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Yet another truck 'no start, no spark' 98 GM 1 ton

blakes said:
are you 100% sure on that?

Immediately after replacing the ignition module, the tach DID indicate ~200 rpms for a couple of seconds on the first crank. Nothing since.
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We’re just fake internet people, you are the one who’s there so I’m not questioning what you saw.
Are you sure what you saw wasn’t the initial movement you see when you key on? That gauge movement might be a red herring. I’d trust what the live data says vs. the tach in the dash.
 
Not saying this is always the case. But I've replaced more pickup coils then ign modules or crank POS sensors from 1988-1997. Those TBI TBI/vortec if I'm remember correctly will not send fuel if pickup coil is bad. Yes the ign module if bad won't send fuel either but the pickup coil comes first. This is from memory but I had to do troubleshooting to find this out. When your starter spins the motor and dist spins...pick up coil sends it's signal to the ign module. If the coil is bad it gets no signal and then whatever the module is supposed to do regarding fuel pump doesn't happen.

I've swapped ign modules from running truck to truck in our fleet when a no spark no fuel comes up bc it's quick and easy elimination process. Almost every case I've ended up having to pull the dist and replace the coil.

There's also a fair difference in price between a module and pickup coil. So I wouldn't just throw parts at it.

Also not 100% sure but I believe it's been mentioned , if your oil pressure sensor is faulty or not connected you probably got a no spark / no fuel. Go back and check your work to see if something is missing.

Both pickup coils and oil pressure sensor could be bad too....that'd be a double whammy. But I'll say this with a fleet that has about 10 1988-1998 gm trucks left in it...i haven't had to replace a oil pressure sensor. Take that with a grain of salt.

Good luck....there's like over 10 threads about no start no fuel on this site too, search.
 
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blakes said:
are you 100% sure on that?

Immediately after replacing the ignition module, the tach DID indicate ~200 rpms for a couple of seconds on the first crank. Nothing since.
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Yes 100% sure my tach does not move until engine fires.
Take a plug out to physically see if you have spark.
Or take the coil lead and stick your finger in the end and have someone crank to see if you have spark.
Seriously, start by physically checking for spark at the plugs then work your way back.
 
Ringading said:
Yes 100% sure my tach does not move until engine fires.
Take a plug out to physically see if you have spark.
Or take the coil lead and stick your finger in the end and have someone crank to see if you have spark.
Seriously, start by physically checking for spark at the plugs then work your way back.
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I have spent much of the day on this.

I think you are right about the tach not moving until the engine fires.

Here is what I have done:

  • cleaned up and checked various wiring including grounds. I wanted to rule out any mouse damage as this sits in a my shop with a mouse problem. None found although there is a harness resting under the steering column on a tubular steel support and a couple of those wires may have rubbed through very slightly. Took care of that.
  • physically pulled the coil assembly/bracket that includes the ignition module. The coil ohmed out at 660 using my cheap tester with only one ohm setting. I thoroughly cleaned the two holes where I think the coil bracket makes ground to the intake plenum. These were dirty and not making good contact.
  • charged both batteries on my solar for several hours. They got to full float. This also means the PCM was without any power for several hours.
I reconnected everything and attempted to start. The tach didn't move, but the engine DID attempt to start and sputtered. The tach moved up while the engine was sputtering.

I sprayed 5 seconds worth of starting fluid directly into the top hole where the plastic vortec cover goes near the the throttle body. The engine sputtered and the tach moved.

So now I think I have a fuel problem even though the fuel pump does come on when I turn on the key and with HP tuner manual control. I changed the fuel filter last year. The truck did sit for a couple of years prior to me buying it. I suppose crud could have clogged the fuel filter or I got a bad fuel pressure regulator.... I need to find my fuel pressure tester and test fuel pressure...

Does anyone know if a vortec 454 will actually start on starting fluid? I've never seen an engine NOT start on starting fluid assuming all else checks out, but don't know about engines that have direct injection....
 
blakes said:
I have spent much of the day on this.

I think you are right about the tach not moving until the engine fires.

Here is what I have done:

  • cleaned up and checked various wiring including grounds. I wanted to rule out any mouse damage as this sits in a my shop with a mouse problem. None found although there is a harness resting under the steering column on a tubular steel support and a couple of those wires may have rubbed through very slightly. Took care of that.
  • physically pulled the coil assembly/bracket that includes the ignition module. The coil ohmed out at 660 using my cheap tester with only one ohm setting. I thoroughly cleaned the two holes where I think the coil bracket makes ground to the intake plenum. These were dirty and not making good contact.
  • charged both batteries on my solar for several hours. They got to full float. This also means the PCM was without any power for several hours.
I reconnected everything and attempted to start. The tach didn't move, but the engine DID attempt to start and sputtered. The tach moved up while the engine was sputtering.

I sprayed 5 seconds worth of starting fluid directly into the top hole where the plastic vortec cover goes near the the throttle body. The engine sputtered and the tach moved.

So now I think I have a fuel problem even though the fuel pump does come on when I turn on the key and with HP tuner manual control. I changed the fuel filter last year. The truck did sit for a couple of years prior to me buying it. I suppose crud could have clogged the fuel filter or I got a bad fuel pressure regulator.... I need to find my fuel pressure tester and test fuel pressure...

Does anyone know if a vortec 454 will actually start on starting fluid? I've never seen an engine NOT start on starting fluid assuming all else checks out, but don't know about engines that have direct injection....
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Cardboard creeper with tarp underneath if on snow/ground.

Disconnect line past fuel filter towards the engine, put a small bucket under it all. Some rags wrapped in there to soak up the spray.

Ignition on, should prime the pump and send fuel to injectors. If fuel is coming out of filter, reconnect. Test the fuel line at the motor. Go from there.
 
Air chuck at fuel test port for hack diagnostic pressure check. I think the fuel pump stops priming when pressure at the pump exceeds a certain limit. Working pressure after the FPR you replaced should be above 55psi.
1996-1998 Vortec is sequential port injection not batch fired. Crank position sensor will tell which injector to fire. You can back probe the injector connector to see if it is firing.
 
Needs 60psi. I had my 5.7 stop running because the pump would only hit 50psi.

Put a fuel pressure gauge on it.

Gtrplyr78 said:
Cardboard creeper with tarp underneath if on snow/ground.

Disconnect line past fuel filter towards the engine, put a small bucket under it all. Some rags wrapped in there to soak up the spray.

Ignition on, should prime the pump and send fuel to injectors. If fuel is coming out of filter, reconnect. Test the fuel line at the motor. Go from there.
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That doesn't say anything about pressure. It's not a carb, you actually have to put a gauge on it. :flipoff2:
 
Well guys, if there was ever a time to HGTD, this is probably it, but I won't. I will make some edits above to basically say that a 98 454 DOES NOT show RPM on the tach while cranking. It does show RPM the instant the engine fires.

Root cause: out of gas :eek:

To my defense, here a few facts:

  • The gas gauge does not work (my mechanic buddy who owned the truck for most of it's life could never figure out why not)
  • I live way up the mountain and ALWAYS fill up with gas when I bring it down. However, I've had issues with the filler neck on the flatbed and failed to fill it completely up last time I took it down the mountain. This coupled with the fact that it was running STUPID rich with a bad FPR and the fact that I did plow some snow on the mountain, it ran out and I simply didn't think about this.
  • It ran PERFECT up my pretty steep driveway right up until I parked it on a flat spot. It NEVER hit a lick after sitting.
  • I've been troubleshooting a no start, no spark issue on my rig and reading all these thread about GM ignition modules going out, bad wiring, coils, pickups, etc fogged my mind.
So in short, I should have validated the basics which are FUEL, spark, compression.

Flame away :beer:
 
Chevy_man said:
Needs 60psi. I had my 5.7 stop running because the pump would only hit 50psi.

Put a fuel pressure gauge on it.



That doesn't say anything about pressure. It's not a carb, you actually have to put a gauge on it. :flipoff2:
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Moot point now, I was merely after making sure there is flow of fuel from the tank, OP said filter might be clogged. Hence the suggestion I made.

Then again we might have all dodged a bullet, with his out of gas update - perhaps he would have lit a cigarette while under there:flipoff2:, you know to see better hahaha
 
Gtrplyr78 said:
Moot point now, I was merely after making sure there is flow of fuel from the tank, OP said filter might be clogged. Hence the suggestion I made.

Then again we might have all dodged a bullet, with his out of gas update - perhaps he would have lit a cigarette while under there:flipoff2:, you know to see better hahaha
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That's why I was pointing out that it's silly. Without pressure fuel doesn't do any good.

He could flow 20 gallons in a bucket and still have a bad pump.

Since the vortec has a nice Schrader valve right on top of the intake it's a 5 second task to get a fuel pressure reading.

It's way easier to check pressure first, than get covered in gas to learn nothing :flipoff2:


Especially since it may still have the factory poppet injectors that are fired by solenoids in the spider releasing fuel, and that fuel has to be high enough pressure to force the injector open.
 
I honestly didn't know about the scrader valve on the fuel rail.

What I don't understand is why it didn't start on starter fluid????
 
blakes said:
I honestly didn't know about the scrader valve on the fuel rail.

What I don't understand is why it didn't start on starter fluid????
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You didn't have enough to keep it running, probably for the best, as you can kill the O2 sensors with that stuff.
 
blakes said:
I honestly didn't know about the scrader valve on the fuel rail.

What I don't understand is why it didn't start on starter fluid????
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Because the starting fluid you buy these days sucks ass. If you don't believe me, spray a puddle of it in the ground and look ight it on fire, and see how lazily it burns.
 
Just to clarify the fuel pump relay/oil pressure sensor stuff for someone else reading through this with similar issues.

The fuel pump relay is turned on (by the computer) for about two seconds when you turn your key on. This is done to prime the system. It doesn't run until it hits a certain pressure or anything, its just on for two seconds then off, thats it. Once you start the engine, the oil pressure switch (three wires, one is for the oil pressure gauge, one is power in, one is power out) closes when it sees oil pressure. This is where your fuel pump gets its power to run while the engine is running. A bad oil pressure switch cannot cause a no spark situation, nor will it cause a no fuel pressure before you start it situation.
 
Johnny Longrifle said:
Because the starting fluid you buy these days sucks ass. If you don't believe me, spray a puddle of it in the ground and look ight it on fire, and see how lazily it burns.
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I don't doubt you.

But the same exact can of starting fluid will get my old 555c backhoe (with no glow plugs) started pretty good. Obviously different as that is an old diesel.

And like I said, I sprayed it for like 5 seconds.

I realize I made a silly mistake by not checking fuel pressure on the 454, but man, I would think the starting fluid would at least get it to pop.

With regards to the tach not spinning until after the engine fired. My 2000 taco does the same thing. Tach doesn't move until the engine fires. I could have sworn it did. On the same note, my rig with AMC 360 and GM HEI 100% for sure DOES show RPM while the engine is cranking prior to firing.
 
Johnny Longrifle said:
Because the starting fluid you buy these days sucks ass. If you don't believe me, spray a puddle of it in the ground and look ight it on fire, and see how lazily it burns.
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Get a can of the John Deere stuff from the dealer. Spendy, but much higher ratio of ether. Works way better.
 
BustedCrank said:
Just to clarify the fuel pump relay/oil pressure sensor stuff for someone else reading through this with similar issues.

The fuel pump relay is turned on (by the computer) for about two seconds when you turn your key on. This is done to prime the system. It doesn't run until it hits a certain pressure or anything, its just on for two seconds then off, thats it. Once you start the engine, the oil pressure switch (three wires, one is for the oil pressure gauge, one is power in, one is power out) closes when it sees oil pressure. This is where your fuel pump gets its power to run while the engine is running. A bad oil pressure switch cannot cause a no spark situation, nor will it cause a no fuel pressure before you start it situation.
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Yep. Went thru all of that, 96 Tahoe 5.7 Vortec. After replacing a known bad starter (broken nose cone). And a suspected, proven true, bad fuel pump. Some good vids on uTuber for this.
 
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