Stumble off the line.

[9c1twiggy]

94 caprice 9c1.
I had a cracked head, so I replace them with stock heads that were milled .015. While I was at it, I did the home plate delete, put super comp hooker headers on, air pump delete and deleted the egr tube from the header to the back of the intake.


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[9c1twiggy]

And not it stumbles bad off the line. And seams slower overall.


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[DougDePew]

Optispark status?

[4DoorSS]

I've heard that hesitation can be a result of a defective EGR. Not sure what removing it would do or if this needs to be programmed out. Maybe something to consider.

[9c1twiggy]

I haven't touched the opti. I'm considering the delteq upgrade. The egr valve is still in place just not the tube.


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[4DoorSS]

Originally Posted by 9c1twiggy

. The egr valve is still in place just not the tube.


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If the tube is removed, I would think the EGR system is inoperative.

Not sure what removn the egr does for you. Did you follow a documented process on removing the EGR tube/setup and how this may affect an otherwise stock lt1. I still have mine installed (z28 egr) with my hooker super comps. Maybe someone who has deleted the EGR will chime in. But don't think you can just remove the tube and have the engine running normally without doing something else.

[cletus284]

Did you also unhook the EGR vacuum line? Have you had your PCM reprogrammed to eliminate EGR?

If the EGR valve is still functioning, its going to let the engine suck in unmetered air, which will cause issues.

Also, when the PCM, if not reprogrammed, commands the EGR on, it also does several things to compensate for the EGR entering the combustion chamber, including a significant amount of spark advance. This needs to be programmed out.

[SimplyTheBeSS]

From Qalo's SS Handbook -

Hesitation, stumble, skipping, missing
Probably the most common problem among our cars. Remember hesitation and stumble are more than likely fuel, exhaust, or intake related and skipping and missing are common among ignition and timing problems.

Hesitation and Stumble
· EGR Valve and/or Solenoid
· Fuel Filter Clogged
· Fuel Pump going bad
· Fuel sending unit connections melting on fuel pump
· Catalytic Converter clogged, glowing red
· Idle Air Control Valve
· MAF Sensor
· Throttle Position Sensor

Skipping and Missing
· Heat shield grounding on the plug, remove them.
· Bad Spark plug wire
· Bad Spark Plug
· Optispark going bad
· Ignition Coil going bad
· Plugs are arching, check at night.

[SimplyTheBeSS]

Originally Posted by cletus284

Did you also unhook the EGR vacuum line? Have you had your PCM reprogrammed to eliminate EGR?

If the EGR valve is still functioning, its going to let the engine suck in unmetered air, which will cause issues.

Also, when the PCM, if not reprogrammed, commands the EGR on, it also does several things to compensate for the EGR entering the combustion chamber, including a significant amount of spark advance. This needs to be programmed out.

I agree with this. Most of the time people have stumbles, it is because additional air until the motor which is not being anticipated. Make sure everything is tight and get your air pump and EGR programmed out.

[9c1twiggy]

I think I'm just going to put the egr tube on for now. Hoping to build a 383 soon. Then ill get all tge programming done at once.


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