Help! Engine wont idle

[nova385]

I finally installed my 383 stroker in to my nova. I started the engine up broke in the cam and let the engine idle for about an hour. Turn it off for a bit then ran in agian for a hour. Everything was working great the engine was producing tons of vac. the temp was good and the oil pressure good. Once I tryed driveing the car on the street I drove a few hundred feet and the engine shut off. I tryed starting it back up but the only way it keep it on is if I keep my foot on the gas. The car wont idle it as soon as I take my foot on the gas the engine shuts off. I check and the vacum hoses and there all properly connected and the fuel pressure is a 7 psi. Any suggestions as to whats wrong?

[68protouring454]

maybe idle screw loosened up and fell out?? check the carb out
jake

[dhardison]

Carb not properly sealed to the intake? Take some carb cleaner and spray around the base of the carb, if the RPMs drop you've found a base gasket leak. Sounds like a loss of vacuum somewhere.

Also, what's your initial timing set to. Maybe too low?

HTH,
Dan

[TurboLark]

Did it backfire up the carb? If so you may have a blown power valve.

[toofun]

I ask only because I had the SAME EXACT PROBLEM with my old car about a year ago. I put in a stroker 383 then I started it, broke in the cam and let it idle IN PARK. When I tried to put it in gear it would die on me and not stay started. I heard everything from timing to carb/vaccuum leaks.

Problem was I had a STOCK torque converter in my automatic tranny that DRAGGED the motor down causing it to die out when put in gear. If you have an automatic, willing to bet you need a higher STALL converter to correct the problem. I went to a 2400 stall and it corrected the problem immediately.

[nova385]

The engine did backfire when it went out. I changed the power valve like you guys suggested and it didnt fix the problem. I idle screw is still on the carb, and all the vacs are correctly connected.

It cant be the stall because I have a 2400 stall converter...

I'm stumped cuz the engine was runing perfectly fine then all of a sudden this happens

[paul67]

Does the tail pipes look black, does it start cold without choke if so it could be that the fuel pressure is to high and not allowing the float to shut the fuel off try dropping the pressure to about 5. I always run at 4.5 on a sbc 350 what dia fuel lines are you running
paul67

[toofun]

OK,

If your car wont idle unless you press on the gas then I have to think that you have a problem with the idle circuit in your carb or the distributer skipped a couple of teeth and the timing is off. When you mash the gas you are bypassing the idle circuit and squirting fuel straight into it. How old is the carb? Is it new? If you want to test this theory then I would swap out the carb with a buddy if you can and see if the car starts and idles. If it does then you have an internal problem with your carb and should have it looked at. If not you can eliminate the fuel part of the equation. Pull the distributer as well and inspect the gear. Some applications require you to use a brass gear. Maybe someone else can elaborate on this.

Mark

[woody80z28]

I'm having a similar problem with my Camaro's 355. It's a 4-speed that stalls when I attempt to take off, and no it's not just that I need to give it more gas.

With the vacuum advance set as close to the intake manifold as possible without hitting it it idles ok and is 4 degrees retarded, but it won't take off.

However, I switched the plugs on the distributor to one spot off so I'd have room to make it about 8 degrees advanced, and it idles way too high (even with the idle screw with no adjustment left in it) to get an accurate reading with a timing light. I've tried moving the advance around to find a sweet spot but can't. The car will move on its own power, but it idles beween 1700-2100 rpms.

Any ideas?

[paul67]

You could have to much vac and its pulling the timing ,whats it like with vac off dizzy, had this on range rover V8 . it did it when it got warm.Also what about the vac on the auto box?
paul67.

[nova385]

Where is the idle circuit located?

I bought the carb in a swaptmeet, I just pulled it apart, replaced all the gaskets and cleaned it up with carb cleaner. It ran great up until this point. So I really dont now how old the carb is. Its a Holley 750 CFM with vac. secondaries.