1.6 8v TBI - TPS rich Misfire - Need help.

[fixkick]

Ok everyone. I have a reoccurring issue with my TPS sensor or something else if someone can help me find out what it is.

I have a 1.6 8v TBI engine swapped into my samurai and the motor always misfired at 3000 to 3200 rpm when under partial throttle when I got it. After testing the original TPS I found that it had a dead spot in the carbon strip and I assumed that was the issue. NO YEAR TOLD (from DONOR CAR ) wow)

However two new aftermarket TPS later it still has the same problem with the misfire at 3000 to 3200 rpm. The misfire is caused by running full rich and I can see it on my wideband O2 sensor. It hits 9.2 to 10.2 when that misfire happens.

Funny part is if the TPS is completely disconnected mechanically and electrically the problem is non existent. I just get a slight hesitation as soon as I touch the throttle.

If I have it mechanically disconnected from the throttle body and still plugged in electrically the slight hesitation with the throttle goes away and it runs fine at 3000 to 3200 rpm.

Its is like the TPS or ecu does not like that signal as it revs up.

I would like to get this resolved.

The Two new TPS sensors pass two out of three tests on Fixkick.com tutorial. The idle circuit should start off somewhere between 0 to 50 ohms and hit 500 before infinity. Both new units form summit racing (TH147) read 320 ohms starting and as I turn them they hit about 400 ohms drop down to 200 ohms then hit infinity.

I guess they are just crappy parts.....

The fixed resistor ohms are in spec and so is the other test for the full sweep ohms test. No holes like my original. At least from what I can tell with my fluke digital meter.

I would apricate some suggestions.

NO YEAR TOLD (from DONOR CAR ) wow) 1989 to 1995 (USA only years) engine and EFI and matching year TB and all parts, same year>????????????????????????????????????????????????????????
8v engine ended here gone in 1996, (EPA laws) (no ECU numbers told, dash 56Bxx (what is XX)

3000 to 3200 rpm when under partial throttle when I got it?  parked, driving and if driving flat ground , hills and is the foot steady?  (throttle use is complex, please tell this?)

i guess this wideband 02 is planted on the end of tail pipe and not messing with the real sensor O2 front?, on top exchaust manifold.
misfire
RICH
and is not the TPS,  with foot held steady
no TPS ever sets fuel mix, only when Acceleration or de-acceleration.  (TPS bad causes hesitation when and aggressive right foot only)
TPS is only for ENRICH mode, until the slower MAP wakes up and set fuel mix right, + 02 trim at steady throttle foot
what happens is TPS sees right foot not steady (steady means TPS not effecting fuel rates, ok>?>) and when you move the foot fast the ECU sees that rate of foot movement
then goes to ENRICH mode, 02 off line tool on hot engine, all answers here are hot engine if engine is not hot that IS YOUR failure)
then after a few seconds, the MAP sensor wakes up, (at throttle advance all MAPS are slow, to react.  that is why the TPS is there, to ENRICH fuel to let the MAP wake up.
The TPS reports at the speed of light (near) and never does the MAP, it is always late reporting this TPS dead makes normal cars go lean at throttle tip in,  all cars with EFI.


A far better test is this:
 
In fact unplugging the 02 front is 10x more useful to pull, wire and never the TPS.  try that yet, put back TPS.?

you just learned how OBD1 works (any OBD) it is MULTI modal,  in fact like 2 different ECUs.

when you removed that  TPS you the activated big old nasty LIMP HOME MODE.  ECU #2 goes on line so to speak (virtual ECU 2)
on  normal car engine (yours is not) doing what you did causes, rich and misfire.
LIMP HOME (aka, suzuki fails safe or on real JEEP ,just LIMP) and are all really  truly EMULATION mode.
when 1 sensor goes dead the ECU goes to LIMP, CEL lamp glows and the dead SENSOR IS NOT EMULATED, with software (firmware ) that use other sensors to emulate the dead one.
this is how all EFI cars can drive home with dead sensors,... (it is a wonderful feature)

IN YOUR case, the engine AFR air fuel ratio, at the injector is hugely rich before remove sensors.,, at  the omg 10:1 is rat nasty rich.

 
with the TPS  gone the poor ECU can not use  its TPE for limp home emulation at all so goes to MAP only LIMP.
BTW,  if MAP goes dead the ECU limp emulates it with TPS,  oops.  tricky no?  no suzuki books on earth cover, how this LIMP works only that it exists in crude terms.

what you have only proved (not easy using limp diagnose anything , most times all it does is burn up the CAT)
LIMP HOME means RICH, and also some go to retarded spark timing, on new car 0BD2, the CEL flashes and the cars guide tells you do not drive fast , or CAT will be damaged)
Rich like that is very bad for any CAT and invites nasty #2 melted cat CORE. very very bad that.


On this  frankenkick I've no idea what is missing on the engine, or EFI  or  not stock. I can only wonder and scratch my head.\

Rich has many causes,  and it sure is not TPS, TPS is also for preventing lean out with a fast right foot.. ( and with right foot raised fast, from high throttle ,enables CUT FUEL)

I will assume spark is perfect, as that will cause misfire but mostly never at only 1 RPM  ( weak spark loves to fail; up hills under load, with higher combustion pressures)
Causes all:
Rich 101; 8valve only , this is speed density system.. not even close to 16v air density system.

1. too high fuel pressure,  is your fuel pump stock, or some crazy high  GPM rated pump off some v8 engine car or worse? (race pump hype)
   
2. FPR,  bad, fuel pressure regulator, bad, many this old are just NO GOOD now,  does the vacuum port leak fuel ,yes, it is bad.
   
3. injector is leaking and bad,
   
4. Injector o-rings (x2) are cracked or just leaking fuel.
   
5. MAP bad, or hose to it clogged or cracked or leaking. (on 89  kicks has filter here, omg bad)
   
6. O2 bad or manifold to it cracked and leaking (it sucks air after each putt if cracked and 02 sensor goes MAD/nuts)
   
7. ECT stuck low temp so the ECU think  engine cold and goes SUPER rich but, 300ohms is 180f water temp , get engine hot , pull plug to it and sensor reads 300 ohms , yes?
   
8. IAT, bad, will cause slight error but this too is one more ECU input for fueling, if reads low (temp)  more fuel is added. and you have too much fuel.
   

basics:
there is more, is engine compression at 160PSI, throttle blocked open, and is vacuum steady? at 19inch HG, hot engine? is hot idle 800RPM??????

NO EFI made runs right it the cam belt slips.l (or nasty lower cog key sheared) when the belt  slips compresson falls by even 1/2

There are 6 ECUs in 1 ECU. (or simply MAJOR MODES)

• cold start and run , ECT reads COLD for any reason, even bad. ECT.  bad themostat , missing thermostat , or the floating thermostat error.(5mm thick rubber ring missing)
  
• hot run closed loop. (YOUR ENGINE FAILS THIS) (lacking a real scan too you will never know this or real SCOPE at 02 pins "Cell?" and see it not swinging fast. there.
  
• hot run enrich mode (TPS caused !) lasts until MAP wakes up, (catches up) (TPS is for enrich mode, fuel cut mode and idle speed switch mode at idle..
  
• Hot WOT. o2 off line EGR off line. (max HP is NOW)
  
• Limphome (Happens for all the below but not backup.)
  
• backup mode, CEL LAMP is fully dead, ecu is dead.  (pure hell. and flooding engine)
  

"certain level" means engine goes super rich and even misfires,  LIMPHOME IS VERY CRUDE fueling. is the correct words.
FSM (factory service manual words)