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305TBI Crate Engine Swap Runs Poorly

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Old Aug 4, 2021 | 6:39 PM
  #1  
chinsky's Avatar
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Default 305TBI Crate Engine Swap Runs Poorly

I recently swapped the engine in my 1991 Chevy K1500 Scottsdale. It was a direct replacement with a remanufactured GM 305 TBI. The new motor runs, but with a few new problems that I think are linked to emissions, fuel pressure or timing. Looking for experienced opinions on what might solve the problems.

The problems that I am experiencing include
1.) a lack of power
2.) stumbling/hesitation at ~2300rpm
3.) occasional power surge when pedal is pressed, leading to a service engine code 43 (ESC malfunction/ knock sensor).


My timing is set at TDC. I have also tried to advance it 4 degrees. Still haven't done a fuel pressure check.

Here are the items which I replaced during the engine swap:
  • Engine (block with assembled heads),
    • New block assembled
    • Heads assembled
      • valves adjusted according to recommendations
  • Cooling
    • Radiator
    • thermostat
    • temp sender
  • Spark
    • Distributor + cap
    • coil pack
    • new plugs and wires 10k miles ago
  • Emissions
    • EGR
    • TPS
    • MAP Sensor
  • Fuel
    • Fuel Filter

Does anybody have any thoughts on why this motor is running poorly?

Last edited by chinsky; Aug 4, 2021 at 6:41 PM. Reason: Didn't proof read
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Old Aug 4, 2021 | 8:31 PM
  #2  
kevinkpk's Avatar
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From: kevinkpk
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Originally Posted by chinsky
I recently swapped the engine in my 1991 Chevy K1500 Scottsdale. It was a direct replacement with a remanufactured GM 305 TBI. The new motor runs, but with a few new problems that I think are linked to emissions, fuel pressure or timing. Looking for experienced opinions on what might solve the problems.

The problems that I am experiencing include
1.) a lack of power
2.) stumbling/hesitation at ~2300rpm
3.) occasional power surge when pedal is pressed, leading to a service engine code 43 (ESC malfunction/ knock sensor).


My timing is set at TDC. I have also tried to advance it 4 degrees. Still haven't done a fuel pressure check.

Here are the items which I replaced during the engine swap:
  • Engine (block with assembled heads),
    • New block assembled
    • Heads assembled
      • valves adjusted according to recommendations
  • Cooling
    • Radiator
    • thermostat
    • temp sender
  • Spark
    • Distributor + cap
    • coil pack
    • new plugs and wires 10k miles ago
  • Emissions
    • EGR
    • TPS
    • MAP Sensor
  • Fuel
    • Fuel Filter

Does anybody have any thoughts on why this motor is running poorly?
Does this have a tps?
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Old Aug 5, 2021 | 10:46 AM
  #3  
chinsky's Avatar
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Originally Posted by kevinkpk
Does this have a tps?
Yes. I replaced the TPS. No change.
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