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Discussion Starter · #1 ·
99 Prelude SH trying to restore this beautiful girl, but the last owner didn't make it easy. To set the stage, she has an S2 intake manifold and TB....she's also had an IAC, FITV and it appears an EGR delete.
My problem is that just about every sensor downstream of the IM are showing shorts to ground. The IAT, the ECT, the PHO2S, all giving error codes clearly indicating shorts to ground. My question is, could anything have been done during the manifold install or IAB, EGR, FITV, IACV deletes that could be causing these, OTHER than a nicked wire? Should anything have been done to the now dangling harness plugs, like jumping them, to keep the continuity of the sensor ground wire? Trying to avoid having to rip out and rebuild the harness. Thanks for any help or advice.
 

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You can delete the IAB and FITV without resulting in any issues.

EGR will give you a CEL as well as IACV.
Neither would give a short to ground CEL.

Check if the O2 sensor pins are all intact and 1 is not fully seated.
 

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Discussion Starter · #3 ·
It's definitely not the sensor itself, because I just replaced it with brand new Sensor one, issue remained the same, old and new, but like I said, it's not just the PHO2S, its also the ECT and the IAT sensors, and they all share a common ground. But I don't think it's the pun on the ECU, because the MAP and TPS also share that ground, but they are fine. The wiring schematic shows a "junction connection" at the "lower rear of the engine"... wondering if the screwups is at that junction, but not sure what the junction connection looks like.
 

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It's definitely not the sensor itself, because I just replaced it with brand new Sensor one, issue remained the same, old and new, but like I said, it's not just the PHO2S, its also the ECT and the IAT sensors, and they all share a common ground. But I don't think it's the pun on the ECU, because the MAP and TPS also share that ground, but they are fine. The wiring schematic shows a "junction connection" at the "lower rear of the engine"... wondering if the screwups is at that junction, but not sure what the junction connection looks like.
There is a plug beneath the intake manifold with a matching blank cap, I believe this is referred to as a junction but cannot recall if it's for injectors or something else. There is also a crimped cluster of grounds within the harness loom.
 

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Discussion Starter · #5 ·
Do you happen to know, approximately where, along the loom it is? Past the injectors, past the IAT, I appreciate the help, guess I'll be tearing into the loom, because jumping all these sensor grounds over the fault is ghetto as hell, looks like crap, and I don't trust my wiring to hold up, even if I solder them, I'd rather just bite the bullet and fix the loom right. Thanks again so much!
 
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