1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

I know I have posted a couple problems already, and I appreciate all those who have been trying to help. I really like my car, but it seems to have multiple problems all at once, but this is one of them that have had since I first drove and I haven't been able to figure it out yet and I don't feel it is a good thing, compared to some of the other problems I've mentioned.

Whether the car is cold or hot , it usually idles pretty high, sometimes when it warms up or sometimes before it may even warm up the idle may come down a little bit, but most of the time it is idleing way higher than it should enough that I can stop the car and take my foot off the gas and it'll go on its own pretty good. So let me explain where the idles have been at and while driving.

When I first crank it at cold, it may quickly go up to like 3000 or 3500 RPMS but then as it should come down but has been hanging out between 2000 and 2500 when cold. and if I put it in gear when cold, may idle around 1500 w/o gas just holding the brake while its in gear. Sometimes after a minute it may come down a tad but not much. when driving it let's say I put it in drive with the brake and do not touch the gas. it'll idle between 1200 and 1500, when it park it may idle between 1500 to 2000, the tach goes up faster than it actually starts to move and sometime goes up to between 3000 to just barely touching the first warning color sign I think between 4000 and 4500, before moving, it doesn't shift hard or jerks when shifting but the RPMS go way up each time and very quickly. takes a second and then it moves pretty fast, even with the loud muffler that I am trying to replace right now.

I have sprayed all sorts of stuff around the intake and check for vacuum leaks hadn't really find anything evident. I did have that knocking in cylinder 6. New spark plugs, wires, cap/rotor and ignition coil. I even replaced the control module and pick up coil, because the control module tested bad. there was a code 34 MAP sensor at one point but it never showed up again after I cleared codes and may have been in there already when I bought the car. I actually went and bought one tonight, just plugged it in to see any difference, none. I did replace the IAC because it was sort of stuck and I did have it reseat with the key on (but not the engine) but that didn't really matter. I have no other engine codes since.

I don't know why it idles so high and I am not sure what direction to go next. I thought TPS, and when the TPS goes out in my VAN (not Camaro), I know the symptoms and it doesn't spit any engine codes, it just surges up and down and sometimes trans slips or shifts hard.. but I only get high idles whether in park, in drive sitting and while moving.. the tach is way high than it should be. I did put a different fuel regulator on . ive changed the pcv valve and all my filters.

its a 305 TBI V8 engine. on 1992 Camaro. the egr valve does move when you open throttle.. it doesn't idle very smooth when just in park or sitting I mean you can feel it idleing a little rough.may be exhaust contributing there too because the muffler is loud but working on getting that changed. otherwise, I don't know what else to think. head gasket leak but I don't know. I did a coolant pressure test but that came out okay there. I have adjusted the valves. was trying to think of easier things before hooking compression hoses up to the spark plug holes and things. but I don't know what else to do. Just didn't want to replace a dozen sensors, even without engine codes (which I donot always get).

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Remove the throttle body, clean all the ports & passages, & replace the base gasket. That gasket sometimes will get sucked in causing a vacuum leak.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

What is the ignition timing at idle with the brown wire disconnected?

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Well, I had just recently, I mean like within the past week recently adjust the engine timing and it was steady at 0. when I tighten the hold-down bolt to the distributer, it slightly tends to move a tad, but I tried to hold the cap and tighten it and double check the timing, it didn't bounce around or anything so it seemed pretty steady.

I did tighten the TBI bolts they did tighten more (I know there's a torque and I have torque wrenches) but just wanted to see if any small adjustment might help. I could/can try and replace the gasket, it's in expensive, just might have to scrape off stuff from the old. I've done a lot of work on the Camaro I used to have (pulling intake and heads off of it over those years) but I can try that.

I did go out and buy a CTS sensor . I had no engine code, but I've seen posts about those, and it wasn't expensive, im in that process right now.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Well I replaced the TBI base gasket. It wasn't cracked or broken but hard, but I replaced it anyway. I replaced a bunch of vacuum lines as well. many easily cracked and snapped the minute I pulled on them. I changed my muffler, prob need to go have parts of the pipes welded closed, but not as noisy. I did change the CTS sensor, I haven't let it warmed up yet, but it is cold idling at about 2500 in park and about 1500 in drive. I'll go back out and let it warm up and see if it drops at all.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

OKay when warmed up it's between 12.5 and 15 in park idleing, but in drive with brakes it only goes to about 1100 rpms or 1200 rpms, just about the 10 mark. and it'll drive ya if you let go of the brakes. Also can here the ignition coil buzzing again, and it goes up with the rpms (hear it better in park or when it idles past a certain point) and when you left off the noise will drop below what it was then go back up a little bit. it's not the lifters, its a whole different noise, almost more a buzzing but its from the coil because I've had my ear very close to it when it was mounted away from the engine. (but I've moved it back to where it originally went) and replaced the coil. so maybe it's a loud coil, not sure there.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

This sounds pretty darn familiar I have a 91 5.0 tbi and the freaking thing idled way high it often would spin the rear tires as I sat at a wet intersection and it made mountain winter driving dangerous to say the least. Try letting the car go through its idle changes when it drops as far as it's going to(you know the car best) try unplugging the tps with the car running and see if it drops. Try doing the same with your cold air charge sensor if yours has it it's the round wired sensor in the air cleaner. I replaced my cold air charge sensor and bam idle at 650 the tps made it act funny in general just an easy check if you have the means to a less primative test on these sensors go for it but this worked for me. I'd say also check iac but you mentioned you'd already replaced it.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

I had the same problem in my Astro.... with a 4.3. I could not find any rhyme or reason for it... but, after breaking a bolt off in the intake when attempting to change the thermostat, I ended up having to pull the intake...... Once everything was reassembled, started it up, and it idled MUCH lower than it used to.... Thought I had done something wrong, till I realized it was now idling the way it should. :)

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Just went through something similar with my 91 TBI firebird, Was idling at 1500 and ROUGH. Turns out a few things were wrong - vacuum leak from a cracked line, TPS was way off at idle, and IAC wasn't functioning correctly. If you haven't already I highly recommend going through the idle setting procedure on the how to pages, it helped me because while everything was wrong I was able to set a correct idle, which quickly was lost. Replaced the IAC, did the procedure again and got down to about 800 idle. Noticed TPS was off and replaced that, which was the final key. for me TPS voltage needs to be around .53-.55 at idle and 4.00+ at WOT.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Would this be the same on a 92 Chevy pickup with a 305 tbi, but running 350 injectors, computers, knock sensor, and esc module. I'm having to run it 30 degrees off tdc on cylinder one to make it level out and have a top end and bottom end

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

So instead of setting the timing at "0" which is factory spec, you're setting the timing at 30 degrees advanced?

I guess that's telling you that your advance system is faulty.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

You did pull the wire when you set the timing right? The one near the blower motor


iac idle screw in too far. Read the section on setting it

My 91 305tbi used to do same thing. Low and behold old dead vacuum line near the charcoal canister was bad. Check the hoses a 26 year old car has plenty of bad ones... I replaced all sorta of parts. Iac tps,map, you name it heck even. New edelbrock intake and egr. And it was a simple vacuum leak.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Is your accelerator return spring broken/disconnected/missing? It would connect to somewhere along the edge of the driver's side valve cover

Mine was missing and I replaced it with a universal one from Autozone. It cut my idle from 1100 to 500 rpm when idling in gear, and from 1100-1500 to 700 rpm in park.

My setup is a bone-stock 88 Firebird 305 TBI with the TH700R4 if that helps for comparison purposes.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

I drove and rebuilt my stock 92 several times from the a frames to the IAC (idle air control) as i was told it was called. Names dont matter though. What matters is i can fix you up. When my 92 did this it was a bad egr valve and a poor tuned iac screw. There should be a screw on your throttle body that holds your throttle open just enough to let your car idle. Too much and you get high revs poor shifts ( due to syncros having trouble catching up.) And your problem in drive as well. In which your car goes all on its own. Try adjusting your your IAC screw and see if that fixs your issue ..works as youd think tightne ooens it up more lossen close the throttle off.

1985 Z28 camaro 305 v8 high idle 2500 rpms
 

I recently put a edlebroc intake and a 600cfm summit 4150 Holly style carb. Had the timing set by some guys my idle is still to high, before I changed the carb and intake it would idle at about 900, they also took the vacuum advance off the distributor said when it was in it was making the idle even higher, it seems we messed with everything floats, idle and curb idle no luck on getting a nice idle,. Any ideas

Re: 1985 Z28 camaro 305 v8 high idle 2500 rpms
 

Well that's concerning, and not right if it's plumbed /set up correctly.

Re: 1985 Z28 camaro 305 v8 high idle 2500 rpms
 

Why are you posting in the TBI forum if you don't have a TBI?

Which one?
Which one? Far as I know, all the Summit carbs are 4010 style. I think Holley builds them exclusively for Summit. Either that, or Summit bought the tooling from Holley.
You need different helpers.

What is the initial timing? What is the total timing? What kind of choke does the carb have? Does the choke work? Any chance the fast-idle cam is why the engine won't curb idle? Describe the PCV system.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

This may not sound relevant but it is. At least on the 3.8 anyways. Switch out with a different battery as well as inspect/address any slack in the serpentine belt. All them sensors and whatnot at the intake requires specific volts and amps to function as intended. Restrict some volts or amps to em and you'll soon find out how 99% of the time? It's the easiest thing to initially fail.

Re: 1985 Z28 camaro 305 v8 high idle 2500 rpms
 

Well I'll tell you something about that high idle you're going to have nothing but problems with it best thing to do is Rip all that fuel injection Crossfire crap off of their put a high-rise in a holly on it will solve all your problems all of them dude

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

You take all that TV I rip all the vacuum out all you got to do is put a high-rise and a holly on here and all you need is racking to the carburetor you don't even need the EGR man I don't have one and I'm not running it I got rid of all that crap it's beautiful no problems solve them all and kick it wiring harness you just try all that crap back if you

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Okay I'm going to tell you this one more time this is going to solve all of your problems take the manifold off put a high rise and a Holley carburetor on there you don't even need the sensors okay all you need is oxygen sensor that's it with all that garbage I am serious I had the same problem and when I got rid of that TBI system salt all of them every one problem I had idle problem sensor problems gone I run vacuum to my brake booster I run vacuum to my cruise control I run vacuum to my crankcase ventilation Josh and vacuum to my carburetor I don't even mess with the distributor at all don't even unplug the distributor leave it it'll work just fine oh and did I mention you don't need that EGR crap get rid of i

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

I'm guessing your car runs and emission-tests about as good as your communication skills. Around here, they teach sentence structure, punctuation, and capitalization in about third grade.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Check your throttle position sensor for it may have gone bad or if your brakes are hard to operate you may have a vacuum leak inside the brake booster is the reason why you're not finding it outside spraying

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

dear mr buttrammed

seek advanced education and punctuation 101.you are typing randomly but none of what you are saying is relevant or makes any sense.
removing efi then replacing it with a carb is not the answer,that's just more problems waiting to happen and another messed up car.
just because something works after macgivering it doesn't mean its right,efi "when working as intended" is far more efficient

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

REALLY?! This is a statement usually made by people that do not understand CFI AT ALL and since they can't figure it out, they rip it all off and put a carb on it, which usually doesn't solve the problem. The real issue more than likely with a CFI system is, too many BUBBA's had their hands in the mix and only compounded the issue. Also, punctuation and spelling IS key on any forum when responding. I makes it MUCH easier to figure out what you are talking about and not just a run-on sentence...FOREVER. :doh: My CFI runs well, in the mid 12s. Jus sayin'.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

I agree with using TBI. Can get them bored and use bigger injectors and more efficient. Efficiency=H.P.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

How do I get out a broken spark plug from a 2002 Dodge 1500 pickup?

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

is the porcelain part broken or is the metal part of the plug seized in? you will need to soak it with penetrating oil then maybe try an extractor or hammer a socket on,it depends on the scenario that is involved.
let me know and ill try to help you,you can also drill out the old plug then chase it with a tap but you need to be extremely precise as to not screw up the threads in the head.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

Will try on Friday and let you know where I get. Thanks

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

I had the same problem with my 92 Camaro and the fix for me was a holley 650 tbi with 2" barrels had to re wire the tips and injectors to the different plug connectors but it completely fixed everything as I had done all the checking that you had done. I am a certified mechanic and it had me stumped until I installed the holly but I admit I had to do a few modifications to bolt it on had to machine the spacer plate to except the bigger 2" barrels and the major one was to drill and tap for the iac because I used a tbi that was made for a carb engine it had its own stand alone computer and wiring harness but if you have the mechanical ability its a great addition to the car mine runes great unfortunately I got T-boned in it 3 months ago but IV got a new 92 25th anaversery edition 5 speed that im fixing to do the same thing to because this one just all of a sudden dies while idling at a stoplight but il keep you informed if it makes any improvement on my new one

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

I have skim this. Was the problem fixed? I am having a similar problem with mine. Just bought it mice ate a good chunk on the wiring. I'm doing a carb but it is not cranking and no fuel pump. I literally put the battery in for the first time tonight I was just seeing if I could get it to crank. I have bypassed the vats and curious on where I should start checking. wiring under the desk is a mess I thought I cleaned everything up in the engine bay. Just looking to see if anybody else has had this problem

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

mine did something similar. turned out the mass airflow sensors vacuum hose has come off. put it back on and it was good.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

MAP sensor, not MAF.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

what your describing could be one of 20-30 things especially if you are dealing with a mice chewed harness.you need to trouble shoot one issue at a time and make sure it is good ,corrected properly and satisfactorily before moving on to the next thing.trying to do 10 things at the same time always ends the same way(badly)either you fixed everything in the engine bay or you didn't,theres no " i think i might have" its only "yes or no".....its hard to diagnose something you cant see with dozens of unknown variables and sub standard half A$$ed wiring fixes.we want to help,we need to know exactly what the current state of the car is,no guessing.

Re: 1992 camaro 305 v8 TBI idles very high and shifts at high idles
 

With all the changes you have done have you tried to reset the computer by unhooking tje battery and leaving the positive and negative wires connected for 10 minutes I have done this on my truck and it seemed to help