2010 Yukon 6.2L DIY DOD Delete / Engine Rebuild - Starter issue - RESOLVED

[jjmasterson]

RESOLVED

There was some strange anomaly. When I pulled the plugs to test the starter without compression, it turned over just fine. When i put the plugs back in, it also started right up. When rebuilding, I put the plugs in before putting the motor back in the vehicle, then put heads on, and buttoned everything up. Being a first rebuild, once I had the plugs in, I felt the resistance of the compression, which was pretty significant compared to no compression. I figured it was normal. Regardless, it's up and running now. Really appreciate the feedback from folks!

J



Hey there,

6.2L had a burnt valve and chipped piston. Did a rebuild with new:

- Pistons and rings
- Valves
- Lifters (LS7 DOD delete)
- Chevrolet GM OEM Camshaft L96
- Cam bearings
- Oil pump
- Valley cover
- Spark plugs
- Plug wire
- Battery

I went to start it up, and crank was a bit slow but eventually started up. Sounds great. No issues when running. Each time it was started is seemed like the cranking was slowing or labored more and more, until nothing but a click. No start. Jumping the relay will get the starter to crank VERY slowly. Labored.

Testing:

- Battery is charged 12.53v (Tried a 2nd battery. Battery is not the issue)
- 12.53v at the starter main
- Engine is grounded
- Voltage metering on starter drops to 10.30v during jumping the relay
- Starter relay is good
- Starter fuse is good
- Replaced starter - same result
- Not terribly difficult to crank it by hand but can feel the compression
- Remove plugs and engine cranks normally

Is there some sort of compression issue I'm missing when doing a DOD delete?

Video Start with Key

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Video Start by jumping relay (with plugs in)

New video · Thursday, May 1, 2025 🎬

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MUCH APPRECIATED!

 

[donjetman]

12.53 is not a fully charged battery
Also, load test the battery with a load tester.

 

[Charlie207]

12.53 is not a fully charged battery
Also, load test the battery with a load tester.

Should be enough though, right?

 

[Joseph Garcia]

As @donjetman recommended above, take out the battery, take it to a local auto parts store and have it bench load tested.

Also, did you closely inspect the battery main wires? They often rot from the inside out, so you should check the resistance of those main wires with an Ohm tester.

Confirming the above two, you should be able to establish whether or not the full charge/amperage required to start the motor correctly is available.

 

[petethepug]

You can have a battery that reads 12.53v and still have a bad cell. Think of it as trying to start a truck with 2 9v batteries or 18v wired in series. The voltage is there but the CCA aren’t.

 

[jjmasterson]

Thanks all! I also tried another battery from my F150 which runs well, and ran jumper cables from it directly to the starter and jumped the solenoid. Same slow crank from the starter. I'll load test my car battery also.

 

[mikeyss]

Did you have the main caps off at all? The reason I ask is because years ago I had this same issue with a 383 stroker I had built. I was young and I experienced at the time, and found I installed the main caps in the wrong locations, and the starter did the same thing as what yours is doing.

 

[jjmasterson]

Did you have the main caps off at all? The reason I ask is because years ago I had this same issue with a 383 stroker I had built. I was young and I experienced at the time, and found I installed the main caps in the wrong locations, and the starter did the same thing as what yours is doing.

Thanks for the feedback! It's my first rebuild so very much could have missed that. I was careful to make sure they went back to were they came from and used existing bearings, as they looked ok. I didn't do a plastiguage tho. Maybe I should have? The crank seemed to spin ok after I re-assembled it.

 

[j91z28d1]

I'd pull the plugs and turn the motor over by hand and see if you feel t binding up.

 

[donjetman]

Thanks for the feedback! It's my first rebuild so very much could have missed that. I was careful to make sure they went back to were they came from and used existing bearings, as they looked ok. I didn't do a plastiguage tho. Maybe I should have? The crank seemed to spin ok after I re-assembled it.

If there's a mechanical problem causing the binding?
drain and look at the oil
remove and cut open the oil filter
there will be a lot of metal.

 

[jjmasterson]

I'd pull the plugs and turn the motor over by hand and see if you feel t binding up.

Pulled plugs and turns over by hand easily. Even turned the key and starter cranks engine normally. (Without plugs)

 

[jjmasterson]

If there's a mechanical problem causing the binding?
drain and look at the oil
remove and cut open the oil filter
there will be a lot of metal.

When I pull the plugs, the crank turns by hand just fine. Compression issue?

 

[j91z28d1]

how old is the starter? if you're a 100% sure the cables are new, tight and ground is solid. I've seen starters get weak but not completely fail. I believe there's 2 different power ratings for starters gm used for these trucks too.

 

[jjmasterson]

how old is the starter? if you're a 100% sure the cables are new, tight and ground is solid. I've seen starters get weak but not completely fail. I believe there's 2 different power ratings for starters gm used for these trucks too.

The starter is new. Going to swap it out for the old one (which probably worked fine. I bench tested it and it fired up)

 

[j91z28d1]

The starter is new. Going to swap it out for the old one (which probably worked fine. I bench tested it and it fired up)

worth a shot, but if it's still weak too, you either have a weak battery or bad cables/connections.

bad cables that look perfect are the 2nd most common thread around here just after low oil pressure.

hooking battery cables from one battery to another unless it's from a running car doesn't always work right. I've done that myself and confused me when it didn't help. battery cables, especially today's thin ones are better at charging the dead cars battery up from the the running car than actually powering the starter. best to physically swap batteries from a known good car if you think a weak battery is possible.

 

[Fless]

If the starter swap doesn't fix it, verify the voltage at the starter while it's cranking. Low voltage there can indicate a bad battery cable, ground, or a bad battery.

 

[jjmasterson]

If the starter swap doesn't fix it, verify the voltage at the starter while it's cranking. Low voltage there can indicate a bad battery cable, ground, or a bad battery.

Just load tested battery. Came back good and fully charged. Checking cables. If I bypass the starter cable from the battery and use a jumper cable directly from pos battery to starter, will that simulate good cable connection?