I really need help from you guys I don’t know a lot about cars but since I’ve gotten my 3rd gen I’ve been really trying to understand so recently my timing to my car was moved I say timing because you can hear how high the car is revving while it’s idling in park once I go from park to drive my car drops Rpms and stalls out on me it’s been doing it a lot recently and it happens to me on the freeway which was pretty scary not really trying to die as a 28 year old inside my z28 lol also I’m not sure if it’s worth mentioning but after driving for a while and cruising in my car I hear this weird like humming sound coming from under where the gas tank is at ?? Last weeks I did replace my gaskets to my valve covers and after that that’s when my car started acting up. I’ve attached a video so you guys could see what I’m talking about I have a longer video but I had to cut it down from 50seconds to just a 6 second video

 

To start off, that isn't a carburetor. That's dual throttle body injection (TBI) known as "Crossfire". It was the "high performance" offering from the factory for the first couple of years of third gens.

I have never had one of those, and haven't worked on them, and consequently don't know much about the system.

I do know, however, that the TBIs (Crossfire) was fed by an in-tank electric fuel pump, which is the humming you're hearing.

Try posting on the TBI forum. Those guys should be more helpful.

 

thank you so much for your response and for pointing me to the right direction I really appreciate your help brother have a blessed day 🤙🏼

 

I know about CFI.

Your first two check should be looking for a vacuum leak and checking fuel pressure. You can easily test fuel pressure by "T'ing" into the rubber fuel hose where it runs from the frame rail, to the hard line on the engine. Pressure SPEC is 9-13 PSSI....those engines most definitely "like"12-13....the high end of the spec.

Same goes for ignition timing; spec is 6*, IIRC, but the factory spec is way WAY too conservative and they typically like 10+* base timing. Mine was best at 12.


Does the vid have sound? I can't hear any, but I see it shaking pretty good. Did you pull plug wires when doing VC gaskets? I would double....triple....quadruple check 'em.

 

the video should have sound I’m not sure if it got cut out during upload but it should have sound, im definitely gonna check that out later on but the main issue is that we set the timing to the lowest setting and for whatever reason the car shoots the Rpms back up high and the car begins to rev at 2500-3000Rpms on park and once i go on drive after 10 seconds they drop to 500Rpms and the car dies on me this is the most I’ve been stressed as she’s my daily and need her to get to work lol I really appreciate everyone helping, you guys are awesome and I truly appreciate you guys taking the time out of your day to help me out

 

I hear you on the timing. It's possible that your harmonic damper has slipped so your reference for setting the timing is wrong, but that usually results in rought running if/when the timing is way too far advanced...not "revving at 2500 - 3000 RPM. To ME, the First thing I'd focus on would be this:
Plug wires/firing order. That shouldn't cause hi idle either....but many times, when you've just done a thing....then you got a problem....Hmmmmmm.....

 

so I did as you said followed the harness and found an unplugged connector now I’m gonna see if I can’t find where it goes it seems like it might be a connection for check valve? Or am I wrong does the check valve have a plug you have to plug into??

 

Vacuum leak. Plug in a vacuum gauge, it should be at least 15" and steady at idle, probably closer to 20" hg. You can also check for it the shade tree way by spraying choke cleaner around the intake area and listen for the engine to drop in rpm. Not recommending this method but there are times when it has worked. Probably left off or misrouted a vacuum line.