy carb). I’d say check your carb settings and timing since it sounds like you’re going to do some of this. My warm-up idle drops to around 700 rpm after cold idle around 1000 rpm. Hot idle is around 450 as I recall as I’ve not driven the car for a few months. It’s always an easy start; I floor the pedal once or twice to set the choke and starts after a few cranks. If it hasn’t run for a few weeks, I need to give another pedal push or two.

Choke wire (red) connects to a key-on 12V source – google connections for eddy’s, there are several how to’s about this, or check your carb instructions/manual if you have them. I have the stock manifold and had run into a hassle some years ago; found out the spacer I had was ported (for a different carb) and the throttle plates were smacking against the plate. I got an open spacer solving that. While not related to hard starting, since you mention a spacer (not sure if it’s for your carb?), I’d check for possible vacuum leakage.
 
Hey guys, I'm an idiot, I totally forgot to answer!

I'm now pretty sure that it was the choke-setting and/or the carb spacer.
I set the fast-idle screw again, oiled the choke wire and laid it to another position. It's much smoother now...

I now have the following procedure to start the car:
-Fully open the choke
-Push pedal to the metal 5 times
-turn key -> engine starts in max. 10 seconds (depending on temperature and how long the car stood)
-step on the pedal -> fully close choke
-step on the pedal again -> open choke to two-thirds
-have fun

I noticed the car doesn't like a fully open choke, I need close it again so the engine doesn't die. After that everything is fine and I can literally drive directly after start. No babysitting anymore :) That also means I keep the manual choke but now I know how to use it.

Another thing is that I ordered the correct spacer for Eddie-carbs. It wasn't cold start related but the engine behaves more direct and smoother. Same problem like Ron H, plates were smacking against the spacer plate.

I, too, ordered step up springs and needles to richen up the air-fuel mix since the plugs are a bit too white for my taste.

Want to thank you for all of your input and tips. :thumbsup:
 
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