J18 MPFI - TPS % value at warm idle

[t3tom]

Hello,

I have a question about my 2001 US/CDA spec Suzuki Esteem with the J18 MPFI engine.

The TPS has not been moved and is adjusted to the 0.5V factory value.

With an OBD2 scanner hooked up, the live data TPS % parameter shows 0.0% whenever the car is coasting in gear, or during warm idle. Is this a normal condition? On my other Suzuki product (G10 SOHC TBI) the OBD scanner reports around 10% TPS % at warm idle. Is this because the ISC motor actually moves the throttle plate, whereas the MPFI J18 engine uses the IAC to provide idle air while the throttle plate remains absolutely closed?

[fixkick]

Hello,

I have a question about my 2001 US/CDA spec Suzuki Esteem with the J18 MPFI engine.

The TPS has not been moved and is adjusted to the 0.5V factory value.

With an OBD2 scanner hooked up, the live data TPS % parameter shows 0.0% whenever the car is coasting in gear, or during warm idle.
first off OBD2 has parameters that show many forms of TPS , one is raw percent other is corrected, so at 0.5vdc is not raw ,but corrected is 0%
see>?
some cars use absolute TPS others corrected, if at hot idle it sees .5v =10% so then corrects all readings at absolute -10% equals adjusted, or 0% at idle.
see/?

Is this a normal condition? do not compare cars this way ever, each car uses its own rules.
and percent is ever even used, here what the TPS does.
at near .5v idle controls go active hot engine.
if you get above 4v or say 80% angle, that is wide open throttle rules , rich mode and EGR off
then when driving, idle controls are off but the ECU looks for fast moving TPS angles, (fast only, not %) this activates enrich mode.

the only bad % is if too high say over 1vdc (IDK exact) the ECU fail file to regulate idle.


On my other Suzuki product (G10 SOHC TBI) the OBD scanner reports around 10% TPS % at warm idle. ( forget this, unless idle hot fails)
Is this because the ISC motor actually moves the throttle plate, whereas the MPFI J18 engine uses the IAC to provide idle air while the throttle plate remains absolutely closed?

I guess,. the G10 is throttle by wire TBW, if yes, it must never be compared to any wire less (no TV electric motor )ever. sorry./
Dont worry TBW, it will tell you lf any of that goes wrong. for sure.

in any case the 2 cars are different, even designed by 2 different engineering teams,. The TBW is way more complex.

what matters is that he ECU knows its own inputs, and does.
the newer 99 cars, the TPS is autocalibrated each time you key on.
on my scan tool , i can see all pids, every one for TPS, volts, rad and compensated. this makes it more clear seeing that,
i can even setup my own scans to reach any PID address in the ECU, and present it any why I want, Palmer software is best. this way.
cheers

[t3tom]

Thanks for your reply and detailed Info! I learn a lot from your website and appreciate what you do for us Suzuki enthusiasts.

The label on the TPS % parameter says "Absolute Throttle Percentage %" on my scanner screen, so I assumed it was not a relative corrected value. My J18 engine control components look just like a transverse FWD version of the Sidekick Sport with the same engine.(as shown on your J18 info page).

Both the Esteem and my Swift have cable actuated throttle valves.

When I bought this car used, it drive differently than my Swift, in that during shifts, the engine had zero dash pot effect. Ie revs dropped immediately to 750 rpm when lifting off the gas pedal. Also, engine braking was quite pronounced in gear, for the same reason. I thought this characteristic was like the old pre-emissions cars where engine revs responded instantly to gas pedal inputs.

So I guess what I am intetested in is if my engine was a J18 Sidekick Sport, should the engine respond the same way? Ie. Revs drop to idle speed during pedal off shifts, and zero dash pot effect during in gear deceleration?

I will also read up on Palmer software and maybe getting a more capable OBD2 scanner.

[fixkick]

Thanks for your reply and detailed Info! I learn a lot from your website and appreciate what you do for us Suzuki enthusiasts.

The label on the TPS % parameter says "Absolute Throttle Percentage %" on my scanner screen, so I assumed it was not a relative corrected value. My J18 engine control components look just like a transverse FWD version of the Sidekick Sport with the same engine.(as shown on your J18 info page).

Both the Esteem and my Swift have cable actuated throttle valves.

When I bought this car used, it drive differently than my Swift, in that during shifts, the engine had zero dash pot effect. Ie revs dropped immediately to 750 rpm when lifting off the gas pedal. Also, engine braking was quite pronounced in gear, for the same reason. I thought this characteristic was like the old pre-emissions cars where engine revs responded instantly to gas pedal inputs.

So I guess what I am intetested in is if my engine was a J18 Sidekick Sport, should the engine respond the same way? Ie. Revs drop to idle speed during pedal off shifts, and zero dash pot effect during in gear deceleration?

I will also read up on Palmer software and maybe getting a more capable OBD2 scanner.

[fixkick]

a neck snapper, dash pot effect.
the J18 is same, engine, (the mounts on the block might be different, the CKP sensor wildly different and the ECU to match it.) and new CMP on cam left rear.
I do not know the Swift, ECU at all, never used one.
but is quite different.
the j20 engine parts swap, the j20 is stroked j18 engine. good to know for finding parts, infact some SPORTS are upgraded to j20 and the ECU seems happy, (CKP changed out)
J20 has new head, for chamber changes, CC sizes.
this is the ckp horror... (even the G16 is different , same year, on Esteem. a real hail puller, with CKP errors endless, until eyes see it.)
http://fixkick.com/t-belt/snouts/images/...-cog97.jpg
the newer J20B has lots of changes, (above is J20A,96.97)
the key factor for Next snap is DP controls.
what make it work.
sure TPS below 1v, (the FSM will even telly when the DTC for TPS low fails. in the pages covering DTCs. on that Swift)

my guess is the engine must be hot, over 150f ,180 to 200 f best.
the motor is on the TV ?

the Suzuki engines , even swift, sue different throttle bodies, in different countries, due to lower costs needs or smog rules of that country (laws)
as does TPS calibration needs or if needed at all (autocal on newer cars) but i digress.... but 2001 cars are very difffent from

our J18 uses the ISC to do dashpot effect. (all hot water control-ed IAC are retracted)
2001 US/CDA spec Suzuki Esteem with the J18 MPFI engine. (1999 to 2002 generation it is) what transmission?
the engine has a serial mark.
26 ECUs offered that generation, but 2001 , is just 4 ECU (usa) 2 are A/T and 2 are MT the VIN is change (serial end numbers) 15204404~ is NEW ecu for M/t and A/t
why Ive no clue. there.
the IAC is an electric motor, and does not open the TV at all its a motor controlled, air valve, that mounts to the plenum , simular to the EGR valve. motor operated too.

this valve can stick but that causes high RPM. not low. and snap.

my guess wrong ECU?
id need VIN and transmission type to say ECU p/n, and can.
that Throttle body ,has water hose, and a IAC thermal valve of some kind and must retract if not the ECU will get confused. id look here first.

the TB only has 1 part sold , the TPS (by suz)
the MAF inside is not sold by Suzuki only by 3rd party aftermarket Hitachi. it can fail. or need cleaning.

are you missing DTC code P1700 (does your scan tool do P1xxx codes , factory codes? at all?)
in the year 2001 suzuki , used year code 1, (2000 = Y) so engine code, is J181nnnnnnn the 1 means year 2001. nnnnnn is raw serial. that is one way to find engine swaps , the codes.

my guess is the ECU is confused.
do to wrong inputs somewhere.
is engine ECU in closed loop mode, before and after throttle cut, hot engine?
is hot idle at spec.
if you turn on head lamps +heat fan same time , does rpm hot old at 800RPM or fall fast? ISC(iac electric) regulation must work or DP will not.
The DP effect is TPS triggered, my guess below 1v. (what ever the manual says for TPS error thresholds , that is it)
if hot idle speeds or regulation fails, i do that first fix.

i think the IAC (motor) is stuck.
when at cruise, the ECU may shut it down due to unused status cruising, (IDK) then as you cut the throttle in gear, the engine brakes you, but the ECU then open this IAC motor to do DP effect.
This is very complex here in the software, my jeep is even more complex it memorizes cold starts and knows where to open the valve, for any cold start temp.
and my old 4 liter loved to stick the ISC (motor IAC) , until my cure. (Russian, gun lube from Siberia)(sprays on , feels like teflon fry pan coating) magic stuff.
the reason the old jeep failed is the motor was to small in the IAC. (design error)

cheers, to you.

[fixkick]

j18 facts. 2001 swift to J18 Sport 96-98 Sidekicks.
CKP sensors, match.,pn/
CMP match, too.

sport sport has 3 throttle bodies.
96/97 suffix 77EA0
98 fed, suffix 77ea1
98 Calif, suffix 77eb1
the 99 to 02 ESTEEM had but one TB, suffix 77EV0 (prefix on all are 13400-)

so getting wrong TB can be hard, to discover. super hard. (for water thermal valve cold idle reasons, size and TPS type and MAP type)

The ECU changes, my guess< (smog only, or EGR or evap changes)

[t3tom]

   
   
   
   
   
I took some pictures of the engine and ID stickers as well as looked at the engine block stamped ID which is J181119422

The PCM behind the glove box has these markings stamped on the back:

33920-69GL - 1
069GL
1.8 E33 MT
8T ( in large letters)
FI-420A A2 1314
Hitachi Ltd Tokyo Japan


The car is a 2001 Suzuki Esteem 5 door wagon. It is a 2001 5 speed manual transmission J18. The used car came with dealer service records, which indicate the engine is original to the car.

The OBD2 scanner I used is an Autel 519 and it reports no current DTCs and no codes pending. CEL is off.
The scanner shows the engine goes into Closed Loop after about 1 minute of idling warm up after cold start.
I think the fast idle device (wax pellet plunger pushing against a small cam) is working but it does seem to take longer than usual (about 3-4 minutes) to fall from about 1400 rpm to 750 rpm. The coolant temperature at closed loop is about 82 degrees F. The car does not settle down to 750 rpm warm idle until the temperature gauge needle is at mid point (about 180 degrees F reported by the OBD scanner)

If I switch the headlights on, the idle does not always speed up, but it generally holds at 750 rpm or slightly higher and then slowly returns to 750 rpm after about 4 seconds..

The TPS part number label reads: HITACHI SERA483-06 (C 12 07)

[fixkick]

suzuki does not publish all sensors they use for TPS, not ever. only going to Hitachi can you see what it fits.. sorry.
think the fast idle device (wax pellet plunger pushing against a small cam) is working
but it does seem to take longer than usual (about 3-4 minutes)
to fall from about 1400 rpm to 750 rpm.
The coolant temperature at closed loop is about 82 degrees F.
The car does not settle down to 750 rpm warm idle until the temperature gauge needle is at mid point (about 180 degrees F reported by the OBD scanner)
if the wax IAC is fully retraced hot, its ok.
the dash pot software should work, ever clean the IAC (electro motor) device.
they all get sticky this old, same with that EGR over yonder ... motor drive egr.
the G16 uses solenoid modulated IAC (ISC electric) and love to stick too. endless with that huge EGR./PCV smoke cloud of death.

yours seems to work great but consider it needs to not stuck at at any points in its valve range, now that takes a clean valve.
cheers.

[t3tom]

Thanks Fixkick!

I will clean the IAC this coming weekend and report back. By the way, the Hitachi says my TPS also fits the 2.0 Vitara

[t3tom]

Update: I removed the IAC valve. It was pretty clean internally, but I cleaned the shaft with some carb cleaner and reinstalled it. There must have been some recalibration going on, because it took 2 engine start/run trip cycles to settle down to what I consider normal idle behavior.

After warm up, the first start/run trip cycle had the idle rpm racing up between shifts (rpms rose to about 1600 rpm between/during shifts with clutch pedal depressed.)

After the engine cooled off, a second trip cycle revealed idle rpm revving (surging) up and down slightly between 750 rpm to 900 rpm.

After the third trip cycle the idle has became steady, with headlights and blower fan off. The car now demonstrates a predictable dashpot behavior between shifts. The rpm no longer drops off suddenly when lifting the gas pedal during shifts. If the engine is revved while the car is stationary, the idle takes about 2-3 seconds to return slowly to 750 rpm.

Thanks again Fixkick! For future reference, is using carb cleaner the best way to internally clean the IAC valve?