97 Tracker - Poor Idle, Hesitation

[Mike8500]

I'm having some trouble determining the problem with my 97 Tracker. It's got about 190 000kms on it and has been running good up until lately. It has always been a little hard on fuel due to lift, bumpers, winch, bigger tires etc.

A few months back, I noticed that it was pinging quite badly under load on the highway. I tried mid grade fuel, with no difference. About the same time, I got a P0400 EGR code. After some research, I ended up cleaning out the EGR Tube as well as the port in the intake. I just removed the air intake tube, opened the butterfly and used a long screwdriver to clear the blockage. This solved the problem of the P0400 code and the pinging was gone.

Fast forward a couple months, and I notice that the idle is starting to become erratic, first slightly, then over time it becomes jumpy and the motor shuddesr, almost stalls, revs dipping from down to almost stalling up to about 1200 rpms. Initially, when I was driving, the problem was not noticable, only at idle. Eventually the idle became more erratic and I started noticing hesitations and bucking at part throttle. If I go more than 1/2 throttle when I'm driving, the problem doesn't present. Only under light load or idle.

I've replaced the O2 sensor, checked the TPS resistance for idle switch and a full sweep to look for dead spots. It checked out just fine. I pulled the Idle control valve just to eliminate it. It seemed fine, no major buildup. Also I didn't really think this was the problem since the hesitation and missing occur even above idle. I have new plugs (old plugs were BLACK!), checked the cap and rotor and cleaned up the contacts.
I manually cycled the EGR valve by pushing on the diaphragm just to make sure it wasn't stuck, it definitely moves freely.
Most of the time, there are no codes and no CEL present. One time I did get a P0121 TP Circuit Performance Problem but I reset it and it hasn't showed up since. I feel the TPS sweep and idle switch test rule this out.

I did unplug the MAF to trigger limp mode and the idle smooths out and hesitation/miss disappears.
I'm not sure what I should do from here.

Any insight or suggestions would be greatly appreciated.

Thanks,
Mike

[fixkick]

Hello and welcome!
The EGR surly can case pinging. when dead.
no scan tool to see what's Up DOc.?
use the full scan, of all PIDS, using a real scan tool,not just a code reader.
hot idle engine:
ECT reads live at 180F holding? 82C. or more if running hotter STAT.
in closed loop at idle? stated in scans it does.
02 sensor swings nice,?
LTFT near minus 5% not -40 or +40%?
#4 exhaust header tube not cracked, (under shield)
121's are real if it repeats.
when you manually cycle the EGR main, the engine must drop; from 800 normal hot RPM to 400 or stall. did it, if yes, the egr paths are ok. (this car is mono port, just 1 path)
that maf test implies its too lean, normal.
so it bogging below 1/2 throttle (says lean)
low fuel pressure,? FPR bad,?
put back maf, and remove o2 sensor, (unplug it) change symptoms. if yes, look for exh. leak near 02.
are you subject to smog testing, MOT or what ever? it is called there.?

cheers and happy new year




.

[Mike8500]

Hello and welcome!
The EGR surly can case pinging. when dead.
no scan tool to see what's Up DOc.?
use the full scan, of all PIDS, using a real scan tool,not just a code reader.
hot idle engine:
ECT reads live at 180F holding? 82C. or more if running hotter STAT.
in closed loop at idle? stated in scans it does.
02 sensor swings nice,?
LTFT near minus 5% not -40 or +40%?
#4 exhaust header tube not cracked, (under shield)
121's are real if it repeats.
when you manually cycle the EGR main, the engine must drop; from 800 normal hot RPM to 400 or stall. did it, if yes, the egr paths are ok. (this car is mono port, just 1 path)
that maf test implies its too lean, normal.
so it bogging below 1/2 throttle (says lean)
low fuel pressure,? FPR bad,?
put back maf, and remove o2 sensor, (unplug it) change symptoms. if yes, look for exh. leak near 02.
are you subject to smog testing, MOT or what ever? it is called there.?

cheers and happy new year




.

I do have a bluetooth OBDII transmitter and Scan XL to do datalogging.

Hot idle it reads about 92*C.

I'll double check but I'm pretty sure it was in closed loop at idle.

O2 sensor is swinging properly, except when the vehicle almost stalls it drops quite low for a split second.

LTFT is normal.

I will check exhaust manifold for cracks but didn't see or hear anything after changing the o2 sensor and checking for leaks.

The 121 code showed up once and has not returned. It popped up after i let it sit there and idle rough for about 10 minutes.

When I pushed on the EGR diaphragm the engine stalled.

When the MAF is removed, it runs smooth with a slightly higher idle (1200rpm) Could this not also indicate it running too rich?

I'll try unplugging the o2 sensor and see what happens.

There is no smog testing where I live.

Someone mentioned the cat could be plugged??

Thanks for the help so far.

-Mike[/color]

[fixkick]

97 stick or automatic.2wd, or 4wd? the 97s in N.america are all 16v MPI engines.
the cat clogs, no WOT full power. not possible there.
so cat is OK;
and the brick inside is there, or p0400 full time...

the erratic idle is key here, most simple to diagnose, for sure with scan tool data. live
its misfiring to drop below, 800. did it? and that 1200 is surge with foot off throttle.
idle misfire, (tool lean or too rich it must be as it does this)
if it happens as coming to stop sign, we usually those pesky EGR main sticking as the EGR closes just 1second before a stop.
and can stick there.
but will never cause 1200 rpm.

nor the bogging, how can a bogging engine do 1200 via ISC , it cant. (why would it go to 1200. my guess, is metered air leaks or unmetered leaks on a gross rich engine.)

are all vacuum hoses ok? not cracked for fell off.
is the main air pipe, sealed up end to end from TB to MAF, any leaks here are lean causing. (all metered air leaks cause racing)

the old spark plugs were black, id hate to ignore this very good evidence
seem the ECU is in limphome , or was.
or the fuel pressure is high and (bad FPR is common this old) and runs rich all the time.
if true.
then idle can hunt has it misfires. (400 >800 and repeat) not 1200.
the key is misfiring. im sure you'd feel that happen, hear, feel and see engine shake or if 5sp, feel the shifter shake hard? (its connected to engine, unlike a A/T)
but no P30x codes,. misfire (did you check pending codes for this code)?

make sure Brake booster does not leak.
the ECu can go tad nuts with leaks, it tries to correct and fails and then ISC goes nuts, it can reset and then hunt. (but never seen a 97 do that only older" a bug there")

that 121. ( driven hard this can set)
performance
i think that is driving code, it is.
it sees huge air flow, (maf) but with wrong vacuum in the plenum.
or the opposite,
basically means air flows contradict, throttle angles grossly.

FSM SHOWS:
that 121 is Incongruity between the 3 sensors. basically throttle angle is not agreeing with the map. under load, >25 gr/sec on map

pretty smart test, 3 ways, maf/map/TV angle.
my guess is the bogging engine under normal avg. load tripped 121 due to low vacuum.
when you loose power, the drive steps harder on throttle, and vacuum falls like rock.
bam 121.
or misfires, do same thing, gross loss of engine power, and vacuum drops. with throttle above 35degrees.

---

on different track.(no pun)
IT hesitates.
off idle or tip-in hesitation is some cases..., the TPS bad. if and only , it blogs (not misfire ) AND, it catches up (the catch up is MAF waking up)
all engines go lean, at TIP-in (that huge air slug lacks fuel)
the ecu instantly goes to enrich mode, here, if not, the TPS failed. (it is the instigator of that event (and your foot sure)

if the fuel pressure was low, WOT would fail and the maf will not cure the lean, do to lack of pressure at the injectors)
on old FPR, that sticks , can stick at any point, if it sticks open fuel pressure is low all the time.
the 16v FPR gets tortured to due to every time you move your right foot it moves with you (Vacuum) at WOT the FPR adds 6 more PSI fuel pressure (depends on altitude)

one idea is to keep watching pending codes some times, the DTC are hidden there. (marginal failures that speak loud))

i guess the key here is , bog or misfire, the cause.
are spark plugs still white?

[Mike8500]

Its a 97, 4dr, auto.


So I may have misspoke when I said 400-1200rpms erratic idle. Looks like it's more around 400-900 as you can see in this video I took.

https://www.youtube.com/watch?v=Aim1VTu8...e=youtu.be

At about :33 I rev it up and then try and hold it about 1200rpm (with the pedal). You can see that even above idle, it randomly dips and stutters.

I've unplugged the ICV and it instantly stalls.

Unplugged the o2 sensor and it didn't make any difference.

I checked for air leaks on the intake tube, adjusted and re-tightened the hose clamps just to be sure. I used propane to see if I could get it to rev up with no change.

I inspected the vacuum lines and didn't see anything out of the ordinary. Wiggled them around to see if there were partial leaks. No change.

The engine does shake hard when it misfires.

Here is a video of the engine bay. It doesn't show up that bad in the video but the motor shudders even when it rev it up to about 2500.

https://www.youtube.com/watch?v=SgYgrPP6S0I

I haven't checked the Fuel Pressure. Is there a way to do that (shraeder valve somewhere?)

The 121 code showed up with it idling in my driveway. It returned a second time today while letting it idle.

My ScanXL program decided to quit working today. No idea why, but I'm looking at purcahsing some new software to diagnose/datalog. Any suggestions?

[fixkick]

0:15 at 15 seconds, see that drop, that is fast , looks like total spark loss or total injection lost or both, for brief moment.
it is misfiring, (but may be at a more deep level)

ok, but now test the ecu
insert the diagnostic jumper, pre 96, on your car look for communications loss.
key on , see 12s , sure (pre 96)
now start engine
sill flashing
wait or the same event at 0:15, that anomaly.
does the 12 change cadence? die, or not finish off a code fully, ? ecu bad.
ever check for the classic bad caps in the ECU./?
The scan tool , if you log data, at , 0:15 may show proof of some input to ECU , going bad, on the fly
or the scan tool could show loss of comms....( that happens if ECU reboots while running, not good that)


the , no shraeder, sadly. but and easy add with the rail adapter.
there is an adaptor for the rail. for $13 or
the hose in the kit, with gauge, that fits the 6mm test port on the gas filter banjo.
usually if fuel pressure drops rpm just slowly drops. (the idle controls and FPR like to prevent drops)
121. bad vacuum if , the TPS is working,. not glitching.... only scope sees tps best.
one more test
with timing light attached, to say #1 cyl, at the 0:15 events, does the strobe suddenly halt?
if it halted and injector 1 , id say the CMP is flaky, remove distrib side connector, make sure pins look clean.?

im sure your ISC is ok and the rpm goes below the spec, 800 only because of the gross misfire.. forget rpm find why , spark and fuel drops.
if not spark drop its fuel.
if is fuel loss, might be, fuel pressure, drop or was low all along and drop even more.

egr trick if needed, make sure its closed, parked, engine off
take off top egr hose, top of rear plenum at TB.
off it and plug it with golf tee, end EGR not wanting to close. as a test. parked blip the EGR main 3 times, 1,2,3 (for luck) hear it go thump, thump , that is full closed.
with EGR out of picture can help testing. for sure if likes to stick. some do , but only real hot.

that shudder in misfire. is the cam belt fresh, not slipped, do the sneak a peak test, yet, is the crank pulley at 94ft/lbs an no all discovered loose???????? (this is day 1 check this)
day1, the day you 1st get car. do....on all G16s.
the pump. (Fuel)
29.8–37.0 psi
running, and adds lots more (6psi) gunning engine, the pressure gunned can match key on pressure, (get near) that is 35.6–42.7 psi

---

pump tests
http://www.fixkick.com/INJECTORS/pump.html

the front rail adapter
http://www.summitracing.com/parts/ATM-2267/

the cheap filter hose
harbor FRIGHT(sic)
has this
http://www.fixkick.com/INJECTORS/TBI-conn-1w.jpg

for near zero bucks,... is your filter fresh?

---

conclusion lots of misfire
if not spark causes.
then its fuel.
not sure of lean misfire or rich.
oops made a 97 error above, on code12, (me bad)

---

http://www.harborfreight.com/fuel-inject...92699.html
$20
far right hose is SUZUKI prefect fit.
no cutting anything, ever.


all adapters made , by every one here.. from store bought to hand made....
http://www.fixkick.com/INJECTORS/Schrader-vales.html

---

its holding closed loop at idle.
if yes, id bet the fuel mix is not lean or rich. and is spark dropping out.
closed loop is STOICH.
but ??? that could drop out too.,, so fast you cant see it with scans.
scans are slow on this old slow ECU.
one way to see it, using real scan tool is to set up a scan that only scans one sensor PID at at time
like 02.
log that. mine could do about 10 a sec.
my Palmer software this is super easy

just 1 example (97 has great SCan-abilties if exploited.

see the bottom blue line, you can shut all off and just watch B1S1 (means front 02) to see if it swings fast at idle and not go nuts , at the ):15 event. or at 2500 rpm steady parked hot.




or log rpm
see if it goes to zero at drop. seen in 0:15 event.
the dash guage is a toy, the scan tool will snow true rpm, and FAST response,
or see pending DTC pop (up then off) or see real DTC pop. keep in mind the ECU will clear some spark failure events super fast, like CMP) and that it can't see TPS angle glitches at all(it thinks, its crazy kid driving?LOL)
id watch them all, all PIDS and same time for DTCs , carefully to see any wild changes, at the EVENT. (15)

---

on a running engine there is vibration
and things like to fail then or hot.
the MAF rap test.
at idle gently rap side of map casing with back handle of screw driver, pretend hitting your teeth this gently,
see RPM change is a bad MAF.
defeat the VSVs? to see if they are messing up, pinch there, input hard vacuum hoses.
what is plenum vacuum steady 19" HG , at hot idle is typical. steady. (but at the 15 Event it will drop, but is victim)

id check spark with my strobe first.... for sure. (strobe = automotive ignition timing light)

---

note me hitting 64g/s with my maf, Radical flogging the engine, to bench mark it,.....
ignore mpg that is instant mpg, and is low FLOGGED.
LOL

---

hope my long post helps you, i'm off to below the equator now... heading to the sun,, the beach.... and fun.

[Mike8500]

Ok I used an el cheapo software called Scantool.net for windows. No graphing or logging, but it does show some PIDs.

MAF is clean by the looks of it (refreshing at 4hz) it shows anywhere from 3.6-5g/s

TPS shows up with a buttery smooth sweep (Key on Engine Off, sweep slowly from 0-100% with no jumps or dead spots).

O2 sensor is swinging from about .15V up to .95v regularly.

Long term fuel trim is at -9.4%. This may be a clue.

Short term fuel trim was -24% at idle with a small amount of fluctuation.

This maybe is linked to black plugs? Bad injector? Bad Fuel Pressure?

Is it odd that the ECU goes closed loop before the engine is fully warmed up?

[fixkick]

no the top o2 makers spec ,show a 9 second wakeup time
wide open throttle good up hill.. maf goes over 50gr/sec
if it can , check fuel pressure.
all 4 spark plugs matter, 1 black and 3 not.

yes that software sold (on fleabaY was stolen 10 years ago.) old and very simple... check the help about version. see that/
old old and rip off from makers.
its like bare bones ....
but better than nothing.... lol

got a flat spot, and does catch up. but can you then flog it up a hill using all 95HP. attain it.
to do a test drive , all modes are checked,for normal power
no sure how far you have gone doing all that. idle, tip-in accel, bogs, catches up, but what next. HILLS.
the maf is the key here and fuel pressure.

one car we found hear all test pass.
so found the 4 injectors clogged. 1/2 way.they have 10 micron screens
id do fuel pressure. and Fpr test, and leakdown and last balance test all with on tool

---

one more test for TPS
accelerate from different points, and gears)
the TPS has many angles.
if section is bad the others are not,
say it fails at 30deg tip in , so try 40, and 50% if those work the TPS might have worn spot in its carbon,as all do eventually


cheers for deep down south, SouthAmerica.

[Mike8500]

Small update, Fuel Pressure Regulator was shot, found fuel in the vacuum line to the intake. Have a new one on it's way,hopefully install it tomorrow.

All 4 plugs were black, but the plug furthest back (#4?) was slightly less black. This makes sense since it was ingesting fuel through the FRP vacuum line which fits on the front.

Eliminating that fuel leak from FPR through vacuum line to intake should help, and I'm guessing the diaphragm leak was causing high fuel pressure in the rail. No wonder the fuel trims were negative. It's trying to pull fuel to get the o2 sensor reading right.
Currently I'm not doing any driving tests, I have a few things loose as I was checking sensors and for vacuum leaks. Will see what happens after the new FPR and then maybe take a drive.

'm still processing the long post above but thanks for all your help so far. Invaluable experience you have.

[fixkick]

seems this is common now...
all that is true
the diaphragm dead will make the acceleration weak, due to lack of rising fuel pressure to match need (vacuum drop)
hope it solves all issues, for sure some...

happy trails

the trim is complex , it may store say 16 trims , (diff,loads./rpm)
and will be trying to correct the errors, and cant , correctly with this form of chaos,
the trim corrects and no sooner corrected ,its wrong....