Curtisyz54

iTrader: (5)

Ok I have a 86 305 tpi. The car, (When it wants to) WONT idle I have to drive with 2 feet, It runs just fine other wise. But it wont idle. I have to keep it going or it will die. But sometimes and even for a week it will be fine. Then like today, it wont idle by itself. I replaced the MAF and its still doing it, So i don't think its that.

Please if anyone has any idea help me. I'm really confused.

Possibly?

Throttle positioning sensor?
Blown head gasket?
bad ecm?

I know that it DOES have a blow intake gasket as it has some antifreeze going down the side of the block. But it did this before it had a blow intake gasket.

black_irocz

Hey Curtisyz54, I'm having the exact same issue also & it just started yesterday. the last time i had my car out for a drive, was about a month ago for a 100+ mile drive & all was fine then...

Can anyone please help us....???

- 89 IROCZ 305 tpi

Curtisyz54

iTrader: (5)

Yup Like now, it will start up go to high rpm's like a cold start then after driving it, it will just stall. so I have to keep it going with the throttle down a little. Then I shut it off an the same cycle happend again.

Then i was just messing with it and I tried starting it and it just stalled and did that over and over. Its really wierd.

Sully89Firebird

yeah i am having the same problem. i have to use two feet at stop lights and stop signs so it wont die. it gets down to about 500-600 rpm in drive and i have to keep my foot on the gas a little to keep it going

pr1689

It sounds like the CTS to me (coolant temperature sensor). When the one in my sons car had gone bad, that is how it acted. Also, check for any vacuum leaks, especially around the charcoal cannister.

Sully89Firebird

if my temp sensor was bad wouldent my temp shown on the temp gauge on the dash be wrong then? And where do i go about finding the temp sensor, any specific place along the coolant stream?

pr1689

No, the coolant temperature sensor is what feeds into the computer and not into your temp gauge. That is a different sensor.

The CTS is located, at least on my sons car, right under the throttle body. I've found that its easy to get to if you remove the throttle body, which isn't all that bad.

If the CTS is malfunctioning, it feeds the computer all kinds of wrong info and it causes the computer to try and compensate, thus changing the amount of air, gas, etc. which causes the car to idle and run poorly.

It should have a black and yellow wire running to it from the wire harness. Its under the throttle body and is screwed into the intake manifold.

It seems like I remember reading somewhere about how to test one with the DMM, but I'm not positive. You may try searching for that or maybe someone here will post about it. But from what you've described, that really sounds like it to me.

Hope this helps.

Thanks,

Pat

Sully89Firebird

Thanks for the help pat. i am going to replace it because i am sure the one i have is the original which is 20 years old. haha.

pr1689

You're welcome and I hope that solves your issue. I know it did on my son's car. But do also check for vacuum leaks and that is a pretty common cause of erratic idles too. :-)

good luck and please post back with your findings!

Pat

Curtisyz54

iTrader: (5)

Well Im thinking it might be my egr valve?

Sully89Firebird

yeah after i do the CTS i will do another good check of a vacuum leak. if that still dosent solve my problem i am going to OHM the injectors and see whats going on in that direction.

Curtisyz54

iTrader: (5)

Thats normal idle for a TPI. Mine always is at 500-600 rpm.

transam85dudeman

fellas fellas. i can help, when i bought my ride back in 05' i bought it running like that... anyways, my case it was the fuel pump. But to temporary fix the problem, i ran that NOS fuel injector cleaner.. If i had a ride that stalled everystop, the first thing id check is the fuel pressure. next the timing. does it idle okay in park? and only under a 450 Rpm load with tranny in gear does it stall?.. sounds to me that maybe its a fuel problem. next i would suspect an ignition problem. vacuum leak could cause this, but not always. check the fuel pressure, should be around upper 30-lower 40's psi. and the tps could be maladjusted. test that too. it should be around .555 volts at idle. and if you spend money on a coolant temp. replace the wire connector too. it wouldnt be the MAF because the MAF creates hesistation around 1500 rpm not at a stop. mmm. if it is electrical then maybe its a failing coil. i need some more detail. (clogged Cat) if you can just try to detail a little bit more.

and the guy whos car starts his ride and stalls, thats a coil failure, let me guess sometimes it works then after 3-5 mins stall and doesnt start? ya coil. plus you guy should pick up a Haynes manual. it had the OHMS specs for the injectors, coil resistance, and theres the Ignition control module to look at, you can get it tested for free at autozone, just dont manhandle it, and pickup thermogrease and put a little on the bottom of the module when reinstalling it. These cars are fixable, i doubt its mechanically unless youre losing compression. because our early TPI cars are all electrical, theres more to hassle with. the egr wouldnt give you such problems, but the EGR solenoid would. but even then you shouldnt be stalling at a stop because of the egr solenoid. .. im pretty good with cars.. i just hate working on my car during the summer-HOT a** garage. hot. post replies fellas

Curtisyz54

iTrader: (5)

I dont have a cat. But I dont think its fuel. Cause the car does it when it wants to. Iv had the car for over year, and has done it a few times in the past. Now iits getting somewhat bad, But if i reset the computer. it wont happen for a while. Also I over heated the car a few times. and thats when it comes back.

Sully89Firebird

Alright, sorry i dont mean to hijack this thead like i feel like i have been doing. my fuel pressure reads 38 psi, i never checked the tps. i just upgraded my whole ignition system, MSD cap/rotor, 8.5mm wires. autolite double plat. plugs, and i replaced the ingition module. i am thinking CTS, then vacuum leak maybe then i will OHM the injectors.

transam85dudeman

if you reset the computer and it runs then tell me that the computer has compensated with maybe rich to lean ratio. when you reset the computer it become automatic default mode. until the computer learns the sensors. everytime you start your car. the computer goes into open loop mode until the O2 sensor heats up to 600F* and if the MAT (Manifold airtemperture, and coolant temperture reaches over 66*F. when these all get heated, then the computer goes into closed loop mode, and constanly monitors all sensors and changed the fuel curve based on the resistance from the sensors. theres three coolant sensors BTW (one for the fan, one for the engines computer, one for the dash temp gauge.) the one for the computer is the one to replace IF you really suspect thats the fault. not likely i think. The computer's temp sensor is located on the front of the block.i had to take out my alternator to get to it. try checking your timing.. should be at 6*BTDC, fuel filter is cheap and always recommended a change every 4 oil changes. check to see your fuel pressure regulator is connected to the vaccum line to the plenim

Sully89Firebird

yeah i changed my fuel filter about 300 miles ago along with the oil change. my timing was set really advanced to compensate for my bad ignition module. now the timing is set to 6* BTDC so that is fine. how do i check for my fuel pressure regulator being connected to a vacuum line? and where does it go into the intake plenium?

transam85dudeman

whats a CTS, and 38psi is good. if its a vacuum/idle problem, try to check the idle air control valve in the thottle body and check the vacuum passages in the throttle body, they get clogged, and also check the vapor canister solenoid, sometime the solenoid can get stuck open constantly releasing fuel vapors and riching the engine out. you guys getting any codes thrown at you?

transam85dudeman

the regulator is behind the plenum and connects into the plenum via vacuum line which is only 8 inches long made of hard vacuum tubing. theres only two vacuum lines going into the plenum in the back, a and two in the throttle body. the back two vac lines (one just for the regulator, one for the acces. like cruise control and vacuum rez. a really low tech way to test the vacuum for the regulator is to suck the regulator from the vac. line off the plenum.

Sully89Firebird

CTS = Coolant temp sensor. i had my mechanic look at the iac valve and he said its working good and i recently cleaned the throttle body. i dont know where to locate the canister solenoid, i am not gettting any codes just an intermetint SES code at startup.

transam85dudeman

(sully) try checking the pickup coil resistance and continuality, its under the igntion control module. i dont got my book in front of me but sometimes it can fry, when i replaced my pickup coil the permenant magnet in the coil broke in 5 pieces. it was telling the computer to fire at different cylinders when it wasnt supposed to. the pickup coil tell the computer exactly where the rotor is. you said you did a dizzy upgrade, but the only thing not replaced was the pickup coil.you should try to test the tps for the hell of it. with the diagnostic a and b grounded. take a volt meter on the lowest dc volt setting and test the top two wires going into the tps, should be between .45volts-.65 volts, mines at .555 volts .
i use champion plugs in my TA, i didnt like the autolite. i use NGK four prong on my bimmer 60 bucks

Sully89Firebird

lol i got my book in front of me haha. isent the coil on the left side of the cap/rotor? i remember unplugging something when i redid my heatercore and needed more room for my hands. other than that i havent touched that.

transam85dudeman

if you unplugged something by the heater core it could of been the EGR solenoid electric connector. but i just remembered your coil isnt in your cap because of the heat coil failures these cars had, yes your right. but theres another coil. its a pickup coil it plugs into the ignition control module. along next to the condensor. the pickup coil looks like a donut, its around the dizzy shaft under the ignitioncontrol module.it has two 18 gauge wires coming from it.

Sully89Firebird

hmm i dont remember ever seeing or touching a doughnut looking object. ok i will check the condition of the coil. its under the ignition module and like under the distributor cap/assembly. i dont think i have an internally coil in the cap itself

84transam87

i had the same problem with a 74 chevy nova. ended up being the distributor hold down bolt loosened up so every time the car started the distributor turned taking the timing with it. maybe its just a timing issue...good luck

transam85dudeman

yeah you have an extenal coil, but that coil is for the plugs. the coil im talking about is the coil for the computer to "know where the rotor is. i lost my dizzy rebuild pics (damn) but i found a gm pic, its not HEI, but you can see it in the back ground, this is merly an example of location. we cant even say if thats the problem. could be something else. but when i had idle issues, it was my coil one time, and the other time it was my pickup coil. (hence the permenant magnet broken in 5 spots. im pretty sure this may be it. after i replaced the magnet, started right up. but i had to time it again.