ford question who can figure this one out

[noslowharley]

well i need some help, i got a f150 on a trade ,1989 4x4 5.0 , this thing is idling at 1300 rpms, i have changed the iac valve the tps sensor,new gaskets on everything i replaced , coolant temp sensor ,as well as new plugs, new wires,dist cap and rotor, fixed 6 vacuum lines that were broke,checked timing,everything else is checking out good egr valve is good and still this thing still idles high, the engine is a 1995 or newer because i just yanked all the wires off and put them back for a 89 model and it was wrong , i then wired it for a late model and it worked , has the newer intake on it as well that reads 5.0 on it not powered by ford like it should. i am at wits end what am i missing must be something i am missing this thing is driving me crazy .

[coupe performance]

well i need some help, i got a f150 on a trade ,1989 4x4 5.0 , this thing is idling at 1300 rpms, i have changed the iac valve the tps sensor,new gaskets on everything i replaced , coolant temp sensor ,as well as new plugs, new wires,dist cap and rotor, fixed 6 vacuum lines that were broke,checked timing,everything else is checking out good egr valve is good and still this thing still idles high, the engine is a 1995 or newer because i just yanked all the wires off and put them back for a 89 model and it was wrong , i then wired it for a late model and it worked , has the newer intake on it as well that reads 5.0 on it not powered by ford like it should. i am at wits end what am i missing must be something i am missing this thing is driving me crazy .

Take the pcv valve out, and plug the hole in the intake. Then crank it up and remove the oil filler cap. Put your hand over the hole and see if it has pressure or vacuum after about 15 seconds. If it develops pressure, you are good, if you develop vacuum(sucking your hand on the filler hole), you have a vacuum leak on the bottom of the intake manifold. This is a check you need to make if you dont find any other vacuum leaks.

[a93stang]

Are you 100% sure there's not a vacuum leak somewhere? I've got a 94 with a 351w that did the same exact thing and a TPS fixed it, then the tranny started going out so now the truck is on ebay. :doh3:

[noslowharley]

i have pressure, i am sure no leaks,i took off the vacuum harness and fixed all leaks while off, my tps had no adjustments so i just bolted it straight on is there some special procedure to install it i have read to turn it clockwise but there is no adjustment

[donb]

does it surge at all & how does it drive

[noslowharley]

no surge at all , drives good running rich

[donb]

u mite want 2 check the map sensor 4 cracks

[noslowharley]

i took the map sensor and plugged it up on a 88 and it idled fine i started swapping parts so it would not cost so much

[88StangGT]

i know he tps can be adjusted by backing the bolts out a little bit and moving it. Hook a volt meter to it and tap into the green wire and when tightening the bolts down get the number close as u can to .98 y 5.0 had same problem it was a bad sensor and was told to do this.

[noslowharley]

my tps has no adjustments just 2 small mounting holes for the screws mounts straight on no play

[88StangGT]

use a small file. Hook volt meter to it and see what it shows.

[Blue_gt]

change the mass air sensor

[noslowharley]

not a mass air engine 1989

[wc351]

If it is a differnt intake try turning down the idle screw.

[BlueOvalBoy]

If it is a differnt intake try turning down the idle screw.



x2

[vortech_95-gt]

x2x3. Have to pulled the intake tube off and visually inspected the butterfly inside the throttle body to ensure it doesnt have a piece of trash in it holding the blade slightly open , or possibly a bent blade?

[George]

Since you say it is running rich and a fast idle it makes me think it is not sensing engine temperature. Therefore it stays on fast idle and a rich mixture.

[noslowharley]

the idle screw is not touching, when i had the throttle body off i cleaned it very good and it looks perfect, i replaced the coolant temp sensor as well, , i also pulled my hair out and that didn't change anything ether

[93blucoupe]

Check the length of the throttle cable. If the cables to short you'll be able to back the screw off to where it doesn't touch and the cable tension will hold the throttle open.

[wc351]

If the cable is not the problem, recheck your timing. If that does not reveal anything then try spraying starting fluid around all of you vacuum lines and there connections just to make sure that you have no leaks or a cracked line, even though you replaced the lines they can still get cracked or cut when installing them. Otherwise :why:.

[noslowharley]

ok i have hosed down all the intake and lower intake ,unhooked the throttle cable ,screw backed off, i hooked a meter on the tps and got it set to 0.98 and 4.98 wot , none of the helped , the idle is at 1100 that is as low as it will go when engine is warmed up, i will keep digging and see what else i can find

[BlueOvalBoy]

i replaced the coolant temp sensor as well,



Which temp sensor did you change? There should be 2 of them 1 works the gauge and the other works the computer. If the 1 for the comp goes bad it will run rich and high idle. All though it should idle a lil high and a lil rich on cold start but return to normal after a min. or 2.

[noslowharley]

yep i replaced both the sending unit for the gauge and the temp sensor for the computer , that fixed the gauge but not the idle

[noslowharley]

well i am leaving for work on friday and will be out of town for 14 days and then i will start back on the truck i am at whits end and need a break , it is just frustrating