(Kind of a mild rant...) Roughly how warm does it have to get outside before my p.o.s. (91 camaro, stock lo3, 5 speed) will stop with the 1700rpm cold idle b.s. for 3-6 mins. ?
It's really starting to irritate the f___ out of me every morning (along with other reasons I could say why I hate this TBI heap of ___). I'm ready to just light the dammed thing ablaze.. if it weren't for needing it for transportation.
It wouldn't bother me if it could cold idle at a reasonable rpm... like 1200 or so. Does it really have to idle so high ?
Aside from a bat.. is there a solution ?

 

Yes, lower the IAC counts so its more reasonable on cold starts. It wont sit there and idle at a zillion rpm forever. Other then that, youll just have to deal with it. Mine did that stock and I hated it as well. Especially in the snow. The car would just keep going even with the brakes on.

 

Chances are your tach is off and it is really not ideling that high. It idles that high to build the necessary oil pressure and raise the temps faster in a cold engine. It is better for the engine in the long run.

 

I'd question the tach being that far off because when it warm idles, the idle rpm is 700(ish). Also, compared to my Firebird which cold idles at 1200 or so, the sound (cold idle rpm) is considerably higher between the 2 motors (both 305's).

As far as good for the motor... it's clocking 157xxx at the moment... I'm just happy it's still running "smoothly"

I figured the cold idle was a PROM thing but, in a small sense.. hoping it was just something else. Doesn't hurt to ask though.

The main part was, which I didn't say but, was basically answered, was the idle just seemed so outrageously high (cold start then jacking straight up to 1700rpm didn't seem to 'heatly' on a cold start IMO).

The biggest problem I had coming to terms with it was my TPI cold idles high for roughly a minute as to where the TBI just carries on and on and on which is annoying as hell.

I appreciate the answers much though guys. Thank you.


If anyone bothers to read this far.. I have one other question.
I know TBI is kind of limp wristed on power but, mine is lacking even more so. It's very hesitant with throttle input...ie: push gas pedal.. hear noise like something is happening.. accelerated normally (as in light cruise accelerate) or even less than. When letting off, it will step (literally) up in responce.
Would this be a good sign of lack of fuel ? I'm assuming lack of pressure (drop) just lets solid droplets of fuel out of the injectors when the pulse increases during WOT making for a crappy acceleration until the motor has enough rpm (intake velocity) to start breaking up the fuel before it reaches the cyl.. is that a wrong thought ?
It hunts when coasting even if the IAC is unplugged.
The TPS, MAP, coil, cap, rotor, plugs, filter, air cleaner and EGR have all been replaced. I don't have the gauge to test FP.

(if any parts isn't coherent.. you'll have to excuse my semi-drunkeness and feel free to correct me)

 

You are thinking to much. I think you are just used to the lack of power the LO3 makes in stock form. Add some miles to them and things can get worse. You may want to make sure your 02 is working ok and bump the timing a bit. Those are few things that can put a little umph into your ride.

 

that was one I forgot.. the o2 was replaced when I 1st got the car (12k mi ago roughly). It had a plug wire off on the drivers side making it feel like a bad fuel pump. The sensor was cooked and replaced at the time of the wires, etc.

While I don't have alot of expectations from the poor lo3, I did test drive an 88 TBI t/a prior to buying my 91 which had considerably more throttle 'pep'/responce (don't read that as actual speed).

I am constantly reminded it is total limp d___ compared to my 'bird but, here is the problem I'm getting that leads me to think the fuel pump (or related delivery parts) is going south.

I have replaced the timing chain 3k-ish miles ago with a double roller to assure timing was accurate (it was idle loping after the ignition fix which I know the lo3 doesn't have that kind of cam to do). The timing is 2° after remarking the balancer which, has spun 10° off (and my be an additional problem as well).
If I try to floor it in 1st just after letting out the clutch for some "spirited" (as well as you get for the motor anyways...) it just bogs.. the exhaust gets louder (more air passing through the motors) but yet, it just moderately accelerated... and I mean like.. stop and go traffic accelerate.
If I were to ride the clutch with a high rpm drop and floor it.. it actually responds and "moves".

The prior owner knew nothing of the car.. he just bought is from a friend because his wife liked the color (go figure) and they had 2 other f-bodies (quite nice ones actually). I asked about the clutch (which is now about dead) and the FP due to the hesitation when I test drove it.. he knew of no service to either.

When I got my 'bird many moons back.. it had a bad FP as well which made it hesitate, stumble, and jerk. I am just guessing that a TBI's lower pressure wouldn't cause quite the dramatic problems from perssure loss as a TPI would but still, affect throttle responce.

Also (as if I weren't annoyingly rambling on long enough huh ?), I'm leaning towards the FPR being on its limits end. Once in awhile when the 2 second prime goes, there will be a similar sound from the engine bay like a coffee maker squeezing out its last cup of coffee (you know that awful gurgle/suck sound they make).

I'm willing to replace both since it's not a big deal to do but, I'd like to have some extra input from a little more knowledageable people than myself that I'm looking in the right direction.

I appreciate your time (just for reading this) and any input guys. My apologies for being so long winded..... Thanks.

 

i wouldnt loose any sleep over it. When cold, the stock calibration is set so the motor will have a fast idle up to around 1500 rpm, which will probably be closer to 1700 to 1800 rpm on your tach. Not much to be done about it unless you chage stuff in the prom. A little tinkering will get it not to flare so high and get the idle to come down quickly to the curb idle speed when cold. Some motors might not run as well cold but I havnt noticed any problems with mine. So long as it isnt humid, it runs the same no matter what the temp is.

 

Well.. I 'rebuilt' the TBI tonight (gaskets and strainers kit). The internal passages were all suprisingly clean for the milage.

Anyways, the throttle responce seems slightly better (almost wants to go now) and the 'fsssssshh' from the TB (injectors) sounds a little more healthy but, it still lacking in the "powere" dept. and the idle still hunts. The PS switch is unplugged as well (as a guess towards another cause of the hunting problem). Probably changing the FP out tomorrow. If that doesn't help then I guess it f___ it and I'll just have to live with sub-weed eater power performance.

On a sort of similar note.. the cold and start idle kick isn't quite as bad now though...

Next step... , match and gas soaked rag in the filler neck to the tank

 

The PSPS wont have much effect on the idle, jsut wont be any help from the computer when the ps pump is loading the motor. I dont know why your being so hard on the RS, in its purest form its really jsut basic transportation with some sporty sheet metal rapped around it. It wont go fast but itll run for a really long time and get you back and forth. Oh, about the IAC, its best to take the pintle out and clean it as well as carefully clean the IAC itself, lubricate it, and reassemble. Dont use any harsh solvents as tehre are parts inside that can be damaged. Might not be a bad idea to replace it altogether. I know my stock one was completly frozen in the park postion when I got it. Wouldnt move at all, just buzzed. didnt have any trouble with idle hunting, but the idle jsut never seemed to come down

 

Thanks for the responce dimented. I guess I'm making it out to be I drive this poor car like it's a top fueler but, that's really not the case, honest. I know it's not a fast car and rarely do I drive it as such. Just once in while, I need something more than Geo Metro acceleration (which is probably faster at this point) to merge into traffic.

The power problem I'm referring to is, it has almost no desire to go at all and I don't mean roasting the tires off type go.
I'm talking about normal taking off in 1str gear.. "oops.. didn't see that car coming on as fast as it is, need a little 'oomph' to get some speed so I'm not rear ended" type go.

Once on the move, if you were to press the gas pedal anything over ¼ way... it does nothing (aside from noise) different. It doesn't even try. All you get is that quardajet bog sound w/o any movement (and I've owned an lg4 which now seems like an impressive performance motor compared to this one).

As far as hunting idle.. I apologize for being vague.
The problem there is, at a stop, it idles fine. It's when coasting to a stop with the clutch released. Untill the car reashes 10-5 mph, the idle will hold at about 1200 for 2-3 seconds and drop as if it were going to die then jump, hold, etc. untill the reached speed.
It does the same thing even with the IAC unplugged (and doesn't throw a code either which seems odd).

The IAC is about 4 months old (which is another thing I forgot to mention in the list of things replaced) and the passage, as cleaned tonight, was extremely clean. A small amount of build-up just off the throttle blades in the passage but, that's it. I have been chasing this hunt problem since aquiring the car months back and my IAC, as yours did, just made noises. The idle speed was differnt at every stoplight though instead of just constant.

I really would just like this car to be at stock performance. As it is, I'm getting about ¾ to ½ of that at best, and that's when it feels up to it. Sometimes just taking off from a stop it's fine untill the clutch almost fully engauges and then it jerks (like it wants to die) and then goes (does it randomly shifting to other gears as well depending on throttle position...a nd yes, I've been driving standard shift cars for 10 years now so, I know how to drive one )

I do enjoy fuel injection but, this dammed thing is really making me miss my old 280k+mi lg4.. at least it would go when really needed.

 

hahaha! I know the feeling. Wont budge when you want it to. Still worthwhile to check the fuel pressure. Also might make sure the base time is correct and that there arnt any ignition problems that might cause a weak spark. You could also start advancing the base time up by a few degrees and see if it helps. Maybe its just too retarded and the motor bogs down from not having enough timing. The stock stuff is weak enough, last thing you need is to have even less timing due to an incorrect balancer or something.

 

Dimented: would it be wise to look at the IAC while the car is exibiting a high idle or eratic idle? being a manual could one cycle the iac so seated and disconnect it and not use it? i have 2 iac's and one is non functioning and is seated(from what i can see). the other is functional. so i get some use of it but only 50%. also i believe there is a cycling prtoccess it needs to go through so ecu knows its relative position. possible out of synch with ECU?

 

The ecm goes through the process of cycling the IAC to reset it every time the car is shut down. If you want to seat the IAC, just short the usual pins A + B in the aldl connector and the IAC should fully extend to its seated postion and you can then disconnect it if you want to.

 

dimented: straightenen me out on this. i thought i read when replacing the iac(as he did) you need to manually set the pindle distance on new unit. or is is preset by factory? i dont think it is a plug and play is is? when you trip the cycle so to speak does it know enough to bottom out in throttle body? if it does bottom out without any adjustment for distance is then the steps in eprom the retraction to allow air into venturi measured in milimeters of withdrawl or something? my iac shows 0 steps when engine up to temp in closed loop and the visual inspection bears that out as far as i can see. i am swaping out the crossfire to a 454 TB so i am aware i need to adjust eprom for iac.

 

No, to my knowledge the ECM doesnt have any way of knowing where the IAC is, only what its commanded the IAC to do. It basically steps the IAC till it gets what it wants or reaches a limit. On shutdown, the ecm will sweep the IAC to its extremes and then park the IAC in its park position. Even if the IAC is way off, as long as it still works properly, the IAC will return to where it should after the motor has been shut down after running a bit. Theres really no need to reset it as the ecm does it for you. When you short the pins and put the ecm into field service mode, it just keeps stepping the IAC the whole time, even after its bottomed out. You can even hear it buzzing away even though its closed.

 

Well.. just pissed away a few hours changing the pump (which did actually need to be done as it still had the original one in it) because, it didn't do jack s___ for the hesitation/hunting problem.
And.. for the grand kick in the nuts.. the fuel sender (literally) fell apart while I was taking the sender out so now, I don't have a gas gauge either
Interesting enough... it's the same fuel sender (the actual unit,, not the arm obvoiusly) that was in my bud's '72 truck.. imagine that huh ? lol. The difference is the truck sender had a spade connector rivited to is as to where mine just had a copper pin with a male spade slipped over it and the pin was center punched to hold it in place (I forget the actual term for that method)

As far as the timing.. 2° seems to be it's 'happy place' running 87oct. I screwed with that yesterday since it was to cold to do the pump. Anything above where it's at and I get minor pinging taking off from a stop. Any less timing and I'd go faster pushing.
I don't remember but, I think I replaced the coil when I got the car and did the original tune-up. I'd have to check.

I really appreciate the help in trying to locate the problem alot. It's nice to have another brain to pick once in awhile.

I believe I'm just going to have to live with the problem.. throwing parts and guessing just isn't worth the effort anymore.