'94 Tracker hesitation/stuttering at low RPM smooth idle

[dstaheli]

I have a Samurai with a '94 tracker 16 valve engine. It has recently started stuttering and chugging a bit just above idle when I am accelerating slowly or cruising at low throttle. gas mileage has been pretty low also. when giving it a lot of throttle it doesn't seem to have any problem. Runs fine when cold. I have disconnected the TPS and it runs fine (no hesitation). I did a test of the TPS. It is callibrated correctly and the resistance changed smoothly through the whole range. I have disconnected the vacuum line from the EGR main and it seems to hesitate less. I disconnected the EGR solenoid and EGR main vacuum line and it seems to hesitate less but still slight hesitation sometimes. I cleaned ERG main no change no change on stuttering but i don't ever get CEL after cleaning EGR. I did a running test on the EGR valve and it seems to flutter while holding a constant RPM not sure if that is normal. I feel like the stuttering might correlate with the EGR fluttering but hard to confirm while driving. Any ideas??

[fixkick]

yah the egr runs only off #4 exhausts tube, the modulator could do that, (not bad) just at low rpm the modulator diaphragm will flutter.
i dont think that is it. code 51 is EGR, and means only that egr is dead.
is the cat missing? the cat makes the EGR work other wise its dead. or super weak.
hot only stuttering.
is it misfiring, or bogging or only a hesitation on fast right foot actions.
Spark is first. got good spark wires? HV wire set?
removing TPS turns on CEL, and ECU goes to limphome mode, super rich and retard timing
do you have full power up hills hot.?
clean the maf.
check FPR for regulation? (key on pressure, idle pressure and WOT can reach key on pressure but not fully)
run it with 02 unplugged?

if it was EGR, id make sure the vents on the EGR modulator are not clogged.

at idle the part called "B" here will flutter. the filter and vents must be clean and good cat to get a bark. to bottom hose.
each putt or bark closes V valve, the faster it flatters the more EGR you get, called modulation. The power of the putt is created by the CAT back pressure, and how many hits a second.

http://www.fixkick.com/sensors/EGR/modul...tioned.JPG

[dstaheli]

So I did a little more checking into the fluttering egr. I checked the vacuum coming from the egr solenoid. It stutters also on off every few seconds. The vacuum in the intake manifold is steady. I have attached a video. I also check the signal to the egr solenoid. I am assuming it is ground controlled?? The continuity to ground flutters in and out every second or 2. This happens at a steady throttle. Is the egr solenoid supposed to do that? If not what would be causing the signal to go on and off like that? I am thinking there must an input to the ecu that is fluttering causing this symptom. Am I on the right track? If so which inputs should I check. Thanks for your help!!!

[fixkick]

do you have CAT, if not the EGR is useless, please answer 1 question, and the cat must be 1.6L sized not for 5 liter Cadillac )try to know I cant see under your hood on this custom car./)(.
the solenoid must not cycles at all parked idling, the idle switch is closed the ECU sees that and the solenoid valve VSV is closed.
If the valve stutters that too is wrong. (the ECU would be messing up if that happens.)
The VSV has 12vac (14v running) on one side of the coil in the VSV then the other wire goes to a transistor (seen on my ecu page) that turns on, and grounds this node
and the Valve closes, but never parked, at 800 rpm hot idle.
the EGR is dead on cold engine and dead, at idle and dead at WOT, and on newer cars dead not moving car (96+ up)
also there is no ported vacuum at idle to the VSS .
all i can think of is TPS calibrated wrong and the idle switch is at the hairy edge and opens and closes ever engine shake, this would do 2 bad things, make EGR nuts, and make idle controls nuts.

The VSV is open cruising, fo sure moving, and never WOT. so if it flutters that solenoid the ECU sounds to me, it has bad CAPS
we see that all the time up to 95 (including) and gets so bad all vsv on the car go nuts, and more.

idle switch bad, (set wrong) but not the cause moving, as all TPS switches are super open moving, the TPS guts inside would have to be cracked inside, as seen on my TPS page, guts.
or bad ECU and most times 99% bad caps. the corner cap wins the failure here.

with that cap bad the ECU reboots over and over like mag pie bird and VSVs reset each time. even ever 2 seconds,

the ecu is only programmed to open VSV on this car , off idle and cruise and never WOT. (a bad TPS will set flash codes, but you have 12s right?


i assume you found the DLC connector and use the paper clip to get the codes DTC right
or is these some custom car with custom harness lacking all that GOOD stuff????? i cant see it ,so.... what is there, is any ones guess.

[fixkick]

are you running stock suzuki harnessed, y/n.

if not lots can be bad, even bad grounds (many) can make the ECU go nuts.

[dstaheli]

It has a cat. Stock Sammy cat. I think it has stock Suzuki harness. But I did not put the engine in so I am not sure exactly everything that’s there. I do get 12s with the jumper on the cel plug. I have got 51s a few times.

The solenoid valve is always closed when at idle. When I give it enough throttle so the egr wants to kick in is when it starts fluttering. I have the rear wheels off the ground turning to simulate driving. It seems to be closed at the right times but when open it flutters open/closed.

I have unplugged o2 sensor and the car still stutters. I have totally disabled the egr valve still stutters just a little gentler stutter. Unplugging tps I’ve never noticed stutter. TOS passes all the tests for idle switch adjustment and smooth voltage increase through full ROM. If ECU caps were bad do you think I would still notice the stutter with tos unplugged or would running rich and retarded timing cover that up or would no input from tps cause ecu not to restart? Any good tests to see if ecu is restarting? Thanks for your quick reply’s this is very helpful!!

[dstaheli]

It ran good for a while and gradually developed the stutter. Some days it is worse than others but pretty much always noticeable now once warmed up.

[fixkick]

the VSV all by itself , cycles.

you stand next to engine, hot or cold it does this.
it is idling,
you see the vsv is closed (zero vacuum to the modulator valve.
you then by hand raise the throttle by hand and the vsv goes nuts, right, starts chattering, that is the ECU messing up,
what is TOS, ive never hear that.? Terms oF service, Transmission Out of Service? are you outside USA>? Are in Canada or from there using terms only used in Canada?
or TOS is TPS? a TYPO,?
there are 3 valve in the EGR chain
VSV (EGR)
MOD
EGR main, so what does this mean.
I have totally disabled the egr valve still stutters( try to be exact you touch, )
OR THIS
I would still notice the stutter with tos unplugged
AGAIN WHAT IS A TOS.? I have never heard of that, its no ISO/ or ASE names..
the only facts I have so far are.
The VSV is acting nuts, when not at idle it is chattering,
and the idle switch is ok, TPS calibrated but the throttle bet by hand is raised alot and no way any Idle switch can stay up past say 1/4" throttle rotation by hand, inpossible.
in fact it opens (TPS idle about 30 thousands of an inch, very very very soon in throttle action
so what else can make the ECU mess up the VSV,
only one thin the corner CAP I told you was bad, never seen one not bad, (unless new ECU, or repaired by me,, or car stored in cold barn for 20 years) they all fail. every one does.
the cap is there to keep the 12vdc power system (and noisy nasty generator hash ) from landing on the ECU regulators.
when it fails, the regulators go NUTS, then the 5vdc inside the ECU goes nuts (noise = nuts) and then chips go nuts, and the ECU reboots over and over in this endless cycle of nuts.
they all do that every one, this old (sooner too)
what else, sure, the grounds bad to the ECU.
the stock car had a huge number of very important grounds, that are all lost do to engine swaps.

here they are.

see this table I made, its for fixing just that type of problem.
table 2 left side is your car, 92 16v
the first 7 , g100 down
http://www.fixkick.com/Good_Bad_Ugly/com...lures.html

[fixkick]

The ECU holds the VSV open when the throttle is raised off idle, the last years of these 2 generations of G16b , the last one needed rear wheels to turn (mph > 0 in dash)to open the VSV
i bet yours does not need rear tires off ground. as seen in 1996up.
at no time do they stutter, the VSV is either open or closed, not stuttering.. ever. or its bad. news.

The ECu goes nuts for 2 reasons
bad CAP #1
bad power, grounds mostly here.
head lights dont dim when vsv goes nuts (turn them on)
battery voltage over 14vdc when vsv goes nuts? (bad alternators can blow out 1 or 2 phase of diodes inside or even short them and make HUGE 12vdc power noise (giant) even will find C1 in the ECU is weak (not spec) and so is 2 problems. one helps the other fail.
i use scope to see noise many shops have none.

ever even looked at the ECU lid off yet.?
C1 leaking acid, or sides split, or bulging or blew its lid, looking is a magical thing on things that look bad. but sure looks alone are not proof of good. if looks ok only meter proves that.

if you had the real FSM book , it shows every inch of the harnesses. ever ground every inch, and if you had that, youd see all those harness pig tails for ground if that harness is even stock.
the case of the ECU uses a different ground,
that enables all inputs filters. in the ECU. so the ECU has many grounds, all must be good.
what is your ecu part number dash 58Bxx or 77Exx what is your xx? http://www.fixkick.com/ECU/ECU16v_92-95.html
here is the corner cap c103 is real number, in the corner below is old sammi leaking like mad.
http://www.fixkick.com/ECU/hell/html/image_6.html

[fixkick]

moving any suzuki efi + engine, 1992 into any sammi, one must be sure to not forget the grounds, and put them back right.
to the correct places,
and the body to battery straps, too.
all of them matter.