91 tracker stalls while driving

[saturnbremen]

I just bought a 1991 4wd tracker 1.6l, 8valve, fuel injected, 3speed automatic with 177k miles. Its stock and looks like it had a nice life. Engine was rebuilt sometime in its life. Starts right up like a champ. Idle is kind of low, around 400-500rpm, but it idles nice and smooth when cold.

There is a wire running from the +battery terminal to the red wire on the throttle body Fuel injector plug.
I assume they hooked that up because the ECM is broken.

Symptoms with this tracker:
It stalls when it warms up while driving, acts like its not getting fuel, playing with the gas pedal doesn't always help so I have drive close to the side of the road all the time.

Then starts right back up so I can drive a few more miles.

Sometimes it wants to stall when waiting in the McDonalds drive thru, but playing with the pedal keeps it from stalling.

The gas gauge shows different false fuel levels while driving. I think thats a faulty fuel tank sending unit.

What I have checked:
The ECM 50v 100uf capacitor is fried. I'm putting a new capacitor in tomorrow night.

Anyone know what could be causing the stalling?

[saturnbremen]

update 1:

I dropped the gas tank. The wire going into the fuel tank sending unit was rusted loose so I removed the unit. The wires inside it were broken. Impossible to repair. Ordered new sending unit from rockauto. 3 hours later part is in Fedex hands. Thank you rockauto guy.

Checked the vacuum modulator on the 3speed auto tranny. Undid the line and tranny fluid came out. Explains the white puffs of smoke coming out when I let off the gas.
The problem is there are 3 types of vacumm modulators available at Napa. no stripe, green stripe and double green stripe. The one in the tracker is so rusted there isn't any way to tell which one it is.
I need help!
Which vacuum modulator?? Reminds me of when the Templer told Indiana Jones, "Choose wisely..." There isn't a wooden modulator!

[saturnbremen]

update 2:

I just finished replacing the blown capacitors on the ECM board.

[saturnbremen]

My next concern is the 12 +battery terminal wire that was connected to the fuel injector wire. I read here that the injector coil "might" burn out.

If the car still starts with that wire hooked up, does that mean the injector is still ok?

[jtgh]

that's easy , last guy found ecu has a bad injector driver.
it is DUAL rail driver.
one pulls to ground, other pulls to 12v inside ECU.
he burned up the 12v driver transistor, (got to find out ,why first?)
i have a schematic and the pn for this circuit
link below;

what you are doing now is overloading the pull down transistor, it will blow next.
i call this the stuck on mountain kludge, the last resort.

your 2SB1020 is burned out.
here is my page:
transistors

My ECU is bad now what?

no where else will you find this data.


last:
why did last PO do what he did.?
he was just following some other guessing bloke and threw it on .
or the driver actually did fail and the NOID lamp will not flash.?

but if the later, then that wire in your harness is shorted to the body some where a
and the transistor will blow again.

there is no dedicated fuse, there is no codes for this.
you now know exactly where it is and the actual pn.

bad news , these used to be easy to get parts are not hard.
MCM electronics does not carry them ( did for 30 years, not now)
rotten shame that is.

ive been contacting NEC in China for parts, , they have them.
but want me to by 10000 of them.
do a google on it ,
depressing.

[jtgh]

vac, mod.
i am sad for NAPA
is it a napa part or a real part with real MFG name and pn.
like Dorman xxxx
or standard parts company,

try rock auto.

sometimes for parts you have to go to suzuki, they have it and so does ever GM.

suz PN 26980-61A00

also, when buying after market parts,
go to the mfg site on line, look up part and see why they are different.
it will show the parts and explain.
end sellers are famous for being clueless to facts.
infamous is the word.

here is my guess.
it has 3 modulators for the 3 class weights of vehicle
2door , 3 door , and or 8v and 16v
and power.

give me the name and pn , i will find it.
www. is amazing how easy it is today.

[jtgh]

https://www.trademotion.com/partloca...&siteid=214330

whole thing, not just diaphragm end.

some may sell just end piece.

suz. sells 1 pn for 90-95 2wd or 4wd.
in 1996+ the pn changes.
so best i can tell, is year sets the case.

[saturnbremen]

Originally Posted by jtgh

that's easy , last guy found ecu has a bad injector driver.
it is DUAL rail driver.
one pulls to ground, other pulls to 12v inside ECU.
he burned up the 12v driver transistor, (got to find out ,why first?)
i have a schematic and the pn for this circuit
link below;

what you are doing now is overloading the pull down transistor, it will blow next.
i call this the stuck on mountain kludge, the last resort.

your 2SB1020 is burned out.
here is my page:
transistors

My ECU is bad now what?

no where else will you find this data.


last:
why did last PO do what he did.?
he was just following some other guessing bloke and threw it on .
or the driver actually did fail and the NOID lamp will not flash.?

but if the later, then that wire in your harness is shorted to the body some where a
and the transistor will blow again.

there is no dedicated fuse, there is no codes for this.
you now know exactly where it is and the actual pn.

bad news , these used to be easy to get parts are not hard.
MCM electronics does not carry them ( did for 30 years, not now)
rotten shame that is.

ive been contacting NEC in China for parts, , they have them.
but want me to by 10000 of them.
do a google on it ,
depressing.

Bro, awesome info. Thank you! It looks like I will have to buy a working ECM from my local tracker guy if I can't buy and installa new 12v driver transistor. I had the hopes that just replacing the caps would fix it.

Could the fuel tank sending unit wire, shorting out as it hit on the metal gas tank, have caused the 2SB1020 to blow out?

[saturnbremen]

Originally Posted by jtgh

vac, mod.
i am sad for NAPA
is it a napa part or a real part with real MFG name and pn.
like Dorman xxxx
or standard parts company,

try rock auto.

sometimes for parts you have to go to suzuki, they have it and so does ever GM.

suz PN 26980-61A00

also, when buying after market parts,
go to the mfg site on line, look up part and see why they are different.
it will show the parts and explain.
end sellers are famous for being clueless to facts.
infamous is the word.

here is my guess.
it has 3 modulators for the 3 class weights of vehicle
2door , 3 door , and or 8v and 16v
and power.

give me the name and pn , i will find it.
www. is amazing how easy it is today.

I bought the one with NO stripe" vac mod today. Its all they had in stock, so much for "choose wisely". I compared the old and new and they look identical. I hope it works, if not I'll clean it off and return it and get a junkyard one. The guy down the road has 33 trackers and samurais so parts isn't a problem, just what he wants for them is.
If you could find out what the one with NO stripe vac mod is for...
Rockauto didn't have any in stock.

[saturnbremen]

Originally Posted by jtgh

your 2SB1020 is burned out.
here is my page:
transistors

My ECU is bad now what?

http://carfix.stufftoread.com/ECU/Tracker-ECU-91wa.jpg
This is exactly what my ECM looks like too.
Where is 2sB1020 in that pic?
NEVER MIND, I FIGURED IT OUT, THE BOARD HAS ALL THE PART NUNBERS ON IT.