Mystery pigtail brown and brown/white stripe

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“Customer Vehicle” I’m not a mechanic lol
1997 GMC K2500 5.7L
This truck was brought to me for a crank no start, I found the ignition switch bad got it running. Tightened up some valves(covers were already removed) after reassembly there’s a two wire pigtail resting on top of the passenger side valve cover. It’s maybe 4” long and doesn’t reach anything I can find. Some of you here may know me from gmsquarebody and know wiring isn’t my specialty and this engine has way more wiring than my regular 350’s.
 

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WV_Dave

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My 94 4.3 has it. It's not plugged in to anything. Always assumed it was the hood light that mine's missing, but was never sure.
 
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Checked on his other truck, 1998 k1500 and that pigtail is non existent. I guess I can rest assured it’s not too important? I get to replace an ignition switch and harness tomorrow so hopefully you can start it with the key after.
 

GoToGuy

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The service manuals are free, have you looked in section 8, engine compartment wiring diagrams location's?
 

east302

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Looks like the purge canister diagnostic switch. Basically an early version of an evap emissions pressure monitor.
Adding to the above, see link below:


I believe they changed the EVAP components for 98; mine doesn’t have that connector, either.
 

GoToGuy

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This is engine sensor controls. Excluding alternator, ac compressor.
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Alright it’s the same as that other thread has. I’m going to assume this is missing on this truck. I didn’t remove it. Does it have anything to do with running rough? I jumped 12v to pink wire in ignition switch to fire the truck and it sputters a little and if you just breathe on the throttle it’ll start and run after but reeks of fuel and run rough. If you touch the throttle again it gets worse. Codes PO102, PO108, which are MAP and MAF? The air cleaner was off so I assumed those codes would be present? I haven’t touched anything in this engine other than trace wiring to find why it wasn’t getting spark and tighten a couple rockers and loosen a couple. (Stated obvious rocker rattling) used the procedure of TDC #1 compression and do half of the rockers I don’t remember which exactly. I did small increments until resistance was present while spinning the pushrod then did almost half turn. Rotated engine 360° do other half of rockers. Some were very loose and some were rock solid. I know 0 previous work done to this truck, it got brought to me a week ago after purchased with a crank no start. Previous owner lacked in some skills (tightening anything, crank position sensor was less than hand tight)
 

east302

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How is the fuel pressure? Spec is 60-66 psi key on, engine off.

Here are the diagnostic tables for those codes for a 98. Should be the same or close enough for a 97, maybe they’ll help.

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