EGR vs Purge Solenoid Ive got a similar problem with a truck that I'm putting back together. It's a 1993 c1500 with the 4.3. Long story but i dont know how it was originally so I'm just having to basically go off internet pictured. I also found a 4.3 at a junk yard but it didn't have the purge solenoid and only had an egr solenoid.

So here's my problem: I've been reassembling based on the assumption that I had an EGR solenoid. The bracket that it mounts to can have either the EGR or EVAP cannister purge solenoid mounted, but not both.

So with the EGR solenoid i have a home for all the vac lines (not that that matters anyway because again everything's being put back together based purely on assumptions). But when I go to connect the electrical, it won't plug into EGR solenoid. Not only that, but if i mount the purge solenoid, then i have no home for the egr line from the valve. That's what made me realize that the harness plug is for the evap purge solenoid.

So does anyone have pictures of where the vac lines connect on a 4.3 with a vacuum EGR if i have no egr solenoid valve? And I say that i have no EGR solenoid simply because i have no plug for it and my harness is the only thing i can guarantee is original.

 

Is the emissions sticker still under the hood? There’s a 3 letter code beginning with R that’s needed to determine the type of EGR/emissions control your truck uses. If you don’t have a plug in the harness, chances are good it’s a vacuum regulated solenoid (although chamber I think is a better description) so the 3 letter code can confirm what type it is and what the routing should be.

 

No there is no sticker ... actually there is no hood (long story). But after doing some more research last night i was finally able to verify via an AAP picture of the EGR plug socket that i do in fact have a plug for the egr, it's just way over by the brake booster because i apparently reinstalled the harness a few inches off. I'll fix that easily.

So I guess that solves that problem, but does anyone have a diagram showing proper routing of vac hoses to/from the purge solenoid and TBI for my setup? I'm guessing far right goes to one nipple on the solenoid, the other solenoid nipple goes to the canister? Which nipple is which? Is 'CAN' supposed to be telling me something?

 

I should’ve clarified - the emissions sticker is typically located on the air filter housing or on the upper radiator shroud.

Either way, this should be the correct diagram.

 

Does this help? I swapped a 5.7L into my 1994 C1500 that had the 4.3L, and the 5.7L had the solenoid while the 4.3L did not. My harness had no plug for the solenoid either. I took these pictures while looking at my friend's 1991 C1500 with 5.7L and no solenoid. As far as I can tell, I have no driveabilility issues.

 

You are the man Gumby22, thank you.

 

@Chris94, unfortunately it does not, I need the solenoid side of those lines. And ... it looks like your line coming from (going to) the canister goes straight to the TBI bypassing a solenoid altogether. I've got a connection in my harness for the solenoid so my line from the TBI has to go through the solenoid to the canister. But I appreciate the reply, any help is good help. Thanks for taking the time.

 

Sorry about that, I saw your post about finding the plug for the solenoid after I posted a reply. Best of luck getting it all sorted out.

 

Ok, i do have a follow up question ... the diagram only shows two outputs from tbi, one going to the pcv, and one to the purge solenoid. I've got 3. Typically the driver side goes to purge solenoid/cannister so if i need to route it through the solenoid to the canister that's understood. But what do i do with the line on the passenger side of the tbi?

 

The passenger side is the vac supply for the EGR solenoid.