95 blazer wont start

cupa · #1 03-20-2005, 11:25 AM

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.

dmbrisket 51 · #2 03-20-2005, 12:27 PM

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

BlazerLT · #3 03-20-2005, 05:12 PM

What fuel pressure were you getting?

We need the actual numbers.

cupa · #4 03-21-2005, 05:58 AM

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.

rlith · #5 03-21-2005, 07:05 AM

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?

cupa · #6 03-21-2005, 07:36 AM

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.

rlith · #7 03-21-2005, 07:39 AM

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

cupa · #8 03-21-2005, 08:01 AM

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

rlith · #9 03-21-2005, 08:07 AM

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)

cupa · #10 03-21-2005, 11:20 AM

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

BlazerLT · #11 03-21-2005, 02:19 PM

Quote:

Originally Posted by cupa

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.

rlith · #12 03-21-2005, 02:21 PM

Quote:

Originally Posted by cupa

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.

dmbrisket 51 · #13 03-21-2005, 02:34 PM

^well he didnt LOCATE it

cupa · #14 03-21-2005, 03:18 PM

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

BlazerLT · #15 03-21-2005, 05:33 PM

Quote:

Originally Posted by cupa

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

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

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