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Topic: Tuning

in Forum: C3 Fuel, Emission Control, and Exhaust Systems


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Tuning (1/6)
 8/31/08 10:19am
msbmws
Former Member

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Dale, IN - USA

Vette(s):
1974 Corvette Project


Joined: 8/30/2008
Posts: 8

So I picked up my first C3 friday nite. (read my post in the introduction forum if you want pics, video, and some details).

We got it running off a gas can yesterday.  It requires starting fluid to fire up (choke not hooked up?).  It revs up and has power from idle.  If I dump the gas pedal hard from idle, or while trying to drive, it wants to hesitate and even shut off.

Do i need to go through timing the vehicle, checking fuel pressure, and checking all the plugs? 

Does the fuel tank have an external or internal fuel pump?  (IE, my gas can and the hose going to the engine fuel pump is not giving enough fuel pressure....)

Can someone recommend some other measures to try and get it running right?


Thanks in advance for all replies.


Steven
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Tuning (2/6)
 8/31/08 10:43am
lukesvetteLifetime Member
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HOWELL, NJ - USA

Vette(s):
1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.


Joined: 5/18/2004
Posts: 6812

Like my old man taught me, look for the simple stuff first. Good spark and fuel delivery are obvious so you've got the right things in mind. I would go through/change the following (unless you know they've recently been changed):
 
Timing, plugs, wires, cap, rotor, PCV, air filter, fuel filter (I'd change it regardless), vacuum lines/leaks. Basically a good tune up.
 
As for the carb, sounds like you might be a candidate for a rebuild.
 
BTW, did we get you right that you're not using the fuel tank and running the car from a gas can?!?!? Confused 
 
Good luck and be careful!!
 
Paul
Tuning (3/6)
 8/31/08 10:45am
Adams' AppleLifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20129

Welcome to C3VR!!!
I'd be investigating the carb at this point, or possibly a fuel line/hose that is restricted in some way. Your description of the problem leads to a fuel issue, so that's where I would be looking.
Has this car been sitting for a while?

also...your Corvette only has the one mechanical fuel pump, mounted on the engine.
unless someone has added an electrical pump, that is...Adams' Apple2008-08-31 07:47:20

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Tuning (4/6)
 8/31/08 12:44pm
msbmws
Former Member

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Dale, IN - USA

Vette(s):
1974 Corvette Project


Joined: 8/30/2008
Posts: 8

Yah, there was small gas tank in the fender when i bought it.  I used it to get it in the garage, and out once for a test drive.  The previous owner took the old tank out, and never put in the new one.  I dont want to install it now only to take it all out for the restoration. 

I dont have much information about this car, but given its condition, it most likely has sat for a long time.   Looks like someone has done a tuneup, but I havent checked all 8 plugs, or timing. 

My initial aim right now is to get it running enough to move around the shop while I prepare to do all the initial fiberglass work and collect parts to rebuild the chassis when the body is ready to come off.

Good thing for fiberglass.  I have been looking for a project car for a few months, and most all of them are rusted to peices.  I removed the rusted broken seats and about 5 inches of dirt mess under each seat to find a solid fiberglass floor pan.

My son and I love this car and greatly appreciate how valuable this forum has been already.

Steven



Tuning (5/6)
 8/31/08 11:10pm
kstyerLifetime Member
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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!


Joined: 12/2/2003
Posts: 6424

With that fuel system, it could be anything.   Take the line off of the carb and crank the engine to see if it is pumping any fuel to the carb.   Have someone watch, don't pump a lot of gas all over the place.    It's a good idea to put the line into a bottle of some sort.
 
After that, with the "custom" fuel lines, look for pinched lines or other restrictions.
Tuning (6/6)
 9/1/08 4:13pm
Curtis 79
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Elkton, MD - USA

Vette(s):
1979 Black T-Top


Joined: 8/22/2008
Posts: 13

I had a problem with mine that drove me crazy for months. It drive great, but when you put your foot in it, it fell right on it's face. I finally gave up on the rochester carborator and put a Street Demon 650 on. It is smaller than the original Rochester, but it really did wonders and is the easiest carb to work on. There are lots of good carbs out there and some swear by the rochester, but it didn't work for me. As everyone else said, vacuum lines are something to look at. The weights in the distributor could be stuck. Take your time and work through it. The Haynes Repair model may be a good investment. It can be picked up at most local parts stores for $25 and it really helped me a lot.
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