Good morning all! Hope you can help me with another issue. I have a 89 Iroc with a 305 TPI, auto trans. I just changed out the injectors, and all the ignition components and had the car purring like a kitten. But now after running it to work (about an hour drive) it has a really high idle...almost 2500 when in park or neutral! I've also been having problems with low speeds, it pushes you along, no matter what I do I can't run 25 mph w/out holding the brake. Any advice would be great!

 

I have close to the same problem. I have an 85 305 tpi in my trans am and it does the same thing. Really high idle,feels like it "pushs". i have changed my iac,my tps, the timing, plugs, wires,cap,rotor,vaccum lines,etc etc......i have yet to figure this out and i have been searching like mad through the archives been as of yet have found no answers.....if anyone can help us please lend some advise............thank you.

 

do ether you have any ability to data-log? and are you sure you have a stock chip? are you throwing any codes and did you adjust the "minimum air" screw and did you disconnect the battery for 5 or so min after replacing everything?

 

i have taken out the screw....lol......and i dont even know what data logging is. i have no codes at all. and after all this im just gunna sell this thing and go back to my old fox body.

 

THESE MEN ARE BOTH OWNERS OF EARLIER MODELS , PROIR TO 1996 , IT SAYS THE
ITEM WORKS ON 1996 AND LATER YEARS , NOW HOW ABOUT SOME RESONABLE ADVICE !

 

tps sensor at .54 +-.08,iac valve measure distance from gasket mounting surface to tip of pindle 1 1/8 ,reduce if greater,use a maf cleaner to clean maf sensor,also check relays

 

THANK YOU FOR ALL YOUR WISDOM, THE MAF SENSOR HAD LESS THAN 1,000 MILES BEFORE I BROUGHT IT IN FOR REPAIRS . WHEN THE CAR WAS RETURNED TO ME BY THE SHOP , THE SHOP'S DRIVER HANDED ME THE KEYS MENTIONING THAT THE TEMPERTURE GAUGE WAS PEGGED AND WAS NOT WORKING , I MMEDIATELY CHECKED IT OUT . HE HAD BEEN DRIVING THE CAR WITHOUT THE COOLING FANS CONNECTED TO THE BATTERY , THEY HAD BEEN WIRED DIRECT WITH A SWITCH INSIDE THE COXPIT. WITH THE CAR STILL OVERHEATING , I BEGAN REPAIRING THE WIRES.AND SEEING TO IT , THAT THE FAN WERE OPERATING ALLOWING THE ENGINE TO COOL DOWN. YET , WHEN I TOOK THE CAR IN , THE TEMP GAUGE WAS WORKING . SO WHEN THE ENGINE WAS COLD I DISCONNECTED THE GAUGE
ALLOWING IT TO RESET, BUT WHEN CONNECTED THE GAUGE WAS STILL PEGGED. I AM OPEN FOR SUGGESTIONS .

 

WHEN THE 89 IROC WAS TO BE SMOGGED THE GARAGE I TOOK IT TO, RAN IT TO A MUFFLER SHOP WHERE THEY INSTALLED A CAT.CONVERTOR.THE OWNER OF THE MUFFLER SHOP WHILE HANDING ME THE BILL . MENTIONED THE CAR WAS RUNNING RICH .THE GARAGED WHERE I TOOK IT FOR REPAIRS HAD TAKEN IT TO BE SMOG TESTED .WHERE IT HAD PASSED ,AND HAD BEEN APPROVED ,YET WHEN STARTING UP AT HOME I SMELT RAW GAS AT IDLE AND HAD NOTICED THAT IT WAS BURNING GAS AT AN UNUSUAL RATE.ANOTHER ISSUE THAT HAS TO BE DELT WITH AFTER AN EXSPENSIVE AND TIMELY AMMONT TO GET MY CAR BACK. IS THERE ANYONE KNOWLEDGEABLE THAT HAS THE ABILITY THAT CAN CORRECT THIS ISSUE .I VALUE THIS WEBSITE LIKE SO MANY FRUSTRATED OWNERS THAT HAVE TO DEAL WITH ISSUES WHEN THEY'VE PAID TO GET VEHICLES BACK CORRECTED. I WOULD RATHER NOT DEAL WITH THE DOWN TIME , WHEN ALREADY BEING SEPARATED FROM MY CAR FOR 30 DAYS & 12 Hrs. BEING BILLED AT SHOP PRICES.DOES ANYONE HAVE SUGGESTIONS THAT I CAN ADDRESS ?

 

cdoavrick try replacing the o2 sensor if is not fearly new also check the fuel pressure,try disconecting the vacuum line that goes to the fuel pressure regulator and notice any fuel

 

For the overheating make sure the sender temp sensor wire is connected to sensor,make sure the wires to fans are right and then check the fan relay if still over heating noticed if any of the fans are really working

 

You probably need a new thermostat

 

THE THERMOSTATE WAS REPLACED BY THE SHOP AND THE SENSOR TO THE RELAY IS CONNECTED TO THE BLOCK , IT WAS MY FIRST VISUAL CHECK , AND THE COOLING FANS
ARE WIRED DIRECT ,WHERE I HAVE THE OPTION OF TURNING ON/OFF INSIDE THE COXPIT. ANY OTHERE SUGGESTIONS , THANKS FOR REPLYING !

 

ALSO THE O 2 SENSOR WAS REPLACED WHEN THEY HAD MADE THE REPAIRS , THE ONE THEY HAD REPLACED WASN'T BADLY CARBONED UP , YET WENT AHEAD AND CHANGED IT OUT BEFORE THE CAR RAN RICH . THANKS AGAIN !

 

Check on driver side a single wire for sender temp sensor,on passenger side a single wire for the secondary fan, the primary fan kicks in about 220 based on the information from the coolant temp sensor i will sugest to wire fans the right way and check if the turn on if not is a bad relay, or temp sensor not working properly and still need to check your fuel pressure 40.5-47 psi

 

JUST RECENTLY HAD REPLACED ALL 8 INJECTORS , YET I'LL BUT YOUR IDEA ABOUT CHECKING THE HEAT SENSOR , ALTHOUGH YOU'D THINK THAT WHEN IT WAS IN THE SHOP , THEY WOULD HAVE CKED. INSTEAD OF RETURNING IT KNOWING IT WAS PEGGED.
WHAT YA THINK?

 

Not sure about that but if the wire is conected to the sensor and the gage is not working could be the sensor itself or the gage,now if thats not work make sure your fans are a least turnning when powered and if work check your radiator and make sure the thermostat opens or is the right one for this car

 

PICKED UP A NEW BRASS TEMPERTURE SWITCH. PLAN ON INSTALLING IT AS SOON AS
WE HAVE NICE WEATHER , IT'S BEEN RAINING AND VERY GLOOMY WHERE I AM AT .
THANKS AGAIN

 

Have you checked the fuel pressure since mentioned about smelling gas at idle, the brass sensor is the coolant temp sensor or the sender?

 

cdoc and Elpulpo, Do you realize you've completely hijacked this thread? What does your overheating have to do with high idle? In the future, start your own thread. BTW, check the CTS(black wire and yellow wire, at the front of the intake manifold) and also your FPR for a possible ruptured diaphram.

 

No relation on over heating and idle problems but any sugestion maybe useful

 

I know. I see you on here alot giving good advice. I just wanted to keep things on track.

 

No problem man i see your point but thanks, im just trying to help based on books and self experiences

 

NO HARM ,NO FOUL , I RESPECT YOU MEN, AND FEEL THIER IS NO PLACE BETTER TO GO
AND GET INFORMATION. OWNEN'S NO FIRST HAND HOW TO RESOLVE SIMILIAR ISSUES,
LIKE ONCE SAID, IT'S BEST TO TALK WITH MEN ,WHO HAVE WALKED IN YOUR SHOES!
NOW, JUST HAVE ONE QUESTION, ONE MAN USED THE ABREVATION FPR . SAY IT WAS POSSIBLE RUPTURED DIAPHRAM , I TAKE IT ,HE WAS REFERING TO THE FUEL MIXTURE ISSUE . CAN SOME ONE ELABORATE , I MYSELF I AM UNFAMILIAR , PLEASE ! AGAIN I VALUE THIS SITE AND THOSE KNOWLEGABLE THAT SPEAK FOR US ALL , THANK YOU !

 

Fuel pressure regulator(FPR). The diaphram ruptures allowing fuel to enter the vacuum line. My only concern is that someone is going to look up this thread searchng for help with a high idle and find that this thread has very little to do with high idle. There are many threads on rich mixture. Or you can start your own. I'll be all over it as this my area.

 

ASE doc thank you for pointing about this thread,we will focus on it.

 

Back to high idle discussion, I'm having a very similar issue and i can't figure it out. Everything seems to be connected. I'm missing something and it's driving Me crazy!! Anyone open to suggestions?

 

have you check the tps .54+-.08,the maf sensor,iac valve are there any codes?

 

Also, check timing and look for manifold air leaks.

 

Whoa! That was a lot of info to dig through! Thanks for the feedback. (By the way not all of us are men-there are a few of us girls up here. LoL) This weekend I re-adjusted the tp cable as it was pretty tight and that seems to have stopped the maintaining low speeds problem at least while I've been driving locally (I haven't taken it on a long run yet - which is when it really seemed to act up the most). I think I'm still going to check the tps sensor just to be on the safe side.

 

the tps is suppose to be .5 -.7 V on the 85, but it would like you to put it at .5

 

As far as I can remember, before 1990, all GM TPSs were set at .5 +/- .050 (.45-.55).

After 90, GM went to self zeroing throttle position on most vehicles, meaning that each time the ECM is powered up, the ECM reestablishes zero throttle position regardless of TPS voltage, as long as TPS is below 1 volt.

 

in the technical articles here it says .54 +/- .07 in my service manual in the TPS error code section is says it'll work as long as its under .7, but in the installation section it says to set it to .5, i'm sure above .7 you'd have drive ability issues ?

 

Do I need to disconnect the battery for 5 minutes after changing out the TPS? Sorry for n00b questions but I'm used to carburettors and all this TPI stuff messes with my old-tech head!

FWIW I have the same issue in my GTA. I get 39 MPH at idle!

 

Any TPS fault code will automatically clear once the problem is solved. The code will erase from memory after 50 key cycles. Be sure to check MAF voltage or air flow at idle. It should be about 1 volt or 5-6 grams per second. ith a scan tool you can also check the IAC counts to see if the ECM is trying to bring idle down. If it is, you may have a faulty IAC or unmetered air leak. Fuel trims should reveal an air leak if everything else is right. Check timing.

 

I have a 90 5.7 IROC auto trans and I have no service engine light but a high idle and both fans are inop. The car starts beautifully but cannot be driven and when I shorted my AC switch the fans still were inop. I am stumped and about to sign off on a car I really hate to put away.

 

Make sure the throtle body is clean,but sounds like the iac valve is going bad