Crank No Start

1997 C1500 5.0L

Hard start problem has been getting gradually worse over the course of 6 months. Have to throw starter fluid and then she fires, especially when cold. After initial morning run, truck starts all day no problem.
About 2 months ago, crank but no start. Fuel problem right? So ran my starter fluid routine...NOTHING.
1. Fuel pressure a little on the low side of spec
2. Checked ignition with tester on one of the wires. Weak and intermittent, so checked coil wire... It disintegrated in my hands and.nothing on the tester. So Ran tester directly on coil ...SPARK! So bad coil wire right?
3. Spark tester on New coil wire..spark!
4. Spark tester again on a plug wire....spark!
5. Starter fluid direct into throttle body..NOTHING..not even a cough.

I've never had an internal combustion engine (car lawnmower chainsaw) NOT briefly fire as long as there's spark.
Even if there was no fuel, the motor should catch briefly.
If ANY part of ignition not working (cranksensor, IM, coil, dist cap, bad grnd) I would think there would be no spark.
If timing chain problem it would not be gradual. This truck ran smooth and powerful after the initial morning dose of starter fluid and would fire right up and run strong the rest of the day.

As long as mechanical timing and valves opening closing properly shouldn't the spark fire the starter fluid?

Or spark is too weak or completely out of time. Spark is not big fat and blue but is very noticeable.

Any ideas appreciated.

As you have probably learned from research, the CPFI fuel system is very sensitive to fuel pressure. The specification is for a minimum 61 PSIG. I've seen them start at 58 pounds, and on occasion run at 54 pounds (as a record low running pressure).

If there is reasonable spark at the end of the plug wires, the next thing to check is the spark plugs themselves. I've seen a LOT of plugs still running the engine with over 0.090" gaps, and the some with side electrodes nearly eroded away to the rim.

Agreed. Spark at the plug-end of the plug wire does not mean spark across the plug gap. Spark across the gap is what matters.

When I see a failed coil wire, I immediately suspect excessively-high ignition voltage due to failing plug wires, excessive plug gap, even excess rotor-to-distributor cap terminal gap. Failed coil wires are also associated with a worn-or-missing carbon button on the distributor cap, that touches the conductor in the rotor.

Fuel-fouled (or fouled for any other reason) can cause a no-start situation. "Worn" plugs may require more voltage than the system can produce; and/or cause misfire.

Be aware that the Vortec distributor has a known history of wearing-out the distributor gear, which does not change the ignition timing, but does change the alignment of the rotor tip-to-cap terminal, increasing the chances that the spark jumps to the wrong terminal. The plastic distributor also has a tendency to wear the bushings for the mainshaft.

As you know, low fuel pressure is another problem you need to address. How old is the fuel filter? How old is the pump? Is the pump getting proper voltage/current, or is the wire harness/relay in disrepair?

Agreed about marginal fuel pressure but since I'm on a roll with ignition I'll stick with that for now. That starter fluid should ignite like it's been doing until the no-start issue. I've also noticed having to top off coolant quite often with no major obvious external leaks although lower hose has been moist.

Hoping a head gasket is not gone. Truck has 177k miles

Will pull all plugs and check compression all the way around. Then check rotor and cap for for proper alignment and any carbon tracks. Will inspect plugs for bad signs. Then new plugs w/ proper gap, new wire set and if necessary clean and or replace distr cap.
Assuming engine mechanical good and distr sending spark to the right cylinder, I'm gonna get that starter fluid to light up if its the last thing I do this year. Then I worry about fuel issues.
Thanks for the tips. Will keep posted.

Before a head gasket, I would suspect an intake gasket, or even a cracked intake from backfire.

Fired up today.
New plugs and wire set.
Compression 165-195 psi with difference being within the 70% recommended by GM manual. All compression built up smoothly over 3-4 cranks. Rotor appears timed correctly at #1 wire when #1 at TDC so engine mechanical appears good.
Old plugs appeared ok. Dist cap mildly oxidized and cleaned with spring tab on rotor nudged up. Cap screws may have been a bit loose.
Fuel pressure still on low side so that's another issue.

Still can't figure why starter fluid I've been using for 6 months would not start the vehicle. Grab some old gasoline out of a chainsaw, poured that directly down the throat of the throttle body, and she fired right up for a few seconds. Then I reconnected fuel pump relay and she fired right up and ran nicely for several minutes while I put the tools away. My gut is telling me that something is intermittent along with the low fuel pressure issue, but at least I got some combustible fluid to light today and that was my whole goal. Going to button everything up and drive it for a few days and we'll see what happens.

If it hasn't been done already, check the power supply and ground for the fuel pump. The ground connection on a C/K truck is just ahead of the LR wheel opening under the box. The power supply includes the fuse and its socket, pump relay, and connections between that and the pump.

Thanks for tips on fuel. The hard starting over the months does sound like fuel issue.
I'm also gonna check the expiration date of that d*mn starter fluid. Maybe it goes bad in the can!?! Sheeesh!

Most starting fluids are based on ether and a propellant. Unless the can leaked, I can't imagine how the ether would evaporate.

These fuel pumps are very sensitive to voltage for producing sufficient pressure. A little resistance at a connection (including the ground) can make a substantial difference.

Suspicions confirmed, and more bad news. Ignition back up to Snuff and truck is running. More than likely that bad coil wire and the rotor spring tab seemed a little compressed . Still the hard start. Fuel pressure right at 40 which is way below recommended, so easy check will be ground circuitry to see if fuel pump starving for good ground path. If not, then it's pressure regulator or pump itself. (Fuel filter changed )

However, even more bad news. Remember that missing coolant I mentioned? Looks like oil is getting a little milky. I'll change the oil to flush out any coolant and then truck will be used on a minimal basis until I can figure out what I want to do.

Shouldn't be any coolant leaks into the cylinder because pressures are good. Possible coolant leaks from passageways into oil gallery? I don't know enough about this engine although I have read that there should not be any passageway between coolant and oil in the block itself .

Maybe an intake manifold leak as suggested earlier, like on the Buick 3.8 L intake manifold. Done several of those. Why did I think I was going to get off easy? Dang it.

Thanks for the tips. Will keep posted.

Fuel pressure right at 40 which is way below recommended, so easy check will be ground circuitry to see if fuel pump starving for good ground path. If not, then it's pressure regulator or pump itself. (Fuel filter changed )
Don't ignore the "positive" side of the fuel pump wiring. Poor connections or corrosion on the contact points can cause low voltage and poor amperage delivery to the pump.

Looks like oil is getting a little milky. I'll change the oil to flush out any coolant and then truck will be used on a minimal basis until I can figure out what I want to do.
Sure the oil isn't contaminated with condensation and/or fuel?

I would let the truck sit overnight, so the water has time to separate from the oil. Then pull the oil pan drain plug. If you see coolant come out, you'd know.


Shouldn't be any coolant leaks into the cylinder because pressures are good.
What "pressures"? Cooling system pressure? Cranking compression pressure? Something else?


Possible coolant leaks from passageways into oil gallery? I don't know enough about this engine although I have read that there should not be any passageway between coolant and oil in the block itself .

Maybe an intake manifold leak as suggested earlier
Intake gasket leak would be the most common...but a cracked head or block casting, or even a cracked intake manifold could leak coolant that would find it's way to the oil pan.

For fuel:
Will check fuel pump connections positive and ground visually. Then later move to some other tests.

For coolant issue:
Cylinder compression tests seemed normal.
Also going going to do a cooling system pressure test.

It's possible condensation but we're pretty dry here in the Southwest. This is not a daily driver . Only use the vehicle once every couple weeks so it's hard to gauge how often I'm refilling coolant but besides refilling coolant every so often with no visible leaks externally, there's Milky oil , and I'm smelling acrid odor around the vehicle and I'm seeing a little bit of white out the tailpipe. We'll also pull the drain plug and see if coolant is present.

Thanks for tips. Will post back.

Intake gaskets are suspect if coolant is mixing with oil. Those have been updated from the original design. If you've seen it in a Buick 231 V-6, you know the situation.

However, it seems that isn't the only issue, since coolant in the oil should have no effect on fuel pressure.

Will check fuel pump connections positive and ground visually.
Pointless. Connections can "look" good yet have high-resistance.

Verify voltage as close to the fuel pump as practical (typically at the rearmost connector before the harness goes "up and over" the fuel tank.) The fuel pump must be RUNNING, so do this with the engine running. GM uses undersized wire, so ~2 volts less than alternator voltage is probably acceptable.

Check for voltage on the ground wire as close to the fuel pump as practical. Again, the pump must be RUNNING. Same undersized wire, (but not as much of it) so ~1 volt is probably acceptable.

With two volts of loss on the positive side, and one volt of loss on the ground, the fuel pump will be running on ~11.x volts when the alternator is charging at 14.x volts. Sux, but that's GM's wiring harness. At 11 volts or less, you have wire harness problems.

... GM uses undersized wire...

Amen to that. I've seen that in other brands as well, probably since all of them are trying to trim weight and costs.

your truck is the 5L engine ....the engine is a 200K miles total damage.... the 5.7L engines of the trucks are 400K miles looks great ..

Hallelujah to Schurkey! Appears to be no coolant in the oil. Passed the "cook and crackle test" - cook a couple drops of oil from dipstick in cup of tin foil and listen for crackling. (This has to be done after engine has run to allow coolant and oil to mix). Then pulled drain plug after engine cool to allow potential coolant to settle to bottom of pan. None found.
1.Still have coolant disappearing though. Is there any way the coolant is being suck directly into the cylinders and burned?
2.There are two wet spots of coolant - one up by the intake manifold and one down near the lower radiator hose. The amount in those locations is not even puddled, it's just wet which to me doesn't explain the amount of coolant I have to keep replacing . That's why I asked coolant being burned. Radiator was replaced last year so no problem there. I will address the Leaky hose/ radiator joint. We'll have to think about a manifold gasket job. Done several of those on Buicks and although doable, it's not fun.

Electrical connections to fuel pump front and back appear mechanically and Visually to be good, but that's not always a guarantee proper voltage/amperage. Still gotta use starter fluid occasionally so there's that but at least I can use the truck now. Will keep posted

Intake gaskets can also leak into an intake runner(s) and not necessarily have a path to the crankcase (mix with oil). Any coolant leak into intake tract leak would be amplified when the engine is running due to the intake runners being in a vacuum. Coolant would burn/vaporize in the combustion cycle and be ejected with the exhaust. There would be no indication of dripping, pooling, or external loss.

You mentioned in post #6 that "Old plugs appeared ok" but did any of them appear cleaner than the rest? That could be an indication of the presence of coolant in that chamber.

The fact that you found no traces of coolant in the oil is a really good thing, since the chance of wiping out main and rod bearings is minimized.

One plug did appear half black half tan I thought was odd. I generally number everything as it comes off the engine as a reference but been pretty slammed lately so it's possible I missed it. Will check new plugs in a couple weeks. I'm thinking maybe a block test would help?

BlueBowtie must be clairvoyant. Started truck yesterday and spun 3-4 revs and stopped dead cold. Did it again for 3-4 more revs and stopped cold again. Where have I heard that sound before? Oh yea. When intake manifold gasket failed on LeSabre and engine hydrolocked! So...finally got motor running and thick clouds of white smoke filled driveway along with #6 misfire and 3-4 other DTC codes. (Forgot what they are right now). Pretty good indicator THAT'S where all my coolant has been going! Pretty sure motor is tired at 170k miles. I could have top end redone and fix the issue but then would put a lot of new stress on the bottom end and risk losing engine months later. I think I'm gonna confirm with my mechanic and look into a Jasper reman with 3yr/100k mile warranty. Considering what new pickup trucks are going for, and not wanting someone else's problems, I think thats a better option. Transmission is good and even if it went out a year from now that's about $2200 + $3500 for the new motor at least I know what I have.

It's tough to argue with that assessment. At 100K, it would be sensible to take care of the top end and expect another 100K out of it. At 170K, the return on investment (both cash and time) is less certain. A rebuild with all the upgrades to address known issues seems like a ticket to another 150K+ of reliable driving, whether the rest of the driveline wants to play along or not.

Then again, it's easy for me to spend your money.

It's tough to argue with that assessment. At 100K, it would be sensible to take care of the top end and expect another 100K out of it. At 170K, the return on investment (both cash and time) is less certain. A rebuild with all the upgrades to address known issues seems like a ticket to another 150K+ of reliable driving, whether the rest of the driveline wants to play along or not.

Then again, it's easy for me to spend your money.

Just for my education, what are we contemplating here? Sounds like a new intake manifold gasket is the fix so why are we talking about replacing the engine? Last time I did an intake manifold on a 350 vortec was less than 8 hours, I'd say that's worth it to keep the truck running for occasional use, but maybe I'm missing something...

the 5L engine is 200K miles then its done !

A '97 pickup in New Mexico is usually a little different compared to a '97 pickup on the DelMarVa peninsula. The one out west might actually have a body, frame, and some service life left in it. A '97 pickup here along the Wisco/Ill-noise border probably has seen 300K miles and been crushed for the metal to make six Toyotas by now.

It also seems that "could have the top end redone" means paying shop labor and parts to swap intake gaskets and potentially get it running for a while. Since it is possible that coolant has already gone where no coolant has gone before, there is the chance that bearings may have been washed. Add to that the 170K or timing chain stretch, ring wear, bore tapering, and oil pump gears spinning, a 305 can't be expected to be factory fresh at that point.

If it were mine, I'd probably reseal the top end and keep an eye on it. If Trio is paying to have the work done instead of DIY, I can understand the curiosity over the benefits of an engine swap with a guaranty for $3K or top end repair for probably most of $1K with no guaranty beyond the fact that the mechanic will deposit your check. A reman L31 (roller cam 350 Vortec) can still be had for under $1,800 minus the intake and oil pan, so the interest in the swap is understandable.

Mechanic confirmed fairly extensive coolant leak into the engine. Redoing intake manifold was an option, however I've decided to pull the trigger on a reman engine with warranty. Shop called and confirmed my suspicions about a weak fuel pump and a new Gremlin reared it's ugly head. Apparently the old distributor had enough slop in it where he had trouble with timing on the new engine. So we're doing a new distributor and a new fuel pump. It's going to run a little more than I thought but like I said, I'm in no mood to drop 15K on a used truck with who knows what going on. Over the past couple thousand miles I've got pretty much a new cooling system, (radiator, all hoses, wp, thermo) mostly new ignition, and now with a new fuel pump I should be okay for 3 -5 more years. I appreciate all the suggestions. Now I gotta get back to two LeSabres with high STFTrims. See you in the Buick forums.

I hope it works out for you. A fresh engine should give some peace of mind for quite a long while.

the 5l engine changed it ...... then the junkyard changed the engine .
how many miles of that junkyard engine .