Poll
Question: motorcraft TPS vs other name brand TPS
right now im having trouble with choosing a tps for my car. It hesitates and stalls once in a blue. Tell me which ones you prefer
we need more votes people
my TC hesitates and stalls all the time. but my tps is only alittle over a year old. I'm running the napa tps.
Why do you think it's the TPS causing the hesitation/stall?
If possible, I buy Motorcraft...
TPS, TFI, PIP, ACT, ECT, EGR, etc...
Have you actually checked the TPS base voltage? What about timing ir a vacuum leak?
iv checked the timing and changed the IAC and changed the tps it works a little bette rbut i bought a KEM brand tps . Im wondering if motorcraft is better.
Did you ever adjust the TPS base voltage? Neither brand will work worth a if you just bolt in on. They MUST be adjusted.
Well, only if the voltage is not between 0.8 - 1.1 volts or so. The ECU zeros on the lowest voltage it sees & that becomes "0". This was done so that they would not have to adjust them at the factory. The only reason I give a limit is that less than ~0.5V & greater than ~1.2V, the ECU considers the TPS to be defective, otherwise it goes with it.
Well if he didn't even check it...who knows....
An incorrectly adjusted TPS could be the cause of your problem. Get a multi meter and check the voltage. You can get a multi meter for ~$15 at Advance Auto Parts. If it's off and you adjust it you'll notice a difference. The car should run much better.
The TPS is not adjustable.
The voltage is adjustable. Just hook up the volt meter to it and move it till it's at about .98 volts. When I first put mine on I just threw it on and took the car for a spin and it bogged bad. The TPS was at 1.6V with the throttle closed. I adjusted it to .98 volts and it's run great ever since. A volt meter will also tell you if the TPS voltage increase is smooth as the throttle opens or if it's jumpy. It should be smooth for proper operation.
I've never seen a TPS at 1.6V! In that case you would definitely want to put it into the range where the ECU doesn't think that it's failed (between 0.5V & 1.2V). It really isn't supposed to be adjustable though as the factory would never want to have to adjust such a thing in a production environment. One of the holes is oval - but only to account for mechanical tolerances. Most people have to drill it out to get any real "adjustment" out of it - does that seem like Ford intended it to be adjustable? With aftermarket TB's there
is a variable being introduced that didn't exist at the factory. Also, some people adjust the throttle stop screw (which should almost never be touched) to try to "adjust" their idle. This, of course, will affect the TPS voltage and could push it out of range. Most good aftermarket TB companies (Accufab for instance) tell you to
never touch the throttle stop screw as it is properly adjusted at their facility.
From the Ford strategy document for A9L processor (applies to all Ford ECU's though):
Ford never intened to have the TPS be adjustable.
well i tested the tps and it says its 1 dc then turn offf the engine and turn on the key and pressed teh gas and it went up to 5 dc and then down and it decreased and increased while bringing it up again
so thats good?
The '87-'88 TC and other 2.3s are adjustable, original 5.0s are not... If its not in the .7-.9v range with the IAC disconnected and the base idle set about 550 rpms(hot, stockish engine. If it has a cam 800-900 is more the base idle range and what I use), I'd be filing the holes and setting it in that range. I had to do the same on my 5.0 as voltage was at 1.1v on the Motorcraft TPS that came on my new 65mm T-Body....
The stalling problems occurs when the base idle is at a point so low the engine will stall with the IAC disconnected. This was the problem with a lot of the early port EEC-IV engines(I had this problem on a fairly new '90 Aerostar, that at the time no one knew what the fix was). As the throttle body became carboned the base idle would decrease, eventually getting to a point the IAC had problems responding quickly enough to maintain idle without stalling occasionally. This is why the air adjuster plate was devloped, so the base idle could be increased without resetting the adjustment on the throttle plate and upsetting the TPS voltage(this fix assumed it was in range). The theory was, install the adj plate and leave the T-Body dirty so no adjustments should be required in the future. Of course cleaning the TB and saying piss on the air bleed adaptor would have done the same thing... But would require preodic cleaning of the TB...
wow so 5.0s cant be adjusted . wow someone here told me a site were the turbo coupes have adjusted tb and that you have to do teh same thign for the 5.0 . I guess i wated my time doing that. Well i checked teh dc voltage and it was 1dc at idle and with engine off key on and pressed the gas up anbd down and increaded to 5 dc and decreased back to 1 dc . and also replaced it with a motor craft. Is the dc good?
Re-read my previous post till you understand what I'm saying... The TPS voltage is secondary(but none the less important) to the base idle setting...
In theory, there is no way to adjust the idle without a tuning device. If you turn in the throttle stop screw without having the TPS voltage go above 1.1V (& you can "adjust" it lower it if it does go above 1.1V), then you may be able to stop the stalling. The Idle Air Control (IAC) may not be working properly after that, but it may help - it's how I used to do it before I got the TwEECer.
You can make sure it is adjusted properly by doing what TC50 was saying. Disconnect the IAC valve. Start the engine and set the idle to ~550RPM with the throttle stop screw. Check to make sure TPS is within ~ 0.8V - 1.1V. Reconnect IAC & restart the car - this should get it close to where it should be. There are writeups on how to do this posted on the some tuning & other sites.
Oh, and 1V at idle & 5V at WOT is good, except I hope you have higher accuracy than that. I would rather see numbers like 1.03V @ idle & 4.72V at WOT. 1.26V rounds down to 1V, but this would mean the TPS is out of range!