IAC valve or TPS?? almost crashed.....

justi88 · September 20th, 2010, 11:22 AM

Well to start my 5.0 had issues with idle, every time I pressed the clutch the rpms would rise and come down after a few seconds and stay like at 1200 rpms. This problem was causing heating to my car and I don´t live in the U.S. so the only solution was adapting an IAC from a ford bronco.

So I picked it up from my mechanic and the idle wasn´t totally fixed but it was better, so last night i took for it a spin and gave it throttle until reaching like 80 mph when the throttle stayed open and I could´nt stop the car so I pressed the clutch and the rpms when way up until the red line so i turned the car off and pulled to the side of the road. This scared the .... out of me and I´m really pissed of with my mechanic.

So what i really want to know if this is caused by the IAC valve?? If it is I will buy the oem for my car. Please help me out to find out what is the problem...

93hatch · September 20th, 2010, 11:26 AM

neither, your cable got stuck is my guess. The throttle stop is pretty close to hitting the bolts on the tb, cruise control cable coudla got stuck, it was something mechanical is my guess

408gt91 · September 20th, 2010, 12:07 PM

Cable for sure. I bet the casing is dried out.

justi88 · September 20th, 2010, 02:38 PM

Are you guys sure that its the cable?? After the IAC was changed to the bronco type the idle was way up but no its a bit lower but it still hangs....

Maybe there is a way to check if its the IAC or tps???

408gt91 · September 20th, 2010, 03:23 PM

Take off the iac and delete it, if it still hangs up i bet its the cable. Only time ive had idle jump that high was due to the cable. Either sticking or by me matting it. Its possible seing that its from a bronco. I used a 95 on a 93 once and it surged high but didnt stick and rev all the way up, that sounds more like the cable.

justi88 · September 20th, 2010, 03:39 PM

ok 408gt91, by deleting the IAC what do you mean?? do i simply take it off and see if the idle still changes?? or by taking it off do i have to cover the port with something??

93hatch · September 20th, 2010, 03:48 PM

just unplug it

408gt91 · September 20th, 2010, 06:55 PM

^^^unplug. Its process of elimination.

fogged306 · September 20th, 2010, 06:59 PM

The IAC motor doesn't have enough of an opening to let enough air in to actually bring your engine to redline. The only way for that to happen is a stuck throttle. Like these guys have said, it's most likely a stuck cable. Replace it with one from a newer Toyota and you should be fine.

justi88 · September 21st, 2010, 06:48 PM

ok guys thank youI´ll check the cable and throttle body without IAC and let you know, just had a little problem with the fan last night and the car overheated... I´ll make a different post if I still have problems with heating...

98FireyGT! · September 24th, 2010, 04:44 AM

Originally Posted by fogged306

The IAC motor doesn't have enough of an opening to let enough air in to actually bring your engine to redline. The only way for that to happen is a stuck throttle. Like these guys have said, it's most likely a stuck cable. Replace it with one from a newer Toyota and you should be fine.

justi88 · September 25th, 2010, 01:01 PM

He is right, I´ll would change the cable from a toyota, most of the cars in my country are toyota so somethings just have to adapt... Anyway I found a shop that makes new cables so I´ll go with that

fogged306 · September 26th, 2010, 02:47 PM

Originally Posted by justi88

He is right, I´ll would change the cable from a toyota, most of the cars in my country are toyota so somethings just have to adapt... Anyway I found a shop that makes new cables so I´ll go with that

lol, I was definitely just kidding about that. If you can, go with a stock replacement, that would be the easiest way to go. I would also check the pedal itself and disconnect the throttle cable from the throttle body and actuate the throttle body arm by hand and see if you feel any binding.

justi88 · September 26th, 2010, 09:05 PM

its going to be very hard to find the stock replacement here, buying a stock one from the U.S. plus taxes plus shipping... its not worth it, i´ll just find something here... also checked the pedal and its very loose and cable also so I think thats the problem... i´m thinking about buying the oem IAC from rockauto.com at 55$... don´t want that bronco IAC in my car

Red95_5Oh · September 27th, 2010, 11:58 AM

Originally Posted by justi88

its going to be very hard to find the stock replacement here, buying a stock one from the U.S. plus taxes plus shipping... its not worth it, i´ll just find something here... also checked the pedal and its very loose and cable also so I think thats the problem... i´m thinking about buying the oem IAC from rockauto.com at 55$... don´t want that bronco IAC in my car

dude i work for fedex and i could send you a cable if you paypal me or something... i get massive discount on shipping. So you'll just have to pay the part and shipping cost. I can get a rough quote for you if you want. PM me.

kpoirot · September 28th, 2010, 10:36 PM

It could be sticky throttle body too and that would make the throttle stick open and if you changed the IAC could have made the change. Take some carb cleaner to the throttle body. Clean out the gunk.

justi88 · September 29th, 2010, 12:32 PM

Originally Posted by kpoirot

It could be sticky throttle body too and that would make the throttle stick open and if you changed the IAC could have made the change. Take some carb cleaner to the throttle body. Clean out the gunk.

what do you mean it could have made the change when i changed the iac??

September 20th, 2010, 11:22 AM	#1
justi88 Regular 1994 5.0 Mustang GT Join Date: Feb 2009 Location: Cochabamba, Bolivia Posts: 112 iTrader: 0 reviews	IAC valve or TPS?? almost crashed..... Well to start my 5.0 had issues with idle, every time I pressed the clutch the rpms would rise and come down after a few seconds and stay like at 1200 rpms. This problem was causing heating to my car and I don´t live in the U.S. so the only solution was adapting an IAC from a ford bronco. So I picked it up from my mechanic and the idle wasn´t totally fixed but it was better, so last night i took for it a spin and gave it throttle until reaching like 80 mph when the throttle stayed open and I could´nt stop the car so I pressed the clutch and the rpms when way up until the red line so i turned the car off and pulled to the side of the road. This scared the .... out of me and I´m really pissed of with my mechanic. So what i really want to know if this is caused by the IAC valve?? If it is I will buy the oem for my car. Please help me out to find out what is the problem...

September 20th, 2010, 11:26 AM	#2
93hatch Banned 1992 Lx 11.39@119.24 Join Date: Jan 2008 Location: Az Posts: 11,644 iTrader: 0 reviews	neither, your cable got stuck is my guess. The throttle stop is pretty close to hitting the bolts on the tb, cruise control cable coudla got stuck, it was something mechanical is my guess __________________ [QUOTE=93mustank;2577445]We speed tested my right arm for quickness in shifts... So he could design the cam for proper shift recovery.[/QUOTE]

September 20th, 2010, 12:07 PM	#3
408gt91 Regular Join Date: Aug 2007 Location: ya mudda's house Posts: 204 iTrader: 0 reviews	Cable for sure. I bet the casing is dried out. __________________ 408stroker/tf track heats/scat crank/h beams/srs fordged/351sportsman block/trick flow rrkrs/msd dist/edelbrock victor5.8intake/aeromotive fuel system/accufab 80mmtb/pro-m80mm,maf etc.

September 20th, 2010, 03:23 PM	#5
408gt91 Regular Join Date: Aug 2007 Location: ya mudda's house Posts: 204 iTrader: 0 reviews	Take off the iac and delete it, if it still hangs up i bet its the cable. Only time ive had idle jump that high was due to the cable. Either sticking or by me matting it. Its possible seing that its from a bronco. I used a 95 on a 93 once and it surged high but didnt stick and rev all the way up, that sounds more like the cable. __________________ 408stroker/tf track heats/scat crank/h beams/srs fordged/351sportsman block/trick flow rrkrs/msd dist/edelbrock victor5.8intake/aeromotive fuel system/accufab 80mmtb/pro-m80mm,maf etc.

September 20th, 2010, 03:48 PM	#7
93hatch Banned 1992 Lx 11.39@119.24 Join Date: Jan 2008 Location: Az Posts: 11,644 iTrader: 0 reviews	just unplug it __________________ [QUOTE=93mustank;2577445]We speed tested my right arm for quickness in shifts... So he could design the cam for proper shift recovery.[/QUOTE]

September 20th, 2010, 02:38 PM	#4
justi88 Regular 1994 5.0 Mustang GT Join Date: Feb 2009 Location: Cochabamba, Bolivia Posts: 112 iTrader: 0 reviews	Are you guys sure that its the cable?? After the IAC was changed to the bronco type the idle was way up but no its a bit lower but it still hangs.... Maybe there is a way to check if its the IAC or tps???

September 20th, 2010, 03:39 PM	#6
justi88 Regular 1994 5.0 Mustang GT Join Date: Feb 2009 Location: Cochabamba, Bolivia Posts: 112 iTrader: 0 reviews	ok 408gt91, by deleting the IAC what do you mean?? do i simply take it off and see if the idle still changes?? or by taking it off do i have to cover the port with something??

September 20th, 2010, 06:55 PM	#8
408gt91 Regular Join Date: Aug 2007 Location: ya mudda's house Posts: 204 iTrader: 0 reviews	^^^unplug. Its process of elimination. __________________ 408stroker/tf track heats/scat crank/h beams/srs fordged/351sportsman block/trick flow rrkrs/msd dist/edelbrock victor5.8intake/aeromotive fuel system/accufab 80mmtb/pro-m80mm,maf etc.

September 20th, 2010, 06:59 PM	#9
fogged306 MM Fanatic 89 GT Join Date: Apr 2007 Location: NY Posts: 4,875 iTrader: 2 reviews	The IAC motor doesn't have enough of an opening to let enough air in to actually bring your engine to redline. The only way for that to happen is a stuck throttle. Like these guys have said, it's most likely a stuck cable. Replace it with one from a newer Toyota and you should be fine.

September 21st, 2010, 06:48 PM	#10
justi88 Regular 1994 5.0 Mustang GT Join Date: Feb 2009 Location: Cochabamba, Bolivia Posts: 112 iTrader: 0 reviews	ok guys thank youI´ll check the cable and throttle body without IAC and let you know, just had a little problem with the fan last night and the car overheated... I´ll make a different post if I still have problems with heating...

September 25th, 2010, 01:01 PM	#12
justi88 Regular 1994 5.0 Mustang GT Join Date: Feb 2009 Location: Cochabamba, Bolivia Posts: 112 iTrader: 0 reviews	He is right, I´ll would change the cable from a toyota, most of the cars in my country are toyota so somethings just have to adapt... Anyway I found a shop that makes new cables so I´ll go with that

September 26th, 2010, 09:05 PM	#14
justi88 Regular 1994 5.0 Mustang GT Join Date: Feb 2009 Location: Cochabamba, Bolivia Posts: 112 iTrader: 0 reviews	its going to be very hard to find the stock replacement here, buying a stock one from the U.S. plus taxes plus shipping... its not worth it, i´ll just find something here... also checked the pedal and its very loose and cable also so I think thats the problem... i´m thinking about buying the oem IAC from rockauto.com at 55$... don´t want that bronco IAC in my car

September 28th, 2010, 10:36 PM	#16
kpoirot Regular 1995 GT 5.0 14.66 Join Date: Dec 2007 Location: Adams, MA Posts: 84 iTrader: 0 reviews	It could be sticky throttle body too and that would make the throttle stick open and if you changed the IAC could have made the change. Take some carb cleaner to the throttle body. Clean out the gunk. __________________ Mods:Underdrive Pulleys, Ram Air w/ K&N Filter, Rebuilt T-5, 3.73s, High Flow H-Pipe, Energy Suspension Poly Motor and Tranny Mounts. Soon: Un= headers, Centerforce Clutch, Steeda Tri-Ax Fidanza Alumnum FW, BBK 75mm TB, EGR Elim.

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