Question about 1989 GMC Suburban

1 Answer

How do i test my fuel pump to find out if it is bad or not ?

Posted by Anonymous on

Ad

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 1,857 Answers

Spray quick start. If it starts then you know its fuel related. Then turn key on while someone listens to the pump thru the filler neck. It should run for about 2 seconds then shut off, If you hear it, and the car starts with quick start then the pump failed. If you do not hear it you will need to verify you have a 2 second 12v pulse on the green or grey wire at the connector. If you have the signal then the pump is bad. If no signal then you either popped a fuse, relay. or the PCM failed. Go to mitchell1diy for wiring diagrams and procedures. .

Posted on Jul 21, 2010

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

I have a 2002 gmc yukon will start then die out i can hear my fuel pump charging could my fuel pump be bad ?


Could my fuel pump be bad ????? Rather then guessing , i suggest you test fuel pressure to know for sure . Videos on youtube showing how . You will need to buy a fuel pressure testing tool . (55-62 psi) VIN: (V, T,U)

Feb 11, 2017 | 2002 GMC Yukon

2 Answers

What may cause low fuel pressure 00Linc ls v8


Could be pressure regulator, clogged filter, or pump going bad

Jan 11, 2016 | Cars & Trucks

1 Answer

Have a 1990 Chevy Silverado pickup 350 Put a new fuel pump fuel filter screen fuel pump relay Fuse electronic control module cap rotor new injectors. Injectors won't spray but they have power. Fuel pump...


Disconnect the wire connection to the fuel pump, turn it on and test for 12V (or whatever your car battery voltage is) at the leads coming from the battery. If 12V is present the problem is the fuel pump. Test the continuity of the pump circuit at the same time (no power on for this test). set VOM to resistance attach to both leads going to pump. If reads 0.00 continuity is OK. If no reading pump circuit is open, pump motor is bad. I have had them bad right out of the box. Good lesson to learn whenever possible, ALWAYS bench test new parts before installing.

Aug 10, 2014 | Cars & Trucks

1 Answer

2001 acura mdx wont start. cant hear fuel pump.


going backwards, ? (yes, i to check volts first) but...
you check fuel pressure cranking, (is press in spec or not?)
the FSM covers this, 1/.2 the cars only get pump activation,,
cranking and running, never just key on (the fsm shows this fact, i didnt look for you)
Yours is older loop system, not dead head.
there are 5 test just for the pump, (actually more)
pressure cranking and running, (leakdown test and injector balance tests and shut test for loop version) on V6 that 6 +4 ,10 total tests.
once the gauge is in place we do all 10s tests on v6.

ok say my pressure spec. is 40psi cranking and i get 10.?

spec: 32-40 running, pSI, vac, hose conn. (cranking will be more)
in loop systems the cranking pressure is about 10 PSI more.
after it starts, the vacuum sucks pressure from say 50psi to 40.
(its also altitude compensating)

Voltage checks, (any voltmeter)
use a voltmeter to see if full power reaches the pump.
i check voltage and its 8v. (bad) cranking volts can be near 11v due
to battery load, 200amps or so... what i do is measure battery crank
voltage and expect same to pump , using the 0.5v rule. (drop)
the connector over here to pump is all corroded. ,,
fix that and bam, now full presssure
or i find a bad fuel pump relay, replace that and bam.
or i find 0v, to pump.
i find relay bad. (simple tests on relay) (its not bad ECU)
ok i find 12v. at pump. so what is wrong?, i check my fuel pressure
regulator at the fuel rail, its stuck wide open because the shunt test
passed (one of 4 tests above) so new reg and bam, 40psi to rail.
i can test the reg with my hand vacuum tool that all shops have.
i can see pressure, running and cranking and check fuel pressure
with no vacuum (50psi?) then pump it to say 20 "hg (simulates idle)
and see 40 pSI, and check the diaphram for leak down.
my reg was bad.
there are other tests:
1: fuel pump current. (if excessive, its a bad pump)
2: scope test or use a current probe on pump and see it spiking
like made, , it has bad commutator and will die so.

there great videos on all this at. Duane's site.
http://www.youtube.com/results?search_query=fuel%20pump&sm=3

check the pump cranking

do not hot wire the fuel pump relay
if you slip 1/.8" you blow up a nice $400 ECU, (or more)
the ECU drives this relay (with a transistor, you dont want to explode)
if you feel compelled to hot wire things, disconnect the pump
and hot wire that.
now the relay.
it has 4 pins 12vdc in, 12vdc out to pump (contacts)
and 2 coil pins.
you put your meter to coil pins (across) i get 12v to coil cranking and running, that is the ECU working right
i get 12vdc in and zero out the contacts, the relay is bad.
lets say you see 3v out, that can be a shorted pump. or wire grounded out to pump. I check the current with my amp clamp and see 15amps
the pump is bad. most draw 4-6amps. normal.
i keep an open mind, what is bad, its only the pump 1/2 the time
or less. maybe 1/3? (reg, pump, wires and friends)
corroded connectors big time...some even burned up.





Feb 09, 2014 | 2001 Acura MDX

1 Answer

How do I put inline fuel pump in silverado 2500


What's the fuel pressure ? Hook up a fuel pressure gauge an test it yourself . fuel regulator ??? It's a fuel pressure regulator . I was starting rough and I had a diagnostic done. "They" said it was the fuel regulator.
Hard starting - not starting rough . What year is the truck , what engine does it have . If they don't know for sure what's wrong you better try another repair shop that know's how to diagnose .
Electrical problems can lead one to believe the fuel pump is bad . Doing voltage drop testing on the electrical circuit is a very good test.
Testing Electric Fuel Pump Problems with Voltage Drop Test
Plus doing current testing can pin point a bad fuel pump .
059 Engine Hard to Start or No Start Current Test for Fuel Pump

Sep 05, 2017 | Chevrolet Silverado 2500HD Cars & Trucks

1 Answer

Whole fuel system


The main fuel pump in a Volvo is really well built and rarely fails (Bosch simply makes great fuel pumps). A good survival trick if you think a main fuel pump might be bad... give it a quick tap with a wrench. For best results, if possible, tap the pump when cranking the engine (while power is going to the pump). If the pump is bad, often the tap will make it come to life and it may stay running until you shut it off. This trick can get you back on the road and get you home in an emergency. If it's a bad fuel pump relay, this will NOT work as there will be no power going to your pump. If this is the case, you might try the below relay bypass "jump" trick to get power going to the pump. TESTING YOUR FUEL PUMP
How to "JUMP" the fuel pump circuit at your Volvo 240 fuse panel:The fastest method to make the main fuel pump run (bypassing the Fuel Pump Relay) is by jumping two circuits at the fuse panel (left side driver's kick panel).

You can make a jumper from a wire with stripped ends or even a straightened paperclip. Jump the circuits on the right side of the fuses for best results
For a 1979-84 240, jump fuse circuit #5 to #7.
For a 1985-93 240, jump fuse circuit #4 to #6.


If the main fuel pump doesn't begin running when jumped (you should definitely hear it humming), you either have a faulty fuel pump or faulty wiring to the pump (bad wiring is really common under an old 240, near the pump). This test of course assumes your battery is good.
If one of the fuses blows during this test, the pump circuit wiring is shorting to ground somewhere between the fuse panel and the pump.

thx



Jan 18, 2012 | 1984 Volvo 240 Series

2 Answers

1995 dakota fuel pump relay. If the relay is bad,


If fuel pump relay is bad yes it will still get spark.
Sonds like you do have a fuel pump, or fuel pump relay problem, most likely the pump.

Oct 11, 2010 | 1995 Dodge Dakota

2 Answers

Car won't start and fuel pump wont shut off when I put my key in the ignition and turn the key


You may have a bad pump or fuel pressure regulator. You will need to pressure test the fuel system.

May 14, 2010 | 1993 Ford Mustang

1 Answer

1999 Grand Prix GT 3.8 won't start. Fuel Pump?


Testing fuel pump pressure an doing fuel pump electrical circuit testing should be done rather then guessing . Could have electrical problem that mite make one think it was a bad fuel pump . A couple simple test's to confirm , before replacing an finding out it didn't fix the problem .

Testing Electric Fuel Pump Problems with Voltage Drop Test
Plus the fuel pump is controlled by the PCM - engine computer via a fuel pump relay .
Fuel pump electrical circuit diagnosis no fuel pressure testing GM

Oct 29, 2017 | 1999 Pontiac Grand Prix

Not finding what you are looking for?
Cars & Trucks Logo

157 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts

yadayada
yadayada

Level 3 Expert

78936 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6927 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...