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Could really use some help
is car in USA? if yes harbor-freight has a $20 fuel pressure guage with the suzuki 6mm hose there? that fits all suzuki stock filter banjo fittings. my guess stock filter is gone, and so are the stock banjo's" I cant see your car nor see mods done wrong, or any of that, many parts on this car are super hard to get now...... or very expensive from SUZ
1. Yes Car is in the US Illinois to be specific.

i re-read all your posts.
so the coil wire was hacked. (i see that splice there and is never good to allow that ever)
the injector wires hacked ?
2. That is correct a there was a hack wire that was going from the coil wire to one of the 2 injector wires, without the hack wire in place the injector would not fire at all. That was a special project from whoever had it before me.
and the ECU replaced right?
3. The ECU was sent in and repaired. It was said that there was a burnt out injector circuit and that was reapaired all else appeared good in ECU. That was done and put back in couple weeks ago. I also ran 2 new wires from out of the ECU to the injector harness like you suggested. Did not seem to help. BUT it did allow the car to run and fuel without the HACK wire. So in my mind progress but still not fixed.
back near post 30 ish, you showed fuel pressure ALL WRONG. 18psi is ALL WRONG. as is 20. !!! IF IT IS , ? then this car will bog like HELL.
when did you fix the fuel pressure.?????? I can't find that anywhere. nor how done , exactly....
4.I did use a fuel pressure gauge kit I borrowed from Orileys and found that fuel pressure was low like you thought. I then replaced the fuel pump in the tank and 70% of the metal fuel lines from tank to throttle body with new soft fuel line hose. This seemed to make a big change in the car but still was not 100% correct (this was before I got ECU Fixed and hack wire was still in place). With new fuel pump in place it was reading good fuel pressure. After driving in like that for a month or two it got real bad one day we were idling around field edges in first gear for hour or so and since then it has been really bad.

it takes 2 things to get good pressure, (not counting clogged socks or filters wrong pump or bent pump output side lines and the like.
a good pump that can do 60psi shunt test, (output blocked) at FPR return line, this test in in the suzuki book and on my pump page. Did you do a pump shunt test?
5.I have not done a pump shunt test I will perform this test.
then a working FPR, most this old are dead, and leak. to the return line, so easy to prove. ask./
so if the FPR works you get your 31 to 40 PSI is spec. as sealevel, are you at sealevel
6.Yes I am roughly at sea level
the pressure does not change at wot, like all 16v MPI engines do.
the pressure fuel only change for altitude.
same pressure key on
same pressure, running at any speed.

what is your idle pressure? at idle, and gunned for 1 to 3 seconds WOT.
do you have fuel pressure gauge, does it fit to the filter test port.?
7. I do not have test port. Everything was very rusty and had to replace filter with inline style and different hoses. I can you the T like you suggest in the next post. That is the style of hose and clamps that I am using. Is not leaking.
as it must,. there is no under hood test point on any 8v. so... deleting the rear one will make diagnoses, impossible.
do not use carb fuel lines or carb clamps only 100PSI rated fuel system parts, are to be uses, EFI rated. or you will get a leak.

here is your system, this is first, as the ECU is wholefully unable to cure bad pressure, nor know its wrong, ever. it must be right.

when you remove the vacuum line from the FPR,does the nipple there leak fuel, is yes the FPR is bad.
8. I have not checked to see if it is leaking fuel here. I will check that. Last I messed with that it did not appear to be.
ps. idle surge is a other issues. might be above and idle speeds we fix last when engine runs correctly. (power full , no misfiring)
9.We will address this once we have other issue figure out. Thanks
if the ECU can not control idle , IT surges the ISC valve( super dangerous today, ask toyota the cost of the error, recalls,etc)

you need to meaure the pressure correctly
or buy a new FPR and pray,
but in the end, if the pump fails the shunt test its no good or wrong pump.
i cant see what you did, but my guess,
put the TEE fitting, in place of the filter., then the gage attached,

34psi min. (41 is par, at sea level and 34 , up on pikes peak) (the higher the altitude the lower is fuel pressure, or the injector flows to much fuel)
if the pressure is 50 to 60 the FPR is jammed, (bad) or return line blocked,pinched or clogged.
if the pressure is way low(it was) then the FPR is bad(stuck open bad) or the pump is no good.
if the shunt test fails,(with return line pinched) then the pump is NO GOOD. (wrong pump , bad, or its sock clogged, or hose inside near it is cracked and leaking inside tank unseen.
that covers them all i think.
10.I will check fuel pressure out and do the shunt test and see what kind of pressure I get. Thanks again for the help. Will report back later.
All right so i checked fuel pressure. 15 PSI key on while pump is running. when pump shuts off pressure falls to about 5 PSI maybe little under. When the motor is running it gets up to about 15 and flutters a little around that 15 mark. I pulled return line off the fuel pressure regulator and am getting NO fuel through the regulator at all.

I did replace the fuel pump right at a year ago with a GMB 520-1021 Electronic Fuel Injection Pump. https://www.amazon.com/gp/product/B00D44...UTF8&psc=1 Is a link to the pump that i bought and installed.

Why would pressure fall off as soon as the pump shuts down? Pressure Falls off immediately and sharply not like a slow leak down from 15 to 5. It is nearly an instant drop. shouldn't the system hold pressure or is it back flowing through the pump. I have no leaks anywhere else in the system that i can find. Would sure think that a leak this substantial would be pretty easy to spot after cycling the pump a dozen or more times.

Thanks for the help!
"Virtual SIGNATURE 92 8v , hacked ECU etc, saga 2."

no sidekick on earth runs on 15psi. not one.! sorry... not going to happy, nice you have a guage no?
the regulator is closed because (spring inside is closed valve 100%) the pump feed is dead. if the pump cant do 60PSI it's NO GOOD. period
that is what the SHUNT test proves, and will fail here too,

what matters only is that meter. the pressure dont lie, no matter what pump you bought or how long ago, take actions on facts, and 15PSI is all you have now.
1: 12vdc not making it to the pump, 14v running., (alternator voltage minus about 1v due to cheap crap suzuki wires, but normal)
that is first, voltage, no DC motor makes full PSI power lacking full voltage. none do.
so volts is first. at the tank top and to the motor. inside.
2: if that happens and the pump hose inside is not split as most are now after 28 years old can be.... 1989 to now or your year.
3:bad pump. GMB, (is not GMB junk pumps?) why not use a top branded pump>?

that is correct the pressure holds for long minutes,
ever think the drops is from tank pump out to top of pump rail lid? Inside the tank
the pump in the tank has check valve, is that missing, ? that IS WHAT holds pressure, and (fpr not leaking and injectors not leaking)
it really does not matter now. leak down, after all the PSI is wrong, and is a FIRST ORDER FAILURE, fix first first hard failure on all cars made injectors.

its not leaking outside the car, nor is the FPR leaking, if the injectors are no leaking then its not there either.

so remove the air horn top of TB
see that injector there
key on, no leak, it will squirt fast for super short time called, the prime pulse. on all 8v made. some do not squirt, for sure with 16psi and air in the lines.
but key on 3 times, and key off, if the injector stays off, then its ok, if the pressure went to 30PSI (id dont) then the injector stuck on, then it would leak from 30 t0 5psi fast. or zero. fast
if you want unplug that 4 pin injector connector, 2 pins are injector
now key on, there will be no squirt now, ever. not possible is injector is OK.
now if PSI is not 30 the the pump is bad or its hose bad.
you already know the FPR is shut down but you can pinch its return line (called the shunt test) and PSI is 50 to 60. if 15 the pump is dead, there are no other out of tank leaks now, here.

easy tests NO?

the pump is rated at 60 PSI.
it does that shunted.
then the FPR opens and regulates that to 30.
that is all there is there, for pressure, the FPR must be good,too. for sure not stuck open, as many do, but you proved it's not it. but might be later,(oops failiure 10>?)_ when the pump works other things can fail..

for sure no all pumps are equal../not by a mile.
some last and last others are pure junk from china, "no name' brands
if it was my car and after all that labor to pull a tank , id not buy a cheap brand.
id buy BOSCH.
the Spectra (they make some of the finest no rust tanks made too)
see the yellow section there those are trash pumps,
the $25 price on CARTER (old huge name in pumps and CARBS) scares me, ( my guess are $5 china pumps re-badged by the bad guys)

see purple section.
its not easy to measure the voltage to any pump, after all its on top,l where only mini mouse can walk.
one way to test it is tank out is a dummy load on the 2 wires,
using a 5 amp load. 2 to 3 ohms resistor (60watts) (or connect an old head lamp there) both beams connected at once.
best is head lamp, test.
put it across the 2 pins, at pump (pump unplugged and out) the measure voltage key on , see 12vdc there, no 5, not 6 not 8 , 12, lowest is 11v) keyon for 3 seconds
see lamp be BRIGHT,
if that passes, then the new pump has chance.
or inspect all 4 connectors end to end on the pink /black wire pair from pump to relay.
no rust,
we are 6 chapters in now.
no signature yet by you,
no door count, i had to read them all again and not one mention of doors but by me begging
as always here we beg and beg, endlessly for your full car spec.
92 8v, what?

the 2door cars harness are not any where like the 4door. this is a fact
so not tell this fact makes helping near impossible. ;

'the 2 doors as my pump page nags. over and over
is the left rear tail light, the pump ground is there, G402 ground is it.

seen here, see all those pump connectors that all can fail so easy after 25years.

see this.

see mine? see bright brass, see my dielectric grease there preventing , next failure , that all do.? the water spray can reach there from LR tire. not a great place there.

all that is on my "now that you know the pump is bad" what to do page.
well first take of the gas CAP and check pressure now.


wrong FUEL FILLER cap there, the tank pulls a vacuum and renders that pump NEAR USELESS. sucking a vacuum is impossible. or near
the correct cap has vacuum breaker inside, its NOT OPTIONAL and MUST WORK.
see that photos of the collapsed fuel tank cause buy a wrong $5 cap.

some can believe you, so photos dont lie.
thar she be.

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