2000 Blazer No Spark

[83cutlass]

next step

1. Turn OFF the ignition.
2. Probe the ignition coil harness connector terminal C with a test lamp connected to B+.

Is the test lamp ON?
if yes, repair short to ground between coil and module.
If no, make sure you have 12 volts at the pink wire terminal A at coil, which I think you said you did. then check for poor connection/terminal tension. if ok then its the coil thats bad

[Oldsmobile Doctor]

Installed a hub on a 98 Bravada while I had it I swapped the crank sensor the Bravada ran fine but the Blazer now starts but dies right away can hear the fuel pump running for about a second after it dies swapped the sensors back and will still start but die I think it is possessed

[Chris Stewart]

So it runs while the starter is engaged?

[Oldsmobile Doctor]

It will continue to run after returning key to run position but just a secound or less. Ran out of daylight last night plan on hooking up fuel gage next.

[Oldsmobile Doctor]

Fuel pressure was about 60 than 50 than 55 than back to 60 jumping around. Unhooked gage from hose to pump a little into a gas can to check for water, wife said she just filled up. Than the pump stopped running, beat on the tank got it running but still not enough pressure to run. Pumping the tank now,Why do they always die when the tank is full?

[Oldsmobile Doctor]

Replaced the fuel pump and my 60 lb fuel gage pegs when I start it drops to 55 runs for about a second than dies. If I put some gas in the throttle body it will run longer. The security light goes out in about two seconds when I turn the key on

[Oldsmobile Doctor]

Did the Passlock auto learn procedure and it is running for now no clue about the spark

[New2000blazerowner]

Hey Oldsdoc? I'm on this same problem all ready waisted $$ on a ign coil and Crnk sensor. I have not went thru the fuel pressure check, (as I tried starting fluid right off) then realized no spark. Your last comment is confusing to me, how did you do the relearn when there was no security light to watch?
Also as far as fuel pressure goes, I have not found any clear info on whether or not low pressure would cause no spark, do you know the answer to that? Any help would be greatly appreciated, just spent 4k on this still have 30 day tags and it cut out a few times on my way home. Died pulling in driveway and no start since!!??

[Oldsmobile Doctor]

I replaced the computer which on a 2000 has to be flashed for the VIN number. After install the security system will let it start but kill it after about 2 seconds.Verify no spark by cranking with a sparp plug hooked to a grounded old plug. Let me know how that comes out.

[Tech II]

What did you spend $4K on?

The SECURITY system will not prevent spark.....it will prevent the injectors from firing.....

You have the coil on plug setup on a 4.2? Or a distributor on a 4.3?

Low fuel pressure will not cause no spark.....you need to see what the pressure actually is, when there is no spark....if no fuel pressure AND no spark, I would be concentrating on the crank signal......

If you have good fuel pressure, and you have replaced the coil(so I guess this is a 4.3), and there is no spark out of the coil, this has to be addressed first....checking the distributor cap/rotor comes later.....

This has an ignition module.........the question is, is that module controlling the coil....it can only do this if it is receiving a signal from the PCM...the PCM create the signal for the ignition module, only if it is receiving a signal from the crank sensor....I know you installed a new crank sensor, but the question is, is the PCM receiving it? This is where a scan tool is invaluable.....

So, if the crank sensor is ok, and the wiring between it and the PCM is ok, if the PCM is ok, and the wiring between the PCM and the ignition module is ok, then I would assume it's the ignition module.....

All coils work the same way......the primary coil is grounded by the ignition module...but that doesn't create the spark....what it does is create a slowly building magnetic field around the secondary winding.....when the grou nd is removed by the module, that magnetic field QUICKLY collapses, and high voltage is created in the secondary coil.....so either the ignition module is either not receiving a control signal from the PCM, or the module is bad....

[New2000blazerowner]

Okay I think I found what I was looking for, getting ready to go try this today. See I have followed all the test in the tree for troubleshooting ignition system.
My results kept leading me to no pulse signal coming directly from the CPS itself. Here is a link to another problem found for the no spark condition;
http://blazerforum.com/forum/engine-...o-start-68126/

It only makes since to me at this point that this has to be where my problem is. I know for sure I have no spark, and I have no signal at CPS but voltage to CPS and thru Cps ground test good. Oh and key point I am working with a new sensor after the first failed this test (and yes I know the new sensor could possibly be bad).

I will post results after I do what camaroman and 1 other person list as the fix. Oh and the vehicle is the LT model 4.3 and its what I paid $3.950 for has 105k actual miles and in great condition. (the LT model in case you don't know has all the bells and whistles including all leather int).

Also Doc if your still having an issue you might want to try this as well!

[Oldsmobile Doctor]

The post is 4 years old the Blazer and is long gone a guy posted on cregs list that he wanted a 4 door suv I called him and put him in it.

[New2000blazerowner]

Okay so far not getting any change, but I also didn't mention that when I start the test for the crank signal wire ign on and before I start manual turning of crank. I am starting off everytime (old sensor and new) with .5 -.6 volts and I can here clicking and buzzing (fuel pump/injectors) as soon as I touch ground??

Does that sound right, could I have a hot short somewhere on the signal wire to pcm?

And sorry about the age of this post guess I should have just posted a new one just thought you might have figured something more out. And congrats on the good riddens of your Blazer doc!

[Oldsmobile Doctor]

Just letting you know I won't be trying any thing. Also I can't look at my truck to see how things are laid out. I do have wiring diagrams though. I need to be sure that there is no spark so I don't tell you to check the wrong things. First thing is to check for 12 volt + at the coil's pink wire when the Ing is on. Depending on that I Can tell you other things to check.