# 70 gto cold start issues



## Tiger Joe (Aug 18, 2021)

Trying to fine tune my 70 455. Car is all original. I had original qjet rebuilt so I know it’s good to go. 

issue- cold starts the car cranks over too long in my opinion and almost sort of floods when it does start- chugs and smokes a bit. I have to step on the gas to Rev it up clear it out. Then it’s fine. And will be good the rest of the day.

my first question- did a 70 gto use the R terminal on the starter to give 12v during cranking? I don’t have one on my car which I found odd. is there a chance someone removed it or Pontiac didn’t use one?


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## Tiger Joe (Aug 18, 2021)

adding in here my searching seems to indicate Pontiac didn’t use the R terminal, at least not in 70.


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## ponchonlefty (8 mo ago)

sounds like the choke needs adjustment. how long does it sit?sometimes the fuel can evaporate and cause it to crank a little more to fill the carb.


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## PontiacJim (Dec 29, 2012)

Tiger Joe said:


> Trying to fine tune my 70 455. Car is all original. I had original qjet rebuilt so I know it’s good to go.
> 
> issue- cold starts the car cranks over too long in my opinion and almost sort of floods when it does start- chugs and smokes a bit. I have to step on the gas to Rev it up clear it out. Then it’s fine. And will be good the rest of the day.
> 
> my first question- did a 70 gto use the R terminal on the starter to give 12v during cranking? I don’t have one on my car which I found odd. is there a chance someone removed it or Pontiac didn’t use one?


Your symptoms and description indicate that the choke needs to be correctly adjusted.

It would appear that the choke is shut when you first start the car - so not enough air is entering the intake and causing a rich condition of gas and thus it won't start.

When you do finally get it started, the extra gas/rich condition still exists and thus the engine will smoke out the exhaust and run rough until the cylinders are cleared of the rich condition and your choke has somewhat opened up. When warm, your choke would seemingly be open and you no longer have any issues, so it fires right up.

Adjust your choke.


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## Tiger Joe (Aug 18, 2021)

I just got the carb back from Lars so it was all setup properly.
Doesn’t matter if the car sits for a day or a week I have the same issue. I verified yesterday I get a shot of fuel before trying to start so car should start after sitting overnight.

even if I had an issue with the choke pull off shouldnt the car start immediately? I verified I have a pump shot of fuel and the choke is closing.


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## PontiacJim (Dec 29, 2012)

Tiger Joe said:


> I just got the carb back from Lars so it was all setup properly.
> Doesn’t matter if the car sits for a day or a week I have the same issue. I verified yesterday I get a shot of fuel before trying to start so car should start after sitting overnight.
> 
> even if I had an issue with the choke pull off shouldnt the car start immediately? I verified I have a pump shot of fuel and the choke is closing.


Re-read my previous post- adjust the choke, it is closed too tight when cold.


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## Tiger Joe (Aug 18, 2021)

Choke is set 1/4” open. Exactly where Lars tuning paper says it should be.
Reread my previous post. Even if I had a choke issue (which would explain chugging) why wouldn’t the car start immediately? I have a shot of fuel and the choke snaps closed. Why wouldn’t it start?


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## ponchonlefty (8 mo ago)

could it be an internal fuel leak?


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## Tiger Joe (Aug 18, 2021)

Well might have found it. Have no idea but somehow my base timing had slipped to like 30 degrees. Maybe I didn’t tighten the hold down enough when I set the timing.

so warmed it up and reset my timing.Obviously too hot to find out about cold start so try again tomorrow morning


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## dadspackard31 (Dec 2, 2019)

Tiger Joe,

When you do a cold start let us know if it truly was the timing causing your hard to start when cold issues.

Thanks
Tom


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## PontiacJim (Dec 29, 2012)

Tiger Joe said:


> Choke is set 1/4” open. Exactly where Lars tuning paper says it should be.
> Reread my previous post. Even if I had a choke issue (which would explain chugging) why wouldn’t the car start immediately? I have a shot of fuel and the choke snaps closed. Why wouldn’t it start?


TG: :"I have a shot of fuel and the choke snaps closed."

PJ: The choke should not snap closed in this kind of heat - unless you are above the arctic circle. In this summer heat, the choke should already have partial opening, and not "snap closed." So in my opinion, based on what you posted, the choke is too tight. If you had hot starting problems that included the smoke/chugging, pedal down to clear out the engine, then I would have said you have a fuel spill over, ie bad gasket, leak, heat causing boil over of gas out the carb and into the intake.

TG: "my base timing had slipped to like 30 degrees."

PJ: If your base timing had slipped to 30 degrees Initial, and the distributor's mechanical weights are typically another 12-14 degrees, 30 + 12 = 42/44, and your vacuum advance adds another 10 degrees, 42/44 + 10 = 52/54 degrees, your engine was not detonating/rattling like a box of shaken marbles?

Since everything is all original, it could be the harmonic balancer outer ring has slipped and it isn't 30 degrees, but shows 30 degrees. I would double check this to make sure the timing is what it is supposed to be or you may damage the engine.


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## Tiger Joe (Aug 18, 2021)

Well tried my cold start this morning. One pump to set the choke hit the key and the car actually tried to start too fast. Gave it another shot of fuel and it started. Idling with no chugging.

I don’t know at what temp the choke spring starts to open but this choke functions just like all of other carb’d cars here in PA. Just for the hell of it I checked the 3 others next to it in my garage this morning and they all closed too.
As for timing. I know the balancer is correct because I verified TDC when I put a new timing chain in. Amazing no the car did not rattle and shake. I actually had the vacuum advance disconnected so that helped some I’m sure. My only guess is that I didn’t tighten the hold down enough when I was tuning the car a few weeks back and it was slowly increasing timing, which is why I was noticing the starting issues more. I’m shocked it ran as good as it did.


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