89 sidekick low idle and dies without other accessories on

[taylorworld]

ok guys i am am stumped. i have checked everything and replaced a lot of stuff on this vehicle and i am out of ideas. it runs fine and idles at 800rpm when either the lights are on or the heater fan is on but when no other electrical accessory is on it runs rich and drops idle to 0 and dies. i have cleaned all the ground wires that i can see except for the fuel pump one behind the tail light. i have a constant 39psi fuel pressure when running i have tried two sepperate fuel pressure regulators and it has a new fuel filter on it about 100 miles ago. any ideas? ive tried too much stuff to type out... is there any common problem that causes this? ive used this site, several factory service manuals and Jerrys website at guides. and only jerrys page says 24 to 29psi fuel pressure while running so thats one guess.

1989 suzuki sidekick, TBI 8 valve, manual trassmission

rebuilt computer with code 12

idle adjustment screw set at 1/4" but i just bought a spare throttle body and its set at 5/16" (the one that opens the throttle plate/butterfly)

[jtgh]

39 way too high ?huh?

but then I dont have spec on 89. not a real one.

BIG QUESTION;
can you keep it running with extra gas pedal (this adds air only, really) ?
yes, then it is starving for air. ( or running way to rich cuz of too high pump pressure and flooding)
if not, sounds like clogged injector.
or something else.

Still lots of things to check ,
top of list is , is the engine ok. Compression over 150 and vacuum at idle steady 19inches and no shaking..
[ its on your long list for sure ]


if engines is ok.

i do not have fsm for 89
but my library card gets me this at pub.lib.
DATA BASE SAYS:
24.1-39.8 keyon, no start. ( may take 3 or more keys on , to get this high)
idling 24.2-29.9.psi.

so I say (could be wrong, no fsm) the pressure is way too high idling. 10 psi is way too high.
that is a lot.
CAUSES:
this can be a pinched return line at FPreg to tank. (connect it to bucket while testing)
bad FP reg. (put a hand vacuum pump on it and range it ! running) validate it works.
if it dont , it's bad or the return line is plugged for sure.

clogged filter (yours is new)
and a bad vacuum port for the FP reg.

make sure the FP reg is connected to the correct nipple, for vacuum.
if wrong , FP reg will fail. check vac source routing and paths clear.

I think you are close.

I do not have vac,diag.for 89.

[jtgh]

ranging FP reg.

key on no start.
39psi .
pump that hand pump. you MUSt BE ABLE TO DROP THAT pressure way down.
like below 24 PSI:
if you can then the vac source is bad or wrong.

[taylorworld]

ya ive checked everything else and now im pretty sure it is the regulator. i tested my friends 1.3 TBI samurai and its 29psi fuel pressure during idle. it has a new fuel filter and ive checked the return fuel line so all that is left is the fuel pressure regulator or possibly they fuel pump. a couple weeks ago i tried to use a vacume to lower the regulator PSI and i couldnt get it down much at all. but whats weird is ive tested two other old regulators and they are both 39 psi while running. my new regulator should be here monday so i can test that theory.

[taylorworld]

welp i got in my new fuel pressure regulator and tried it out and go tthe same 39 PSI but now i dont get 34-39 psi with key on and no start even with the old regulator i only had about 5psi so took the fuel tank off and the sock filter on the pump was really clogged up and the tank was rusty. i pressure washed out all that i could and ordered a new fuel pump and sock filter. the whole kit was just a few dollars more than just a filter for some reason. im guessing that bypass in the pump and the sock was causing the high pressure. what do you think? i also cleaned out all my fuel lines and return lines by blowing compressed air thru them. if all this dont work im going to be shocked hehehe

[jtgh]

yes, i agree, serious problems.

not being able to suck down the pressure at FP reg, is not good.
it must go down.
Im not sure about all the things that can go wrong in the pump.?
dead, low, intermittant we see.


your symptoms to me say the return line is blocked.
but it is not , you checked it.


my return line when pinched makes 60psi. (pump limits it to this )
manual says only do this for few seconds as it can hurt pump.

i can not imagine why your hand tool can not reduce the pressure 10 psi.
cept:

blows me away.
are you messuring pressure at the filter. test port?
then I think? a clogged up filter full of rust is causing the high readings.

the 8v gauge port is on the INPUT to the filter.
so if tank is rusted, it fills the element in the filter post hast and pressure goes way high
and holds there. making FPreg , useless. (the filter acts as its own regulator, false)


Im sure you are on track.

thanks for sharing.

[taylorworld]

ok i am still stumped!!! oh ya, how is everybody today?

ok new fuel pump is in with a cleaned tank and a second new fuel filter. i get 41psi fuel pressure. out of 3 fuel pressure regulators 2 used 1 new they all have the same fuel psi. the vacume hose for the fuel pressure regulator is completely clear. i CAN vacume them all down to about 31psi with my hand pump at 27in.hg. i get the same psi with the fuel return hose hooked up and with it going into a gallon container so i know the return line is clean. when i had the gas tank off i blew compressed air through all the fuel hoses going to the tank and everythign seemed clear. any ideas?

[jtgh]

that is wierd.
the FPreg is working. 10 psi Delta.

vacuum port in TB clogged, nah you checked that.

the electrical malady has me spooked, (no one has ever posted a problem like that here)

I am now suspiscious of your alternator.
what is your battery voltage at idle and running 2500 or so.
14.7v is max.

could turning on accessories help lower the voltage to lower?

I get my pump pressures from pub. lib as 89 fsm are like hens teeth.
i chech 2 sources and those nums i posted are what they said.

back to elect.

the ECU has a circuit that measures battery voltage and reduces injection for high alternator out,and opposite as you go towards 9v mininums.

ok, the ecu can be bad too, thinking the battery is at 9v when at 14.7 real.

or the voltage at ECU is wrong some how.

you sure your grounds are good at Dizzy base and at Thermostat housing.
ECU is sourced to these.
and the ground behind battery and all ground straps on front edge of fire wall.
and the ground from battery neg. to the top starter bolt TIGHT !

check the voltages at the battery and at the ECU pins for battery or at
the Dome fuse (ecu memory this is) for 12.5 to 14.7 v range

the ecu will set rich and lean due to lower or higher voltages to the injector from the battery. it works very good, when it works.

the Load issue, you have noticed is #1 clue.
it could be power or a bad eCU.

i hope it is not the idle dropping real low when lights fan and loads are on?
if idle drops too low the ALternator will in fact go dead, but that is legal , the
ecu compenstats the fuel injection from 9 to near 15vdc.

so load should NOT help mixure. it should just make all voltages perfect mix.
nothing less.

that is one strange problem, makes hair on neck stand up.

interesting....

[taylorworld]

alrighty, heres some voltages

battery votage key off = 12.88 volts
at idle = 14.47 volts
at 2000rpm and all other rpms= 14.47 volts
dome lite = 14.26 volts

one other thing that i havent figured out is the check engine light stays on all the time. when i flip the mileage switch under the dash(the one that comes on every 50,000 miles i think) it starts flashing engine codes. so i leave in the position that leaves the check engine light on all the time.

any more ideas?

[jtgh]

perfect battery and altertnator.
so is dome voltage.

with switch hard over , that is SES with solid light.
but key on , so is key on and no start, the only diff, should be bright or dim glow.
if you see codes, flashing then you left the jumper in.
what is the code
12?


i looked up the pn for 89 and 91 ,
fuel pumps, the only diff is long and short for 2dr and 4dr, diff gallons side diff depth pumps. Ive seen this before.
then the regulator

the reg is diff! and that has me bugged as it looks exactly the same.
so it must be diff pressures.
89 is -61a00
91 is -56b00
also the injector is diff Pn, too.
i hope you have a 60a32 (mt) 60a42 (at) ecu.
it is quite diff. i hear.

but i do not know why? just that it is on 89's.

here is my pinout drawing for 91,
if it is the same for 89, then you can check all the pins
and find out which ones drop in voltage when you turn on head lights and or fan.

see attached schematic.

see below page. scroll to PINOUT and the pages marked page1 page 2 .. 4

My ECU is bad, now what?

those shows the voltage on all pins, normal.
how ever doing the test is hard.
i usually have to remove ECU and plug it back in after it is near floor.
then i can back probe the conns. meter red and meter ground to body ground.

when you turn on the HL , one of these pins will drop. radically.

hard problem.
sorry you are having to deal with one so hard.

I wish i had 89 fsm. it would clear up the differences.

cheers.