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Discussion Starter · #1 ·
help help help help help help help

ive been messing with this thing for hours, and finally i got fed up with it, and took it off. with the TPS out of the Throttle Body, the lowest voltage reading i can get is like 2.60V. Yesterday i was trying to re-set the idle, following the Ford Racing procedure. I adjusted the thrttle stop screw with the IACV unplugged, set the TPS to .98V, and then turned the car off, but to the ON position, and the TPS was at like .96V, so I set it back to .98V. Then i disconnected the battery for 15 mins, and plugged it back in. The first time, I was idling too high, so i did hte same procedure again and then it was too low, so I did the same procedure again, but then I couldnt get a low reading no matter how far I turned the TPS. SO then i redid the battery thing again, and then the voltage was even higher, at like 3.4V while idling, and the car was idling at like 1500-2000 RPM.

So i got fed up with it, took off the IACV and the TPS, and the lowest reading i can get on the TPS with it off the TB, but still plugged in it 2.60V. What the h*ll is wrong with this thing? how can it work one second, then not work the next time?

I cant get a new TPS until monday, if that is even the problem. IS there any way to fix this, or trick the ocmputer or something?

Keep in mind I have an SN95, its a 1994.

HELP MEEEEE

I am workin on it right now, if anyone has any ideas, please respong ASAP or call me, PM me for my cell phone number.

Thanks a million guys
 

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Check the signal wire (red) with an external ground (up to anything metal and solid) and make sure it is getting 5v. Also check the ground by hooking the voltage meter ground into the black wire plug part and the red part of the volt meter up to the red wire on the harness. It should read 5v also.
 

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As long as your tps is linear with engine rpm and not fluctuating too badly, I think it is fine. It is under a little bit of tension when installed on the tb, so the reading will be different. The main thing here is, don't worry about the voltage reading at idle in your car. All 94-95 mustangs were different from the foxes in that the computer reads the voltage at key on, engine off, and sets that value to zero for the idle speed. I would stick the tps back on and not mess with it, take off and clean out the IACV real good. Stick it back on and use the idle stop screw to adjust the idle. If you still have problems let us know why you started messing with it in the first place in detail so we can help you better. It also wouldn't hurt to take off the EGR valve and clean it out too. That will help with the idle.
 

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Discussion Starter · #4 ·
the problem is i cant "just leave it" because when i plug the IACV back in, it idles at like 2000 rpm. i just replaced the IACV like 5k ago, so i know thats fine.
the reason i started messing with it in the first place is because the guy at ford racing told me to adjust it because:
1) sometimes, after driving, the car will start to want to stall, so he said to clean off the MAF with non-chlorinated brake cleaner ... so i did (when it was cool).
2) when i am really low in the RPMS, like 1000 - 1500, and im not on the gas, then i go back onto the gas, the car will jerk, so i have to puch the clutch, rev it up a few hundred RPM, then easy off back into gear, and itll be fine. but thats becoming to be more then a pain in the @$$, so he said to re-check the TPS.
ive done it before, but i dont think i ever followed the correct procedure. so i did it twice, and once it idled low, and the next it idled high, so when i tried to get it just right ... i couldnt get the TPS below like 1.1v while in the TB.

so i dont believe that i can just leave it how it is, because at 3.5v, the computer thinks im at WOT, but im idling ...
im not gonna waste a shitload of gas because the TPS is f'd up ... if ti even is the TPS
 

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Discussion Starter · #6 ·
no. if i did that, wouldnt the car stall because it wouldnt know how much fuel to deliver?

the only thing i disconnected was the IACV
 

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I really don't know why a guy at ford racing told you to adjust the tps. He is one of the first people that should know the tps on 94-95 5.0's is non-adjustable. You can actually adjust it, but it makes no difference. I tried a couple of times on my 95' before, and it made no difference. Then I read the manuall and found out how it works. If you have the tps correctly installed, and at key on engine off it is reading more than 1.5 volts, I would look into replacing it. Don't assume just because the IACV was just replaced that it is not bad. I actually did have a bad tps on my 95 5.0, but it did not act like what you are describing. Even if the tps is disconnected, the engine will still run. The computer knows how much fuel to give from the mass air meter, not the tb or tps. Let us know what you find out.
 

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Discussion Starter · #8 ·
i thought the TPS told how much fuel? key on engine off, it reads about 3.5 or something. i will check the ground today, and if thats not it, ill replace it. but i do need to get it the 4 miles to work with about 5 stoplights, so we will see... and then i need to get to napa, twice, once to order the part, and once to get it...
ill let everyone know
 

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Discussion Starter · #9 ·
ok well i replaced it, because the ground was fine, and now it runs a lot better after setting it to .97V, then resetting the computer by disconnecting the battery.

now tho, i slammed it in 2nd, a and the motor was goin, but the car wasnt goin anywhere? i dunno? then, while lettin off the gas, it was almost like the car kept coasting. i dunno if its supposed to do that, or if its still not set right, or what. any ideas?
 

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Discussion Starter · #10 ·
one more thing, when i set the TPS to .97, should it be with the motor on, or with the engine off key on?
 

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YoshiBluedevil said:
one more thing, when i set the TPS to .97, should it be with the motor on, or with the engine off key on?
Read my posts above about adjusting the tps.
 

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Always set it with the motor off, keys up.
 

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Discussion Starter · #13 ·
any ideas as to why the car felt like it kept coasting, or why it was revving but not goin anywhere?

it SHOULDNT be the clutch because that was done like 6k ago when i got the motor.

also, when i first start, it seems to stay reved at like 1500 for a few seconds, and then gradually come down the the 900 idle, then if i tap the gas, itll stay up for a sec, then come back down ...

any ideas? is that the TPS being off? or could it be the IACV? or the MAF since i just cleaned it? or since the EGR leaks a little at the EGR tube (Where it the tube from the headers connects), could that do it?
 

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if you got your IAC valve from Napa auto parts or any aftermarket auto parts store for that matter then it doesnt matter how new it is, it could still go bad, my brother has put 2 fuel pumps and 2 iac valves from auto parts stores one right after the other because they are junk. there are some parts that you should really just go to the dealer and get OEM
 
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