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Old 11-20-2009, 10:33 PM
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Default Silverado studder/hesitation, bad acceleration

Ok heres the deal, i have a 2000 silverado 2500, its the new body stlye with the 6.0 and the 4l80e transmisson. I recently did a motor swap to a lower mileage motor. Ive worked out most of the bugs but this last one is starting to **** me off. If your at a light and you floor it it runs to about 50 and the rpms continue to rise but will never switch gears until you back off the gas. Its reading no codes except 160 and 140. Both are rear o2 sensor codes so i know those have nothing to do with it since they dont affect fuel/air ratio.
What ive done so far.
-fuel filter
-plugs, wires and coils all 8
-map sensor
-cam sensor
-crank sensor
-mass air flow sensor
-coolant temp sensor
-cleaned throttle body and new intake
-IAC valve
-TPS sensor
-knock sensors

Im stumped i dont know where to go from here, should i of had the ecm flashed when i did the motor swap? its the same motor and tranny but from a different year.

Anyone have an idea???
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Old 11-20-2009, 11:16 PM
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sounds like you have a shift problem assuming that you set the TPS right...........i would have a tranny shop look at it....the 4l60e the (4l80e's little brother) has the same problem when they start to get over about 80,000 miles on them.....does it shift at all? or does it stay in first gear?? My advice is have the tranny checked out or change the fluid and filter money is on a tranny problem
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Old 11-21-2009, 07:02 AM
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After the motor swap was the crankshaft variation relearn done? If not I would do this before anything else. You may have to have the dealer do this with the scan tool. Dont know if a aftermarket one will have the function?
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Old 11-21-2009, 11:02 AM
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Is it necessary to adjust the tps sensor? I didn't think that trucks sensor was adjustable. How do I adjust it?
And what about the crankshaft variation. Explain to me what that is.

And ive also flushed tranny, and dropped the pan and changed the filter

Last edited by Townjester23; 11-21-2009 at 02:13 PM.
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Old 11-21-2009, 09:24 PM
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The crankshaft position (CKP) sensor is mounted in the front of the engine behind the harmonic balancer. The CKP sensor works in conjunction with a 3X (4X on V8 applications) reluctor wheel mounted on the front of the crankshaft. The CKP sensor has a B+ power supply, a ground, and a signal circuit.

As the crankshaft rotates, the reluctor wheel teeth interrupt a magnetic field produced by a magnet located in the sensor. The sensors internal circuitry detects this field and produces a frequency which the control module monitors on the signal circuit. The control module uses this signal in order to accurately measure crankshaft velocity, which is important to ignition control spark timing, fuel injector timing, and for misfire detection.

The control module can detect small variations in the CKP sensor and reluctor wheel. These part tolerances must be learned by the control module before an accurate CKP signal can be determined. At high engine speeds, slight variations in the following components make misfire detection difficult:


Reluctor wheel

CKP sensor

The control module learns variations during the Crankshaft Position System Variation Learning Procedure, and compensates for these variations when performing misfire calculations. Only a scan tool can command the control module to perform the Crankshaft Position System Variation Learning Procedure.

Perform the learning procedure after the following actions:

A control module replacement

Any operation or repair involving the crankshaft, the CKP sensor, or the CKP sensor to reluctor wheel gap relationship

An engine replacement
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Old 11-22-2009, 02:16 AM
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My make and models crankshaft position sensor is located behind the started, no the harmonic balancer. Its also new. I talked to gm today and they said that if i unplugg the cam sensor, crank sensor, ecm, motor swap etc...Its gonna throw off the timing somehow. He also said that it more than likely wont throw a code(MIL INDICATOR) until ran on a diagnostics machine. Ive already replaced EVERY sensor on the 6.0 liter beast so this has got to be a computer issue.

I do appreciate all the help yal have thrown my way, Ive been inside and out on theses motors and trannys so feel free to throw any issues at me -Townjester23
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Old 11-22-2009, 06:56 AM
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Exactly!!! It will throw the timing and fuel values off until you (Time it) run the crankshaft varaition relearn. This is running on the old engines values. If your old motor say had a loose timing set and you put a new motor in with a tight chain and dears you will still be running of the old engines timing values. This procedure has been around since 1998. I looked at your first post on all the sensors you have replaced. Did you torque the knock sensors when you replaced them? I have seen if they are over torqued they get too sensative and will retard the timing quicker without setting a code. Are all the grounds for the pcm clean and tight? Just a thought. But I still think your problem is in the Crank Variation.
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Old 11-25-2009, 11:28 PM
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Well this is great, now ive got a po300 multiple cylinder misfire. Crappy gas mileage, poor performance. going to the dealer next week to reflash the computer and and do the crankshaft variation.
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2000, 2500, 60, 97, acceleration, chevy, crappy, hesitates, hesitation, liter, mileage, o2, problems, sensor, silverado, studders, timing

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