carb help

87IrocTim · Member Joined: 10 Jan 2006 Posts: 448 16836.12 points

i just bought two edelbrock carbs from some guy that lives near me. they are both electric choke, mechanicle secondary 600cfm marine carbs. one is brand new out of hte box, and the other is remanufactured, both for 250 dollars. my question is, i hooked up and tuned the brand new one, and it works fine. i had to bring the carb to the garage down the road, to get vacuum line plugs put in, but when i ran the car, there was no vacuum suction. i noticed because the manual first and second gear worked fine, but it wouldnt change into drive mode. the vacuum lines were making no suction at all. the PCV line works fine. does anyone know what i have to do to get these vacuum lines to work?

clay · Posted: Tue Apr 18, 2006 6:28 pm Post subject:

I would guess the one to the right of the PCV is constant vacuum and the one to the left is ported due to its higher location on the carb. Not very famaliar with Edelbrock, but I would just take the carb off and spray cleaner into each vacuum port and see where it comes out. It should come out somewhere. That would be the easiest thing to try. Clay

87IrocTim · Member Joined: 10 Jan 2006 Posts: 448 16836.12 points

thats the hting, i think they are purposely blocked off. if you look up marine edelbrock carbs, they do not come with vacuum line and pcf plugs.

af2 · Posted: Tue Apr 18, 2006 6:49 pm Post subject: Re: carb help

[quote="87IrocTim"]i just bought two edelbrock carbs from some guy that lives near me. they are both electric choke, mechanicle secondary 600cfm marine carbs. one is brand new out of hte box, and the other is remanufactured, both for 250 dollars. my question is, i hooked up and tuned the brand new one, and it works fine. i had to bring the carb to the garage down the road, to get vacuum line plugs put in, but when i ran the car, there was no vacuum suction. i noticed because the manual first and second gear worked fine, but it wouldnt change into drive mode. the vacuum lines were making no suction at all. the PCV line works fine. does anyone know what i have to do to get these vacuum lines to work?

[/quote

It seems you have the line in the right place. My Question is. How much silicone is used? I have seen ports plugged with it and no one ever knows. Adam

Aerosmith · Posted: Wed Apr 19, 2006 11:52 am Post subject:

If you look on theur website they have the manuals avail to download if you don't have one, I used to run a 1406 Edelbrock and couldn't figure some stuff out so I called them. They were really helpful and told me about the download..they will also mail you a manual for whatever carb you have. Those are by far the easiest carbs I ever tuned once I understood what was going on with it, just didn't flow enough for my 383.

af2 · Posted: Thu Apr 20, 2006 4:09 pm Post subject: Re: carb help

[quote="af2"]

87IrocTim · Member Joined: 10 Jan 2006 Posts: 448 16836.12 points

there is a functional plug above the butterflies. will that work for a vacuum line? and both front vacuum lines have no suction.

af2 · Posted: Thu Apr 20, 2006 8:05 pm Post subject:

87IrocTim · Member Joined: 10 Jan 2006 Posts: 448 16836.12 points

well it is jsut a plug that comes down on an angle, and its basically just a small hole above the butterflies. im going to try that as a vacuum line, but i think you have to pucture the metal plate behind the vacuum lines. i appreciate the help.

Big Dave · Posted: Sat Apr 22, 2006 3:58 pm Post subject:

You could splice into the vacuum line for the power brakes with a T-fitting. Wouldn't be ported, but constant vacuum is better than none.

af2 · Posted: Sat Apr 22, 2006 7:21 pm Post subject:

af2 · Posted: Sat Apr 22, 2006 7:50 pm Post subject:

WOW! I totaly brain farted. You don't need vacuum to shift into high gear. What the hell was I thinking? The vacuum is for down shifting and slowing the upshift via modulater that is hooked to the vacuum line. You need to give more info at this point and let me think for a decade before I can give advise. Laughing

# 1 is what trans. Sounds like a T 350. Adam

clay · Posted: Sat Apr 22, 2006 8:30 pm Post subject:

No modulator vacuum would raise line pressure to a point that he would have to really turn the motor hard to get enough govornor pressure to get a shift. I'm wondering if you have a shift kit that provides a full manual control type shift from the 1-2 manual detent position and ignores modulator signal but basically returns to normal in the "D" positon and therefore won't shift into high gear. Seems like I remember some transmissions going to max line pressure in the reverse and the 1 and 2 positions and ignore modulator signal without a shift kit. I know the 200R4 and a 700R4 do (well they ingore the TV cable, same difference), haven't tested a 350 or 400 to know for sure. Is there no passage going anywhere from the two smaller nipples on the front of the carb? This makes no sense if there isn't. Why would they put the nipple on the carb in the first place? Strange.....Clay

87IrocTim · Member Joined: 10 Jan 2006 Posts: 448 16836.12 points

its the stock automatic tranny's that cam is the 3rd generation IROC-Z's. the tranny worked fine until i put in the new carb that had the vacuum lines blocked off. my tranny has gears 1 and 2 spots, a drive spot and an overdrive spot. i was jsut thinking about it, there is a second cable at the throttle linkage that is not hooked up at the moment. does that cable allow it to go into the next gear after using the one and two manual gears?

Big Dave · Posted: Sun Apr 23, 2006 7:41 am Post subject: 8)

Throttle position sensor not hooked up will cause quite a few problems (even being out of adjustment will). Wonder how much damage that did? Yes the extra part left over has to be connected. That lets the computer know you are stepping on the gas, and controls the shift points.

Big Dave