2000 chevy blazer

[jasom]

2000 chevy Blazer,4.3 114,000 miles. Put a new fuel pump in it about 8 months ago and a new fuel filter on about a month ago. Its hard to start when cold and from the posts I've read it seems to be a fuel pressure issue. Where is the fuel pressure regulator Located? Is it seperate from the fuel pump itself?

I can see I'm gonna have to buy a fuel pressure tester. Does it screw on to the gas line under the hood?

Any help would be appreciated,Thx.

[MT-2500]

Originally Posted by jasom

2000 chevy Blazer,4.3 114,000 miles. Put a new fuel pump in it about 8 months ago and a new fuel filter on about a month ago. Its hard to start when cold and from the posts I've read it seems to be a fuel pressure issue. Where is the fuel pressure regulator Located? Is it seperate from the fuel pump itself?

I can see I'm gonna have to buy a fuel pressure tester. Does it screw on to the gas line under the hood?

Any help would be appreciated,Thx.

Was that a junk Airtex pump? or a good AC-Delco/delphi pump?
The fuel pressure regulator is inside the upper intake under the big plastic cover.
The pressure test port is left rear of engine on the large fuel pressure line.

But before throwing parts at it test things out.

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold and fuel pressure testing guide line.
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.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding 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 in system.
Post back fuel pressure readings.

[jasom]

[quote=MT-2500]Was that a junk Airtex pump? or a good AC-Delco/delphi pump?

Honestly I dont remember what we put in. My brother works at a dealership and I needed it done as soon as possible so I had him order it and we just through it in.

Thanks for all the helpful info!!

[MT-2500]

[quote=jasom]

Originally Posted by MT-2500

Was that a junk Airtex pump? or a good AC-Delco/delphi pump?

Honestly I dont remember what we put in. My brother works at a dealership and I needed it done as soon as possible so I had him order it and we just through it in.

Thanks for all the helpful info!!

You are welcome.
A good fuel presure test will find the problem.

Not many Aitrex fuel pumps will pass the pressure test.
Good luck

[jasom]

[quote=MT-2500]

Originally Posted by jasom

You are welcome.
A good fuel presure test will find the problem.

Not many Aitrex fuel pumps will pass the pressure test.
Good luck

I'll try to get ahold of my brother and see if he can remember what brand he ordered. I just got off work and went out to start it up and it would'nt start. So I went and got some gas and dumped it in the throttle body and it started right up. I let it sit for a half hour and it started right up. It seems only to do it when it sits for several hours and today it wasn't even cold out. This blazer has went from starting good to starting like shit to not starting at all in 3 days. Hopefully I can get a fuel pressure gauge tuesday and do those tests.

I have another question though if it is the fuel pressure regulator is there a gasket on the bottom of the upper intake that will need to be replaced?

Thx again for your help!!!

[MT-2500]

You are welcome.
Run the pressure test and post back pressure readings before throwing a pressure regulator at it.

[jasom]

Originally Posted by MT-2500

You are welcome.
Run the pressure test and post back pressure readings before throwing a pressure regulator at it.

Ok did the pressure test today and at cold start psi was 60
running it was at 55psi
did leak down test and after 10 min it was still at 55psi
I didn't do full pressure test in fear of cracking that plastic looking return line.
Also I aked my brother about what type fuel pump we put in and he said it was either airtex or carter,but I'll bet it was the airtex.

I did go see a mechanic too and he thought the pressures looked good. He did mention I might want to look at the plugs and dist. cap.

[MT-2500]

Pressure is not good.
You need 65 on a cold start.
62 to 65 running.
Even 2-3 lbs low can put a hurt on it.

Also check the fuel pump direct pressure at fuel filter in line .
Should be 95 -105 full pressure.
You have to have good full pressure and also volumn for the fuel pressure to hold good running pressure.
And always test on the road and after running 45 minutes or more.
And check pump running voltage and grounds.

If you have to replace the pump always go AC-Delco/delphi fuel pump.
Good Luck

[jasom]

Originally Posted by MT-2500

Pressure is not good.
You need 65 on a cold start.
62 to 65 running.
Even 2-3 lbs low can put a hurt on it.

Also check the fuel pump direct pressure at fuel filter in line .
Should be 95 -105 full pressure.
You have to have good full pressure and also volumn for the fuel pressure to hold good running pressure.
And always test on the road and after running 45 minutes or more.
And check pump running voltage and grounds.

If you have to replace the pump always go AC-Delco/delphi fuel pump.
Good Luck

So I asume your thinking its possibly the fuel pump being weak. Whats a good way to clamp off the return line so I can check full pressure? Also Will the fuel pressure gauge hook up to the fuel line at the fuel filter?

[MT-2500]

Originally Posted by jasom

So I asume your thinking its possibly the fuel pump being weak. Whats a good way to clamp off the return line so I can check full pressure? Also Will the fuel pressure gauge hook up to the fuel line at the fuel filter?

You have to run the test to see if fuel pump or other.
You will need a adapter to fit the linegoing to fuel filter.
Most you can slip a rubber hose over line and then to fuel pressure gauge.
Good Luck

[jasom]

Well I was thinking to much I guess. Changed the spark plugs and the blazer pops right off. They were deffinately in need of changing. Hey thanks for all your help MT!!

[MT-2500]

Originally Posted by jasom

Well I was thinking to much I guess. Changed the spark plugs and the blazer pops right off. They were deffinately in need of changing. Hey thanks for all your help MT!!

You are welcome .
Thanks for posting back what you found.
Glad you found the main problem.
Good luck