amf133

I just boguth my dream car, a 1981 Corvette with the 350 5.7L V8 engine. I just bought the car and theres problems with it already. I dont know much about these motors and really need help. Car starts right up but has a low idle and eventually dies if you dont keep giving it gas. When you do give it gas it kind of pops and doesnt really want to just rev up. I was thinking it was the egr or the vacum lines but im not sure. Can someone please help and let me know what they think it could be.
Thanks
Andrew

a1sensei

Does it just do it when cold, or does it do it when it is warmed up too?

God bless, Sensei

amf133

it does it mainly when its warmed up but does do it when it cold too

a1sensei

There are a number of things it could be.

Yes, check and see if the EGR valve is stuck open,

Also check the timing: warm up, unplug the 4-pin connector at the distributor and set for 12-14 BTDC (the manual says 6 BTDC, but just trust me). Then re-connect the plug.

Check for vacuum leaks: look for disconnected/ dry rotted hoses, spray WD40 around the carb base as the engine is idling and see if the idle goes up when you hit a certain place.

You may just need to adjust the idle screw up a little, but otherwise it sounds like there may be a problem with the carb. Try these things and let me know what happens. I'm sure it won't be any major thing to fix it.

God bless, Sensei

SY81VETTE

I am having the same exact issue. Got the car a month ago. It has a Holley 4150 carb and I still have the original carb
​​​​​​

Tonio

Might be a plugged port in the idle circuit. I just went through this on my '72. The carb's base plate gasket was the wrong one...the idle port was blocked off, killing fuel flow at idle.

Also, check the little vents in the carb throat that are under the choke butterfly at the primary side....make sure those tiny ports aren't plugged. I use a 0.024 MIG welding wire to run into them to make sure they are open/not clogged.

FB#1

Check the vac hoses on the carb, especially on the inside/outside of bends.

Bikespace

Did it do it since it was new, or did you change something?

Check the vacuum first, then do a proper ignition timing. Search the forum for Lars' method. Also check all of your plug wires.

Here's a link that may help, with a response from Lars, assuming you still have the '81 ignition system:
https://www.corvetteforum.com/forums...te-timing.html

Reaper19

First I would follow Bikespace's advice. I have an 81 and went through all of the checks with some fine tuning using Lars techniques and got the carb fine tuned after rebuilding. A lot of it will also depend on the condition of the carb.
Is it dirty?
When was it rebuilt, if ever?
Are all of the CCC (computer) electronics still working?
Any error codes or check engine light?
Are all of the vacuum lines connected properly?
Is there a vacuum leak?
What is the timing set to?

There are many different systems to check. If you have a 1981 shop manual there a some very good detailed troubleshooting charts included. If you do not have a 1981 shop manual I would pick one up as well as an AIM (Assembly Manual).

prostreeter

mine acted up the same way, replaced o2 sensor no problems since