Hi all, I'm a newbie. I just inherited a '87 T-Birb Turbo Coupe with 223,000 km. It' runs great, doesn't leak or use a drop of oil. But it has an Idling problem. Usually it appears after the first stop and start. For some reason the idle will stick at around 2000 RPM. My brother said that when it happens, turn the key on and off, so that the engine doesn't turn over, and it will correct it. But that's not fixing it. He had a mechanic look at it, and he said it was a problem with the plunger getting stuck. I guess he tried to find the part, but couldn't find a replacement. But some times, I can sit at a red light, and it will slowly climb. Cycle the iginition, and it calms down.
To me it seems to be electronic. But I don't know.
Any ideas?
try running codes. maybe a tps problem.
Plunger == Idle Air control valve?
Does it have a hard time starting, or tend to roll back in forth while at idle?
x2
paperclip = code reader
Yes at a red light, the idling does goup and down between 1000 and 1200 RPM.
But it always does start fine.
I just spoke with my brother who talked to the mechanic who said it was the computer that's causing the Idle Air Control Valve to stick. Replacing the Idle Air Control Valve won't help.
Any ideas what computer is in this car, and where I might find one.
If I have to change it, are the anything I have to setup again, like idle and such?
Dont believe the "mechanic"s. The guys here know way more than any regular old mechanic.
CHECK YOUR TPS VOLTAGE... Common problem on 2.3T... Won't necessarily cause a code...
Remember, I'm a newbie with this car. Can I check it with a voltage meter, and if so how.
I'm really thinking it might be easier to replace it with a working ECM, but find one is like pulling teeth.
If anyone has anyone suggestions where I can find a replacement, please post it.
How do I take the TPS voltage, and what should it be?
Ask, and you will recieve....links to other pages because it need not be repeated here..
http://www.allfordmustangs.com/Detailed/581.shtml
Ask and you will receive...links to other pages that explain it better
http://www.allfordmustangs.com/Detailed/581.shtml
I copied this from the article in danzajax link
1) Loosen the two screws holding on the TPS, (The screws can be very stubborn, so make sure you have a good quality screw driver that fits snug and has a long handle for lots of torque, or you might strip the heads) just enough to able to swivel the TPS with force.
2) Pierce the "GREEN" wire with the pin and hook the positive (+) lead from the voltmeter to it.
3) Ground the negative (-) lead from the voltmeter. Use a good ground, like the engine or other grounded metal source.
4) Turn your ignition key to the run position, but do not start the vehicle
5) Rotate the TPS until you achieve .98 to .99 Volts (For stock or slightly modified engines).
6) Tighten the screws on the TPS and recheck.
NOW this isn't totally correct... The voltage reading SHOULD be taken from the green to the black wire, NOT the engine block...
ALSO the setting for .98-.99 volt is BS... You'll never notice a difference anywhere from prob .8 to .99... At 1v or more you're flirting with a high idle issue... Set it for .9v and forget it...
IF this is your problem(likely) you can throw 40 ECMs at it and NOT fix the problem...
That was just the best description I found.
OK, you all make great sense, and I purchased a new TPS. I've located the current one, and it looks simple enough for even a newbie like me can do.
This one has where the screw holes are, there not just holes, so it looks like it can be adjusted, not like the factory one. If I put it in, and it's not in the right position, it will probably just idle too low or too high, right?
TIA.
stop listening to dumb asses who dont own these cars and start listening to our dumb asses,,, ok?
In retrospect, your first mistake was to make a major purchase without verification that the part you replaced was defective. Anyone can shotgun a few parts and just toss em in. Few want to learn how to diagnose the problem, and even fewer know how. Its too easy to do so since its so easy , might as well just join the crowd and keep it a secret. Its not like we dont do this stuff everyday you know.
was your old tps marked with a ford part number?
What was the voltage on the green wire to the black wire with the KOEO? (Key On Engine OFF)
Anyway, no it wont idle too low, it will just idle. If someone has messed with an idle set screw then yes, perhaps.
anyway,,
you need to learn how to pull the codes.
check out my DIY link below and follow the instructions. Also, the seach feature works here so just type "pulling codes" and see whats in here.
I suggest http://www.therangerstation.com
then click on tech library
next click on the eeciv codes section and there will be a diagram on how to install your jumper.
otherwise,, just do this.
run engine until it is warm and the temp guage has moved to normal driving temp.
shut off car.
locate your six pin and single pin test connector near the driver strut tower.
install a paperclip from the single pin test connector to pin 2 of the six pin connector.
(pin 1 and 2 along the top row)(pins 3-6 along the bottom row)
turn your key on only and watch the check engine light. it will strob in pulses with two digit codes.
example:
blink blink,,,,,,,,,,,,,,,,,blink blink blink blink = code 24
you can also add in a buzzer so you can hear your codes per below but for now , you should only use a paperclip so you can get use to the process.
First of all I was listening to the, what you call "dumb asses" on this site.
Second, I tested with a voltmeter using the procedure noted above, and the voltage was not increasing/decreasing while pressing/depressing the throttle. There were spots where there was no change in voltage, while the throttle position was changing.
Third, I don't think I need to be talked down to, just because I'm new at this. I maybe be new at this, but I'm not an idiot. So take your "its not like we don't do this everyday you know" attitude and shove it.
The check engine light never comes on. So I don't think the computer memory will have any info.
IF you'd posted that you had checked the voltage then much of Scott's reply would have not been necessary... 90% time we give out info on how to diagnose the problem and get replies, "well I repl xxx, yyy, zzz, and it still does it, what now"???
And we say check codes, and get "uuhhh, no how you do that??? OR "no I don't have a volt meter"...
A properly set TPS should sweep smoothly from approx .9v at closed throttle, to around 4.5v at full opening...
Probably 3/4 of the '88s do not have a active check engine lamp, it was disabled(no bulb) a few months into production... I do believe the Canadian deliveries are an exception...
OOPS forgot yours is a '87, still would be a good idea to check...
Doesnt he know how to read the previous posts. Just because I didn't post what the readings were, doesn't mean I should be insulted.
From your previous posts, I'd say Scott's reply was more than justified... Again YOU didn't give any info regarding any troubleshooting performed, only you purchased a TPS...
throw the tps at it just for fun. Then read codes. There is a way to do it without a check engine light. Also, you will get codes even if everything is working fine. So I would check to see what codes you can pull. Do a couple of searches, or maybe ask...
I was rude,, sorry for that.
The above sounds like you disconnected the tps. There is no way your car would run or start if you got the above readings and you tested using the steps posted.
you can test the tps two ways.
Resistance=
key off engine off
set meter to ohms
disconnect the tps from engine harness
prob the black to green wire
move throttle linkage increasing the resistance
ohm meter should increase smoothly
****its best to use an buttstuffog meter and watch the needle sweep***
slowly increase to max and decrease to min and note any needle or reading fluxuations.
replace if you see any signs were the needle or reading suddenly drops to zero.
Rrepeat above test reading from the orange to green.
VOLTAGE
key off engine off
set meter to Vdc
leave tps connected to engine harness
probe the green wire with a stick pin
probe the black wire with a stick pin
connect black meter lead to black wire stick pin
connect red meter lead to green wire stick pin
turn key on
take voltage reading (should be less than one volt.
open throttle slowly
****its best to use an buttstuffog meter and watch the needle sweep***
slowly increase to max and decrease to min and not any needle or reading fluxuations.
replace if you see any signs were the needle or reading suddenly drops to zero.
Rrepeat above test reading from the orange to green.
If you cant get your tps voltage to read less than a volt ,, use a chainsaw file (round) to file the mouting holes for the tps in such a way that will allow you to rotate the tps CCW while mounted and the tps screws snug and the meter hooked up. Mine is set at .7vdc but less than a volt is all you need.
If you have a check engine light (i dont own a TC) socket , stuff a bulb in there.
To pull codes not using a check engine light, you must have a very warm engine otherwise you are going to throw out coolant sensor codes and various other things.
Key off engine off
install the paper clip as shown
find you an old bulb with a socket and extend the wires so that one reaches the battery positive terminal.
Connect one side of your bulb to the battery +
Connect the other side of your bulb to the pin shown.
****DO NOT LET THE BULB LEAD TOUCH THE JUMPER
Key On engine off
**have your paper and pen in hand now prior to turning on your key because sometimes this stuff will happen fast.
the engine will spit out some fast codes,, ignore them
The codes will come to you like i typed up before.
its best to be standing comfortable with your paper and pen in hand so that you can see the flashes out the side of your eye while jotting down the codes.....
((this is why i use a buzzer, you can hear the tones and not have to look back and forth worried if you missed a flash or not. Missing one flash means a huge difference))
During the time you are pulling your codes,, it will appear as though it is done dumping them out to you.
You will suddenly see a single lone flash. This one flash is a separator flash meaning,,,
It will separate your "RIGHT NOW" codes from "LONG TERM MEMORY" codes.
Your initial codes are codes happening now so jot those down.
your long term codes are things the eec has collected and documented over the course of 40 warm up cycles.
Your right now codes can be erased by unhooking the jumper wire***WHILE*** the codes are being displayed. I personally have not seen this to be true but it might work on your car.
Your long term or continuous memory codes will erease themselves after 40 warm up cycles. As for this being true, usually you will see a change in your long term codes over time so i suppose its true.
on a side note,,
the rpm your talking about sounds a little too much to be a tps although i could be wrong.
On your engine intake, there will a sensor called the "air charge temp sensor" It should be a two wire connector on the intake somewhere.
IT changes in resistance via a tear drop thermal couple mounted on the end of it. This tear drop thingy hangs down in the intake and if it becomes covered with soot or a film of oil ect,, then the soot or oil acts as an insulator and it can not change in value.
remove this sensor and clean it off with a solvent or perhaps carb cleaner. Install it back and see if that drops your idle down.
the car is looking for all of these variable resistors readings and working out a math formula longer than my leg to determine your idle.
In addition, a slight vac leak will contribute to a high idle as well. there are many tiny hard plastic lines that run here and there and if one is cracked , your not going to get the idle down till its found.
this is not hard to do if you take each vac line one color at a time.
TAN
Black
Red
Green
white
to find a vac leak,, shoot bursts of carb cleaner along the areas of vac connections. When your engine rpm stumbles or jumps , you just narrowed down the leak.
Once you have found your leak,, it would not be a bad idea to locate your vac tree along the firewall driver side.
with the engine running, unplug the rubber nipple cap on the end. the car will stumble or idle high. Spray wd40 in there and let the vac system suck up the wd. Also, move or actuate some heater / AC controls inside. The wd40 will add some lubrication to the various moving parts / diaphrams throughout your HVAC system and various solenoids. Sometimes, large truck mech's do this to lube up various air actuated solenoids ect in thier air systems.
JCassity, no worries.
The TPS was only $40. So if I did read it wrong, I've got a new TPS, and the same problem...no harm done.
The check engine light does work, but it doesn't come on often. I think I've seen it only when I turn the ignition on.
So, I'm going to replace the TPS, and if it doesn't work, then I'll follow your advice on getting the codes.
Thanks everybody. These forums are GREAT!