adjust your TPS (another free hp mod)

[CDW6212R]

I own a 2000 Explorer Sport 4WD 4.0l SOHC with 106k+ miles on it.
I had 1.14 volts, I modified and adjusted it to .96 volts and had a great change in pick up and response. It ran good before now it runs great.
Thank you very much for posting this information, it was very helpful.
Rob

I know that you gained nothing from changing the TPS voltage. If you gained any improvement then it came from something else, like cleaning the MAF, throttle body, or tightening the air inlet pipe clamps. For a 2000 model Ford no TPS adjustment is needed.

 

[gmanpaint]

Do not mess with any TPS since the EECIV cars. The OBDII PCM is smart enough by design that it doesn't matter. So yes, don't touch your 95+ Explorer TPS. Those either work or they have failed, and the voltage is far far off(like 3volts at idle).

My '95 is EECIV. I also have an OBDII port inside the cab. I own a half breed, OBD1.5 I guess. That port reads certain things in my system, just not sure which ones. I have been reading this thread and am intrigued by it. I have an egr issue to solve, and if my engine does not run any better after that, I was thinking of trying this mod. I am looking for DYI cheap mods to help it run better, this one seems to qualify. But this is only one of many things that can be causing my problems, if it works than what the heck? New TPS is only $30.

 

[CDW6212R]

Ford made changes during 1995 for OBDII, and some were full OBDII vehicles. The Explorers were not until 96, so the TPS voltage is important for you and the 95 engine.

Part of why the older Fords are hard to work with is that the TPS is not adjustable. Ford never meant for the TPS to be able to get anywhere away from the PCM set .990 volts. Unfortunately all of the TPS units do have a little wiggle room in the mounting holes. They simply are not precisely made to be right at the needed voltage. Any variance in the manufacturing of the TPS pushes the voltage away from the designed goal. So for the pre-OBDII it is very important to verify that the TPS voltage matches what is in the PCM.

The OBDII PCM has no idle voltage set for the TPS. The 96+ vehicles take the voltage from the TPS each time the vehicle is started. Regards,

 

[gmanpaint]

Ford made changes during 1995 for OBDII, and some were full OBDII vehicles. The Explorers were not until 96, so the TPS voltage is important for you and the 95 engine.

Part of why the older Fords are hard to work with is that the TPS is not adjustable. Ford never meant for the TPS to be able to get anywhere away from the PCM set .990 volts. Unfortunately all of the TPS units do have a little wiggle room in the mounting holes. They simply are not precisely made to be right at the needed voltage. Any variance in the manufacturing of the TPS pushes the voltage away from the designed goal. So for the pre-OBDII it is very important to verify that the TPS voltage matches what is in the PCM.

The OBDII PCM has no idle voltage set for the TPS. The 96+ vehicles take the voltage from the TPS each time the vehicle is started. Regards,

Just for future reference, do you know the manufacture dates for the full '95 OBDII switch?

 

[CDW6212R]

I don't, I have read the posts of people with vehicles from 1995. I have two 95 Crown Vics, which seem to be OBDII, though I have not checked. Mustangs are not in 95 I'm sure of. I'd bet that the high end cars may be the first OBDII models.

 

[gijoecam]

Ford made changes during 1995 for OBDII, and some were full OBDII vehicles. The Explorers were not until 96, so the TPS voltage is important for you and the 95 engine.

Part of why the older Fords are hard to work with is that the TPS is not adjustable. Ford never meant for the TPS to be able to get anywhere away from the PCM set .990 volts. Unfortunately all of the TPS units do have a little wiggle room in the mounting holes. They simply are not precisely made to be right at the needed voltage. Any variance in the manufacturing of the TPS pushes the voltage away from the designed goal. So for the pre-OBDII it is very important to verify that the TPS voltage matches what is in the PCM.

The OBDII PCM has no idle voltage set for the TPS. The 96+ vehicles take the voltage from the TPS each time the vehicle is started. Regards,

I think you and I are the only two people on this board that don't believe the rhetoric... I explained the whole 'RATCH voltage' thing back in the first page or two of this thread... Nobody believes me and insists that 'it works'...

I think it's a placebo effect myself, and aside from the 'it works' argument, nobody has been able to provide and quantifiable evidence that it affects performance in the least.

 

[CDW6212R]

Ditto, a handful of people have made changes to their 96+ models, but it's almost always with other changes. Jon had a bad TPS sensor, which he probably caught because of this kind of thread. I recall fighting the TPS in my first LSC, it ran great at about .976 volts, but I couldn't tell the difference at .99 volts.

 

[gmanpaint]

I just had to go and test mine! I got 1.04 v Does that seem to much out to deal with? Seems pretty close to me, but not sure.

 

[CDW6212R]

Not really, the mounting holes only allow about 1/32" of play, you might be able to move the TPS about .15v or so. I'd play with it just because of the cost of gas, any help is worth doing.

 

[gmanpaint]

Well I just got done doing my X. Got it set to .96

I must have read it wrong the first time, cause I did it again, and got .42, rechecked and got the same.

It did not help my prob at all. I was just wishful thinking it might help, even some, but no.

My idle is still at 1100 rpms, when you stab it (throttle) up to any thing over 2000 rpms and let off the throttle completely, it almost dies out, and when you think it will die,it goes back up to 1100 rpm idle.

I do have a memory code 332 egr right now, but I dont think that will mess up my idle so bad and cause it to die.

 

[WITNEY]

Tps replacement

The TPS I purchased turns clockwise and the Throttle turns counter clockwise. If I turn the tps so that it turns with the throttle, the voltage is 5 v moving down to 1.4 when the throttle is engaged. Is the tps one diretion for one year and different for the next or am I installing it wrong.

 

[JOEZ33]

I've been having some random P0174 and P0171 codes this week, even though the truck is running better than ever. I looked it over today and noticed some rust and staining around the TPS sensor attach screws. I pulled on the TPS sensor and it moved, so its been loose and wiggling around, causing the screws to rub and make metal flakes which rusted in that area. ..........anyways I put a VOM on it, and it has enough free play to vary the idle voltage from .95 to 1.05.

This means if I start the truck and it has a base reading of X volts, but then while driving the X number is constantly changing, it won't have an accurate reading of what my throttle position REALLY IS... I'm not positive that .96 is the holy grail but as long as I have one consistant reading it should cure or at least prevent some odd check eng lights from happening. BTW I set it to exactly .96 volts to be safe. I'll give it a week to see if I get a noticeable difference in drivability and see what my mileage does etc.

 

[Brandon96]

I just did this mod last night. My X was running at .677v and I spent about 45 minutes getting it to .963 volts. I honestly did notice a difference. I own a 1996 4.0 OHV, could that have affected mine? or is it just my imagination

 

[gijoecam]

I've been having some random P0174 and P0171 codes this week, even though the truck is running better than ever. ...snip...

Those codes are lean bank 1 and bank2 codes. They have nothing to do with the TPS.

I put a VOM on it, and it has enough free play to vary the idle voltage from .95 to 1.05.

This means if I start the truck and it has a base reading of X volts, but then while driving the X number is constantly changing, it won't have an accurate reading of what my throttle position REALLY IS... I'm not positive that .96 is the holy grail but as long as I have one consistant reading it should cure or at least prevent some odd check eng lights from happening. BTW I set it to exactly .96 volts to be safe. I'll give it a week to see if I get a noticeable difference in drivability and see what my mileage does etc.

The only effect that would have on the ECU is if it was unable to maintain a steady reading to establish the RATCH voltage when the throttle is closed. It re-learns the lowest steady TPS voltage as RATCH and uses that to determine when you're at closed-throttle/idle. If the voltage was moving around due to the loose TPS, it would likely manifest itself as a high idle,a s I explained on page 7 of this thread... (quoted from the factory service manual)

Idle Speed Control Closed Throttle Determination
One of the fundamental criteria for entering rpm control is an indication of closed throttle. Throttle mode is always calculated to the lowest learned throttle position (TP) voltage seen since engine start. This lowest learned value is called "ratch," since the software acts like a one-way ratch. The ratch value (voltage) is displayed as the TPREL PID. The ratch value is relearned after every engine start. Ratch will learn the lowest, steady TP voltage seen after the engine starts. In some cases, ratch can learn higher values of TP. The time to learn the higher values is significantly longer than the time to learn the lower values. The brakes must also be applied to learn the longer values.

All PCM functions are done using this ratch voltage, including idle speed control. The PCM goes into closed throttle mode when the TP voltage is at the ratch (TPREL PID) value. Increase in TP voltage, normally less than 0.05 volts, will put the PCM in part throttle mode. Throttle mode can be viewed by looking at the TP MODE PID. With the throttle closed, the PID must read C/T (closed throttle). Slightly corrupt values of ratch can prevent the PCM from entering closed throttle mode. An incorrect part throttle indication at idle will prevent entry into closed throttle rpm control, and could result in a high idle. Ratch can be corrupted by a throttle position sensor or circuit that "drops out" or is noisy, or by loose/worn throttle plates that close tight during a decel and spring back at a normal engine vacuum.

 

[CDW6212R]

I just did this mod last night. My X was running at .677v and I spent about 45 minutes getting it to .963 volts. I honestly did notice a difference. I own a 1996 4.0 OHV, could that have affected mine? or is it just my imagination

The base voltage needs to be around 1 volt, it needs to have a range of about 4 volts, thus a maximum of about 5 volts. Ideally you shouldn't want the voltage to be too far from 1 volt at idle, so .5 volts or 1.5 volts would be too far. I'm not familiar with the symptoms you can get with the idle voltage being too far from 1 volt. Usually if the TPS is that far off, something has happened to it and it should be replaced.

To answer your question about .677 volts, that doesn't sound great. If you were able to get a better voltage, great, that may work from now on properly. I would suggest simply paying attention to how the engine runs. If anything changes a lot, check the TPS voltage again. Otherwise check that TPS sensor once a year or if the engine runs oddly at some point. I'd just call it a suspect TPS, but not condemn it. The TPS should be constantly reliable, never change voltage from one day to the next.

 

[Toast]

Can someone explain to me where it would be on a 4.0 sohc?

 

[4x4man]

Very high V

I got 1.70 V !
Replaced and tested with a brand new one (Motorcraft) today and showed 1.73:scratch:
WOT shows 8.1 V !!

Right now I'm wiggling out the holes on the old one to test it tomorrow.

Why so high guys...any idea??

BTW: Engine runs fine on 800RPM, but consumes way to much gas.

 

[seth247]

Perhaps because your vehicle has a different computer style the voltages are different?...

The voltage listed at the beginning of the thread is for first gen OHV's which have an OBDI computer.

Yours has OBDII

 

[4x4man]

Perhaps because your vehicle has a different computer style the voltages are different?...

The voltage listed at the beginning of the thread is for first gen OHV's which have an OBDI computer.

Yours has OBDII

Hi Matt...thanks for reply.

But this high V can't be right...or?
My Haynes book and work shop maual tells me max 5V for WOT and 1.5V for idle.
I'm pretty sure there is something wrong regarding my high milage and I was pretty sure TPS was the guilty one.

Hope my english is understandable

 

[CDW6212R]

The highest voltage should be in the 5 volt range. I would suspect a bad TPS, even the new one. Buy a Ford part for important components like that. The engine will probably do better with 1 volt instead of 1.75v.