Fixing your SURGING IDLE!!! IN HERE!!!

[ryclef331]

Ok so the everyone who has modified their 94-95 Mustang has dreaded the idle surge from day one! My own personal stroker motor car has a chip and tune and STILL likes to surge a bit until it warms up. EITHER WAY, the principals are the SAME! I hate to link off of the site to do this but I haven't found a MORE thorough write up on how to solve your problems than this very site...PLUS it features pics of a 94-95 so it makes it MEGA easy, even for noobs!

Click here to solve your idle problems!

http://www.muscularmustangs.com/iac.php

be sure to click through all the pages! the link is at the bottom of each page.

Remember this! It is imparative that you do all of the steps in the above link in order! Setting the TPS Voltage and THEN setting your idle RPM will throw the TPS Voltage right back off!

 

[d_punch]

i need some serious help with this idle

i followed all steps in order like you said on that link, and it only solved the problem for one day. and it went right back to the same surge and then die.

i was in the process of upgrading my TB and after installing it i went through the process again it idled pretty good but once i turned it off it went back to the same crap.

then the car sat for a couple of weeks, and i figured that iac and or tps is going (they are original) and i went over trying to adjusted the idle on five different times. so i just swapped them out.
first start up i couldn't believe it idle like stock even with all the acc. on . ok it's good for me, turned it off washed her down starter her up now she idles at 2200 rpm.

went through all the steps again (except for cleaning the MAF i've done it 5 times in the last 3 1/2 months) and it still idles at 2200 rpm's i'm ready to give up. an suggestion other than a can of gas and a match cause i already have that sitting in the garage.

Thanks
joe

 

[d_punch]

i did end up fixing it, well i hope.
my advise would be not to buy an IAC from autozone, the one listed doesn't look the same. and it's not for a fox body cause i had them pull one of those also and it was different from the one they had for a 95.
so i ended up taking the ride to a pepboys, since they seem to be everywhere but around me. and bingo the part looks just like the orginal and at the moment seems to idle steady.

so if you like you could delete my useless babble above

 

[ryclef331]

so if you like you could delete my useless babble above

I'm going to leave it actually! Its a good reminder to everyone that the quality of the part you put on your car has a direct affect on its performance!

 

[95_302vert]

If thats all it is im gonna be so happy, my car is doing it pretty bad. it dies on me at least 3 times a week, shit sometimes even three times a day. Tell me if im way off track, my brother has a 89 gt and his was doing that he told me he had cracks in his vaccum lines could that be a problem with mine

 

[ryclef331]

If thats all it is im gonna be so happy, my car is doing it pretty bad. it dies on me at least 3 times a week, shit sometimes even three times a day. Tell me if im way off track, my brother has a 89 gt and his was doing that he told me he had cracks in his vaccum lines could that be a problem with mine

YES! Alot of things can cause an idle surge. Vaccum leaks of course are one of them. Noone can promise that thats the ONLY problem but it COULD be.

 

[d_punch]

so if you like you could delete my useless babble above

I'm going to leave it actually! Its a good reminder to everyone that the quality of the part you put on your car has a direct affect on its performance!

well believe it or not the wrong IAC from autozone was $86.99 and the right IAC from pepboys was $56.98. lol go figure

 

[badass98svt]

^^^ is the IAC still doing the trick??

 

[cobra4978]

What about an idle surge just once or twice when you start your car then you let it sit for a while start it again and it's fine? mine surged really bad tonight then died. i started it again and it did the same thing except this time i kept it alive with the accellerator and drove it on. It only tried it one more time and i stopped it again then from then on it was fine no surging no dying nothing it drives fine and runs normal any ideas? i just swapped out the intakes to a 93 cobra upper and lower and went to a professional products 65mm throttle body and finished with a cold air intake

 

[ryclef331]

What about an idle surge just once or twice when you start your car then you let it sit for a while start it again and it's fine? mine surged really bad tonight then died. i started it again and it did the same thing except this time i kept it alive with the accellerator and drove it on. It only tried it one more time and i stopped it again then from then on it was fine no surging no dying nothing it drives fine and runs normal any ideas? i just swapped out the intakes to a 93 cobra upper and lower and went to a professional products 65mm throttle body and finished with a cold air intake

Try just resetting the computer for allow it to "relearn" the new mods.

 

[cobra4978]

Alright will do thanks

 

[95gtdrop]

its good to know that other people have the same problems.
i really would like to know if it is the iac that needs to be replaced.
i am looking for a permanent answer!
my carwill sometimes die on me three times in a row as well.
other days it wont have any problems. some tiems weeks at a time.

 

[GREG@SN95]

wow...

will this work on an 87 f150?

My pops f150 (302 EFI) has a bad idle problem too...

 

[mp]

Just for the record, I have done all these things twice. Still no good. The only thing I have not tried is drilling a hole in the butterfly. Had a guy tell me it worked on his. It used to work on carbs so why not.

 

[ryclef331]

Just for the record, I have done all these things twice. Still no good. The only thing I have not tried is drilling a hole in the butterfly. Had a guy tell me it worked on his. It used to work on carbs so why not.

What are your mods?

 

[SaleenStang94]

how do u flash the computer? also will u lose ur tune (my was dyno tuned), third will it hard a custom chip?

 

[ryclef331]

how do u flash the computer? also will u lose ur tune (my was dyno tuned), third will it hard a custom chip?

You don't falsh our computers. I'm assuming you're talking about resetting the ECU. If you have a chip, it will not hurt it but IF your tuner was compotent, he turned off the adaptive learning curve in the ecu...I.E. your ecu no longers "learns." If you keep the adpative learning curve on in a chipped car, it will completely skew your chip's tune. Now, resetting the ECU is ALWAYS worth a shot and its free. Some people say disconnect the battery for a half hour or more bla bla bla....here is the fastest way....

DISCONNECT BOTH Terminals from the battery, and touch'em together. This will IMMEDIATELY drain the memory battery in the ECU. Hook it back up...done. ECU is now cleared.

 

[Quick96Mystic]

What do you do when your idle keeps sticking to about 1300 rpm for about a minute and then drops to 800 over and over.. and over again?? (This is for a 1990)

Edit: NVM figured it out O0

 

[NYC94GT]

To be quite honest, I've tried to do all of these things and nothing works to stop surging idle problems once mods are introduced to our "lean" running 5.0's. A lot of what is mentioned in this thread works for FOX body 5.0's and this gets lost in translation from user to user. The only thing that fixes this is to have a chip burnt custom to change the fuel/spark maps set at the factory, or swap the computer/harness and injectors to the cobra FOX style. What I was told from a highly reputable shop in Westchester NY was that when Ford redesigned the Stang to be intro'd in 1994, they had to comply with CALI regs on smog. With the mod 4.6L motor only a few years away they decided to just lean out the motor fuel maps instead of redesigning a whole new program/emissions system. This "lean-out" is what causes the surge we all love to hate. Drilling holes, changing the IA valve, and TPI sensor really doesn't work on our cars. This is the FOX BODY Fix, not SN95. BTW, there is no adjustment on these with our cars. :help2:

 

[ryclef331]

I might just go home and host up the video of my 331 stroker with a 185 heads, cam, intake, 75mm throttle body, 30lb injectors, and 80mm maf....at IDLE WITH NO TUNE.

Thanks for your doubts. Sorry it didn't work on your car. It doesn't always work for everyone for one reason or another. The cars ARE touchy but the methods described above DO WORK. As for adjustments....there are plenty. You already have an idle screw and the TPS doesn't take much movement to adjust it but you can always elongate the holes.

Oh, and why would you need swap injectors just to go to a fox ecu?

I'm not trying to pick you apart here but you're spreading fraudulent information.