Crank-No Start 99 Tahoe 4x4 5.7 - SOLVED

[no cigar]

I'm having an intermittent crank-no start on my truck. This seemed to develop over time when the truck would crank slowly almost as if the battery was dead. One evening the truck died for good and couldn't be jumped so in went a new battery. This did not solve the problem. A few days later the truck starts up just fine. It has been this way now for over a year (I have a truck I drive regularly) and I'm not sure what it could be. When it enters this phase, it will last a couple of days.

When I try to start, it will try to run but it will sound as though the engine siezed and the starter has disengaged. I have youtube videos of this below.

Could this be passlock? I have noticed there is a draw on the battery from time to time.

 

[no cigar]

Would also add that there is an odor of gasoline and also occasionally some smoke that will come from somewhere under the hood.

 

[strutaeng]

It's either the fuel pressure regulator leaking fuel into the engine (flooding the engine) and/or leaking injector (same effect but to affecting cylinder(s).

Hook up a fuel pressure gauge and report back:
A. Key on, engine off: pressure?
B. Same as above after 5, 15 minutes?
C. Engine running: pressure?

Note that flooding the engine with fuel can cause a hydrolock condition, which can result in catastrophic damage such as bent rods (engine is trying to compress a liquid, which is not compressible.)

I mention that because of your description of difficult cranking. May be related, or may be another issue altogether.

Proceed with caution...

Edit: did not watch the video, will try to later.

 

[exp500]

Another test to help point in a direction for Cure- Steady state fuel trims at a couple different speeds 35/45/55/65.
Another test is cycle key to run, off/ run,off/ for a few seconds on run. Then try to start. Post up your results of all your tests, and we will post up our combined knowledge of possibles,

 

[east302]

Could this be passlock? I have noticed there is a draw on the battery from time to time.

Passlock will usually let it start and run for a second before it kills the injectors. Your video doesn’t really fit that.

 

[exp500]

Any Fix Yet? Or any further testing?
I should have mentioned, any miss or no start the first thing to test is Distributor cap / Spark test.

 

[no cigar]

I tried again. Will have to get it towed home as it’s sitting on the street at my gf house.

Still same issues. Cranks, then tries to go only to stutter and buck real hard before the starter seems to lose engagement and spin freely (as in the first video). Does shudder roughly a few times as though it wants to run but just doesn’t.

 

[no cigar]

Also, I didn’t think fuel injected engines could flood.

The truck had a new style spider for about 5-6 years that worked fine. During a maintenance stay at a shop last year that unit was replaced. I assume a new fuel pressure regulator would have come with the new unit?

 

[strutaeng]

Also, I didn’t think fuel injected engines could flood.

The truck had a new style spider for about 5-6 years that worked fine. During a maintenance stay at a shop last year that unit was replaced. I assume a new fuel pressure regulator would have come with the new unit?

Unfortunately, they can flood. Not common, but does happen. I saw the first video and it may be that that "loss of starter engagement" IS loss of compression. Basically, the sound is different because when the starter is trying to compress that cylinder, it just free-wheels... Was the truck running good before?

Before trying to start it again, spin it over by hand with a long breaker bar. You know if one cylinder has lost compression. Then remove the spark plugs and see if any cylinder has fuel in it.

Fuel pressure regulator can leak, and you won't know because it's inside the plenum. You can remove the intake tube and shine with a flashlight as well. Have a helper prime the fuel system with key on run position.

 

[exp500]

Also, I didn’t think fuel injected engines could flood.

The truck had a new style spider for about 5-6 years that worked fine. During a maintenance stay at a shop last year that unit was replaced. I assume a new fuel pressure regulator would have come with the new unit?

Throttle floored will stop fuel flow on startup if needed. Do you have a scanner at all? Any Codes?

 

[j91z28d1]

yeah, check fuel pressure, run a gauge up under a wiper blade so you can see it. that sounds like slow to pump up fuel pressure and then when it does, you're in part off he crank routine that it's flooding.

try cycling the key a few times only to on, not crank to build some fuel pressure before your first crank attempt.

after that, cap, rotor, and if not done in a while plugs and wires, with good parts. caps have always had a bit of a short life for me. I would buy them 2 at a time and toss one in the back for a spare.

 

[no cigar]

@strutaeng

Hook up a fuel pressure gauge and report back:
A. Key on, engine off: pressure? 58/60psi
B. Same as above after 5, 15 minutes? 58/60psi
C. Engine running: pressure? Never got truck running but cranking psi still held around 58/60

 

[east302]

Pressures look good and it doesn’t look like you have a leak. Spark and compression would be next unless it has some codes stored.

Check for spark (and compare quality of each) on all eight, but shotgunning in a Delco distributor cap wouldn’t be a bad idea. I had a bad (new) off brand cap that misfired one plug. Unplugging the offending spark wire actually allowed it to start.

Someone mentioned it earlier, but holding the gas to the floor temporarily stops injector flow. If that works, check the output of the coolant temperature sensor (by the thermostat) with a scanner. If it’s flaking out, the computer may call for too much fuel.

 

[no cigar]

Hey guys, little update here. Still having the issue but the truck has been sent back to the mechanic.

Compression is all good. Around 150 psi on 6 cylinders with two others down around 130-135. All seems to be good there. Is getting good spark and also fuel as well. There is noticeable sputtering and backfiring when trying to start it so he is thinking timing. He's confirmed the engine is timed properly and all the marks are lining up. I believe he's going to replace distributor entirely and if no luck then - move on to timing chain.

 

[strutaeng]

Hey guys, little update here. Still having the issue but the truck has been sent back to the mechanic.

Compression is all good. Around 150 psi on 6 cylinders with two others down around 130-135. All seems to be good there. Is getting good spark and also fuel as well. There is noticeable sputtering and backfiring when trying to start it so he is thinking timing. He's confirmed the engine is timed properly and all the marks are lining up. I believe he's going to replace distributor entirely and if no luck then - move on to timing chain.

Distributor is a possible culprit.

I now see your fuel pressures: those look good.

Still not sure what to make of that odd sound while cranking though...and the compression numbers do look a little low on those 2 cylinders, but not low enough where it wouldn't fire.

Thanks for the update.

 

[exp500]

Here are a couple parts that have worked well for me in the fleet. -

More Information for UNITED MOTOR PRODUCTS DCR820X

More Information for UNITED MOTOR PRODUCTS 9362

When adjusting distributor timing, hold rpm around 1200 steady read scanner cam/crank correlation or whichever your scanner shows. Book calls out 0+- 2 degrees at over 1000 rpm.

 

[no cigar]

I'm happy to report that the issue was the dizzy. Truck has been running for about a month now.