1999 Chevrolet Blazer Logo
P
Peggy Bonneau Posted on May 05, 2014
Answered by a Fixya Expert

Trustworthy Expert Solutions

At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.

View Our Top Experts

I have no fuel pressure where do i start to find the problem

1 Answer

montehammons

Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

  • Chevrolet Master 5,531 Answers
  • Posted on May 05, 2014
montehammons
Chevrolet Master
Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

Joined: Sep 14, 2011
Answers
5531
Questions
2
Helped
1644752
Points
17401

Okay, hey, the fuel pump circuit. With key on, the pump should turn on for about two seconds to put pressure in the line and in the fuel rail on the engine, where the fuel injectors are. When the engine is cranking, the pump is turned on again by the vcm (Vehicle Control Module-the engine computer) signaling the fuel pump relay, just as it did with key on. After the engine is running, the pump is kept on, usually by the oil pressure switch.
No fuel pressure? Then the pump is not turning on, or the fuel filter is completely blocked-which is rare.


You can start at the Underhood Fuse Block. Here is found the fuel pump relay and the fuse for the pump. The fuse is designated ECM-B Fuse and it's 20 amp. If the fuse is good, put your finger on the fuel pump relay. Now have a helper turn the key to on, not start. If the circuit is good to this point, you should feel movement- a slight click. If you feel nothing, and the fuse is good, then the VCM is not sending a signal to the relay OR there is a wiring problem from one side of the relay to ground. If no click or movement under your finger-you will need professional help to diagnose further-checking of the signal from VCM and/or checking the ground wire for that side of the relay.
If you definitely feel a click at the pump relay, and the fuse is good, the power to the pump is sent out from there on a gray wire. Get under the vehicle at the rear and find the electrical connector for the gas tank, and pull it apart. Now you need a test light or voltmeter to check for power on the gray wire in the connector. You might miss the two second signal with key on, so have your helper hold the key in start. While the engine is cranking, the gray wire should have power-battery voltage. If it does not, big problem: possibly a broken wire or short from pump relay to there at the gas tank.

If the gray wire has power with engine cranking, you're almost home: Either the pump has definitely failed OR the ground for the fuel pump is bad. The ground wire is black and it shares the same ground point as your rear exterior lights, so if the lights work, the ground can be assumed to be good also for the fuel pump. And then you need a new fuel pump. But check the gas tank connector carefully for any sign of corrosion, loose terminals, anything like that amiss. Not likely, but check anyway-you don't want to put in a new pump and then find a loose connection! Good luck.

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1helpful
3answers

1995 isuzu pickup wont start sometimes

Fuel Pressure Regulator is located on the fuel rail.


1. Disconnect the negative battery cable.

2. Properly relieve the fuel system pressure.

3. Remove the air cleaner outlet tube(s).

4. Remove any necessary components to access the pressure regulator.

5. Disconnect the vacuum hose from the pressure regulator.

6. Remove the pressure regulator attaching screws.

7. Remove the pressure regulator from the fuel rail.

To Install

8. Discard the O-rings on the pressure regulator and replace them with new ones.

9. Lubricate the O-rings with clean engine oil.

10. Install the regulator into the fuel rail and tighten the retaining screws.

11. Connect the vacuum hose to the regulator.

12. Install any components removed to access the regulator.

13. Install the air cleaner outlet tube(s).

14. Connect the negative battery cable.

0helpful
1answer

98 dodge ram no fuel pressure with key on but will start with extending cranking

There is a check valve inside the fuel pump module that is suppose to keep fuel pressure in the fuel line's an fuel rail . Need a new fuel pump .
0helpful
1answer

Started ran for awhile then died an wont start

Start with the simple and replace your fuel filter, a dirty filter can cause your engine from starting. At worst, your fuel pump has failed and will need to be replaced. Before replacing the fuel pump, inspect all the fuses and wire leads from the fuel pump harness. Note: that the ground wire is separately grounded at the frame, so inspect that for any damage due to corrosion.

You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors. I think each injector is on a seperate driver on that one. Check for pulse to all of them.

You may be weak on fuel pressure, even a couple of lbs low on a cold start will cause a no start. Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems. One test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test, here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure. Later V6 and V8 gm engines should have 60-66 fuel pressure.
* Cold start should be 64-65 lbs of pressure. If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
* Engine running should be 60-66 lbs pressure depending on engine load.
* Full pressure with return pinched off should be 75-85 or more. and if it has a fast leak down after shut off you have a leak.

The 75-85 is only a check on the capable full pressure of fuel pump. If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.
0helpful
1answer

Will not start only backfires and start dieseling.5.7 automatic. hear fuel pump running. ran fine last trip and parked overnight. few times in past week or two. little trouble starting. rough idle for few...

You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.

You may be weak on fuel pressure . Even a couple of lbs low on a cold start will cause a no start. Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.one test is to give it a squirt of carb cleaner not starting fluid. If you get a intake or engine full of starting fluid it can blow things. Carb cleaner will start it if it is a fuel problem and lot safer. Also in the good old days when i was a kid, i used to get a couple of cans of starting fluid and get in the back and have a good starting fluid spraying contest. Good for a big blast if someone lights a match. If it starts then you have a fuel pressure problem. Run the full fuel pressure test and post back pressures.

Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel. Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.


The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.
What are the pressure readings that you have done.
What are your cold start pressure readings?



0helpful
1answer

Truck turning over but not catching

You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.

You may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start.
Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.
one test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.

The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.
What are the pressure readings that you have done.
What are your cold start pressure readings?
Post back what you have.

The other thing to is when was the last time the fuel filter was replaced? The fuel filter may have got to the end of it's like and may need to be replaced, the fuel filer should be replaced every 15,000 miles or once a year to ensure the fuel system is running 100%.

Good luck and keep me posted, be glad to help you get your blazer running again soon.
0helpful
2answers

1997 chevy blazer getting fuel and spark but not starting, only backfiring through carb.

You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.

You may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start.
Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.
one test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel. Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.


The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.
What are the pressure readings that you have when done.
What are your cold start pressure readings?
Post back what you have. Good luck

0helpful
1answer

99 Tahoe engine cranks, wont start

You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.

You may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start.
Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.
one test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.


The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.
What are the pressure readings that you have done.
What are your cold start pressure readings?
Post back what you have.


The other thing to that is common is the (ICM) under the distributor cap. There is a breather screen on the bottom of the distributor that get's clogged with dirt causing condensation promoting corrosion, this was gm TSB for replacing the cap and rotor to make sure it's clean.

Good luck and hope this helps. Merry Xmas.
0helpful
1answer

Car wont start. Has spark, tried Carb Cleaner.

You may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start.
Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.
one test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.

The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.
What are the pressure readings that you have done.
What are your cold start pressure readings?
Post back what you have. Good Luck

1helpful
2answers

On cold mornings, will not start and just "turn over" replace fuel pump and complete tune up ..still the same problem

You may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start.
Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.
one test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.

What are the pressure readings that you have done. Good luck and hope the fuel pump is not a bad one you put in there, it's know to happen.
Not finding what you are looking for?

171 views

Ask a Question

Usually answered in minutes!

Top Chevrolet Experts

ZJ Limited
ZJ Limited

Level 3 Expert

17989 Answers

john h

Level 3 Expert

29494 Answers

Thomas Perkins
Thomas Perkins

Level 3 Expert

15088 Answers

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

Answer questions

Manuals & User Guides

Loading...