What else affects the TPS?
03-08-2012, 06:07 PM
#1
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Thread Starter
What else affects the TPS?
About a month ago after wheeling my truck started rough at a stop light and would not accelerate. Little to 1/4 throttle was fine, but more than that led to rough running, no power and loss of RPM followed by backfiring.
Truck has good compression, proper timing, new plugs and wires, no vacuum leaks, TPS within spec, AFM within spec, full coolant, and a slight exhaust leak that I've fixed at the header to downpipe. Diagnostic pins jumped causes reduced idle and right timing. Fuel pump jumped causes fuel pump to run.
With the TPS unplugged I get lousy mileage, but the truck runs fine. Reset codes, plug in TPS and it runs great for a while and then no power, major bogging down and eventual backfire if held wide open. Unplug the TPS again and back to ok.
With the TPS and AFM testing within specs is there anything else that effects the engine running through the TPS circuit? I'm sick of this running like crap. I do have a denso O2 sensor on the way just to throw in and NGK plug wires to replace the autozone ones just as regular maintenance.
Truck has good compression, proper timing, new plugs and wires, no vacuum leaks, TPS within spec, AFM within spec, full coolant, and a slight exhaust leak that I've fixed at the header to downpipe. Diagnostic pins jumped causes reduced idle and right timing. Fuel pump jumped causes fuel pump to run.
With the TPS unplugged I get lousy mileage, but the truck runs fine. Reset codes, plug in TPS and it runs great for a while and then no power, major bogging down and eventual backfire if held wide open. Unplug the TPS again and back to ok.
With the TPS and AFM testing within specs is there anything else that effects the engine running through the TPS circuit? I'm sick of this running like crap. I do have a denso O2 sensor on the way just to throw in and NGK plug wires to replace the autozone ones just as regular maintenance.
03-08-2012, 06:27 PM
#2
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replacing my fuel filter helped me with the bogging down and coolant temp sensor seemed to help a bit more. my problems started atfer wheeling as well. water played a part i think. I'm still not 100% yet just throwing that out there. I would like to know if the o2 sensor helps you out...
03-08-2012, 06:36 PM
#3
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Thanks for the suggestion, I did replace the fuel filter 6 months ago, so it's fairly new too. It sure feels like a fuel issue, but not sure why unplugging the TPS corrects it. I have heard the coolant temp sensor can cause issues. I'll look into testing replacing that sensor. I'm interested if it's the O2 too. The PO put a Bosch in about year ago and Ive heard that they sometimes don't play nice with older toyotas; that's why I ordered the Denso.
03-08-2012, 07:15 PM
#4
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03-08-2012, 07:29 PM
#5
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No codes. I tested it and it's tested fine per FSM. Also adjusted it for the sake of at least trying. Got it right to I to infinite. Tests show it within spec. It does drop occasionally when going from closed to full rather than increase steadily. I guess it'll get added to the replace list too.
03-10-2012, 08:50 PM
#6
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So I picked up a new TPS and after seeing the difference from closed throttle to wide open on the ohm meter, I know my old one was bad. The readings on the new one are solid with no drop out and no fluctuation. The old one dropped a lot going from closed to wide open.
Last edited by Cmayer; 03-15-2012 at 02:14 PM.
03-15-2012, 12:12 PM
#7
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I think this thing likes my driveway more than the road.
I replaced the TPS with a new toyota part, set it per FSM, and replaced the O2 sensor with an OEM direct fit Denso. The truck ran great for 3 days and then out of no where started acting up on the freeway.
Part throttle is ok, but anything more and it feels like I'm hitting a fuel cutoff. Turn off the truck, start it again and everything is fine for a few minutes and then the same issue. Pull over, unplug the TPS and drive another 40 miles home with no problem.
What the heck is going on?! I hate intermittent issues.
Anyone in So Cal good with these? I'll give a cash and beer reward to anyone that helps fix this.
I replaced the TPS with a new toyota part, set it per FSM, and replaced the O2 sensor with an OEM direct fit Denso. The truck ran great for 3 days and then out of no where started acting up on the freeway.
Part throttle is ok, but anything more and it feels like I'm hitting a fuel cutoff. Turn off the truck, start it again and everything is fine for a few minutes and then the same issue. Pull over, unplug the TPS and drive another 40 miles home with no problem.
What the heck is going on?! I hate intermittent issues.
Anyone in So Cal good with these? I'll give a cash and beer reward to anyone that helps fix this.
Last edited by Cmayer; 03-15-2012 at 12:15 PM.
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03-15-2012, 12:37 PM
#8
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did you ever check the coolant sensor? I read this long thread on here the guy guy had similar issues and he ended up selling his rig. he followed up saying the guy who bought it said it was the engine coolant temp sensor. my truck is fine anywhere around town but when i get on the freeway it sucks. my air flow meter tested bad im waiting on one to see if that helps me. i hope you get yours figured out
03-15-2012, 12:54 PM
#9
Registered User
Start from the begginning (sp) and set the TPS correctly.
First off check to make sure there are no vaccume leaks or cracked vaccume hoses.
1. Set engine idle speed to 800
2. Set timing to 5*BTDC with the Te1 and the E1 terminals jumped in the diagnosis box.
3. Readjust idle, it probably changed by a slight amount with the timing adj.
4. Readjust the timing, again it probably changed a slight amount with the idle adjustment.
5. Now set your TPS per the specs.
See if that helps.
First off check to make sure there are no vaccume leaks or cracked vaccume hoses.
1. Set engine idle speed to 800
2. Set timing to 5*BTDC with the Te1 and the E1 terminals jumped in the diagnosis box.
3. Readjust idle, it probably changed by a slight amount with the timing adj.
4. Readjust the timing, again it probably changed a slight amount with the idle adjustment.
5. Now set your TPS per the specs.
See if that helps.
03-15-2012, 01:20 PM
#10
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Thread Starter
did you ever check the coolant sensor? I read this long thread on here the guy guy had similar issues and he ended up selling his rig. he followed up saying the guy who bought it said it was the engine coolant temp sensor. my truck is fine anywhere around town but when i get on the freeway it sucks. my air flow meter tested bad im waiting on one to see if that helps me. i hope you get yours figured out
Start from the begginning (sp) and set the TPS correctly.
First off check to make sure there are no vaccume leaks or cracked vaccume hoses.
I changed out all questionable vacuum hoses before starting this adventure. I also replace PVC and grommet. I used brake cleaner around the lines and there are no changes in idle. I'm scared to use brake cleaner too close to the TPS as I don't want to kill the new one. All hoses / lines on the intake manifold near the TPS are new.
1. Set engine idle speed to 800 - Set by ear/feeling. Need to get a tach hooked up. I know it was high when I installed the new TPS and 02 because I was hitting the fuel cut with the brakes applied. I turned down the idle to where it "felt" right and now it starts fine, cold idles, and comes down to warm idle fine with or without brakes applied. I may be a bit below 800 rpm though.
2. Set timing to 5*BTDC with the Te1 and the E1 terminals jumped in the diagnosis box. - Timing is right at 5* with the Te1 and E1 jumped.
3. Readjust idle, it probably changed by a slight amount with the timing adj. - Idle was readjusted per above once everything was connected and base timing was set.
4. Readjust the timing, again it probably changed a slight amount with the idle adjustment. - I'll check again to make sure timing is right.
5. Now set your TPS per the specs. - I'll check again as well to see what it's at and adjust as needed.
See if that helps.
I changed out all questionable vacuum hoses before starting this adventure. I also replace PVC and grommet. I used brake cleaner around the lines and there are no changes in idle. I'm scared to use brake cleaner too close to the TPS as I don't want to kill the new one. All hoses / lines on the intake manifold near the TPS are new.
1. Set engine idle speed to 800 - Set by ear/feeling. Need to get a tach hooked up. I know it was high when I installed the new TPS and 02 because I was hitting the fuel cut with the brakes applied. I turned down the idle to where it "felt" right and now it starts fine, cold idles, and comes down to warm idle fine with or without brakes applied. I may be a bit below 800 rpm though.
2. Set timing to 5*BTDC with the Te1 and the E1 terminals jumped in the diagnosis box. - Timing is right at 5* with the Te1 and E1 jumped.
3. Readjust idle, it probably changed by a slight amount with the timing adj. - Idle was readjusted per above once everything was connected and base timing was set.
4. Readjust the timing, again it probably changed a slight amount with the idle adjustment. - I'll check again to make sure timing is right.
5. Now set your TPS per the specs. - I'll check again as well to see what it's at and adjust as needed.
See if that helps.
It just kills me that it runs so good and then randomly runs like a turd.
03-15-2012, 01:51 PM
#12
Registered User
I recently had some issues with my TPS in my 94 22re. I pulled the throttle body off and it was LOADED with gunk. I cleaned that and adjusted the TPS to within spec. All codes are off. One very noticeable thing is when I am slowing down before shifting I let my foot off the gas and the truck REALLY slows down quick. Like a quick, abrupt drop. Maybe I was so used to the way it was for so long this issues comes as a surprise. I don't know.
03-15-2012, 02:16 PM
#13
If you where wheeling in any water i bet you have water in mass air sensor. To fix this take a razor and cut the silicone out around the top plastic cover on the airbox. Then pop cover off and clean with electronic cleaner the blow dry and reinstall cap with new silicone.
03-15-2012, 02:20 PM
#14
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Thread Starter
Originally Posted by toyospearo
I recently had some issues with my TPS in my 94 22re. I pulled the throttle body off and it was LOADED with gunk. I cleaned that and adjusted the TPS to within spec. All codes are off. One very noticeable thing is when I am slowing down before shifting I let my foot off the gas and the truck REALLY slows down quick. Like a quick, abrupt drop. Maybe I was so used to the way it was for so long this issues comes as a surprise. I don't know.
I also replaced the fuel filter, but I want to check the pump pressure and get the injectors cleaned / balanced, so maybe it's time to pull the entire manifold and clean it up.
Last edited by Cmayer; 07-18-2012 at 02:41 PM.
03-15-2012, 02:22 PM
#15
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Thread Starter
If you where wheeling in any water i bet you have water in mass air sensor. To fix this take a razor and cut the silicone out around the top plastic cover on the airbox. Then pop cover off and clean with electronic cleaner the blow dry and reinstall cap with new silicone.
Last edited by Cmayer; 07-18-2012 at 02:40 PM.
03-15-2012, 02:36 PM
#17
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