71 T cold start problem

Neal Boysen · 09-07-2006, 08:10 AM

My 71 T with a 2.2 and zeniths won't start after sitting overnight. Overnight temps drop to about 55-60 F. Timing is set at #1 TDC at 850rpm and dwell is 39 degrees. I'm getting fuel to the carbs and in the carbs. Last Saturday it cranked forever it seemed like, then finally started. I drove about 200 miles that day and started it at least half a dozen time throughout the day and had no problems. It also ran just fine. Yesterday afternoon it fired right up with outside temps around 95 F. This morning it just cranked but would not fire. Any thoughts, ideas, help?

quaz · quaz's Garage

Check the gap on your plugs..........I had a similar problem and my plugs were getting a little worn.

Neal Boysen · 09-07-2006, 09:18 AM

Thanks, Kevin I will check that out. And by the way I have really enjoyed Jay's and your story on your cars!

Neal.

Grady Clay · 09-07-2006, 10:50 AM

Neal,

When you first turn the switch to “on” when cold, do you hear the fuel pump run? Does the “whurr” change tone after a couple of seconds?

Do you “pump" the accelerator a couple of times and then crank? When it finally fires, does it run cleanly on all six right away or does it start on a couple of cylinders and gradually pick up more?

Did this come on suddenly or has it gradually gotten worse?

Has anyone fiddled with the carbs or anything else?

Hard starting when cold with good ignition is usually carb accelerator pumps issue. It can be the fuel drained (boiled) out of the carbs when parked hot and isn’t refilling soon enough in your start process.

Here is a link about hot starting that only remotely relates.
Hot Start with carbs:
Early 911 Warm Start Problem

Best,
Grady

Neal Boysen · 09-07-2006, 12:52 PM

Grady, the fuel pump is working, I removed the fuel line to the carbs, put the hose in a bottle, turned the key on and filled it. Plus I can hear it run with just the key on.

When starting I usually pump once and hold part throttle and it fires right up.

It came on suddenly.

I checked the accelerator pumps and they are working.

I did lean out the carbs about 1/2 a turn. They are now about 2 3/4 full turns out, the owners manual says to start with about 2 1/2 turns out. I can't imagine that would cause the problem.

Any further thoughts?

Thanks, Neal.

quaz · quaz's Garage

Neal, thanks for the compliments on the thread. I enjoy doing everything myself as it is a challenge.

Anyway, just to get yourself going in the right direction, start the car as you normally would, but stop right about when it used to fire. Then just take out a plug or two and inspect it. Wet you got enough fuel, but not enough spark. Then look at your ignition. Dry you are missing a little fuel. The basics will usually lead you in the right direction.

I am sure given enough specifics someone on this board can figure it out.

Grady Clay · 09-07-2006, 02:03 PM

Neal,

In the morning, turn the key to “on” for 10 seconds and then pump the accelerator (all the way off & on) 6-7 times. Does it start sooner, worse or not at all?

This should “flood” it if everything is normal. You can either give it full throttle and crank or come back later and start it. If it starts sooner the accelerator pumps are too low quantity.

If it starts (even sorts) and accepts more pumping, probably the accelerator pumps are on the low side or some aren’t working. The Zeniths have six pumps, one for each cylinder. The next step is to measure the actual pump output with the little glass vial.

We still haven’t ruled out some issue that would interrupt the ignition at first when cold. A test for that would have a helper do the first crank. You could pull the wire from the center of the distributor and hold it (with a suitable insulating tool) very close to the fan housing. You should see a spark on the first time the engine rotates to compression (no more than 1/3 turn).

Best,
Grady

Neal Boysen · 09-08-2006, 12:45 PM

Kevin and Grady, thank you for all the help and advice.

Grady, this morning before even turning the key on I removed the air cleaner assembly and checked the accelerator pumps and I had fuel. So it was not the fuel boiling out as you suggested.

Kevin, again this morning before even turning the key I pulled and checked my plugs as you suggested and all was good.

So now I try to start and it just cranks and does not fire. Well I had an old 12v coil and thought I'd try it, and guess what, it starts right up!
I know this is not the correct coil for the CD ignition so I call around and find a new correct one and change it out. So far this seems to have solved the problem.

I guess a 35 year old coil can go bad, but it still seems odd to me that it was a cold (relatively, 55 F) start problem.

Anyway thanks again for the help and advice. This BBS is just an awesome place to get tips, tricks, advice and help. I hope I can return the favor to someone one day.

Neal.