Turbojoey

where is the location of the manifold absolute/differential sensor and the barometric pressure sensor? I think I know where they might be (on Firewall) but not completly sure. There are two (2) sensors (one on drivers/left side firewall; and one on passenger/right side) both appear similar (flat, rectangular) with an electrical connector going to each, and both sensors have what appears to be a vaccuum port (although only the sensor on drivers/left side has hose connected). Please someone help, I am new to these cars. Trying to narrow down vac leak.

naf

iTrader: (7)

Welcome to TGO.

Driver's side is VAC sensor (with vac hose connected) Pass side is Baro sensor (no vac hose connected. The vac line to the VAC sensor is thin, hard plastic and runs through the harness to the rear port on the carb.

How do you know it's a vac leak?

Turbojoey

I'm guessing it might be a vac leak as the idle is way too high and some hoses are very worn out, i even actually fiddled with one that looked suspect (hard plastic) and it broke away from the sensor. I think the sensor was the TVS (thermal vac sensor) as it has two hoses coming off it and threads into the thermostat housing. I asked the question because it looked as if a vac hose was missing off that baro sensor, but now you cleared that up, thanks! Also, the check engine light is not on and rpm's seem to surge while driving. Already checked electric choke (ok). The last resort is farting with the idle screws, but not too comfortable with that. The car ran fine last year, so this is a pretty new problem.

naf

iTrader: (7)

Ensure that when it's idling high that the throttle is resting on the curb idle set screw (driver's side) and not being held off by the choke - or the idle bump solenoid (I've recently seen a case where the AC control head was broken and caused the bump solenoid to stay engaged.

The TVS on the water neck controls the EFE valve in the pass side exhaust manifold. It's common for those lines to deteriorate due to the heat there.

Your accessories pull vacuum from the port on the manifold, rear of carburetor. You can plug that port temporarily to see if the idle changes.

When's the last time the cap/rotor/plugs and O2 were replaced?

Turbojoey

Thanks so much for this info, it is really helping me out! The rotor, cap and o2 sensor more than likely need attention as well. I will have to check that ac solenoidplunger deal to see if it's working, retracting..... As far as the curb idle , can just turn that screw in or out if everthing else looks ok? Or do I need to go to other side and adjust the fast idle screw under the choke? One last thing, any ideas onhow to make repair to the hard vaccuum lines coming off of the tvs sensor, the line snapped off right at the rubber boot on side of the sensor. Again thanks for the great info!

naf

iTrader: (7)

If the car ran fine before, try to troubleshoot and find the problem before making any adjustments to the curb idle or fast idle. Sometimes all that's needed is a good spray down with carb cleaner to free things up on the choke side, if that's what's hanging up.

You can splice the hard line back together with a small section of appropriately sized rubber line.

Turbojoey

Naf, thanks so much for all your help! I will let u know how I made out.

Turbojoey

Hey Naf, I was able to bring down idle by backing off bump idle solenoid and adjusting the curb idle screw, but when u blip throttle inside car, the rpms get stuck at around 1100 or so. If you push the throttle a couple of times the idle returns to about 7-800 in park. The throttle does not seem to get hung up when I manipulate it under the hood though. Could it be that the throttle cable is bad or worn? Could it also be a sticky throttle shaft? I am out of ideas short of a rebuilt carb.

naf

iTrader: (7)

Spray everything down good with carb cleaner then see how it works.

Make sure the throttle return spring isn't stretched or broke (it should be a dual spring) and that the cable is not crimped somewhere. Otherwise you may want to check that the cable travels smoothly in its sheath and that the pedal is not loose or getting hung up.

Turbojoey

Naf, tried spraying it down and used whole can. all looks to ok with spring, unknown if i saw two or not, the car belongs to friend. the cable and peddle seem fine, but if I pull forward on the throttle lever toward front of car, the tab comes back in contact with the idle screw and all is back to proper idle at about 700-800 in park. I may elect to just find replacement throttle cable or somehow lubricate the existing one. I'd rather start there first than rushing out to get a rebuilt carb (about $500 @ autozone). If I was to grab a new cable, is autozone etc.... an ok place to go, or do they just carry universal stuff? The car sat all winter and most of spring without being driven. All was fine before car was put away (outside). I told him to drive car and maybe it will work the cable a bit and eventually get back to normal. I am stumped and kinda feel like I failed.