DO NOT FAIL to Depressurize the system and follow all safety rules on this page.
You are here because , you are pretty sure, the pump output is WRONG. See the purpose of this system?
Do not let a bad FP regulator fool you!
Do not RUN the PUMP dry, it IS, "fuel cooled and Lubricated" ! Not even, for 1 second! ( or you will burn it up or shorten it's LIFE, greatly !)
If you must test it out of tank, use a pan of oil based paint thinner A.k.A. "stoddard solvent " sold at any hardware store", (safe for plastic it is....!).
I'd not use water to test a pump, as that rusts the check ball inside.
You are here, because pressure is not 30 psi running (or not steady pressure at 30, gunning then engine.) About 30 PSI. It must be steady at all times.
Before doing something dangerous , laborious, or expensive (jerking the tank, comes to mind)
(but if filter is full of rust, the tank is doomed) FPR means fuel pressure regulator, not fuel pump relay.
If the engine doesn't run , you must do all tests during the 3 second rule, that is, key on , over and over to get 3 seconds run time of the pump.
STOP And: (check out some IF'S)
- If the wrong gas cap is on car, & it's missing the cap vacuum breaker ?, stop and take off the cap, got full pressure now? Got the collapse?
- If the external filter is
clogged, the good pump is USELESS, and in fact burns up most
pumps.. working day in and day out, into a dead head !
- If the FPR is stuck full open, then the good pump is now USELESS (low pressure),
- If the FPR is stuck closed the pressure hits 60-PSI , making EFI ,
useless. 60 PSI can mean, the fuel return line is crushed, (clogged)
- The FPreg can not be tested fully, if the pump output, is weak. (shunt test fails)
- If the voltage to the pump is not 12v, the pump will be dead or weak. (yes, do buy a volt meter and check the pump pink wires , end to end.)
- If the fuel pressure
varies, with engine load (parked gunning the motor) there are many causes, but low voltage at pump, or bad FPR or sock clogs.
- If the 2 door car then, check if G402 ground, is bad? (infamous to the max)
- Pumps can fail many a way: dead, weak or draw too much current ! (4 Amp.'s is normal) Do the 5 tests, don't guess.
- Warning, shorted pumps
, overload D.C. power at ECU and crashes it.! This is because Suzuki
gets power from the ECU power buss. Not too bright an idea.
- Do not expect the silly squirt test , to mean much (videos x3). see the pump overload? See a good run. (use a Free GOM video player )
- This video shows good fuel pressure at the 16v rail.
- If the shunt test
fails, the pump is bad, or it's leaking inside the tank (bad hose
there) or 12vdc don't make it ALL THE WAY to the pump.
- If the shunt test passes and live running pressure drops, as you gun the throttle, then the pump sock is clogged.
- If the shunt test passes, that means you most likely have 12vdc all the way to the pump.
- The shunt test does not prove flow, only the Power of the pump. (that it is powerful) In fact, the shut test is at zero flow !
- Testing pressure at the filter port, if pressure is naturally at 60psi, you have a bad FPReg
- Do pull the pump (tank) when the shunt test fails, and there is 12vdc at the pump. Sorry you have to, but it is bad.
- In a full shop , we can check pump voltage and current, or use a scope to see 1/2 dead pumps (current spikes or drop outs) In fact, we do this first.
This page is a FAST track page from the main pump page here , (long version).
Jump to the super fast test, far below:
50% of all pump problems are ELECT. POWER FAILURE. (bad connections ! at 3 major exterior points)
Why take a bath in fuel?, just fix a wire? (by the way, the tank can be tilted down, while it stays in body)
Why replace pump, when some nincompoop, put a non complaint gas cap on car? (missing a OEM vacuum breaker)
Why change the pump when the Fuel pump regulator is bad (stuck open) (on fuel rail 16v or TB in TBI 8v) do the FP reg. tests. Do the Shunt test.
Why change the pump when the injectors are leaking like a fire hose. Do the leak down test.!
Do not forget to drive with gas cap loose to see if tank is pulling a vacuum and all engine power loss, symptoms , STOP !
Again ,Please Depressurize the system if you are going to open any gas lines ! We are not doing that, yet.
Facts you need to know:
This Pump rack (above) is beyond service and WILL be dangerous if that top cap seal, leaks.
If you pull the tank, you may find the tank mounts bad, the shield rusted and bad or the very expensive banjo fittings corroded and impossible to put back, and be leak free.
RULE1: Assume the power feed is bad and fix that, before ripping the tank out.
Suzuki sells only the pump with rack, Rockauto.com only sells pumps (neat) or with racks. So if rack is bad, find a used one, they are expensive new.
You are here because:
- Fuel pressure is low. or out of spec. or zero, or is no longer at 34 PSI minimum. ( use a gage not guessing!)
- Car stalls, because pump output is low or dead, or dies randomly.
- The pump don't buzz at key on. (year 1991 and newer, cars buzz at key on)
- My pump shunt test fails, or my leak down or resisdual tests failed.
I always test fuel pressure at the fuel filter test port a 6mm threaded screw, and a new filter in place. Excessive pressure is usally a clogged filters, or bad FPreg.
Do not fail to RAP on the side of any FPREG to unstick it. (if pressures are wrong) {this is no cure, but proves the reg is bad)
(It is normal for the pump to run, for only 3 seconds, each and every key on and to run full time cranking and running engine.)
The 89/90' year, only runs key one for 3 second below 10deg F. (you must crank these 2 years vechicles, to prime the pump) [ and all Suzuki SPORTS]
If the power feed to the pump Drops below 12.0v or below 14v engine running, you need to correct this voltage drop.
If the ground feed or power fails or gets resistive, the pump will fail to make full pressure, and will be intermittant. The 4 door and 2 door cars are wired up , a tad different.
The pump is fuel cooled and is fuel lubricated, never ever run it dry.!
Never run the pump on low voltage or with a clogged filter , or your pump will die early.
Do not replace the pump, unless the power (voltage end to end ,pink and black) are checked first.
Do not condemn the power feed until ,you measure the pump current , normal is 4 AMPS. (if excessive the pump is bad, at 12vdc) I use a DC AMP clamp meter on the pink wire, to measure this.
The Fuel pump relay ( integrated with main in 89/98 [$98 at Suz] ) is separate relay on all 91 and newer Sidekicks/trackers.
This relay , Black-white power wire, must be HOT full time KEY ON, if not the fuse feed is bad or corroded.
This relay too, must output 12vdc on the pink wire, it if don't find out why.? (the main and fuel pump relay are same P/N can can be swapped)
The relay has 4 pins, the input is 12vdc key on, the output goes to 12vdc for 3 seconds at key on. , By the action of the ECU grounding one side of the Relay coil and the relay energizes.
The 89/90' Kicks you must crank the engine, to get PUMP POWER !
If the power is weak, there is resistance somewhere, so using a voltmeter find that point the voltage is good (12v) and that which it is bad, you now know the point between, are resistive.
If the output of the relay is 12vdc at key on then the relay is good (3second rule) move you meter probes down stream to find the bad power.
The pump resistance is about 3.0 ohms, so if you have body ground and power feed combined resistance of 3 ohms the pump will only have about 1/2 power.
That resistance will be caused by corrosion, damage , or melted wires , contacts or connectors. The feed resistance must be near zero ohms. Make it so.
Measure the voltage at the Fuel pump relay, all 4 pins (91-98) , if that is good (12v on all 3 pins and ECU pin is 0v) then go to the rear of car,
On 2 door cars the fuel pump connector C300 is behind the left rear tail light.
Measure this point too. It must be 12vdc at key on. or the feed is bad.
For those who know all this, go here to see the Schematic.
Do NOT HOT WIRE the fuel pump relay pins, if your jumper slips , you just blew the ECU fuel pump Driver transistor. It will blow out effortlessly and is a $100- $500 error. Do not do that.
Prerequisites:
Fuses are good, battery is CHARGED. 12.5vdc at battery terms. ( you need any voltmeter to work on cars)
Do not measure resistance with the Key ON.
First tests:
1: Ignition key is on. (no start)dash lamps light, CEL glowing? check engine lamp must glow , if not the main power is bad , or ECU dead)
2: Send a 2nd person to the gas tank cap , take the Gas cap off, put your ear to the filler neck hole and listen , next turn key to ON.
Ignore whoosh sound as cap is loosened, that is pressure.
3: The Pump will RUN for 3 seconds, and stop, ( YES ?, then ECU and fuel pump relay are working. The ECU controls the pump at ALL times)
3a: but 89/90 year, you must crank to get prime with pump, (some 1.8L Sports too) It is very hard to hear a pump while cranking. On this year, pressure tests are best done.
There are many ways to detect a dead pump.
a: No buzz
b: No / low pressure at the fuel filter ( its new right ? the filter) test port, or at the 16v fuel rail test port. YOU NEED A PRESSURE GAGE.
c: The Fuel Pressure REGULATOR on the fuel rail or TB , return line, (removed) you see no fuel returning to the tank via this line or nipple.
c1: One removes this hose and checks the nipple for fuel flow, do not Do this alone,ever , it takes 2 people. Key man , regulator man.
c2:
Just because fuel leaves the FP-regulator ,does not mean the pump is good, only that it is spinning, NOTHING MORE.
Only step b: has any hope of diagnosing a bad pump, weak pump or a bad regulator.
If there is no buzz, then that is a Serious problem.
The regulator can stick closed, (too high pressure, or stick open , too low pressure or can fail to regulate)
For the pump to work and work correctly it must have 12vdc as an input and it must produce the following pressures.
There are many fuel flow related tests:
Tests witih SOME VALUE are:
A DIY (mostly useless test) can just feel the FPREG return line for pressure. THE FINGER TEST. "you can actually feel the FPReg hose bulge a bit "
Again, the finger test is a crude method to find a dead pump and is in no way a pump and pressure validation test.
The crack open a fuel fitting leak test is not a good pump test. It only confirms pump is NOT 100% dead, nothing more....
The FP-reg is the fuel pressure Regulator on the throttle body 8v , or on the fuel rail of all 16v Kicks.
First check for the buzzz, then check the voltage at the pump feed wires at the Left rear tail light , then check the fuel pressure at the rail or fuel filter test port, and last check that the FP-reg is dropping the fuel Pressure when vacuum is applied to its diaphragm (with a hand pump or starting motor)
If you cant hear the pump , then the PUMP is dead, for sure.! If power is good end to end.
You are not sitting in the car , but, have your ear to tank filter neck. buzzzzzzzzzzzzzzzzz, ahhh, she has some power , it seems...
Some nicer pumps are very quiet, don't be fooled , listen carefully, at filler cap of tank.
Usually the car starts on test fuel and you are testing the pump for proper pressure.
USING A FUEL PRESSURE GAGE:
The miniumum test pressure is 34PSI on any 8V , key on 3 to 5 times to build pressure, or the same cranking/ running.
The 16V runs: (note the pressure drop , that is the FPreg vacuum port causing that)
- Static test: 1.6L KEYON-nostart ---Suz 35.6–42.7 psi (GM says 36-43 psi) Sport = 1.8L ----38.4–44.0 psi
- Residual pressure test: (aka; LEAK DOWN test) 1.6L Keyoff , min. 28.4 psi for one minute. (leak down spec) , (GM says 26 Psi)
- Running pressure: . 1.6L KeyON-start --- 29.8–37.0 psi (GM says 30-37 psi) Sport = 1.8L ---31.3–37.0 psi, <<<< THIS IS THE CRUCIAL TEST.
If these 3 tests pass,. we move on to other things. Dead injectors?
I do 1 more test the shunt test, I pinch the fuel return line for 1 second (no more) and look for pressure to hit 50PSI. if it don,t pump is bad, or power (DC voltage) is bad (too low)
You may be here because the fuel return line is removed and no gas comes out key on. (repeat 3 times to be sure , the key on , action)
You are here because the Fuel pressure is zero or very low. (at test port)
Find this relay: it is located below ECU and clipped to the ECU bracket.
FP Relay finder, all years to 2004.
Photo for FP relay and MAIN relay ( 89 is integrated relay)
The 2 relays shown (91 to 95) can be swapped, to diagnose a relay, problem.
Here is the linear flow for all fuel pumps
1: Pump dead per above, find the GREEN socketed relay, as the link above shows.
2: With a voltmeter ( or a crappy test light , I hate Test lights , because they lie)
3: Measure the fuel pump relays. wires. (meter on 20vdc range, black lead to shinny body metal , probe with red lead)
What wire? (left rear tail light is easy to find , remove and test)
Schematics are here. please look:
4: As you can see, it's Pink /black wire. 89-98' ( this wire drives the pump directly) IT MUST HAVE POWER FOR 3 seconds ! ( cranking on 89.90 and Sports)
5: Key on , meter red + to above wire and meter minus black lead ,to ground. (yes, find shinny metal ground on the body)
6: Key on, expect 12vdc. if it is zero full time, relay is bad. (or ecu) (ECU will energize this relay for only 3 seconds ,each and every key on)
If the voltage goes close to 12v for 3 seconds, then the ECU and FP relay are working correctly.
If 0 volts, then the is ECU is dead or the relay is bad ( or has no power ) Trace this power feed.
If 1v to 10 volts , then this means the fuel pump is shorted/overload/bad/jammed, or the wires to pump are corroded, or the battery is bad (test 1).
Normal pump current is 4.0 amps. , more is bad. (yes ,it can be measured at the LR tail light. Put meter in series with the pump ground wire or the pink wire to pump)
7: ok at this point our pump is dead and the Fuel pump relay is doing its job. (no?, then replace FP relay or ECU)
8. Now the hard part, how to test power at the tank. ( I look at the connector hidden behind the rear bumper for power )
It is true the connector near the tank (12") likes to fail. as does the wires fall off at the pump tank entrance or corrode OFF.
See some drawing and photos of this job.
a: See Tank photo under car here.
FIRST (2door only) Check the ground at G402 LR tail light , and see drawings above for secret location behind tail light, this fails like crazy on SIDEKICKS.
As does the corrosion of connectors with black and pink/black on the way to the pump (pump power) as seen below in the LR tail light housing.
Note with Wheel/Tire, removed one could see tubing and such. ( but cannot fix things, from here)
b: See pump harness views.
c: My testing the fuel Gage pages.
d: Tank blow up drawing.
You must find a way, to get at the wires near the tank.
3 ways exist. ( a real pain , huh?)
LR tail light.Main Connector. For sender and pump.
Pull rear bumper. (connectors hidden inside on cross member tubing) see Harness link above. 10 screws or so ...
Pull tank. (drain, by siphoning first)
Too bad there is no inspection plate above the PUMP in the body, so we could check the voltage there. 12vdc key on 3seconds and 14vdc running..
You then measure power right at the pump. (yes, very hard to do, the tank can be tilted down)
If the voltage is good (and pressure bad), the pump is bad ( good is 12vdc at pump for 3seconds each keyon)
If shunt test fails the pump is usually dead (if 12vdc is good), if shunt test passes, the FPregulator is bad)
If the voltage is bad, your harness or its connectors (many) are bad. (corroded, or the pump is shorted , or is overloading power feed)
There must be 12vdc to pump (key on for 3 seconds). or you have an electrical problem.
How ever pumps do short, as do wires and melted connectors. ( connect a series connected AMP meter, it will read 4 amps normal)
If the current is much over 5 Amp.'s I'd be suspicious.
So inspecting every inch of the harness , may be required to fix some cars. Sorry it's reality.
The pump if it shorts ,will overload the ECU main power feed.
This will cause relays to click over and over. (ECU my reboot over and over and all solenoids and relays connected, go click ,click , click...)
Remove your Shorts ( no pun).
Example bad Fuel pump feed:
I checked the fuel pump relay voltage and the pink wire is good. has 12 vdc key on , for 3seconds. ( cranking you must do on 89-98 and all Suz. Sport 1.8L)
I then go to the rear left tail light housing i see this large connector wrapped up, ah, I unwrap it and find the pink wire and the pump ground wire.
I measure the pump feed again, It reads 9v.
bad !
i then move my negative meter lead from the body metal test point (yes, the silly body is the ground return to the pump and battery) and run a long test lead to the battery minus terminal.
I then test the pump feed again. it now reads 12v, bingo bad ground.
I then check the pump ground lug (at tail light bulkhead in 2door, or hiding behind panel left side of cargo bay, 4door) it is good.
I finally look at the body jumper ground strap beside the battery, oops, all corroded.
I correct this and the fuel pump starts working with full 12vdc power and runs cooler to boot,
Amazing.....
Comments:
Don't forget you can test the pump by hot wiring it. (carefully, and never with gas fumes and never in side a garage.)
#1 dead pump failures:
Many bad pumps are just a bad ground or a bad connection as stated.
If no power can get to the pump, then no pump on earth can pump.
Check the power first. ( power and ground feed )
Common fails.
bad wires and connectors at the fuel pump.
shorted pump motor.
Wrong Gas cap Collapse below.
Below: a $6 legal OEM gas cap destroyed $500 parts. using a fleabay non Suzuki, non vacuum breaking cap, killed tank and rack and burned up pump running it dry.
DO NOT RUN, AFTER MARKET GAS CAPS. missing the vacuum breaker.
If pump starves, loosen the gas cap and drive home. let cap breath. (but if pump is damaged ,that be too late)
Pump Elect . connections must not be corroded, or damaged in any why. At the connector and at those 2 on pump top terminals.
The below is for a 2 Door car only. The ground on the 4door is behind the left rear seat belt , spool. (retractor)
The 2 Door LOVES to fail at G402 point. In the salt belt, x10 that statement. (goggle "salt belt"
Test 2 is at the second red arrow below , the under bumper connector can fail, at the drop of the hat, and last at the top of the tank seen in insert below.
THE TOP 2 door (only) pump failure REASON !: Many hundreds reported on the forum. Salt belt cars, guaranteed bad, why not just look, takes 1 min flat.
See Ground screw? G402 ? BLACK wires, This is the Pump ground, make it perfectly clean. (and is tank level sender ground ) 2 door only!
Make sure the cable on left, is not chaffing to body and grounding out pump power feed.! PINK WIRES ARE PUMP! HOT side from relay in the DASH.
I cleaned my G402, bright, and greased it with Dielectric Silicon grease, for elect. connectors. Are the Pink wire connector pins, clean?
See Connectors ? look for corrosion on contacts. PINK wires are the PUMP, and 1 black ground wire to the right.
No corrosion allowed here and for sure the G402 or the pink wires !, correct it now.
2door above. , HIGH FAILURE POINT, LEFT TAIL LIGHT housing, Pump power feeds. See pink wires, that is the PUMP power.
The 4door has the larger connector too, but the ground is not located in this crazy spot above.
4 door car the ground is located below. ( it don't fail, how could it?) It can't rust here. (rust, means metal OXIDE formations, of any kind)
very rare for this ground inside to fail but I show it, to be complete.
Schematic section:
16valves : click image to zoom it.
Page 1: (8v is similar but pin on ECU are different)
The 89/90 Kicks do not turn on the pump , unless you crank motor. Staring in 91 the key on event , power up the pump for 3 seconds. 12.6v is the correct voltage. (12v min)
code VIN 6 below is 16v.
The goal is to get 12vdc to the pump. (across the 2 pump wires, it does take 2 wires, and no inline resistance on both wires. or the pump will fail)
Page 2:
1989/90 Schematics.
PAGE 1
PAGE 2
Main PUMP & Control Relay details, with corrections in red.
Pump harness feed in left body.
note: the 89/90 has an integrated main relay and fuel pump.
note: Fuel pump has AND function COIL. (Must be KEY ON , "AND" ECU must permit pump action)
The 89/90 only runs the PUMP cranking or for 3second below 10deg F. (you must crank these 2 year car, to prime the pump if not cold outdoors)
Pump can be seen here. The ports. Is the tank collapsed? are hoses routed wrong? on that white plastic vapor bocking tank?
Jack up rear bumper 12" and get a better view. gets tire out of way or remove tire/wheel.
There is a connector here, that loves to rust and fail.
Below is: $19.99 at Harbor freight(tm) , hose to right fits all 89-98 Suzuki Trackers and Geo Chevy Trackers. It's so cheap , its a way go get just the great test hose.
On mine I put a gringo gauge here.
A top brand USA made gauge and kept, just the other bits. (some of these china gauges, the needle falls of in a week or two., so , consider that)
Better than Nuttn ? Why GUESS at pressure? Get this Harbor Freight gage.
Super Fast testing:
Given: low fuel pressure.
- Go to the left rear tail light , remove the 2 screws, and look inside the body cavity.
- Attach your volt meter to the pink wire and meter ground wire (black) to the body. (red meter to pink, black meter lead to body)
- Key on 3 to 5 times and see 12vdc here. for 3 second (91+) , crank the engine, on all prior years, to 91' and all Suzuki 1.8liter DOHC SPORTS.
if the voltage is less than 12vdc , the problm is uptream. (towards FP relay)
Running the voltage will be near 14vdc. full time , the power feed, does not cycle running.
The ground form the Battery to the body must be perfect , at the battery straps (more than one) and the pump ground wire at the body.
Noobs: (I never mentioned these, in any of my pages, because it's , BASICS) so I must now......
- The Suzuki ECU does not like low or too high fuel presssure, yes, it can compensate for small errors. but not 60 PSI and not 10 psi, at any time. The pressure is NOT ECU MONITORED.
- The Pressure must be like a rock running , Steady pressure at all times. (unless spark fails and ECU cuts all fueling... by command) It must never do this.
- The 8v TBI car starts at near 30 PSI & stays there, key on 3times, or running. (keep in mind the 89/90'
the pump only runs cranking and running and not key on (at normal air
temps) see FSM for exceptions. The pages are all linked here and on the
page before this page, hit the home button above to see said
pages.
- The 16v MPI car starts, a near 40 PSI and drops to 30 PSI running, (about) (vacuum caused)
- The 8v Fpreg is not connected to VACUUM. it is connected to the air horn, or better, at Filtered Atmosphere, it is an Altitude correcting device, unlike the 16v car.
- The 16v FPreg is connected to hard Plenum vacuum at all
times, that is because the Injectors are buried in the intake runners,
totally unlike the TBI car.
- The 8v injectors sits on top the TV plate and is at Atmospeheric presssures.(unless filter is clogged) Vastly different than the MPI car.
- The pump must have a full 12vdc to run right, (11v cranking) and 14vdc running , the higher voltage ,is the Alternator cominng ONLINE.
- The pump can fail in many a way as can the FPregulator , FPreg for short. the pump can go , dead , weak or draw too much current, and can over load the ECU.
- The ECU power buss, feeds the Pump, so in suzuki's infinint wisdom, the pump can in fact case the the ECU to crash, if the pump shorts and internal segement. (common)
- Yes, you can read pump current, using 3 ways, DMM in series , DMM with amp clamp or the much better DSO scope why. See here for the latter.
- A pump with a bad commentator segment shows a current drop,
on the scope, a segment with a shorted winding coil, will show a
current spike, in both cases the pump is weak and bad. !!!
Be that 8v or 16valves.!
What happens in sequence 1.6Liter EFI : (keys in pocket battery charged to 12.6vdc (normal ambients temperatures) 16v in red.
- Inserts key, turns key to ON (dash lamps come on, CEL lamp must come on? or no power to ECU) the pump (1991-and newer) primes to 30PSI (40PSI on 16v) in 89/90 you must crank.
- The prime only lasts 3 seconds, the pump gets 12vdc
then drops to zero volts after 3 seconds. The ECU does that via the FP
relay.
- You crank engine, and pressure holds at 30PSI (40) (pump voltage can drop to about 11vdc cranking this is normal)
- The
engine starts, but can die and lose pressure, if spark fails now,
lost spark (an ECU monitor) kills injections, after the engine starts,
the first moment started and full time running.
- The engine is running now the pressure is at a steady 30psi ( 8v and 16v) and does not drop, even at wide open throttle or on hills.
- The Pump now has 12v to 14.7vdc at all times running. if not the wiring is BAD. There are 2 wires , power(pink) and ground to the pump, and both can fail. There are many connectors.
- What matters is 12v to the pump, not the dash FP relay ,not the rear bumper connector but all the way to the pump. that includes ground to the pump. FP= fuel pump. see pump terms here.
- ANY resistance in this 2 wire path , will stall a pump or make it very weak. rust or corrosion happens.
Version 11 , new noob section, and new bad video links, 1 to the useless squirt test , and 1 video of a weak pump and classic overload. 4-15-2013