95 blazer wont start

hi to all,its actually my doughters vehicle.she has a 95 blazer with the vortex v6 engine.the engine stop running about a week ago,checked for a spark had one,tried some starting fluid and almost started.the vehicle has 140,000 miles,so i changed the fuel pump and filter,checked the pressure and its within specs. still wont crank over.for some reason the its not getting fuel.i have a scan tool but will only read 96 and up.
thanks in advance for any help.

injectors could be clogged, when you turn the key does the pump prime?

What fuel pressure were you getting?

We need the actual numbers.

i believe it was 60 psi,and yes the pump primes for approx 2sec.
i was looking towards the fuel pressure regulator. i read something similar in another thread.

Pull the upper plenum and check for washing, but you have enough pressure. I would meter the wires (make sure that all wires are getting the same resistance). Check the ignition module and coil. Just because you saw spark, doesn't mean you have a strong enough one. Check cap and rotor as well. Though the pump priming for only 2 seconds does concern me.

When you did your pressure test, how long did it hold pressure before it started dropping?

let me refrase,the pump primes for several seconds,when i put some starting spray on the intake manifold it acts like it wants to start.other than that the engine turns over but doesnt even act like its going to start.imho it seems like its not getting any fuel.
ive had clogged injectors on other vehicles,when they were clogged the engine acted like it wanted to start.before this happened the vehicle did the same thing twice but started. i need to get a diagram for the fuel sysytem.

You have a single injector to 6 poppets batch fired. Pull the upper plenum and check for washing. If a poppet is stuck you can try clearing it with an airhose (dealer way) or simply replace the unit. But again your fuel pressure is fine and even with 5 poppets open you should be able to start because it's a batch fired system. I still would be looking towards spark. Like i said, your spark may not be strong enough

l im not familiar with(single injector to 6 poppets batch fired)
also you mention washing,sorry but am not familiar with those terms.can you be more specific.
thanks for all your help

You have a CPI unit. It is a single injector housing that has 6 lines coming out of it. Everytime the injector is pulsed, fuel flows from all 6 lines. This is called batch firing. 96+ use a similar setup but the hoses are fired in sequence (165432).

Your injector unit is located inside the upper plenum. Washing means that one side of the plenum is cleaner than the other because it has been washed with gasoline. This indicates a leaking CPI unit or a leaking NUT KIT (The inbound outbout fuel lines on the drivers side of the intake that connect to the CPI). Your poppets (the end of the injector hoses) are a simple check valve system. They open up at about 56 PSI. So when you said 60 psi, I determined you have enough pressure.

Also, how fast does the pressure drop when the fuel pump stops priming? (ie. when you turn the key off)

I should also note that if your fuel pump is priming and the cpi unit is ok, and you can confirm proper spark power (did you meter your wires and check for arcing at the coil) and your ignition module (attached to the coil) and cap and rotor is ok. It is most likely your fuel pulsator (located inside the tank)

i dont remember seen a pulse locator when i dropped the tank?
thanks for all the help :)

i dont remember seen a pulse locator when i dropped the tank?
thanks for all the help :)

If you want a quick check, remove the top vortec name plate on to of the engine, then remove the round black valve underneath it and take a flashlight and look down into the hole and look for the strong smell of gas and golden washed spots inside.

The washed spots are from the gas washing the black grime that is normally supposed to be in there.

i dont remember seen a pulse locator when i dropped the tank?
thanks for all the help :)

It's called a PULSATOR UNIT, not LOCATOR... It's part of the sending unit. It can be replaced. About 40 bux at the dealer.

^well he didnt LOCATE it :lol2:

i removed that round black valve looked inside,it has black grime,but there was no smell of gas from the inside.
tomorrow im borrowing a fuel pressure gauge from one of my friends who owns a shop to make sure that what im reading is correct.
thanks for all the help :smile:

i removed that round black valve looked inside,it has black grime,but there was no smell of gas from the inside.
tomorrow im borrowing a fuel pressure gauge from one of my friends who owns a shop to make sure that what im reading is correct.
thanks for all the help :smile:

Did you look down into the hole in the plenum and look for washed spots?

i found the problem,now how do i correct it?i used a different fuel pressure gauge and this time it read 20lbs psi?
ive re-readed approx five time get the same results.
ive replaced the fuel pump,filter,whats next?when i removed the old fuel filter it was completely clogged.thinking of taking the fuel tank out again to make sure i didnt miss anything.
thanks in advance for any help? :)

Pull the upper plenum, you will have to replace the CPI unit. It's hosed. (We know your fuel pump is good)

i dont understand,if the cpi unit is hosed,i take it its not holding pressure why doesnt the fuel leak out?it holds fine at 20lbs,is there a way that i can check it? also how much does the cpi unit cost(estimate)
thanks for all your help.

If you're only getting 20 pounds of pressure.... The CPI is leaking... It is leaking to the point of only holding 20 psi. The required pressure for the CPI is 56-60 at start, 61-66 at running. Again, this can be confirmed by pulling the plenum and looking for signs of washing. (It's either the CPI or a bad nut kit, most likely the CPI unit, either way the plenum needs to come off)

tomorrow ill pull the plenum,too tired right now.just so i understand when i open the plenum there should be fuel (leaked) in there,or signs of washing.
also whats a bad nut kit?
once again thanks for your help.

once again thanks for your help.
ok pulled the plenum no fuel leaks,no signs of washing.still no nothing over 20lbs of pressure.
i re-read this whole thread, went back to the auto part store with the box that the fuel pump came in spoke to the mgr.he checked it on their computer system and it was the wrong pump.he was very sorry that they sold me the wrong part.he coulnt understant how they gave me that fuel pump.i reinstalled it,checked the pressure, over 60 lbs.turned the key and started right up. :biggrin:

once again thanks for your help.
ok pulled the plenum no fuel leaks,no signs of washing.still no nothing over 20lbs of pressure.
i re-read this whole thread, went back to the auto part store with the box that the fuel pump came in spoke to the mgr.he checked it on their computer system and it was the wrong pump.he was very sorry that they sold me the wrong part.he coulnt understant how they gave me that fuel pump.i reinstalled it,checked the pressure, over 60 lbs.turned the key and started right up. :biggrin:

Hope you installed a new upper plenum gasket.