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96 Tracker hot idle issue (MAF reverse engineered!) look!
ohhhh, la la, a new one? cute.

(04-23-2013, 11:27 AM)gorkyb Wrote: Ignition timing procedure I followed:

the duty cycle is very hard to set with no scope or the proper duty meter connected to the DLC in the engine bay.
one fast trick is to.... lower the rpm

ISC is still not working as supposed to, idle holds steady but when I turn headlights on it drops and ISC can't regulate,
drops RPM means, that the ISC can not open more,

it's not bad enough to not let me drive the car, pass inspection or cause any real issues but it bothers me so I purchased an used ISC.
Tested both with 12v and what a difference between mine and the one I bought, the replacement one does not leak any air when blowing through and when 12v is applied is a strong snap up and down. Thanks for that input, ive never seen or owned any new iSC, they are very expensive,
I clean and refurb them all. if not, i do used one... for cheap.

I know you show this on video at your page but although video is great, having both side by side in front of me really opened my eyes regarding how inconsistent mine is. for sure , not seeing one , in action ,snappiness, and all, is hard to evaluate it.

The only problem is that all the tubes (air and both coolant tubes) are facing the wrong way, I see that they have little philip head screws that I assume one can take out to remove the tubes, so I am guessing they took it apart and put it back wrong?
im not sure, let me see? but seems you are right , move it to the right direction. are the coils same ohms?

If this is doable please tell me how to do it, I don't want to force it and break it but I don't want to send it back just for someone else to do it and send it back to me wasting time and money on shipping charges.

Picture of two ISC's.

first off , i do feel that pain and confusion. for sure, been there done that, too many times. (Im not sure ,on that screw question at all)
yes, not wanting to break the new one. may I ask what source (was it new? , refurb. , maker , Cardone?)
ok the ISC duty cycle. it's in the 96fsm , you can read the pages there... but getting a meter to work right, can be hard. (off my books page)
200 times a second the ISC modulates, (a scope works best) 2nd best is a meter that has Dutycycle in the dial.

we can fiddle it all to work good, by experiments or use a meter.
The isc cant hold HL. failure: Head lights on,.
so the ISC fails to open enough, (could be or its sticking, many stick, ive soaked many for a week to get them truly free)
but if the ISC is working it should open 100% at 100% duty cycle. this allows it to overcome the HP used by the alternator.
The HL use 140watts (aprox) or about 1/4 HP (horse power, nothing is free) so with fan and HL on, the alt sucks almost 1/2 HP.
with NO ISC? (dead) the rpm will drop. due to that load.
the ECU increases the duty on the ISC and adds air until 800 is reached, mine took about 1 second to react (delay)
if the duty hits 100, and 800 is not achieved the ISC is not opening fully or, has input restricked (i think not)
or the duty was wrong all along. no loads.
let me explain all wrong.
normally when you set duty to 50% at 800 , all is good.
but what if you set the bleed to 800 rpm compensating for too little natural air flow. say
duty is 90% at hot idle and no loads, and 800 rpm , the ISC only has 10% remaining, not enough.
one thing that can cause that is the 5mm screw on the side of the ISC set too tight, this causes a false high Duty cycle.
but if the seat is like a saw blade (or moon surface ) in the ISC , then its easy to get there.

in a perfect kick.
the idle bleed is set to 800 rpm hot , no load.
and duty cycle lands on 50% the ECU can increase or decrease air by 50 at any time. and

simple answer ,1
back off the ISC 5mm allen (ccw) see rpm rise. (adds air)
then CW drop bleed rpm back to 800 rpm (reduces air) this act moves DC lower. a goad would be 50% if you had a meter.
now the isc can open more under ECU control and , correct all alternators loads applied up to 50 amps or near 1horse power added load.

good luck

keep in mind , although the core part maybe the same, he 8v and 16v have unique routing. 8v is on TB and 16v on turned and planted on the plenum left side.
the 8v is unique in all years. 89/90 and 91-95 do not fit any 16v .
the correct pn for any 16v is just one number, 18117-58B00

56B is 8v.
the correct part is here , sold at suzuki. $330 bucks, plus tax and shipping, ouch.
many stores, are clueless to 8v and 16v differences, a disease of sorts.

Not a new one (I wish!) used one from eBay, they cleaned it and spray painted it, you can see it, but it works nicely (compared to my old one)

The question about the screw: holding each coolant and air inlet/outlet is a flat base with a screw hole, through this hole is a phillip head small screw that attaches to the body of the valve in order to fasten the inlet/outlet tube against the body of the ISC, my question was that if it possible to remove these three small phillip head screws so I can re-position the pipes. However, I then noticed that the ISC they sold me is not for my car, I believe the difference is that the one I bought from eBay is for the 8v.

Also, while inspecting my old ISC yesterday I looked into the hole where the piston shows (where one can see the spring around the piston) and saw a little piece of broken rubber (from the seat maybe? ouch)

What I did next was to hold isc in my hand, put two leads on its connector and start blowing through the top hose and applying 12 v (I kept adjusting the allen head screw until I was in the border line where 12 v can move the piston and the least amount of air is leaked by blowing through when no power is applied to the isc)

I then adjusted air bleed screw close to 600 rpm with ISC electrically unplugged and when I plugged it RPM's went up around 45 rpm more but it never got to 800 (HL off)

I did not compare coil resistance between both valves. I have access to a nice scope but honestly this is a tool I haven't used myself before. I will have to go online and do research and start playing with it until I understand it better. I'll take a look at duty cycle on ISC's FSM
1996 Geo Tracker, CAMI, 16 valve, 5sp, 4x4, soft top, 2 door, no a/c
it really is simple ,kinda.
the 200 hz square wave to the ISC,
a perfect motor, with no air leaks, (illegal) has a 50 % duty cycle at the 2 pins of the ISC at 800 RPM.
such that, if you lowwer the motor, RPM down (alternator loads , ir drive with a A/T)
the RPM starts to drop and the duty goes up.
that i,s the time open is longer, say from 50 % to 70% and rpm stays at 800.
if all is perfect and working
you adjust the bleed screw to 50% duty.
as you adjust the screw the ISC /ECu corrects the RPM by changing air flow and holding 800RPM.

there are 3 pins associated with duty on the DLC, a jumper to ground and output duty pin.

try this with a volt meter running, 0v is 0% duty 7v is 50% and 14v is 100%
hot idle, no accessories. idle tps switch closed. at 0v
jumper pin 2 and 4 on DLC next to right front head lamp shell.
connect volt meter from 4 to 6 , 20vdc meter range, the ECU outputs duty to this pin, in diag mode.
adjust the bleed for 7vdc. 50 % Duty is 7v, (fsm steps)

if the idle does not hold to 800 there is an air leak or the isc is sticking or leaking.
optionally you just throw a scope on to the ISC pins and set bleed for 50% .
the period does not change only the duty. period is .005 seconds.

Fsm states "the duty is not less than 28% (or more than 72% if it's OFF Duty measurement)" 28% is a massive air leak.
that is 22% above and below 50% ,that. that is the sweet spot to stay in,, IMO.

here is mine. at ISC pins actual and is set wrong, low = valve closed, i have an air leak here.
1.5x 2 (converts to %) shows 30% barely good, but too close to 28.% i got leaks.
or counter to that, the 3.5ms low x2 is70% low, the ECU is closing the ISC 70% of the time to cure air leaks.

this is cold motor, if hot this is bad duty.
[Image: iac-wave1w.jpg]

sorry you have a 8v isc for 96 , 16v,
i do not know the damage that might happen if those screws are removed. but id not want to send it back at todays postage rates. id try to get the screws out gently.
pen. oil or heated.

how could, duty go wide open 90% percent or more.
easy, EGR leaking the ECU opens ISC WIDE open to save stalling idle.
hello gorky.
i got the China maf, it's in fact made in china, with words on the cover showing that.
i de-potted the PCB inside. easy.
i have rev. engineered , the first phase, photos and page to follow soon. its a 8v Pic micro processor inside, 8pin SMD > 12F683

the bad news is the crappy 5v power regulator used,
they connected the 78L05 regulator to 12vdc pin via a series diode and small cap to ground, very poor protection for the 78L
max input to 78L is 30v max, the cars electrics can do 100v easy during load dumps, and jump starting car battery.
it has minus spike protection but not plus spike and that is not good.
there is an adjustment variable resistor ,inside too, but was potted over. (the potting was some kind of weak rubber coating that peeled right off)
the hot wire is good,as is the temperature thermistor.
im doing some more live tests tomorrow

the board inside was never de'fluxed, i'd bet, hand soldered too...

the board is 3 layer board.
i wonder do any of these china made MAF's ever work? right?
cheers for now.

[Image: china-pcb2.jpg]
It fails the flow bench test, hard.

see below.
I think I fixed it ! (i made web page for it and how to make one better)
First, off, i tested on the bench, it is stuck at 1.5v. (just like in your car)
id not run it long range, not me,but would make spare. (if it works) an emergancy spare, but gorky gut a used one for 1/2 the china price.
(i assume, DD service not toy/hangerqueens or offroad (low range), or pulling stumps)

when i got it , I documented the wiring inside, then i finished the PCB schematic. (pen and paper then cad)

I found that someone (had to be factory) has the HOT wire on the wrong pins. (my guess is the pcb card is calibrated on a jig, 3 trims on resistors done.
then they put the pcb the body and ship it untested ! (nasty QA), the lid was thermal plastic sealed. (welded ) so is original from factory.
i put the wires, back correctly, see my new schematic. The air temp sensor now works and the hot wire, like magic. wired right.

and then used my vacuum cleaner (DIY flow bench), and got 3v , out, increased nicely from 1.5v, as i increased the air flow.
i tested all the parts in on the card and all checked out. (PCB means printed circuit card, as seen above ,3 layers too)

here is that schematic. rev 3.
See TP1 , yours was dead, but now it works great.

[Image: schem1b.jpg]

warning, to readers.
dont spend $100 on this , it's junky.
it was not even cleaned (defluxed) after they "by hand" soldered it and that one part , see photo1 , the ugly part, this part sits, .001" from the power trace, almost shorted. horrid quality controls.!
and the power supply can blow up at any moment, due to poor design. (can be corrected easy , by adding a filter)
I suspect, (yah,think?) they never tested the final assembled product. zero QA. (the uP chip is pre-programmed before installation, good luck getting a unit with Suzuki tables in side. with zero QA.
QA is quality assurance , systems.

YMMV , (your maf may vary , LOL) YCMV, you clone may very , after all, just how may clones are there, or clone shops.?

if, using a CAI system , MOD, cold air insanity
make sure the MAF is not backwards, see arrow? on body.
with CAI it fits both ways, 2.75" O.D. but not on any stock car, as there WAS a mount preventing that.
and do not remove the screen, it's not a screen.
to finish it off, a fast web page linked from the maf test page

Fixkick, hopefully all this work you put in can help reassure trackick users not to buy these clones, although you were able to fix it, you also found out the parts used to make these MAF are very low quality. Thank you for the time and information

1996 Geo Tracker, CAMI, 16 valve, 5sp, 4x4, soft top, 2 door, no a/c
(04-28-2013, 11:23 AM)gorkyb Wrote: Fixkick, hopefully all this work, you put in can help reassure trackick users not to buy these clones, although you were able to fix it, you also found out the parts used to make these MAF are very low quality. Thank you for the time and information


your welcome, do you want your MAF back. i can send it free.
ps; I enjoyed seeing how the circuit for air temp compensation , actual works, inside,
one thing the clones may Undecided do , good, is lower the price of good used, mafs..... silver lining?

Hot idle and all other systems working perfectly. Got another used replacement iac, this time it was the right one. Used dlc plug and voltmeter, set air bleed by reading load at around 7v, car keeps at 800 rpm at hot idle, headlights and heater make idle decrease for a second, then iac regulates.

Whoop whoop!!!
1996 Geo Tracker, CAMI, 16 valve, 5sp, 4x4, soft top, 2 door, no a/c

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