96 blazer problems!

we have a 96 blazer lt 4x4 4.3l highoutput

the truck is having problems with starting up...it sometimes starts..and sometime doesnt..

ive been told to replace my fuel filter..and i did that..still having problems...ive been told my fuelpump is bad....could that be?

my OBD port doesnt read anymore either...ive tried hooking up to a reader with no success..

the fuelpump will not come on for days..then suddenly it will...is the reLAY bad? where is the relay?:banghead:

Hmm, with my other car, I had a problem with the Scanner tool not reading/powering up, I found a blown fuse. Other than that, not sure....bad connection somewhere, bad computer, bad ground, ....

Does your cigarette lighter work, on the trucks the same fuse powers the cig lighter as the OBD port. I think the fuel pump relay is behind a panel in the glove box

Does the yellow check engine light come on key on at start up?

For the hard to start part try this.
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.

MT

Does your cigarette lighter work, on the trucks the same fuse powers the cig lighter as the OBD port. I think the fuel pump relay is behind a panel in the glove box

which relay is it..the L or R?

Does the yellow check engine light come on key on at start up?

For the hard to start part try this.
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.

MT

my check engine light has been on for daaaaaaaaaaaaays....

im pretty sure my fuelpressure is fine...but i will check

my check engine light has been on for daaaaaaaaaaaaays....

im pretty sure my fuelpressure is fine...but i will check

If the check engine light is on it has beeb trying to tell you something.:grinyes:
Check them codes and post back code no.

The ony way to know if the fuel pressure is good is to put a fuel pressure gauge on it.:grinyes: :lol:
MT

If the check engine light is on it has beeb trying to tell you something.:grinyes:
Check them codes and post back code no.

The ony way to know if the fuel pressure is good is to put a fuel pressure gauge on it.:grinyes: :lol:
MT

thats the problem..i cannot check the codes..my obd port wont read! its like the port is fried or something

http://www.troublecodes.net/OBD2/

See if it has 12 volt power on the plug.
MT

are there any online manuals for the 96 blazer?

Yes
It will cost you 24.95$ a year and take 10 minutes to get it.
But well worth it.
http://www.alldata.com/products/diy/index.html
MT

how do i test my fuelpump?????
we dont hear the "prime" when turning to the "ON" position

If the check engine light is on it has beeb trying to tell you something.:grinyes:
Check them codes and post back code no.

The ony way to know if the fuel pressure is good is to put a fuel pressure gauge on it.:grinyes: :lol:
MT



My check engine light never beeped when it came on.. 96 Blazer

thats the problem..i cannot check the codes..my obd port wont read! its like the port is fried or something



I had the same problem 3 months with my port I had a partial blown computer... I bet so do you... The computer isn't fully wasted so it still controls the engine.

I had the same problem 3 months with my port I had a partial blown computer... I bet so do you... The computer isn't fully wasted so it still controls the engine.

did you geta new computer?

we were told by chevy the computer was about to "go" about 6m ago...

My check engine light never beeped when it came on.. 96 Blazer

Well that was a typo errow. But if it had beeped at him maybe he would have checked it.:grinyes: :lol: :lol2: :jump3:
MT

did you geta new computer?

we were told by chevy the computer was about to "go" about 6m ago...


Ok now you have let the cat out of the bag.:grinyes:
Your computer has been for bad 6 mo. ago.:lol:
Your check engine light has been on forever.:lol2:
You wander why it is hard to start.:jump3:
You think the fuel pump is out.:rofl:
But you think the fuel pressure is ok.:smile:
What else have you not told us?:feedback:

Ok first thing is to test the fuel pump. Run the fuel pressure test like I posted to you.
Give us the fuel pressure readings.

the truck doesnt start ....... it hasnt for about 2 days now..

doesnt it have to run to do that test(fuel pressure)?

and when we turn the key to the "ON" position the fuelpump doesnt "hum" anymore

the check engine light has been going on and off since we bought it....but a OBD reader wont pull anything up

heres some info on the truck:

it used to be in mammoth, CA(snow/very very cold) all the time
the chick who owned it moved away to scotland or something
it sat for over a year at her parents house(they never moved it...started it ect) until we bought it....
now its being used for towing..and*was* being driven everyday
now it has 166k miles....

Yes part of the fuel pump/pressure test is key on engine off.
If fuel pump does not go threw the 30 second prime with key on the check for voltage at fuel pump relay prime connector in link below.
http://members.troublecodes.net/crunch/96b.pdf
The link is the fuel wiring diagram.
If the fuel pump will not run or start check the fuel pump prime connection for 12 volts. If no voltage connect a 12 volt fused jumper to it.
That will put power to fuel pump if it still doe not run or start check plugin to it for good ground and connection. If it is getting good 12 volts to it and good ground and still no run replace the fuel pump.
Post back results of your test.
MT

a little more specific...

where would the fuel pump prime connector be located? and where is the ground?

and what shoud i use to test for the volts?

You can go to this link and buy a cd for your truck, They are complete with every thing you'll need.
http://www.autorepairmanualcd.com/index.php
It only cost 25 dollars, and no shipping fees, it usally takes about a week or so to get, but well worth the wait. Don't waste your money on haynes or chiltons. This cd will have all the schematics you will need for your truck.
SC

Most of It is in the pdf I posted.
Open it enlarge it and print it out and read it.
A 12 volt test light will help you on checking voltage and grounds.
If you need more info get a good repair manual or a CD like posted or the On line ALL data sub and it will lead you right threw it.
http://www.alldata.com/products/diy/index.html

Another thought...It could be a bad ignition switch. I heard that's a common thing that goes bad.

i was asking where do i find these wires? like where under the hood?
is there anything i need to listen for when i do the test?

so if i have good ground and 12v the pumps bad?

if its the ignition switch..how do i diagnose that?:screwy: :banghead:

im not too car literate...lol and i dont have much money to spend on repairing the problem...

i was asking where do i find these wires? like where under the hood?
is there anything i need to listen for when i do the test?

so if i have good ground and 12v the pumps bad?

if its the ignition switch..how do i diagnose that?:screwy: :banghead:

im not too car literate...lol and i dont have much money to spend on repairing the problem...

Open the PDF I posted.
Enlarge it if needed and read it. Read the wire colors and the location of the stuff is right under like the relay or fuses or fuel pump ground is right there in the fine print.
Like they say if all eles fails read the directions. If it was a snake it would have done bite you.
Good luck MT

where is the relay box located

where is this fuel pump prime connector? i cant seem to find it

http://members.troublecodes.net/crunch/Fuel.pdf

Also recheck for good hot blue spark to all plugs.
If no spark. Fix no spark problem first. You have to have good ing.spark for the fuel pump to prime.
And do not forget to check EMC bat fuse 9 in the fuse box. It powers the fuel pump and relay.

if it comes to it anyone got a diagram on dropping the tank and replacing the fuel pump? or a DIY....

the truck wants to start..but wont..it fires and shuts off..thats a first in about 2 days

where is the ground for the fuelpump?

*checked..
theres 12v to the wire but no "hum"
the relay and fuse werent blown*

Open the fuel pump wiring pdf I posted for you and read. It is all righjt there.
If you have not got if figured out by now you need to get yourself some good repair info and a good mecchinical minded buddy to help you out.
It looks like it is getting over your head. I would suggest you need to call in some help on it.
Good luck MT