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6.0 LQ4 Cuts Off and On

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Old Feb 27, 2018 | 04:13 PM
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Default 6.0 LQ4 Cuts Off and On

I have a 6.0 LQ4 swapped into 83 K10. Engine will idle fine, but once you give any throttle input the engine starts to rev up to about 1500ish rpm then completely cuts out like the key was turned off, then lights back up around 800rpm then revs up and cuts again. It will keep doing it over and over until you let off the throttle then it will idle fine. Fuel pressure is constant at around 55psi the whole time.

**engine is stock with 799 heads**
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Old Feb 27, 2018 | 05:27 PM
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Check EVERY ground.
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Old Feb 27, 2018 | 07:46 PM
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How about data logging it, and looking for the problem??
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Old Feb 27, 2018 | 09:10 PM
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Originally Posted by Old Geezer
How about data logging it, and looking for the problem??
I have an HP tuners log file. Checked grounds, measured and checked grounds and voltage at PCM etc.

This is on the same PCM that I think may be faulty as my IATs are pegged at 340+F and when you unplug the MAF it still reads 110F. MAP reads 99KPA with key off and 10KPA unplugged via HP tuners scanner.
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Old Feb 28, 2018 | 03:43 PM
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Looks like the IAT cal was a fugged. It was changing automatically when I changed another table, odd....
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Old Mar 3, 2018 | 10:49 PM
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UPDATE:
if anyone else is having a similar issue in a swap I figured out the problem.

The truck is an 83 K10 6.0 and SM465 manual trans. Turns out there was an abuse table that is set to 1600RPM factory. When running a stick you need to change the table and max it out. The PCM was still looking for signal from an auto trans and was putting the engine into abuse mode and limiting RPM to 1600.
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Old Jun 14, 2018 | 03:55 AM
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Originally Posted by bp m1009
UPDATE:
if anyone else is having a similar issue in a swap I figured out the problem.

The truck is an 83 K10 6.0 and SM465 manual trans. Turns out there was an abuse table that is set to 1600RPM factory. When running a stick you need to change the table and max it out. The PCM was still looking for signal from an auto trans and was putting the engine into abuse mode and limiting RPM to 1600.
Had the same issue, but mine was set to trigger abuse mode at 4 000, then it behaved exactly like yours.
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Old Jul 13, 2018 | 01:08 AM
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Default Lq4

My lq4 is also doing this, but not all of the time. Is fuel a possibility?
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