My first post here

Well I was about to adjust my TPS... i got a reading on the voltmeter. But I loosened the 2 screws.. but the modules doesn't seem to want to turn to be adjusted.

It's an 87 5.0 - Am I missing something? I thought it would be straight forward.

Any advice would be appreciated.

Thanks,

 

Try This

How To Adjust TPS
"Muscle Mustangs & Fast Fords"
April 1993

The throttle position sensor is one of those things that falls into the category of "computer stuff" that makes a big difference and is easy to deal with, but average people like us would never know about. Without the proper adjustment, the throttle position sensor (TPS) will give the computer a false reading as to the exact throttle opening. A false reading will limit wide open throttle performance (something we definitely don't want). A voltage reading must be taken using a digital volt/ohmmeter (DVOM) with the Key On/Engine Off and with the Key On/Engine Running. A Radio Shack DVOM, part No. 22-185A, works well for this job.
The TPS is located directly on top of the throttle body and is adjusted by loosening the two phillips mounting screws and swiveling the sensor until the highest reading is found. It may be necessary to elongate the holes with a small file to achieve the desired reading.

The spec range for Key On is from .88 to 1.0 volt; shoot for the .97 to .99 volt. With the engine running, the voltage should be no higher than 1.05 volts.

Incorrect Throttle Position Sensor (TPS) voltage will result in reduced performance. The best way to take a TPS voltage reading is by using two safety pins through the wires coming from the sensor. The positive lead is attached to the green wire, while the negative goes to the black wire. Always ground the meter through the sensor's black wire. This gives a direct, and more accurate ground into the computer

 

Thank you for the advice!!

i did have to file the holes a bit to get the adjustment. It was previously at 2.7 Now it's down to .99 and when starting it is under 1.05

So cleaned the throttle body & IAC... adjusted the TPS.. so far idle is smooth and steady.. but when in Park or Neutral(AOD) the idle stays at 1200-1400. But when I put in in drive it goes to 900. Could this be due to anything that I did?

Thanks,

 

my 88 did that once in awhile when I took out the air.
Seems to me there's a throttle adjusment on the right hand side of the engine and I dropped mine down to 550.
Next time I'm with the 88 I'll have a look for it
(this from an 87 5.0 site)
Get the inside of the throttle body clean. Close up the idle adjustment until the adjustment comes off of the throttle. Screw in the idle screw with a peice of paper between the idle adjustment and the throttle pulling on the peice of paper feeling for the drag. Once you have a slight amount of drag on the paper, remove the paper and turn in the throttle 1/2 turn. That is the starting point for you idle adjustment. Disconnect the battery. Reconnect everything back up and bring the engine up to temp. At that point disconnect the idle air control solenoid. You are now idling at base idle speed. This idle speed needs to be around 550 rpm. Adjust the idle screw to get to that speed,unless you have to back it out from the base setting. If it is idleing slightly higher than 550 don't worry about it. Reconnect the idle air control solenoid and drive the car.

It should be back in business.

 

My 89 was doing this last year,..... exact same thing,.. In fact it still once in a while does it,.... usually corrects itself or when I shut off and turn the car back on,..... check your timing,.. solved 90 percent of my problem. If stock set to around 11 degrees,.. could full advance to 15,... but if stock I wouldn`t go and farther then 13.5. The timing issue definitely helped me. Mine used to idle high really bad constantly till I adjusted it,.. now its very minor and very rare and like I said usually corrects itself.

 

This is also very importaqnt to set as well,.... so do your base idle set,... then check your TPS,... then check your timing.

 

forgot to mention,
on my 81 carbed Mustang I 6 auto I set the Idle at 1000 rpm in neutral and shifting into drive put the rpm around 550 or 600 rpm

 

Thanks everyone so far for the input..

So upon further inspection.. the idle screw was adjusted out almost to the end of the screw..

- so far this is what I have done:

- cleaned IAC and throttle body
- Pulled neg cable for over 1/2 hr disconnected the IAC plug
- Set the car with the idle screw until it idled on its own at about 750
- set TPS to .98

The problem I have now is when in park the idle is at or a bit over 2000 rpm and when I put it in gear it goes down to 1100. It's an AOD btw...

So I left idleing for over 5 mins hoping that it would normalize or learn the new idle but it hasn't... the worse part is when I'm in drive.. the wheels will spin... with the cold weather outside it's a bit dangerous as it won't brake if the rear wheels are spinning..

So I tried leaving the IAC unplugged and drove it... it idled overall quite nicely and the throttle response was quite a bit better than with it plugged in... the only problem with leaving it this way is my cold start warm up of course and sometimes when I blip the throttle it can stall out

Is the IAC bad?? I'd rather pull the IAC and have it stall then to have it at such high rpms and the wheels spinning even with the brakes engaged.

Thanks in advance for everyone's replies...

 

Man this is so wierd my car did the same thing,.. mines an AOD too,... 2000 at park,... car pushing at lights,.... shut car off restart fine for about 5 min or 2 days,.. very intermitent,.... I`m not entierly sure what I did,.... timing solved my problem,.... I replaced my IAC and had seame problem,.. check vacuum lines everywhere for small cracks,.. that was another problem I had. Keep us posted,.. I`d like to know what this is too.

I see you didn`t say anything about the timing,..... CHECK IT!!!

 

Thank you again for everyone's helpful feedback..

I finally had a chance to tinker with it a bit this week. This is what I did:

- Bought new IAC- the rpms went even higher... my IAC was probably going downhill even with the thorough cleaning

So the problem was worse until - just today I bought a new TPS sensor.. followed the base idle setting... set the TPS to .96 , etc

The car now starts with a bit more authority- it starts at 1500rpms (cold outside) then settles to about 800 in park and when I put into drive it goes down to 700. I haven't test driven it yet with all the ice on the road... but so far the idle is pretty stable and most importantly it goes down properly. When I put it in drive it doesn't start spinning anymore..

Will update if there are any changes when I have a chance to drive.