Longtime lurker, first time poster

I recently picked up a 92 RS that had been swapped to what seems to be an older stock Camaro carb setup by the previous owner.

It has a ton of issues to work through, but the one I want to address first is rough idle. Upon starting it surges and wants to die, and goes away somewhat if you get it up to temp. I've searched the forums and it seems that most fixes have to do with the IAC or EGR valve, but if I'm reading correctly I wouldn't have these issues since I no longer have an ECM.

Any clue where to start? I'm no mechanic but I do like to tinker and am decent with tools

 

The problem with this sort of thing is you're not 100% sure where you're starting and you need to establish that. I'd determine if it's an electronic QJ being operated with out the computer first. There's a blue connector on the front of it is. If that's the case swap it off immediately. Easy to spot visually

The second thing I'd do is try fresh gas if it's been sitting. Junky gas can be annoying and do annoying things like clog fuel strainers (may be good to check fuel pressure too especially with it being EFI originally.)

I'd also want to see how the fuel system is configured. Did they use a mechanical pump or put a regulator on the EFI pump? Either will work and although some bypass the pump with a piece of line to the pickup some people run through the pump but it's generally considered ill advised. Kind of a headache to check honestly unless they hacked an access door into the trunk.

Besides this I'd also check the base timing and see where it is. Disconnect the vacuum line and plug it when you do this. Depending on the engine 12-16 degrees is probably about right. Typically I like to set idle by a vacuum gauge. Just go for max vacuum and see what happens.

What's the chances he cammed it by the way? That could affect idle as well.

The well plugs on Quadrajets are also known for leaking but usually that's associated with startup after it's been fully warmed up. See this:

https://www.hotrod.com/articles/hppp...yImageId=14222

Lastly and this is probably the not so great one is if it's a flat tappet cam there's a chance it ate a lobe on the cam or two. Pop the valve covers and see if there's any super loose pushrods. Obviously not a good day but it's been known to happen these days.

 

Awesome thanks for the advice. I definitely have to dive into the fuel system as the fuel gauge is inop (reads empty) which from forum searching seems to be a break in the wiring between the sender and the gauge. Not sure of the fuel pump setup but it allegedly has a new fuel tank, which I assume was done to modify the pump and pickup.

I'm pretty sure it isn't cammed, but the odometer reads 181k and that was before it stopped working along with the speedo so who knows, could have a rounded lobe. I'm working this weekend but will be getting back into it next week

 

It may not be a break in the wiring it could also be the sensor its self. On my Astro it was that the fuel gauge its self was stuck. I'm not sure if there's an intermediate connector that you can disconnect (once again I'm not sure on the Camaros) you can disconnect the wire it should go one way and if you connect the wire to ground it should go the other (e.g. full to empty.) If it doesn't the gauge or wiring to it is suspect.

Probably lower priority than the engine running but still a headache. Trust me I know.

 

That's definitely possible as the only gauge that works in my cluster is the tach. Once the engine is running well I'll be tackling the temp and fuel gauge, everything else can wait.