Slow starting

Tiny
MIKEINMINNEAPOLISMN
  • MEMBER
  • 2003 CHEVROLET EXPRESS
  • 6.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 298,000 MILES
When it happens engine barely starts. Maybe 100 rpm at startup. I've tried a different starter and alternator. Shimmed starter away from ring gear. Different OEM flywheel (old one cracked OReillys one only lasted a year. So I did it a third time with GM OEM one and replaced the old rock hard engine and transmission mount). All new coils OEM. Has recent tuneup 30,000 miles ago. All parts that were replaced as needed. Battery test good. Problem has persisted for over 200,000 miles. Wish I could fix it! Any ideas?
Tuesday, January 21st, 2020 AT 6:48 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

You know, I had a customer a few years back with a 2003 Suburban with a similar issue. The only difference was it was an all the time problem. It always cranked slow. It ended up being the main ground between the battery and the engine block. Internally, it had corroded and caused excessive resistance and power loss. It's a thought. I suspect you already checked these things. I see you are a mechanic. It just popped into my head when I read your post.

Let me know.

Joe
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Tuesday, January 21st, 2020 AT 8:43 PM
Tiny
MIKEINMINNEAPOLISMN
  • MEMBER
  • 3 POSTS
I have but will recheck hot and negative for voltage drop. I've also noticed sometimes the obd network is slowed down a bit. If I plug a obd scanner into port and hit unlock or lock on the remote it takes a few seconds before van locks or unlocks.
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Tuesday, January 21st, 2020 AT 9:03 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Just for the heck of it, check that. Also, the idea that things are slowed down is interesting. I would think it could be related.

Let me know what you find.

Joe
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Tuesday, January 21st, 2020 AT 9:12 PM
Tiny
MIKEINMINNEAPOLISMN
  • MEMBER
  • 3 POSTS
Do you know where the obd splice pack is on van?
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Tuesday, January 21st, 2020 AT 9:24 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

In pic 1, I circled location. Pics 2 and 3 are wiring to it. I overlapped pics 2 and 3 so you could read them.

Let me know if this helps.

Joe
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+1
Wednesday, January 22nd, 2020 AT 7:34 PM

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