TPS % vs Voltage
 

My question right out of the gate is using the Snap On Modis scan tool while viewing TPS% and TPS voltage:

C.T. = 0% / .45V
W.O.T. = 79.5% / 4.5V

With the accelerator completely mashed to the floor (no floor mat nothing restricting pedal from full travel) those are the readings I had on the Modis. I used Fluke auto ranging multimeter (model 115 if I remember right) to read actual voltage (back probing TPS connector) opening and closing throttle same readings, MAYBE a difference of .03V. Should the % be reading 79.5% at WOT? That seems odd to me. Looking at voltage I'd say the controller is getting correct reading from sensor but % is throwing me off. Oh just in case it matters these reads were both done at KOEO. Did happen to run car down interstate with Modis and verified TPS% 79.5 when mashed.

Now for my background and I'm going to request anyone who answers to maybe "dumb" it down a bit for me. I went to auto trade school 12 years ago was ready to take on the auto world yada yada yada, well as luck would have it I fell in to the diesel world and been there ever since with out ever going auto (and by auto I'm referring to cars/trucks gasoline engines sorry sure theres a better term but thats what im going to use). With that being said I have a semi decent knowledge of auto and how things operate troubleshooting wise BUT and this is a big BUT I personally (and I think all diesel world) deal more with readings like PSI, "Hg, Temp, I don't really talk in voltage unless I need to know if a sensor or component is getting correct voltage. It appears auto techs talk a lot in voltage and that means a lot to then but not me, I understand % better than I do "Oh you should be running at 2.75V @ half throttle" I appreciate all help but please tell me what 2.75V is suppose to be % wise if you do use voltage. I think I've covered everything, car has a few minor issues that I've been looking in to not sure if going in to great detail would help. I do not have any DTC's other than the flash code 67 which i believe is upstream O2 lean cat efficiency. If I gradually go in to the throttle the car gets up and goes pretty well. If im cruising and in need of passing someone and I floor it the RPMs jump to about 4,000 (like it kicked down a gear) and speed will either stay at where it was or if im on a hill will start to slow down. Once this happens if I back out of the throttle and ease back in to it, she'l pull great and I can pass someone it just takes forever because I need to ease it. Thank you for reading my novel any idea would be amazing and ill do my best to rummage my decade old knowledge to help answer any further questions.

I'd suggest getting a pdf of the shop manual from automanualsource.com. It is $22 and worth every penny.

In the TPS troubleshooting it says closed throttle is 10% or ~0.5V and 90% or 4.5V when open. Your TPS is operating normally.

What symptoms are you troubleshooting? Use the scantool to get the OBD2 code (it will start with the letter P and have four numbers, like P1234.

My main goal is to T/S the no power I have when mashing the throttle not really worrying about the Cat issue as of this point putting that on the back burner. The only DTC is for the Cat P0420, I only mentioned that just in case it had any involvement in the engines response to quick acceleration. I have the Haynes manual as well as access to Mitchell Pro Demand so access to info isn't an issue but even with those two sources nothing gave me a really good answer if 79.5% was a good reading. A little history I did leave out car has 350,000 miles on it I replaced the injectors a few months back. With original injectors I had very little response when applying throttle slowly I had to really get in to it to get the car moving like at a stop light but it I mashed it to pass someone it'd get up and go. With new injectors I have great response easing in to throttle but if I mash it RPMs with jump to 4000 and vehicle speed will either not change or will begin to decline. Thank you for the response though

Sorry probably should mention I am second owner, Injectors removed as far as I can tell were original injectors. Swapped out with Injectors by G.B. Remanufacturing Part Number 842-12195, bought all 4 injectors at same time and installed all injectors at the same time.

Just me and don't take this the wrong way.

Solve the P0420 code first.

Going by the voltage (0.5 to 4.5V) the tps is working normally. The % is the computer's interpretation of the voltage.

You may want to clean out the throttle body and both sides of the throttle plate.

You may want to adjust the tension on the throttle cable. See the video below.

Another update I went to NAPA and picked up a fuel pressure regulator, installed it in the parking lot. Left from there mashed the throttle and it had power in the higher rpms (didnt blow me away but it was definitely a change for the better). Drove to my work the whole way in and out of mashing throttle, got to work picked up some tools and left. On the way home mashed throttle again, nothing just like it was prior to replacing regulator. I installed the fuel rail pressure gauge, followed procedure in manual removed vacuum line from regulator and started car, car starts idles fine and has 85 psi. re-installed line unpinched and no change still have 85 psi. According to manual with line off and pinched I should be between 47-54 psi, with line installed and unpinched I should be between 38-46 psi. So I took unit back out on road while accelerating i'll be anywhere from 75-85 psi, when I mash throttle and rpms go to 4,000 I have no response like its dead but rpms are high and pressure at 85psi. This is driving me mad according to manual specs I seem to have plenty of pressure, not sure as to why the lack of power when getting in to throttle hard.

Do you still have the 0420 code?

FIXED!!!!!!!!!!!! Turns out I'm an idiot and was not paying attention to detail when I replaced the injectors. I performed the injector replacement correctly but when removing the Fuel Pulsation Damper I had dropped the upper sealing washer and could not find it, so I used a fuel sealing washer with the rubber insert lining. I did not pay attention to the stud on the fuel rail where the fuel inlet banjo mounts to it does not have any openings on the side, the only opening is on the very top. So the fuel travels from the supply line around the fuel rail stud, up into the damper, out of the damper then in to the fuel rail stud. With the standard fuel washer (with rubber insert) that passage way was heavily restricted. So on to the 0420 unless this had something to do with it.

You can clear the code and see if the P0420 returns.

Yup disconnected the negative cable last night drove around and CEL back on I'm 99% sure it's the 0420 code I'll keep updating till I get worked out. Now on that 0420 code (when I had access to that scanner) not sure if I already mentioned this after driving for awhile monitoring O2 sensors I noticed the rear O2 heater never turns off. Is this normal? I guess I was always under the impression once the car was good and hot and in closed loop the heaters weren't needed. Now the upstream O2 sensor will cut on and off.

I'd assume the rear heater remains on the whole time. Maybe it is cooler at the cat?

Watch the signal from the rear O2 sensor. I wouldn't worry about the heater part of the circuit.

Yup it's definitely the P0420 code. I wasn't putting a whole lot of stress on the idea of the heaters being an issue I just was under the assumption that the heaters were suppose to turn off at some point but that could just have been my misunderstanding of operation. I guess because I understood that there was suppose to be a temp rise across the cat of roughly 50 degrees in a correctly operating system due to chemical reaction. Unfortunately I don't have continued access to a data logging scanner so imma be taking educated guess at which part to replace next. The car has over 350,000 miles on it and I am going to be putting new pistons and new rings in it shortly due to the fact it has been burning a fair amount of oil (no visible signs of oil leaks, I've been good at the up keep on those). So I'll keep this thread updated as I continue through. I bought the car 4 years ago with the understanding that the cat had just been replace and the previous owner stated the repair technician claimed the light stayed in after the cat replacement because it was an after market part and the sensors didn't like it (just in general I've never liked that answer being a technician myself I feel that's a cop out). I've previously removed both O2 sensors and did the white vinegar over night cleaning issue is still there so again will be installing new pistons and rings I. The next few weeks and I'll do my best to keep updated for any changes.