engine rpm surge. help needed.

[fixkick]

ok. long work week. i should be able to do some tests sunday for sure.
i plan to check FPR vac hose for fuel..clean the MAF. and do your tap tap tap test on the maf. im going to putty up the port inside the throttle body (for testing)... a few things ive been thinkin about..

fuel filter is old and rusty. it needs replaced no doubt. but the rust on the line makes me a bit... you know... Rust has no friends,

another thought. so we know both throttle cables (thrttle and kick) were adjusted WAY of of whack.

and that also the TPS sensor is turned/maxed out one direction.... (was)?
did they fubar the cables and then adjust the tps to match the cables??? (my guess not that smart, they just jam it in wild attempt to lower idle speeds)
if yes... who knows why. but i know 2 things..

1. this surge was not there until i corrected both cable adjustments (took my time and dialed them in perfectly)
you do know all cables must be slack and why, its dangerous, and doing this wrong is why TBW came in to effect (no more cables to mess up and kill drivers)
if they are tight, there is no way in the world to set any TPS, its impossible...
not only that there is a way on some TB to mount the TPS wrong, (off and put on wrong not indexed) and does the same thing as tight cables. engine RACES
as the backside of the TPS jams the throttle open. again, TBW wins. throttle by wire,,, its hard to get inside the head of Mr. Badguy or nincompoop.
starting up and A/T car with idle at 2500 and shifting in to Drive, causes, some folks to panic, one old lady ran over her kids... many times.

we dont know the surge cause. (is it sensors, or actuators yet) for sure it's one, or just leak (vac) if we had a scan tool it be bingo day.
working EFI blind is hard nor was fun. no tools.blind. a challenge sure.


2. i never adjusted the tps... (nor do i know how) (past tense?) (did)?

ehhhh???

the TPS cal is only because this ECU is old and slow,(over taxed)
autocal was not possible then, just like on a new car, open the FSM search the word auto or learn modes, vast things do that. now. but in the dark ages
of 1987 (when it was designed. 30 long years ago, remember computers thin.(slow and dumb) bingo.


The TPS calibration really is 3 feeler gages, GO, NOGO, CAL. 3 steps, in the manual. the pages are there my page, fsm links.
http://www.fixkick.com/sensors/tests/TPS...tml#matrix
The TPS must be closed at idle no matter what (switch) or its can be a danger to any new driver, (read bad driving lessons)
The TPS is set with .026" preload, that means that it is closed that far in the rotation from THRESHOLD.
THE TPS is not to be closed after .026" (.037) there is .010" uncertainty zone there and must go open at the NOGO point, or the Idle servo will fight the drivers right foot. (note the GM uses there own numbers , and is odd that)

the book pages real are here. page 1:
http://www.fixkick.com/sensors/TPS/TPS96-98a.jpg
see figure C1-11 see those index pins,see how easy it is to land these (installed) this sensor wrong? and even cause it to jam the TV?
it can be installed wrong, and the TV can not close, or installed wrong #2 and the TPS is lagged.

and
page 2 next from the 96 manual and is the same exact proceedures on all 16v 92 to 98'
http://www.fixkick.com/sensors/TPS/TPS96-98b.jpg
step 4 here is the nogo step, using GM sized (odd) feeler.
Step 5 is The GO step, feeler #3 in the set, .020" this assures that idle switch never is open at .020" there are in fact 3 steps and 3 feelers used.

if you read a Toyota manual 92 era, its much the same thing. legacy OBD1 is not unique to suzuki at all.
figure C1-14 shows the magic, 500 ohm rule of carbon there.

here is a tps guts off a damaged engine, from wrecking yard damage.. was hit on engine pulls.
it cracked the ceramic TPS base.
the throttle angle is 5000 ohm POT. (variable resistor seen here) seeing helps no? seeing the real world really does for most.

see the tps idle side there? this is all passive electronics, not transistors here, zero. it's just CARBON.
the TPS wiper pins device is not seen here, its gold wiper.

90degrees is WOT full throttle. the idle switch cliff ( i call it or infinity thereshold) is seen I think at the shinny spot see and 3O-clock there)

http://www.fixkick.com/TPS/TPS-v8a.jpg

how is that.?

surge does have many causes.
What is done is assume all else is bad, prove otherwise then the MAF is bad.
the maf is the most hard thing to test and prove bad (not dead)
after all when and engine surges it sucks more air and the MAF output rises.
but (chicken and egg rules) what if only the MAF output messed up(all by its loansome) the engine AFR would then go rich fast. causing faster RPM.
that is because STOICH is on the lean side or power. see?
on the contrary side, if the maf lied and shows lower output (ecu knows this is less air) the engine would go leaner and slower from STOICH.
one way to prove that is with a real scan too.
you see surge, (goes higher RPM that right foot asks for!)
does closed loop end there,? did the TPS throttle angle change (must not)
does LTFT go wrong? (long term fuel trim(short is to fast for humans , ignore it)
did the rpm rise and MAF did not (oops it is fibbing if yes)
did injection rates change.
all this is OBD2 stuff but is also in the OBD1 too, if you look, see that here.

this raw data was (captured (with communications tool I have) note that OBD1 , we must convert binary to analog values, unlike OBD2.(its free ride that)

http://www.fixkick.com/ECU/Tech1/full_scan2.html