95 Blazer wont start

OK.... Here's the story. I have a 95 Blazer with a Vortec w/160k miles on it. The thermostat went bad, and I overheated the motor, and the cyl heads warped slightly. I had the heads checked and .005 was needed to make them straight again. after re-installing everything, when I tried to fire it up, the fuel pump went bad.

SOO.... I finally replaced the fuel pump and sending unit (sending unit cracked upon removal) and the pump works. But when cranking the motor over it was acting like the battery was low....... Hooked up a charger...... no difference...... Bought a new battery...... same. Turned the lights off in my shop to check for spark (I have spark), and noticed the Ground strap from the motor to the battery sparking. It was loose. After tightening, It still cranks slow, and every once in a while acts like it may start, but never does.

Sorry for the lenghty post, but I wanted to give you guru's all the info up front. I'm really at my wits end with this truck and have a TON of money into this problem already. PLEASE HELP!!!!

Does the starter crank the engine at normal speed and it won't start? Or does it just crank slowly?

Does the starter crank the engine at normal speed and it won't start? Or does it just crank slowly?

it cranks slowly. once in a blue it will crank at normal speed for a few seconds.

Disable the ignition coil and see if it cranks at normal speed.

Disable the ignition coil and see if it cranks at normal speed.

OK, disable it by unplugging the coil from the harness? or unplugging the coil wire?

Safer to unplug the harness connector from the coil.

OK, disable it by unplugging the coil from the harness? or unplugging the coil wire?

OK..... I unplugged the coil, and it cranked at normal speed.... did I fry the coil or something?

Nope. It appears that you may have installed the distributor incorrectly. Do you have a shop manual that explains how to install it? The crankshaft must be at TDC compression stroke for number 1 cylinder. When the distrubutor is installed and fully seated, the rotor must point at the mark on the distributor that is stamped "6". Pictures are always a good thing, http://files.automotiveforums.com/gallery/showphoto.php?photo=51302


You can take the distributor cap off, bump the starter until the rotor lines up with the "6", then make sure the index mark on the crankshaft is on TDC. If it's not, the distributor is not in there correctly, and you'll have to start from scratch. If it is lined up, the distributor is probably off 180 degrees.

Don't forget to plug the coil back in ;)

go with the "Old Master" he's right

go with the "Old Master" he's right

In another post I was questioning where the "V" mark was. I later found it, lined it up with the mark on the crank after my finger was blown off the #1 spark plug hole. I installed the rotor pointing to the 6 on the distributor housing.

Is it still possible for the dist. to be out 180?

Thanks for your replies Old Master.

When you had your finger over the #1 hole and hit the starter, every other puff should feel stronger, that is the compression stroke. The weaker puff is the exhaust stroke. Gotta pay close attention to the puffs. Are you sure you have it right? What I've found that works for me, is disable the coil, hold a finger tightly over the spark plug hole and run the starter. As the engine is turning over, notice the strong puff for a couple of engine revolutions, then time it so you shut the starter off when the strong puff hits. Then rotate the crank by hand to TDC. Takes a little practice to get it right.

When you had your finger over the #1 hole and hit the starter, every other puff should feel stronger, that is the compression stroke. The weaker puff is the exhaust stroke. Gotta pay close attention to the puffs. Are you sure you have it right? What I've found that works for me, is disable the coil, hold a fingertightly over the spark plug hole and run the starter. As the engine is turning over, notice the strong puff for a couple of engine revolutions, then time it so you shut the starter off when the strong puff hits. Takes a little practice to get it right.

I could have the mistaken The exhaust stroke for the intake stroke. I'm working alone, and was turning the crank by hand. I'll go out right now and try it again.

Check the second paragraph of post #8.

Check the second paragraph of post #8.

Thanks. Is it possible to reverse the rotor 180 instead of taking the dist. out?

Nope.

OK- I just reset the distributor, and IT STARTED! But it's running very rough. The Service Engine light came on, which leads me to believe the dist. may be off one tooth. I don't have a scantool to pull the codes. Is there any other way? Any other reason why it would run rough?

You have the distributor very close, if not perfect. Check carefully that it's correct, if it's off even one tooth, the engine will not run properly. Check the routing of the plug wires, make sure the firing order is correct. Very common to transpose cyls 1 and 3 on the distributor cap. Check vacuum lines for correct routing and leaks. Check fuel pressure and leakdown rate. Make sure all of the basics are good, then if the SES light is still on, go after that.

I checked the spark plug routing, and vacuum hoses, and I let it run for a few minutes and the computer adjusted something to make it idle smoother, but when giving it gas it wants to die out.

There might have been a fouled plug or two from all of the cranking you've done. Running the engine may have cleared them. As for the stalling, check the fuel pressure and leakdown.

one good way to make sure your timing is good without a light. take the dis cap off manually rotate the crank to tdc the rotor should be at #1 spark wire then rotate it two full revolutions and see if the tdc is still at #1 wire.

you also might want to use a water spray bottle and spray down you vacuum lines if there is a leak,the engine will die down for a sec when the water hits the vac leak

There might have been a fouled plug or two from all of the cranking you've done. Running the engine may have cleared them. As for the stalling, check the fuel pressure and leakdown.

I have no way to check the fuel pressure. But the pump is brand new. What do I need to check it? How do I do it?

one good way to make sure your timing is good without a light. take the dis cap off manually rotate the crank to tdc the rotor should be at #1 spark wire then rotate it two full revolutions and see if the tdc is still at #1 wire.

Please explain how this checks ignition timing. If the rotor doesn't end up at the same spot each time on the compression stroke, there's a mechanical problem with the timing chain jumping teeth on the gears, or the distributor drive gear slipping on the shaft.

I have no way to check the fuel pressure. But the pump is brand new. What do I need to check it? How do I do it?

Check your AF inbox for instructions.

i said if your timing is good, this will work

Sorry I havn't posted in a while, but i've been short on time to work on the blazer.

Today I pulled the plenum, and the dist. cap. cranked the motor, and the compression hit just as the rotor was on the "6". I turned the motor over by hand on the compression stroke, and lined up the marks. The rotor pointed directly at the "6".

When I pulled the #1 plug, it was soaked with gas. After I put it all back together, after 2 attempts, it started. It ran very rough, and idled around 1100rpm. The "Service engine soon" is also back on. I tried putting the truck in gear, and it stalled, and would not start back up. ANY ideas?

ALSO- I TRIPLE checked the spark plug wire locations, and vacuum hoses. ALL sensors are plugged in.

Check fuel pressure and leakdown rate.

Check fuel pressure and leakdown rate.

I FINALLY got time to check the fuel pressure and leakdown rate.
with the key on, pressure is between 55-60
while cranking, the pressure was 62+

I can not get the truck to start anymore.

HELP!

I FINALLY got time to check the fuel pressure and leakdown rate.
with the key on, pressure is between 55-60
while cranking, the pressure was 62+

I can not get the truck to start anymore.

HELP!

BINGO! You've found your problem! Key on, engine off, pump running, fuel pressure needs to be MINIMUM 60psi. Must remain above 55psi for 3 to 5 minutes after the pump shuts off.

BINGO! You've found your problem! Key on, engine off, pump running, fuel pressure needs to be MINIMUM 60psi. Must remain above 55psi for 3 to 5 minutes after the pump shuts off.

The pump and sending unit are brand new. I just went to double check the fuel pressure... When the pump is RUNNING for the 2-3 seconds the pressure is exactly at 60 psi. when the pump stops running, the pressure drops to 55-57 psi. The pressure stays above 55 psi for over 20 minutes. Sorry I didn't make myself clear.

So, this being the case; is it safe to say fuel delivery is'nt the problem?

There is a problem with fuel delivery. Leakdown is ok, which means the there are no leaks in the plenum, the fuel pump check valve, or any of the lines from the pump to the outlet of the regulator. Next step is determine if the pump is weak or the fuel pressure regulator is set too low, (not adjustable). The fuel return line needs to be restricted to allow the pump to build pressure beyond what the regulator will normally allow. DO NOT allow fuel pressure to rise above 75psi or damage to the regulator can occur.

There is a problem with fuel delivery. Leakdown is ok, which means the there are no leaks in the plenum, the fuel pump check valve, or any of the lines from the pump to the outlet of the regulator. Next step is determine if the pump is weak or the fuel pressure regulator is set too low, (not adjustable). The fuel return line needs to be restricted to allow the pump to build pressure beyond what the regulator will normally allow. DO NOT allow fuel pressure to rise above 75psi or damage to the regulator can occur.

How and where do I install a 5/16” shut off valve in the fuel return line

Anywhere between where the return line leaves the fuel pressure regulator at the intake manifold, back to the fuel tank. Some vehicles have a section of rubber line, you can restrict the flow there with pliers etc, but it's not nearly as accurate as using a valve.