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

[eddieturbo2]

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.

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.

[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)

[fixkick]

not me knowing answer to the green questions above.
It seems you are fixated, on TPS big time.
lets do TPS myths or not lists. (online web sites full of myth) ever tuned a custom ECU you will learn this fast if did, tuning these sensor and Fuel MAPs.

first off this sensor NEVER is used at all just driving at 3000 rpm down a flat road, ever, the ohms is like 2500 and steady the ECU IGNOREs IF STEADY,
the key word there is STEADY.
on this car the primary sensors for fueling are MAP and ECT, not the TPS ever.
yes the TPS finds you moving the right foot fast up or down say cruising the ECU SEES YOU do that, at TPS, TPS is really THROTTLE ANGLE, (seen on all OBD2 cars) new name.
the ECU sees move move your foot down to say go faster, or pass a car, the ECU goes to enrich move from 14.7:1 to about 12:1 never 10.1 ever.
It does this for one reason the slow MAP sensor, if the TPS is missing or dead, the engine bogs (fast hesitation then wakes up fast due to MAP coming online NOW)
the TPS is a super crude device. (you are correct dead spots on it are super bad, and those do cause DTC errors every time. if real.
The TPS is CRUDE, how crude is it well supper crude, this makes it cheaper to make, and accurate is never important (just no shorts and no opens allowed) 0hms bad infinity bad)
on all new cars the TPS is auto-calibrated on this pig only idle switch is calibrated, by humans

the TPS end to end OHMS can be 3000 to 6000 ohms, YES THAT CRUDE and the ECU could care less, this error, The ECU watches voltage only on the wiper arm center pin.
the ECU (ignoring idle switch) only looks to see of the voltage changes.
say driving at 3000 rpm the TPS might read 2.5vdc, (50% throttle angle) 1 to 4 volts is range, par...
the ECU watches this TPS wiper pin close on a hot engine, for fast changes, only, if foot is steady the MAP +O2 set fuel rates NEVER THE TPS.
if the TPS does not fail DTC errors most are good.
The ECU also full time watches for TPS gross errors, called Catastrophic testing and if the sensor shows 0v or 5v ever, DTC sets, in 1second flat.
The flat spot on any TPS output (dead carbon) will cause illegal 5vdc, and DTC will set, for sure driving with DIAG jumper inserted (this is harmess this 1 jumper)
I bet your TPS is fine and you are ignoring DTCs or are not testing for why fueling rates are wrong full time and for sure is not this TPS.


(and yes the idle switch calib, is very tricky, as it not being a true switch makes that true, a silly lame suzuki carbon switch, unlike better cars with real switch
or modern cars that use just 3 pin TPS with throttle angle as idle proof, TV.
the idle switch does many things too.
at idle (TV) wakes up ISC and sets rpm to 800 +-50 RPM..
kills dead the EGR(via VSV)
sets aggressive spark timing maps just for idle (saves fuel and keeps cat cool and less engine heat and less RADiator load
)
or raises idle to 1000 for AC on.

[fixkick]

the main throttle angle TPS variable resistor, (POT.) can be 100% off, in accuracy, huge variances here, brand to brand . super easy to make them in a factory.
5000 ohms is par, (end to end pins) throttle angle pins.
what matters most is voltage out.. on the wiper pin, of the POT.
not only that but the 5vdc on the 5v pin can be 4.75 to 5.25 volts, all this is normal...

eCU limits TPS for DTC errors.
below 4% throttle angle (below about 0.2Volts) driving, you will get DTC codes 22 errors.
the normal voltage idling is 0.6 to 1.5v (see how crude that is?) The ECU does not care here. (only a fast right foot matters)
on the high side the ECU does not like voltages above, dtc 21. some where from 4.2v to 4.75v? the ECU sees this is stuck high TPS failure, code 22..
a broken ground pin sets code 22. or broken 5v power pin sets code 21.

[fixkick]

no year car told, gee hope it is not 89 to 90 year, 91-95 is better, is it?
now lets do RICH AFR fueling rates bad.
testing 1 2, 3.
Does water (coolant ) temps hold steady at 180f ? if not thermostat is bad or wrong gasket used. 92 up uses rubber ring and not paper gaskets.
ECT reads 300 ohm hot engine? or at idle (0.7vdc) ? this means 180F, that voltage. does it?
fuel pressure at spec, at idle and 3000 RPM ., 34-41PSI at sea level , does it? stock car has test port on end of fuel filter banjo bolt 6mm ISO thread.
look for injector leaking at key OFF CUT ? eyes on it, air horn pulled , this engine has no mAF so air horn off EFI runs perfectly.
run better o2 sensor pulled plug? they can fail and force rich FOR SURE STUCK AT 0vdc, hard. most bad 02 stick low by design, failed (makers rules)
ever reCAP the ECU. most need this if never done ONCE.
map sensor tests pass>
see my MAP page yet.
https://fixkick.com/sensors/my-map.html

[fixkick]

running wrong TB on this car? I'm noodling the possible Frankenkick issues.
endless there are.
car not stock means anything possible, unseen. by me.
do not mix years of TB, 89;/90 are not 91 to 95 throttle bodies at all, the injector is not the same.
or the wrong ECU, not matching TB and all sensors , matched year.
this I can not guess, only seeing the engine and ECU side sticker, can i know

[eddieturbo2]

Wow, Thank you for all the info.
 
Let me start off with answering some of your questions.

1) 3000 to 3200 rpm hesitation when under partial throttle is on flat ground in any gear and any speed as long as its at 3200 rpm or so and at a very specific throttle position holding steady. If I give it more gas the air fuel ratio returns to 12.1 and running correctly or if I let off the throttle the air fuel ratio also then returns to normal.

2) I believe this engine is a 91-95 as setting the tps was quite easy with your reference guide.

3) I don't not have to worry about the catalytic converter. It has no exhaust it is just a down pipe. It had a working original upstream 02 sensor but I broke a wire by accident and have since replaced it with a brand new 02 sensor and verified that it works as I can see the air fuel ratio change with it unplugged. The wideband 02 sensor is mounted about 2.5 feet down stream. Note: I just put a turbo on it but these hesitation problems have existed even before the turbo and the broken 02 sensor. All my testing is under normal atmospheric pressures when driving. No boost as all. Just been taking things slow.

4) 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) - Not a race or high gpm pump. It was a factory replacement fuel tank with oem style in tank pump purchased for my samurai. Came from india. It was probably meant for the EFI Gypsy/samurai. It works perfectly. Car stars up and runs great every time. Does not run rich at all at idle or cruising as long as I don't hit that specific 3200 rpm. Does not smell rich or anything even without the mufflers or cat. The computer always keeps it at or near 14.7 AFR.

5) FPR,  bad, fuel pressure regulator, bad, many this old are just NO GOOD now,  does the vacuum port leak fuel ,yes, it is bad. - I have not tested the fuel pressure yet but I have not observed any leaks and the vehicle does not show any signs of fuel issues outside of that specific rpm and throttle steady position at 3200 rpm. I will test this to see what it is doing.



6) injector is leaking and bad - I have not seen any leaks nor do I smell any fuel from it. Seems ok from general running conditions. Never floods and always starts like a champ.

7) Injector o-rings (x2) are cracked or just leaking fuel. - Have not observed fuel leaks related to o rings yet.

8) MAP bad, or hose to it clogged or cracked or leaking. (on 89  kicks has filter here, omg bad) - The hose looks like it is in good condition but I can replace it. It seems to have a small black check valve / filter in it. Should I remove it?

9) O2 bad or manifold to it cracked and leaking (it sucks air after each putt if cracked and 02 sensor goes MAD/nuts) - The 02 sensor is a brand new working part. verified. No leaks from mount location. All brand new. I tig welded the new bung myself. I will test how it runs today without the 02 sensor.

10) 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? - I will double check the wiring to make sure it is working. The sensor is brand new but I will verify the ohms range. It holds temperature perfectly. New radiator, hoses, pump, thermostat and gaskets. Never overheats....

11) 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. - I will check and see but why would this cause the error at a specific rpm and throttle position?

12) running wrong TB on this car? I'm noodling the possible Frankenkick issues - As far as I know no but I will verify with again with your online pictures. But I believe it is a 91-95 engine with mostly stock parts on it outside of my turbo.

[eddieturbo2]

I understand that my TPS may be not be issue but I just wanted to double check on the aftermarket TPS sensor I have.

The manufacture is Standard Intermotor model TH147. Both the first and replacement unit I have are similar in ohms readings.

The fixed resistor between the two TPS units work fine. Pins A to D. 5400 ohms ~ 5600 ohms.

And the variable ohms range from pins B to D also seems to work well. From around 1000 ohms to 6500 ohms with a sharp drop at the very end of the sweep down to 2500 ohms. Not sure if that maters....?

But the only issue I see is with the ohms test form pins C to D.

it starts at 300 ohms ranges up to 400 ohms and drops sharply down to around 220 before opening to infinity. That seems incorrect to me.

Pins C to D should range from around 50 ohms or so up to 500 without holes before dropping off to infinity.....?

Is that acceptable? Or should I return the TPS for a refund?

[eddieturbo2]

Ok, So I reinstalled my newest TPS sensor and I simply calibrated C to D to open infinity at feeler guage thinness .020. Done deal....

I was not able to test the fuel pressure but that may not be the issue after you hear my descriptions below:

1) Ohms tested air intake temp sensor cold ~ 2800 ohms - after motor warm up and good hot drive - 400 ohms. Seems good.

2) Ohms tested water temp sensor cold ~ 2800 ohms - after motor warm up  and good drive - 300 ohms. Seems good but.....

I decided to start unhooking sensors like you mentioned with the 02 sensor. Made no difference. Misfire persisted... then reconnected.

Then unhooked the air intake temp sensor and misfire persisted. then reconnected.

Finally I tried the water temp sensor and it drove perfectly with no misfire and I was able to rev to 5000 rpm under the same light partial throttle.

Ran really good but was running super rich at idle. But no misfires which was a huge improvement.

The water temp sensor is making contact with the computer because I can see the air fuel ratio change as soon as I unplug and replug it.  The simple ohms test seems to make it look like its working correctly but I am not sure. As the Suzuki cools off I have been testing the sensor and it appears to vary its ohms readings correctly.

Note: My timing has never advanced either when it revs up. It seems locked out all the time. I also tested this with the coolant sensor disconnected as well.

[eddieturbo2]

I drove the samurai today while it was ice cold it ran perfectly. But once it warmed up a little and switched over to the hot map the misfire came back.

Note: after resetting the tps the misfire seems to occur at a lower rpm now. 2800 to 2900 rpm.....