db057

I have a 1992 Camaro RS 305 TBI

I've posted several different postings for different problems, but one that never has been resolved is this high idle problem, especially as base idle (in gear) and when idling. The car is in mint condition body, of course everything else expires on me. Still, I want to fix it, and I can use any other input

This is what I have done to the car so far. Some of it was bad, some of it was uncertain. I have no engine codes although there was a code 34 (MAP sensor) a couple months back when I jumped the engine codes the day it died in traffic (2 days after I got it) I had tried to change the map sensor and that didn't matter but I know other symptoms can cause that code to trigger. I haven't seen that code since tho.

I have replaced the IAC valce and connector, the TPS , fuel injectors, fuel pressure regulator, fuel filter, I replaced just about every vacuum hose there was. I sprayed around the carb and engine and no change in idle speed. I had even replaced the valve and filter that plugs into the vacuum power booster.

I have changed the timing chain (but the timing was fluctuating and the old chain was grimy and slacked) and now the timing is at a 0 tdc. I replaced and resealed the intake manifold gasket. I had tighten some exhaust manifold bolts. I have new distrubuter now which came with new ignition module, new cap & rotor, new ignition coil and new wires for it, new spark wires, new spark plugs. new gaskets for the TBI and sprayed clean. new EGR valve.

I bought some sort of cheap smoker machine that may work okay but I haven't used it quite yet.
I haven't checked the fuel pressure , because I don't have an adapter for a TBI.

there is a hum sound, and I couldn't tell if it was from the front or back. I know alternator hum sounds, but this is a low, or high pitch, can rise in pitch a bit with acceleration. Sounds like it coming from the back of the car. I thought it was road whistling noise when you drive past certain concrete roads/building that echoing noise, but its not. I have a new alternator and I fixed the fuse link problem. So I am pretty sure its from the back.

if I am coasting I don't hear it, but the minute I start to accelerate I start to hear it. also heard it with the hood popped and about at 3000 RPMs. or more

I was thinking fuel pump. but the car does start, rough idle, but no noticeable misfires, some stumble/hesitation at low acceleration, but after 3000 rpms or more sometimes it smooths out.. not the best up hills.

Idles high still. base idle is around 1200 in gear. can go up to 4000 before it shifts, but doesn't feel like any slipping of the trans feels like its just idling so high, its like adding 1000 rpms all the time

ive adjusted the IAC valve and base idle. and I can get it down to 750, but if I go too low it starts to buzz, and act out weird. still buzzing sounds from ignition coil. at times may just be static or the way that coil works.

but it seems no matter how low the idle screw and base idle (by extending the iac valve and then unplugging it) no matter how low I get it, it seems to compensate and keeps it around 1200,. sometimes more even at this is at warmed up

also replaced the coolant temperature sensor

is it possible with low fuel pressure to cause a higher idle? (maybe higher vacuum to suck the fuel down) and is that a fuel pump hum sound possibly?

it hasn't died yet. what caused it to die 2 months ago was a bad ignition control module.

I could just replace the fuel pump, but that's a pain.. Any suggestions or am I leaning towards my possible problem? Appreciate it. thanks!

db057

Also, the sound is from the back, but it happens with the push of the accelerator no matter where my RPMS at while coasting. even 2000 rpms or more. will still make sound

Burnin'Bird

Check your tv cable for wear or stretch and adjust or replace as neccessary.

Tuned Performance

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