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Took out Filter harness SES light yesterday

Be very........no, I mean very careful when removing the wire terminals on the Fuel Solenoid - hold the wire terminals with vise-grips while breaking the nuts loose, such that you don't unscrew the terminal bolt(s) - if already loose, remove the wire terminal, tighten the bolt finger-tite, then 1/4 turn more with a nut-driver - those small bolts are the electrical conductors for the FS coil - if loose in the coil assembly, you will get fishbiting - also hold the wire terminal while tightening the nut so you don't break the internal connection to the coil - broken connection, the fish already got the line and pole, and done bit yer as....er, hand.....................
 
Only "S" 1500's had EGR, wherein the sensor on the firewall is the vacuum sensor for EGR - PCM for C-K-P "F" engines (P being motorhome and cab'n'chassis), with no EGR, uses the firewall sensor for BARO - hose need not be disconnected for "conversions"

One advantage of the "S" engine setup is the EGR vacuum sensor is a watchdog for vacuum pump failure
 
Thanks for that Terminal advise.

No I do not have an EGR on my Truck
Thanks again?
PS I checked all the voltages and they were fine.. (of course the truck was not throwing a code at the time ether.
 
Pricey part (filter harness - already have the newest IP harness)....

Installed tonight....will see how it runs during the next week or two....
 
OK I'm lost with this. I thought the filter harness was not needed. Just some thing to cut down interference with the radio. I have a 95. It's probably original but i don't remember seeing any black box. Looked to me IIRC IP harness went to PMD right ? Or am I totally lost ?
 
Acesneights1 said:
OK I'm lost with this. I thought the filter harness was not needed. Just some thing to cut down interference with the radio. I have a 95. It's probably original but i don't remember seeing any black box. Looked to me IIRC IP harness went to PMD right ? Or am I totally lost ?
Click to expand...

The harness that goes to the PMD comes from the IP fuel sol. It's in the middle of the fuel lines on the IP. The black box or filter is in the OS harness on top of the IP.
Leo​
 
So, is the IP harness the same harness to the PMD or different? I think I am clear on the OS harness as described by buddy.
 
These are the 6.5 harnesses in the engine bay, each with a couple or several connectors

PCM harness - along the firewall, with umpteens of connectors tying to OPS, lift pump, GP controller, transmission control harness, and engine harness, thence into the cabin with assorted and sundry other connectors, incl three (count'em: 3!) unto the PCM

Chassis harness - thru bulkhead connector from IGN switch, LIGHT switch, multi-function switch, etc, for lighting, instrument sensors incl coolant temp and oil pressure, fuel level, starting, charging, and power

Engine harness - connects various engine components to the PCM harness back there behind the fuel manager head, incl ESO, FSD, OS, TSM, CPS, ECT, IAT, MAP, WIF, fuel heater, etc, each with connectors

Glow harness - connects the glow controller to the glow plugs

IP harness, teflon - with that mystical black ground wire attached to the top of the IP, connects the Fuel Solenoid terminals to the PMD\FSD connector, thence to the engine harness connector

OS harness - short'n'sweet, 3 twisted pair outta the top of the OS, connects directly to the engine harness connector - also in some cases with an OS Filter inserted therebetween

CPS harness - ties CPS connector to the engine harness connector

As you may have suddenly noticed, that vast number of disconnectable connections between EFI components on the engine and the PCM resulted in the OS Filter, intended to stabilize the digital signals from within the OS module - then GM realized the PCM didn't like the same sorta connections that were suitable for taillites, backup lites, horns, and dome lites, resulting in numerous improvements in various and sundry paths between power, ground, PCM and engine - that, and a little tighten-up in the OS module, FSD, and PCM did the trick for OBD2
 
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