I need to pick your brains....

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Bruce69Camaro
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I need to pick your brains....

#1 Post by Bruce69Camaro » Thu Jun 14, 2012 9:59 am

Ok, the project car is a 1978 Firebird Formula (we think??).

Motor is a 1967 Pontiac 400.

Ok, here we go, first this motor has a mild cam with a noticable loopy idle, Edelbrock intake and a Holley 600cfm carb, 4.10 gears.

First, I went to adjust the air screws and I know I should use a vacuum gauge, but I didn't have one available at the time. So I turned them in all the way and started to back them out and right about a 1/2 turn out on each side is where the motor sounded it's best at.

Does that sound right? I always thought you go in and come out 1 to 1-1/2 turns?

Problem two, on the firewall, right behind the distributor, off to the left, there is a hole, apporximately 1-1/2" in diameter with some wires running into it and then, by surprise, there is a vacuum line which comes off of the front, full port on the carb.

Anyone want to guess what that is for? I haven't dug into things but I can't figure out why there would be a hole, that is open, with electrical line and a vacuum line running into it unless the original owner put it there.

While I'm posting this, I might as well include this as well, his battery keeps draining. He bought a new battery, I checked the alternator and it's sending 14+ volts to the battery. If there was a short, wouldn't there be burnt wires? What else would cause a battery to drain, in less than a week of sooner? I guess the lighting system could cause this correct?

This car is a project and I'm thinking my brother-in-law is now realizing that he got a lemon and should have spent the extra money to get a real Trans Am. So far, with the purchase price, he's over $6500 and the car still needs a new interior, exterior repainted, new shaker hood, wheels/ tires, new exhaust and hopefully at some point, the motor doesn't let go???

I feel bad for him and just want to get this car fixed up for him, but man, first the brake issues and now electrical issues and I'm sure there will be more to come.

Thanks guys.
Those who think they know it all have no way of finding out they don't......... :scratch:

Captain.Canuck
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Re: I need to pick your brains....

#2 Post by Captain.Canuck » Thu Jun 14, 2012 5:25 pm

Not sure on the first question but in regards to the second one i have a guess. Without seeing it, my first thought goes to the climate control. If the vacuum line connects to something on the firewall thats likely where its headed.
To find the parassitic load, connect an ammmeter between battery positive and the positive battery cable and start unplugigng fuses till the ammmeter says zero. the key has to be off and all doors closed.
Thats where i'd start anyway

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Bruce69Camaro
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Re: I need to pick your brains....

#3 Post by Bruce69Camaro » Fri Jun 15, 2012 7:58 am

Thanks, I'll have to try that if the car keeps dying.

I did find the original owner did not have things wired properly in the charging loop, so maybe I fix the problem?
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wikd69
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Re: I need to pick your brains....

#4 Post by wikd69 » Sat Jun 16, 2012 1:56 am

Bruce69Camaro wrote:Thanks, I'll have to try that if the car keeps dying.

I did find the original owner did not have things wired properly in the charging loop, so maybe I fix the problem?
Can you convert it to a single-wire charging setup ? It's simple to do, by crossing the trigger wire to the power lead at the alternator plug. That way, you can take the regulator and all that other wiring, etc., out of play.
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BracketNova
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Re: I need to pick your brains....

#5 Post by BracketNova » Wed Jun 20, 2012 7:03 pm

1 1/2 turns is a starting point for Holleys but I'm not sure about Edelbrock. Old school way to set it is grab a rag and cover the top of the carb for a second or two. It should start to stall and when you pull the rag back up it should recover. If revs up it's too lean, if it dies it's too rich...I think that's how it goes.

I'd definately chase that vac line down. If it is disconnected it will cause issues with the idle. As someone else mentioned it may be for climate control.

Check the cigarette lighter for any coins ;) That'll cause the battery to drain.
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'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
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Bruce69Camaro
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Re: I need to pick your brains....

#6 Post by Bruce69Camaro » Thu Jun 21, 2012 5:34 am

I guess I should update things, first and most important to my in-law and myself, I found the electrical problem.

After I took off the origianl engine harness, I started scratching my head and what the original owner was doing?
He had the wiring so screwed up, it wasn't funny. Put it this way, the guy was wire nuting part of the charging/ starter system together.

So luckily I had my in-law get a wiring schematic and I ran the wires the "factory" way and it has started every time since.
On the Pontiac 400 there was a wire that ran straight from the + battery post to the alternator post and that wire was missing. He was trying to pull power off of ther starter and it wasn't working.

So problem one is solved, now the carb issue, I have the idle mixture screws only a 1/2 out and that is the highest vacuum reading, which was 13". Then I saw fuel dripping out pretty good between the main body and the base, so I told him we need to rebuild the carb or get a new one, so we're doing the cheap was first. Hopefully the original owner didn't crack the base plate, because it was dripping pretty good. Float levels were good and I'm going to make sure, because of the vacuum reading that it does have the right power valve, which should be a 6.5.

Then I found out where the vacuum hose went and the Firebirds use a vacuum signal to work the heater controls, like stated.

Thanks for the help.
Those who think they know it all have no way of finding out they don't......... :scratch:

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BracketNova
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Re: I need to pick your brains....

#7 Post by BracketNova » Thu Jun 21, 2012 5:40 pm

Glad to hear you're getting things sorted out.
"I always compare drag racing to lighting $100 bills on fire, only it's more expensive." - Craig W.

Check out my website...
http://www.findmoneyraces.com


'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
1.4257 60'
1700' DA

13:1 439 BBC
3330 lbs

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