Swamp Hound's 1997 Yukon Z71 Build

[SwampHound]

Ok. Hopefully you can rule out the bottom end.

It's due for an oil change, will drain and change it tomorrow. Check for shavings and what not.

 

[Sampuppy1]

Spun bearings are never good. I hope it all turns out well. If you want you can text me tomorrow and we can try to troubleshoot it.

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[SwampHound]

Spun bearings are never good. I hope it all turns out well. If you want you can text me tomorrow and we can try to troubleshoot it.

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Appreciate it. I might do that.
The part that is confusing me is the non-start issue. You'll turn the key, the dash lights dim under load, and you hear a very short "lunk" like its about to turn over and then nothing. It's the very same issue I had last winter due to a bad battery and cold weather. If it wasn't for that I would have already swapped in a new alternator, but since (to my knowledge) the alternator plays no part in starting the vehicle, it must be a separate issue, or a small part of the overall problem. I will keep looking tomorrow. Also get a video of the non start for point of reference.

 

[TrailBlazerZ71]

Appreciate it. I might do that.
The part that is confusing me is the non-start issue. You'll turn the key, the dash lights dim under load, and you hear a very short "lunk" like its about to turn over and then nothing. It's the very same issue I had last winter due to a bad battery and cold weather. If it wasn't for that I would have already swapped in a new alternator, but since (to my knowledge) the alternator plays no part in starting the vehicle, it must be a separate issue, or a small part of the overall problem. I will keep looking tomorrow. Also get a video of the non start for point of reference.

Could be the alternator. If the alternator isn't working properly, then the vehicle is running off of the battery, and at the same time, the battery is not getting recharged. I would recharge the battery, and have the alternator tested.

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[thz71]

Could be the alternator. If the alternator isn't working properly, then the vehicle is running off of the battery, and at the same time, the battery is not getting recharged. I would recharge the battery, and have the alternator tested.

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But an alt won't cause a no start if the battery is charged.

 

[slowburb]

It would be a good idea to get a reading off the battery during cranking.

 

[SwampHound]

Thanks the the continued input guys. I appreciate it.

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Here's a video of the non start. Truck all most, but doesn't quite fire up on the first try. Then it's nothing afterwards.

 

[Nathaniel2g]

Have you checked your grounds on your starter? I didnt read up, but on my mobile it doesn't even sound like the starter is trying to crank.

 

[Fuzzy]

So have you had the alternator tested yet? I would, at the very least pull the belt and see if you feel any resistance or bumps when you spin the alt around.

E: Here's a TSB that might give you some insight, sounds like it's similar to your problem.

Engine - No/Hard/Slow Start/Backfire/Kickback


File In Section: 06 - Engine/Propulsion System

Bulletin No.: 00-06-04-014

Date: April, 2000

TECHNICAL

Subject:
No, Hard, or Slow Start, Backfire or "Kickback" During
Crank/Start, "Grinding" or Unusual Noises During Crank, DTC P0338
(Replace Crankshaft Position Sensor)


Models:
1999-2000 Cadillac Escalade
1995-2000 Chevrolet and GMC SIT Models
1996-2000 Chevrolet and GMC C/K, M/L, G, P Models
1996-2000 Oldsmobile Bravada
with 4.3 L, 5.0 L, 5.7 L or 7.4 L Engine
(VINs W, X, M, R, J RPOs L35, LF6, L30, L31, L29)


Condition:
Some customers may comment on one or more of the following conditions:


^ Backfire during crank/start
^ "Kickback" during crank/start
^ "No" start
^ "Slow" or "hard" start/crank
^ "Grinding" or unusual noises during crank/start
^ Cracked or broken engine block at the starter boss
^ Broken starter drive housing
^ Broken starter ring gear on flywheel
^ Any combination of the above


Cause:
A condition may exist that allows the crankshaft position sensor to command up to 50 extra degrees of spark advance during engine cranking only. This in turn exposes the engine to higher than normal cylinder pressures which may result in an inoperative condition to the starter drive housing, the engine flywheel starter ring gear, or the engine block at the outside edge of the starter boss.


Correction:
Inspect for a stored powertrain DTC code P0338. This DTC will NOT illuminate the "Service Engine Soon" light. If this code is stored, the Crankshaft Position Sensor, P/N 10456607, MUST be replaced and the remaining components inspected for damage (engine block at the starter boss, the starter drive housing, and the engine flywheel starter ring gear).


Notice : When DTC code P0338 is set, failure to replace the Crankshaft Position Sensor could result in repeated inoperative conditions of the starter or flywheel.


Important : Some flywheel wear is normal; broken or missing teeth and/or cracks, are not normal.


Parts Information

Parts are currently available from GMSPO.

 

[Sampuppy1]

That's a good bit of info right there. Have you replaced the starter recently?

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