Dump pipes and fouled plugs question

[georgethepainter]

I just dumped a 1996 2g 4g63t into my ‘87 mighty max. I’m trying to get the truck to the muffler shop to get the exhaust installed.
I have an 18” piece of 2 1/2” pipe as a dump from the turbo. The o2 sensor is roughly 10” from the end of the pipe. The factory turbo waste gate has a 10” pipe dumping into the atmosphere.
Like I said I am just trying to get it to the exhaust place but the plugs foul right out. Number 3 and 4 foul first. Could the exhaust dump issue be enough to make the ECU think it’s running lean and overcompensating and fouling the plugs?
I’m planning a full diagnostic after the exhaust is installed but I am just trying to get it there. Will the full exhaust make that much difference and should I just tow the truck to get the exhaust installed before diagnosing? Thanks in advance GTP

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[Mello]

I wouldn't think your short exhaust would be able to effect the AFR enough to foul plugs. You joined Aug 2022 yet no vehicle profile yet??? How are you tuning? My thoughts are turn off O2 feedback & adjust your fuel close enough & run in open loop to make things driveable for the trip to the muffler shop.

 

[georgethepainter]

Can I turn off O2 feedback by disconnecting the sensor?

Worked on that vehicle profile

 

[steve]

Can I turn off O2 feedback by disconnecting the sensor?

What are you using for an ECU? That's important to know to answer your question.
The factory ECUs will go into limp mode without O2 feedback.

What size injectors are you using?
What base fuel pressure?
The answer to these might help understand why it's fouling plugs

 

[georgethepainter]

I found a crack in my BISS causing a fairly substantial vacuum leak. After the repair I chased a few dicey vacuum lines and miscellaneous BS . Changed the plugs and it’s running significantly better…thanks for the help