OK, I'm afraid I might catch hell from those of you more experienced than I, which is everyone. Please be patient with me, as I'm basically parroting information I received from about a dozen self proclaimed "mechanics".

Let me summarize the whole thing so maybe someone can say "hey, change your flux capacitor and have a nice day." before I bore them to death with irrelevant details.

Summary:
Won't start. Not even a sputter of gas igniting. Injectors aren't getting voltage and won't open. Fuel pump is new, pressure is good. New ECM installed. No bad fuses found.

Now, for the short long story (not to be confused with a ******* Story, Yuk!)

My fuel pump died, "no fuel pressure at rail" I was told.

Ordered NEW fuel pump. 3 pumps later, finally received "the correct one".

Had it installed, then had vehicle towed home from the shop that did it.

They said "around 50 PSI fuel pressure at rear of manifold exists".

Pump works, but still won't start. "Maybe some kind of computer problem".

It will start up and run when fuel is put into the top of the motor, but dies after it gets burned off.

Someone told me to change the fuel pump relay and pointed it out to me.
Later, when I went to pull out the little box that he had pointed to (behind the glovebox), on it I read "Flasher Relay" or something to that effect.
I don't know why I even included this in the story here, other than to show you what kind of f#cking idiots I have been getting advise from. Not all of them, but some. I can't stand it when someone speaks with authority and they obviously don't know squat. Someone else told me to hook up a bike tire pump to the fuel rail (presumably to the schrader valve) and then start pumping away in order to put "reverse pressure through the injectors" thereby "unsticking" them. I told this to my neighbor, and he didn't stop laughing for 3 minutes straight. He explained why this isn't plausible. He also explained how it might be a bad Cam Sensor. He hooked up his $5,000 computer reader thing, but it did not show us any codes. He took my digital multimeter and checked for voltage on the plug that has contacts for the injectors as I turned it over a few times. He indicated there was no voltage going to the injectors.

So we have a motor that will run when gas is force fed into it, good spark, etc. We have fuel pressure rising to around 50 PSI and holding for several hours after the pump is off (I beleive), indicating good pump, adequate fuel pressure, no back flow to tank.

There is no gas smell, so I don't believe it to be a leaky "Spider".

From what I've gathered, the Crankshaft Position Sensor will control spark, and the Camshaft Position Sensor will control the injectors. But not directly, these sensors both report to the ECM, which tells the injectors to fire and the plugs to spark. It also reports back any errors in the system through use of an OBDII scan tool.

Since it seems like a faulty Cam Sensor would be throwing a code to my neighbors ODBII reader (we were getting nothing), I decided to buy another ECM box. Thinking if this is what tells the injectors to fire (or sends pulses of voltage to it really), and would also tell us if there was a bad sensor, this MUST be the problem. $60 with a NO RETURNS policy confirmed that the ECM was NOT the problem.

1998 Chevy Blazer ECM for sale: $50!!!

Checked all the fuses in the box under the hood (driver side) and in the cab (also driver side). Found out why my ABS Brake light in the dash was aways coming on (since the day I bought it). There was a big black 50 amp fuse that was sitting in one of the slots w/o contacts. Right next to it, there was a slot where there should've been a 50 amp fuse, the legend indicated this was for the ABS. I sure would like to see the difference it has in braking ability now, but I have to make it run first!

So now I was going to try the Cam sensor, only I can't find it. Well, I don't think I can anyway. My knowledgeable neighbor had pointed to a sensor on the lower portion of the motor, passenger side. He seems like a pretty sharp guy. But when I was down there getting prepared to take it out, I started thinking "what the F is a Cam shaft?" I've heard the term "overhead Cams" before, so this makes me think the cams are over the head, on top. But then again, if the Cam was always on top (over the head), then there wouldn't be any reason to specify the "Overhead" portion when referring to some Cam shafts. I don't know, I just had a good feeling that this was my Crank Shaft Sensor (not Camshaft); and it looked like kind of a turd to get my wrench up in there. So I decided instead to come back inside and get on the internet to look at some asian ****, and then maybe post my questions to a forum that seems to have a higher % of smart answers than not.

That didn't work, so now I'm here.
JUST KIDDING!
This is the forum I spoke so highly of, and hence chose to post here.

I'm going to go finish some business at Su_Suk_Dong.com, and then I'll be back.

Thank you everyone, in advance.

Chris

 

your fuel pressure should be higher than 50psi.https://blazerforum.com/forum/tech-articles-diy-29/96-fuel-system-diagnosis-23038/

 

Great information! I want to clarify that he said "around 50 psi", so I don't know exactly what the psi was. Since it is a new pump, I'm guessing it was probably putting out good pressure.

But let me ask you this, what's the likelihood of fuel pressure not being correct from a new pump?

Would a few pounds under spec cause there to be absolutely no gas going through the injectors? Would it prohibit the injectors from even getting a signal to open up?

From your link:
"A lean condition may result from the fuel pressure being below 414 kPa (60 psi ). A lean condition may cause a DTC to set. Driveability conditions associated with lean conditions can include hard starting (when the engine is cold), hesitation, poor driveability, lack of power, surging, and misfiring."

Maybe I missed it, but what is a "DTC"?
Wait, let me guess, Diagnostic Trouble Code?
We get no codes at all, and no start at all.

Should I continue pursuing fuel pressure as a possible culprit here?
I don't have a fuel pressure gauge, so I'm trying to talk you out of that being the problem. :-)

 

i would check it, its very cheap to get a tester. i know the poppet valves off the spider have to have a certain PSI to work properly. im guessing since its not running thats why you have no codes. start with a test.

 

I don't know what exactly a fuel pressure regulator is (mechanically) or where it's located, but I wonder if it's an adjustable type of regulator? ie. can I find this thing and turn a set screw to make minor adjustments to the fuel pressure?



Can I take a bicycle pump and hook it to the fuel rail and start pumping away to achieve greater fuel pressure? and maybe increase horse power at the same time? and perhaps even give me a head full of thick, beautiful hair again?


I posted before I saw your latest reply.
I'll go track down a fuel pressure gauge.

I recall briefly reading about having to put a valve inline somewhere to perform some kind of test. I think maybe it was just referring to doing a back flow test.

Do I just need a simple gauge that hooks to the shraeder valve, and that's it?

Sorry, I guess I can go look all that **** up....
just looking for non-textbook advice.
aka. "... For Dummies."

can you give me a ride to auto-zone?

 

haha. love your attitude bro. i get down when i have car troubles. yep just screws to the test port, theres a pic of where its at on that link.

 

I still haven't managed to get my hands on a fuel pressure guage.

The person who installed the pump said that it was up around the range of 60-75 psi, and it held that pressure overnight, so there are no leaks.

Originally I thought he said it was up in the 50's psi, but he seems to think it's correct.

I was told by one person that the Cam sensor failing would cause the injectors not to work. Yet it would still start up momentarily when fuel was put into the intake, as it does. Then someone else said that if the Cam sensor was bad, it wouldn't even start that way either.

So, if I had a bad Cam sensor, would the vehicle start up at all, even when fuel is manually added into the injector intake?


One more thing to point out... When the vehicle originally died, someone had come to help me look at it to determine why it wasn't starting. He poured some gas into the intake and told me to roll it over. When I did, there was a pretty big bang, accompanied by a large cloud of smoke. I didn't really think anything of it, as it started to run for a few seconds immediately after it happened, so I kinda just forgot about it. But now that I'm becoming a highly trained mechanic (with many, many teachers) I'm starting wonder what that sudden burst of pressure could've done inside the injector intake manifold housing thingy area (ok I've still got some more work to do on my ase).

Would a backfire through the manifold intake mess with the injectors working?

I don't even know what they look like or what's all under the cover. So I'm just curious if there are fragile pieces in there or if they're pretty solid mechanisms.

It's been like a month now that I've been w/o my blazer. If I can't get this figured out soon, I might just cut a hole in the floorboard and do it like Fred Flintstone used to do back in the 60's.

:-) That was a cheap shot to anyone in their late 40's or 50's. Suppose I ought not do that, as this is where my most credible advice is likely to come from!

 

If you have a Vortec (which it sounds like you do) you have only one injector that voltage will go to if it's a CPI type injection system. If it's a true multi-port, forget what comes next. (I'm guessing that a 98 is like the earlier models) There should be a red and a blue wire together coming from inside your intake. Probably a Pink/Black wire hooks to the red one. The way this system pulses is that the Pink/Black wire is hot off of your ECM 1 fuse and supplies constant 12 volts to the injector. The blue wire is a ground and runs from the injector to your PCM (or ECM) which controls the grounding of the injector and thereby controlling the pulses internally in the PCM. So first you have to see if you have voltage to the injector red wire / pink/black wire at the connector for the wires. Should be somewhere above your left valve cover. If you do sometimes the connector gets worn and doesn't make good contact. (Ohsofly can tell you all about this one. He fought it for a couple of weeks.) If you have voltage there then try grounding the blue wire and you should hear the injector actuate. This is what happens through your PCM. We had one guy with a bad Pink/Black wire somewhere in the wire loom and he just ran a new wire off another fuse to make his work. Not my preferred way to fix things but it worked for him. The latest wiring diagram I have is for a 95. I hope this helps you to see how the system works. The PCM does control the pulses just not the way everyone thinks it does. It's actually the last in line. I repeat this is for a CPI type injection, not a true multi=port where every cylinder has an independently electrically controlled injector.

 

Thank you so much. This is the kind of stuff i've been wanting to see/hear. I was concerned that there wasn't anyone out there who actually knew the nitty gritty of these systems. Ok, now I'm ready to do some troubleshooting on this beast, with your help of course.

Before I digest your instructions, let me clear up the type of injector system I have.
It's a... well, I don't know.
But I took pictures!

I assume it's a multi port because of the pair of wires for each of the 6 injectors/cyllnders.
Yes it's a 4.3 vortec...

with Holley glasspacked carbs and overhead-dual-supercharger-cam-booster-valve-thingys.
(Just kidding, I'm trying to be like some of the mechanics I know. Talking about engines/cars that are nice or cool, but driving a Pinto.)

 

Yes, looking at your pictures you have a true multi-port fuel injection system. Man, I hate to burst your bubble but I don't have anything on multi-port injection. CPI, TBI or even carburetor I could hook you up. Do you have any kind of manual on your system? I would really hate quoting you something I couldn't back up with facts. (I see a lot of that if you know what I mean) At least you know what you've got now. I suggest getting some reference material and understand what you're working with and how it works. (I guess it's time for me to do the same) I just can't be of much help now although I will now get educated in a hurry. I'll drop in on your post to see how you're coming along. Sorry. I'm sure there's someone else on this big wide forum that can help. If so, don't be shy. Jump in and get you some.