99 Ranger 5.0 swap - throttle position sensor P0122 code - rough shifts

[mimswk]

I have a 99 4x4 with a 5.0 swap from a 96 Explorer. The previous owner seems to have replaced the TPS plug and put in a new sensor. It has a P0122 code.

The engine harness is from a 99 Explorer - not sure if that makes a difference in this case.

I've tested the sensor - it does have low input voltage (.87 volts - throwing the P0122) but seems to increase and decrease back down smoothly when opening and closing the throttle body. Tapping on it while opening/closing the throttle does not seem to cause any erratic behavior. Wide open reading is around 4.5 - 4.6 volts. Reference voltage seems fine.

I'm experiencing pretty weird shifting - longer shifting on acceleration, crappy downshifting causing bogging, etc.

I know the TPS can cause all sorts of shift issues. Would simply having the low input voltage throw everything off?

The sensor doesn't seem to be adjustable - it does feel like there's tension when I install it. I'm hesitant to waller out the holes and adjust it so it gets close to the 1 volt signal needed so it doesn't throw the code.

I'm not completely ruling out that my transmission (not sure of the model - automatic from an 01 Mountaineer) needs some attention. Just trying to take care of the most obvious issue to fix (TPS stuff) before going that route.

I do have it temporarily wired up - I wouldn't think that I'm having a voltage drop due to that. But maybe?

I really don't like just throwing parts at things if I can help it. Not sure if a new TPS would correct the issue.

Any tips or suggestions?

 

[410Fortune]

okay so you are using a 96 explorer engine with a 99 5.0 engine harness and a 99 auto transmission?

Assuming you are running the 96 explorer pcm?

there are a few wiring differences between a 96 and a 99 5.0
96 uses 3 wire cam pos sens, 99 uses 2 wires
Also the sensors are different in a few places, like TPS, the cam synchro and egr, how did you wire around this? The 96 computer is not going to be happy with the 99 wiring and 99 sensors on the 99 transmission. You see in 1996 many of the PCM sensors send an analog signal, by 99 they are digital.

There are also wiring changes inside the engine harness between 96 and 99


More details needed please!!

 

[mimswk]

okay so you are using a 96 explorer engine with a 99 5.0 engine harness and a 99 auto transmission?

Assuming you are running the 96 explorer pcm?

there are a few wiring differences between a 96 and a 99 5.0
96 uses 3 wire cam pos sens, 99 uses 2 wires
Also the sensors are different in a few places, like TPS, the cam synchro and egr, how did you wire around this? The 96 computer is not going to be happy with the 99 wiring and 99 sensors on the 99 transmission. You see in 1996 many of the PCM sensors send an analog signal, by 99 they are digital.

There are also wiring changes inside the engine harness between 96 and 99


More details needed please!!

Let me back a moment to say that I just got this truck as a couple of months ago, so my knowledge and details about the swap (or swapping a 5.0 in general) are still pretty limited. Be gentle while I work to identify what's what with it - I can imagine that it's kind of cobbled together, and I'm trying to sort it all out.

I just pulled the PCM, and it seems to be from a 99 explorer/mountaineer. See photo. I think this is probably the best place to start - locate the proper PCM for a 96 5.0 - correct?

I'm guessing it's in there because it has a 99 harness. Not sure if the 96 PCM will match up with the 99 harness, so if you have some info on that, I'd appreciate it.

Trans is a 4R70W from a 2001 mountaineer, from info I received from the previous owner.

How would you recommend I proceed from here? Get both a 96 PCM and a 96 engine harness? Also concerned about PATS. I'm assuming
I can program new keys with Forscan on a new-to-me 96 PCM.

Thanks in advance for the help.

 

[410Fortune]

is the cam sensor plugged in? (under the coil pack)
Does it have 2 or 3 wires

can we see under the hood? just some general pics will be helpful
Is this the only code in the computer?
the intake and EGR pictured above are 99 explorer
what makes you think this is a 96 engine?
and
Did it ever run correctly with no codes?

Po122 = low voltage
I would first get rid of those wire nuts AND install an OEM TPS for a 99 explorer


Bare with me...these questions will help determine how they did the swap
It would be quite easy to use a 96 5.0 engine with a 99 pcm, wiring, 01 trans and put them all into a 99 ranger IF they knew what they were doing

 

[mimswk]

is the cam sensor plugged in? (under the coil pack)
Does it have 2 or 3 wires

can we see under the hood? just some general pics will be helpful
Is this the only code in the computer?
the intake and EGR pictured above are 99 explorer
what makes you think this is a 96 engine?
and
Did it ever run correctly with no codes?

Po122 = low voltage
I would first get rid of those wire nuts AND install an OEM TPS for a 99 explorer


Bare with me...these questions will help determine how they did the swap
It would be quite easy to use a 96 5.0 engine with a 99 pcm, wiring, 01 trans and put them all into a 99 ranger IF they knew what they were doing

Cam sensor has two wires. I've attached a few photos under the hood.

The only code it throws is the P0122. I can't say for sure if it ran correctly with no codes or not.

The guy I got it from has said on two different occasions that it's a 5.0 from a '96. I'm not certain if he somehow cobbled a bunch of stuff together (I don't think he did?) or if it's even possible to put the intake, etc. from a '99 and put on a '96 block. Again, I'm just not 100% on what's going on here, but am working to try to get more answers from him.

Maybe it is a '99 after all? Maybe the '96 explorer that he took it from had a '99 engine put in it at at some point? Mysteries, mysteries.

Sure appreciate the help in working this thing out.

 

[Blown]

I don't believe the TPS is effecting shifting. I am currently tuning with that EEC, have tuned the transmission and shifting is not completed with TPS.

Still, I would set it as close to .98 volts and between .95 and .99 One size bigger drill bit than the holes should allow that little adjustment.

 

[mimswk]

I don't believe the TPS is effecting shifting. I am currently tuning with that EEC, have tuned the transmission and shifting is not completed with TPS.

Still, I would set it as close to .98 volts and between .95 and .99 One size bigger drill bit than the holes should allow that little adjustment.

Very interesting. Thanks for that info. At this point, I don't think there's anything to lose by just drilling out and adjusting the TPS and also maybe doing a complete fluid change. Looking at all options here - improper parts combo on the swap, mechanical issue, etc.

 

[410Fortune]

that engine bay is 100% 1999...nothing in there 96 unless its the block, even the heads are 99

How many ground wires are coming off your battery? I see one going to the intake manifold (not good)
The intake is a steel bolt into aluminum lower intake, I do not think that is a good ground for the engine
(You need three good grounds, one to the body, one to the frame and one to the engine BLOCK the cast iron part)

Get rid of the wire nuts, fix the battery grounds
clear the code and lets see where we are at

 

[mimswk]

that engine bay is 100% 1999...nothing in there 96 unless its the block, even the heads are 99

How many ground wires are coming off your battery? I see one going to the intake manifold (not good)
The intake is a steel bolt into aluminum lower intake, I do not think that is a good ground for the engine
(You need three good grounds, one to the body, one to the frame and one to the engine BLOCK the cast iron part)

Get rid of the wire nuts, fix the battery grounds
clear the code and lets see where we are at

Man, that's good to know. Maybe the previous owner is just mistaken on what it came out of.

I'm guessing you can tell what heads it has from the valve cover style - correct? Again, still learning this engine and 5.0's in general. I have had a couple of Rangers over the years, though.

I've got two grounds coming off the battery - one to that bolt on the intake, and a smaller one right next to the battery on the radiator support. Where would the third be? And where would be a better engine ground - is there a typical spot for that?

Also, three wires coming off the positive side. Just adding that info in case it comes up or looks suspect in any way.

 

[410Fortune]

I can tell its a 98+ from the external EGR line, cast exhaust manifolds, intake manifold, 2 wire CPS, mas, air intake tube, returnless fuel, etc etc etc that engine is all 1999 Explorer

They probably mention 96 Explorer simply because that was the fist year of the GT40 5.0 in the sploder
Your engine is all 1999 gt40-p as far as I can tell

that engine ground is not doing you ANY GOOD
the battery to engine ground should be down at the bottom of the timing cover there are two studs that face forward coming out of the bottom of the timing cover, one of those gets the battery ground

Also YOU NEED TO ADD ONE MORE BIG GROUND< FROM BATTERY TO VEHICLE FRAME
Your voltage and power issues might very well be bad battery wiring
Otherwise you will likely keep having all sorts of sensor voltage issues as the vehicle components search for a good ground..........


Also I do not like that aftermarket TPS and wire nuts! Wire nuts have no place under a hood, temporary or not!

3 grounds REQUIRED:
the one from battery to body looks ok
The one from battery to frame is MIA
the one from battery to engine is NO GOOD going to aluminum intake............because steel bolt is going through the upper intake into the lower intake and the lower intake is sitting on top of gaskets, this ground needs to go to engine BLOCK
Intakes make a POOR GROUND

 

[mimswk]

I can tell its a 98+ from the external EGR line, cast exhaust manifolds, intake manifold, 2 wire CPS, mas, air intake tube, returnless fuel, etc etc etc that engine is all 1999 Explorer

They probably mention 96 Explorer simply because that was the fist year of the GT40 5.0 in the sploder
Your engine is all 1999 gt40-p as far as I can tell

that engine ground is not doing you ANY GOOD
the battery to engine ground should be down at the bottom of the timing cover there are two studs that face forward coming out of the bottom of the timing cover, one of those gets the battery ground

Also YOU NEED TO ADD ONE MORE BIG GROUND< FROM BATTERY TO VEHICLE FRAME
Your voltage and power issues might very well be bad battery wiring
Otherwise you will likely keep having all sorts of sensor voltage issues as the vehicle components search for a good ground..........


Also I do not like that aftermarket TPS and wire nuts! Wire nuts have no place under a hood, temporary or not!

3 grounds REQUIRED:
the one from battery to body looks ok
The one from battery to frame is MIA
the one from battery to engine is NO GOOD going to aluminum intake............because steel bolt is going through the upper intake into the lower intake and the lower intake is sitting on top of gaskets, this ground needs to go to engine BLOCK
Intakes make a POOR GROUND

10-4. I'll get cracking on these items and let you know how it goes. I sure appreciate it!

 

[mimswk]

I can tell its a 98+ from the external EGR line, cast exhaust manifolds, intake manifold, 2 wire CPS, mas, air intake tube, returnless fuel, etc etc etc that engine is all 1999 Explorer

They probably mention 96 Explorer simply because that was the fist year of the GT40 5.0 in the sploder
Your engine is all 1999 gt40-p as far as I can tell

A new development - from what I can tell with my limited knowledge, the heads are GT40. Again, still learning. Does that seem to be the case?

 

[410Fortune]

yes those are gt heads not gt40p
So it maybe a 96 engine block dressed with 99 explorer parts to make it more closely match the 99 ranger
Nothing changes, except now you know your 96 engine thinks it is a 99
This is a good thing.......

 

[mimswk]

yes those are gt heads not gt40p
So it maybe a 96 engine block dressed with 99 explorer parts to make it more closely match the 99 ranger
Nothing changes, except now you know your 96 engine thinks it is a 99
This is a good thing.......

Cool. Yeah, it's a mystery machine but I'm slowly figuring out what's what. Going to work on those cables in the next couple of days. Thanks again for the help.