Wierd No Start

Hey all. For those who helped with my sterio question, thanx for the help.

New problem. This time, a 2002 blazer 2wd (although that may not matter). Simply put, the engine will not start. I spent a good 5 hours on it and I have know it has a good spark, it gets air, and it gets fuel. No fuses are bad and all relays are working. I have harrowed it down to one of two things and am asking for a second opinion hoping for the better of the two.

First off, this vehicle has a half tank of gas, so if that is the case it wont be as bad as a full tank. So saying, i'm thinking it has a bad tank of gas. I personally know how bad these trucks can run, if at all, with bad gas. So if this is the case. is there a easier way to get the gas out of the tank by other means than removing the tank to drain it that way, as per hanes manual.

My second thought is, possibly timing chain related. Maybe skipped a tooth or broke all togeather. If this is the case my friends engine is mostlikely F'd. by wich case i probably have a good doner car for spares and upgrade parts. I think this because as u turn the engine over, you can hear it and see it back fire though the throttle body

Any extra thoughts would be very nice to hear. I'm betting and really hoping that its the fuel problem.

I would run a little of the fuel out into a glass jar and see what it looks like. It's easy to tell if it's bad or not. If you haven't already done so, I would check for proper fuel pressure at the shrader valve (61 psi).

There are a couple ways to empty the tank of fuel.

1) There’s a fuel pump test wire under the hood on the driver’s side next to the fender, under the hood hinge. It’s a red wire that has a gray or black plastic cover on the end of it and it just hangs there next to the electrical junction box, not hooked to anything. Put a live 12 volt jumper wire to it and the fuel pump will run if it's not toast. If the pump runs then disconnect the fuel line at the fuel filter, (which is located on the inside of the frame under the driver’s door) put a hose onto the gas line coming from the tank and into a container. Then connect the battery cable, run the fuel pump to empty the tank and then disconnect the battery cable again. Or, you can connect an auxiliary gas pump to the gas line and pump the gas out of the tank.

2) Or, loosen the nut on the rear gas tank strap to lower the rear of the tank just enough to disengage the rubber hose on the filler neck at the rear of the gas tank, then put a small hose into the tank and either use an auxiliary gas pump to pump the gas out of the tank or you can use a siphon. (Whatever you use, it must be designed to pump gas – otherwise you might have a big, big fire) Fire is a great danger when removing a gas tank. I’ve seen repair shops burn down when gas is spilled and a shop light falls into it.

Are the #1 and #3 plug wires reversed cause the drivers side on cap is 3-1-5 order while other is 2-4-6. Is the dist cap/rotor new Delcos - had a bad rotor, another a bad cap, another a very weak coil. Having a spark does not ensure its firing the correct cyl at the correct time or with a good hot spark. Then the crank sensor tells the PCM relationship of when to fire the correct plug. Has the dist been taken out of the engine then I would guess you are off a tooth or more so may have to verufy that.

When is the last time the distributor cap, rotor and wires were replaced? (time/miles)

It sounds to me being it's backfiring while tuning over it's probably timing related. I bet you have a brokin timing chain. To check this do a compresson test on all cylinders. If some cylinders don't have any compression it's your timing chain.

After messing with that truck for a couple of hours, I finally got fed up with it and said F it. I then replaced the fuel in it by way of removing the fuel filter and then turning on the key to let the fuel pump do the work for me to drain the tank. Put some new gas in it, and cleaned the distributor cap and rotor, then tried starting it. Much to my suprize, if fired right up as if nothing was ever wrong to begin with. Now its on its way to an airport some 3 hours away. Thanx for all the help and suggestions anyway.

i'd say timing chain...if it back fires like that....good luck....

Hey all. For those who helped with my sterio question, thanx for the help.

New problem. This time, a 2002 blazer 2wd (although that may not matter). Simply put, the engine will not start. I spent a good 5 hours on it and I have know it has a good spark, it gets air, and it gets fuel. No fuses are bad and all relays are working. I have harrowed it down to one of two things and am asking for a second opinion hoping for the better of the two.

First off, this vehicle has a half tank of gas, so if that is the case it wont be as bad as a full tank. So saying, i'm thinking it has a bad tank of gas. I personally know how bad these trucks can run, if at all, with bad gas. So if this is the case. is there a easier way to get the gas out of the tank by other means than removing the tank to drain it that way, as per hanes manual.

My second thought is, possibly timing chain related. Maybe skipped a tooth or broke all togeather. If this is the case my friends engine is mostlikely F'd. by wich case i probably have a good doner car for spares and upgrade parts. I think this because as u turn the engine over, you can hear it and see it back fire though the throttle body

Any extra thoughts would be very nice to hear. I'm betting and really hoping that its the fuel problem.


Check that fuel pressure.
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.