Firebirdracer82
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- Joined
- May 3, 2025
- Posts
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HI All!
I have acquired a non-running 2003 Tahoe z71 with the 5.3. It is having some issues. I purchased it not running as a challenge to get running, and, after all of the easy things, I am stumped.
About the truck:
5.3, some new parts, transmission has been recently done, prior owner hooked up a manual shift transfer case, and the wiring looks OK for it, kinda. No front axels or front transfer case, so essentially two wheel drive. Story I got on it was it was going down the road and stopped. Sometimes it would run, and sometimes it would not. (What I was told). I have, personally, never heard it run.
The truck turns over a bit... slowly. Very slowly. Maybe it does one turn of the starter and then locks up and the starter starts clicking. Turn the key again, and it does the same thing. Eventually, it won't turn at all.
Initially, I thought it was the battery, so I switched it with one that worked out of my other Yukon. No change.
I cleaned all of the grounds and connections. No change. (The grounds I cleaned were the one behind the front bumper, the one on the driver's side of the block, the one on the rear of the passenger side of the block, the grounds under the driver's door, and I replaced the braided ground strap).
I kinda was stumped why it would only turn over once, so I took off the serpentine belt and tried again - no change. (Tensioner was kinda tight, but still turned). No other pulley was stuck and all turned freely. When turning it over without the belts there was no change.
So, I did the logical thing, and went to the junk yard and got new-ish, clean, battery cables (both positive and negative) and a known good starter. Paid too much and installed those.
For three times, the truck turned over a few times somewhat slow, but regularly. Then, it went back to slow cranking only once and then clicking.
I figured that maybe it was the starter, so I went out and purchased a brand new starter. No change with a brand new starter.
Checked fuel pressure and it was kinda low (but my gauge is a cheap one that always reads low). 53 PSI (which is what gets my other Yukon going so I think the gauge I use always reads a little low).
I decided to check two cylinders to see if an injector was leaking, and on the second plug I lost some threads (so helicoiling is in my future), so decided not to pull more - all dry of the two I checked.
I am not sure how to get this turning to do other diagnostics. (On the three times that it did turn over I checked with my scanner and I am getting RPM so I think my crank position sensor is fine at least).
So, after replacing the starter, the lines, the battery, (and the ignition switch), cleaning all the ground surfaces and putting another new one on the rear of the block... still not spinning over.
My best guess would be stuck injector, but I can turn the engine by hand at the crank bolt with a wrench.
What could be the cause of my slow/no crank?
Thanks in advance!
I have acquired a non-running 2003 Tahoe z71 with the 5.3. It is having some issues. I purchased it not running as a challenge to get running, and, after all of the easy things, I am stumped.
About the truck:
5.3, some new parts, transmission has been recently done, prior owner hooked up a manual shift transfer case, and the wiring looks OK for it, kinda. No front axels or front transfer case, so essentially two wheel drive. Story I got on it was it was going down the road and stopped. Sometimes it would run, and sometimes it would not. (What I was told). I have, personally, never heard it run.
The truck turns over a bit... slowly. Very slowly. Maybe it does one turn of the starter and then locks up and the starter starts clicking. Turn the key again, and it does the same thing. Eventually, it won't turn at all.
Initially, I thought it was the battery, so I switched it with one that worked out of my other Yukon. No change.
I cleaned all of the grounds and connections. No change. (The grounds I cleaned were the one behind the front bumper, the one on the driver's side of the block, the one on the rear of the passenger side of the block, the grounds under the driver's door, and I replaced the braided ground strap).
I kinda was stumped why it would only turn over once, so I took off the serpentine belt and tried again - no change. (Tensioner was kinda tight, but still turned). No other pulley was stuck and all turned freely. When turning it over without the belts there was no change.
So, I did the logical thing, and went to the junk yard and got new-ish, clean, battery cables (both positive and negative) and a known good starter. Paid too much and installed those.
For three times, the truck turned over a few times somewhat slow, but regularly. Then, it went back to slow cranking only once and then clicking.
I figured that maybe it was the starter, so I went out and purchased a brand new starter. No change with a brand new starter.
Checked fuel pressure and it was kinda low (but my gauge is a cheap one that always reads low). 53 PSI (which is what gets my other Yukon going so I think the gauge I use always reads a little low).
I decided to check two cylinders to see if an injector was leaking, and on the second plug I lost some threads (so helicoiling is in my future), so decided not to pull more - all dry of the two I checked.
I am not sure how to get this turning to do other diagnostics. (On the three times that it did turn over I checked with my scanner and I am getting RPM so I think my crank position sensor is fine at least).
So, after replacing the starter, the lines, the battery, (and the ignition switch), cleaning all the ground surfaces and putting another new one on the rear of the block... still not spinning over.
My best guess would be stuck injector, but I can turn the engine by hand at the crank bolt with a wrench.
What could be the cause of my slow/no crank?
Thanks in advance!
