Starting Problem
#11
11-21-2012 | 08:43 AM
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Beginning Member
Joined: Nov 2009
Posts: 17
While changing spark plugs, there were some fuel on plugs (passenger side). A mechanic said that's indication of fuel regulator leak. So the regulator was changed. A pressure test was done again. Key on, the pressure is 59 psi, can I assume the gauge was off calibration a little and call it 60psi?(bury my head in the sand again here). The pressure can hold at 58-59psi for 10 minutes. So changing the regulator helped. However, still need 2-3 attempts to start.
I don't have the kit or knowledge to do the pressure test at the fuel filter. tried to google it but did not find enough information. The mechanic has been helping me did not think the fuel pump had an issue since the pressure is really close to 60psi, although it should be 60-66psi. Now we are suspecting ignition coil (or fuses??). What do you guys think? or is there any test can be done for that?
really appreciate your help thus far. Happy Thanksgiving!!!
I don't have the kit or knowledge to do the pressure test at the fuel filter. tried to google it but did not find enough information. The mechanic has been helping me did not think the fuel pump had an issue since the pressure is really close to 60psi, although it should be 60-66psi. Now we are suspecting ignition coil (or fuses??). What do you guys think? or is there any test can be done for that?
really appreciate your help thus far. Happy Thanksgiving!!!
For your 2002, here is another method: In the underhood fuse panel, connect a fused jumper wire from battery positive to the "fuel pump prime" terminal. This will bypass the fuel pump relay and activate the fuel pump continuously.
With the ignition in the OFF position, fuel pressure must be 60psi to 66psi. This is regulated fuel pressure.
Disconnect the jumper wire, and the fuel pressure will drop slightly, but it must remain above 55psi for at least 10 minutes. This tests the systems ability to hold fuel pressure. If it fails one or both parts of the test, it means a problem exists and that further diagnosis is necessary to determine what the problem is.
If you're showing 55psi, (key on, engine off) and dropping to 52psi, there's a problem. But without doing more testing, it's impossible to know what the problem is. Could be a weak fuel pump, poor electrical connection for the pump, faulty pressure regulator, leaky fuel injector etc etc.
Next step is to check the fuel pump maximum output pressure and the pumps ability to hold pressure. To do that you'll need to modify the pressure tester so it will connect directly to the fuel filter. All fuel flow & pressure must end at the tester. With the pump activated, pressure must be 73psi to 108psi. Deactivate the pump and pressure must remain above 55psi for at least 10 minutes. The results of these 2 tests will determine if the pump is good or bad.
Just an FYI: Fuel pressure readings taken while the engine is running, are meaningless.
With the ignition in the OFF position, fuel pressure must be 60psi to 66psi. This is regulated fuel pressure.
Disconnect the jumper wire, and the fuel pressure will drop slightly, but it must remain above 55psi for at least 10 minutes. This tests the systems ability to hold fuel pressure. If it fails one or both parts of the test, it means a problem exists and that further diagnosis is necessary to determine what the problem is.
If you're showing 55psi, (key on, engine off) and dropping to 52psi, there's a problem. But without doing more testing, it's impossible to know what the problem is. Could be a weak fuel pump, poor electrical connection for the pump, faulty pressure regulator, leaky fuel injector etc etc.
Next step is to check the fuel pump maximum output pressure and the pumps ability to hold pressure. To do that you'll need to modify the pressure tester so it will connect directly to the fuel filter. All fuel flow & pressure must end at the tester. With the pump activated, pressure must be 73psi to 108psi. Deactivate the pump and pressure must remain above 55psi for at least 10 minutes. The results of these 2 tests will determine if the pump is good or bad.
Just an FYI: Fuel pressure readings taken while the engine is running, are meaningless.
#12
11-21-2012 | 03:12 PM
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Joined: Mar 2009
Posts: 8,453
From: Belleville, Michigan
60psi is the lowest allowable pressure, no room for error there. Fuel volume will also be at the lowest allowable. This may be causing the 2-3 tries to start also.
Fuel on the plugs is NOT necessarily an indication of a faulty regulator. Low regulated pressure and or excessive leakdown determine if the regulator is faulty.
You can easily make an adapter that will allow you to connect the fuel pressure tester to the fuel filter outlet... cheap too!
Disconnect the fuel line from the fuel filter outlet.
If you have the quick connect style fitting, this fitting will connect to the filter: http://shop.advanceautoparts.com/web...line+connector
I you have a threaded fitting on the filter outlet, you'll need a fitting like this: Buy Dorman - OE Solutions Steel Fuel Line Repair Kit 3/8 Inch x 4 Inch with 16mm Fitting 800-170 at Advance Auto Parts
Attach a 3' piece of 3/8" fuel injection rated rubber line to the fitting.
Attach a fitting like this to the other end of the rubber line: Tuxedo Park Brewers
Use a couple of the good, not worm gear, clamps.
Then attach your fuel pressure tester to the 1/4" flare fitting.
Fuel on the plugs is NOT necessarily an indication of a faulty regulator. Low regulated pressure and or excessive leakdown determine if the regulator is faulty.
You can easily make an adapter that will allow you to connect the fuel pressure tester to the fuel filter outlet... cheap too!
Disconnect the fuel line from the fuel filter outlet.
If you have the quick connect style fitting, this fitting will connect to the filter: http://shop.advanceautoparts.com/web...line+connector
I you have a threaded fitting on the filter outlet, you'll need a fitting like this: Buy Dorman - OE Solutions Steel Fuel Line Repair Kit 3/8 Inch x 4 Inch with 16mm Fitting 800-170 at Advance Auto Parts
Attach a 3' piece of 3/8" fuel injection rated rubber line to the fitting.
Attach a fitting like this to the other end of the rubber line: Tuxedo Park Brewers
Use a couple of the good, not worm gear, clamps.
Then attach your fuel pressure tester to the 1/4" flare fitting.
Last edited by Captain Hook; 11-21-2012 at 03:17 PM.
#13
12-06-2012 | 04:32 PM
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Beginning Member
Joined: Nov 2009
Posts: 17
Thanks so much for your input Captain Hook. I did not get a chance to test the pressure at the fuel filter before my blazer stop starting for me. A mechanic changed the fuel pump for me and everything looks fine now. He charged me $100 for labor and I thought that was a good price.
#14
12-06-2012 | 04:33 PM
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Beginning Member
Joined: Nov 2009
Posts: 17
Forgot to mention the fuel pressure when key on was 64psi and can maintain 58psi with key off.
Btw: where can I find the fuel pressure test port CAP? I lost it after many test.
Btw: where can I find the fuel pressure test port CAP? I lost it after many test.
Thanks so much for your input Captain Hook. I did not get a chance to test the pressure at the fuel filter before my blazer stop starting for me. A mechanic changed the fuel pump for me and everything looks fine now. He charged me $100 for labor and I thought that was a good price.
#15
12-06-2012 | 07:57 PM
Moderator
Joined: Mar 2009
Posts: 8,453
From: Belleville, Michigan
Take a wander through a boneyard. Most, (1996 & newer) fuel injected GM's use the same cap. It's also the same cap that's used on 1994 and older, (R12 refrigerant) A/C systems for the low pressure side. A good hardware store may even have it: 1/4" female flare cap.
#16
03-12-2013 | 08:18 AM
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Beginning Member
Joined: Nov 2009
Posts: 17
Starting problem came back again!
It started about a week ago. still need 2-3 times cranking to have it started.
Engine light came on yesterday (haven't check the code yet). and I could not fill the gas tank now. The nozzle kept shutting down itself after a little filling. I googled some info. It looks like a venting issue.
Correction
DO THIS
Replace the EVAP vent solenoid with a more robust vent solenoid.
DON'T DO THIS
DO NOT Replace the EVAP canister or other EVAP parts.
what do you guys think? is the starting problem related to the refilling problem.
Thanks
It started about a week ago. still need 2-3 times cranking to have it started.
Engine light came on yesterday (haven't check the code yet). and I could not fill the gas tank now. The nozzle kept shutting down itself after a little filling. I googled some info. It looks like a venting issue.
Correction
DO THIS
Replace the EVAP vent solenoid with a more robust vent solenoid.
DON'T DO THIS
DO NOT Replace the EVAP canister or other EVAP parts.
what do you guys think? is the starting problem related to the refilling problem.
Thanks
#17
03-12-2013 | 02:26 PM
Moderator
Joined: Mar 2009
Posts: 8,453
From: Belleville, Michigan
The slow fill is probably being caused by the anti-siphon ball in the steel filler neck being stuck, or the rubber hose from the filler neck to the tank is kinked. If the rubber hose is ok, rap on the steel filler neck with a small hammer or mallet, right where it connects to the rubber hose. If that doesn't cure the problem, you'll need to remove the filler to see what the problem is.
On the extended crank time... Check fuel pressure and leakdown as described in post # 10.
On the extended crank time... Check fuel pressure and leakdown as described in post # 10.
#18
03-12-2013 | 02:49 PM
Banned
Joined: Dec 2012
Posts: 380
From: Alaska
60psi is the lowest allowable pressure, no room for error there. Fuel volume will also be at the lowest allowable. This may be causing the 2-3 tries to start also.
Fuel on the plugs is NOT necessarily an indication of a faulty regulator. Low regulated pressure and or excessive leakdown determine if the regulator is faulty.
You can easily make an adapter that will allow you to connect the fuel pressure tester to the fuel filter outlet... cheap too!
Disconnect the fuel line from the fuel filter outlet.
If you have the quick connect style fitting, this fitting will connect to the filter: http://shop.advanceautoparts.com/web...line+connector
I you have a threaded fitting on the filter outlet, you'll need a fitting like this: Buy Dorman - OE Solutions Steel Fuel Line Repair Kit 3/8 Inch x 4 Inch with 16mm Fitting 800-170 at Advance Auto Parts
Attach a 3' piece of 3/8" fuel injection rated rubber line to the fitting.
Attach a fitting like this to the other end of the rubber line: Tuxedo Park Brewers
Use a couple of the good, not worm gear, clamps.
Then attach your fuel pressure tester to the 1/4" flare fitting.
Fuel on the plugs is NOT necessarily an indication of a faulty regulator. Low regulated pressure and or excessive leakdown determine if the regulator is faulty.
You can easily make an adapter that will allow you to connect the fuel pressure tester to the fuel filter outlet... cheap too!
Disconnect the fuel line from the fuel filter outlet.
If you have the quick connect style fitting, this fitting will connect to the filter: http://shop.advanceautoparts.com/web...line+connector
I you have a threaded fitting on the filter outlet, you'll need a fitting like this: Buy Dorman - OE Solutions Steel Fuel Line Repair Kit 3/8 Inch x 4 Inch with 16mm Fitting 800-170 at Advance Auto Parts
Attach a 3' piece of 3/8" fuel injection rated rubber line to the fitting.
Attach a fitting like this to the other end of the rubber line: Tuxedo Park Brewers
Use a couple of the good, not worm gear, clamps.
Then attach your fuel pressure tester to the 1/4" flare fitting.
#19
03-12-2013 | 03:03 PM
Moderator
Joined: Mar 2009
Posts: 8,453
From: Belleville, Michigan
This is for testing maximum pump output pressure only. Looks like 2 of the links aren't working. The first one is a 3/8" quick connect fitting on one end and a 3/8" hose barb on the other. Dorman # 800-121. The last one is 1/4" male flare to 3/8" hose barb.
#20
03-12-2013 | 03:59 PM
Banned
Joined: Dec 2012
Posts: 380
From: Alaska
I need to brew me up one if these setups!