Hello There!

Long time I haven't been here, but alas I seek council again.

I have the code 332 showing up, insufficient EGR Flow. I get this code during an KOEO test, and my trouble lights comes on when driving. The light turns off and off as I drive. Sometimes it doesn't come on at all.

I get another code during the same test, code 556 - fuel pump primary circuit failure. Sometimes when I let my engine get to operating temperature, and then cool down for an hour, it takes 5+ seconds of turning over to start. Could the long start time be related to that code? The engine fires up immediately when cold (and I mean like half a turn and its booming)

I have figured out that the EGR port in the manifold isn't blocked, or at least isn't completely blocked. If I take the hose that's connected to the EGR valve and suck on it, the engine stumbles and changes RPM. I also don't believe there to be a vacuum leak in that hose either, because I can suck on one end, with my finger on the other end, and no air pulls in.

I don't think there is a leak before the vacuum lines hit the EGR solenoid, if I put my finger on the end of the vacuum line that the vacuum is coming from that fits onto the EGR solenoid, and have someone turn off the engine, the vacuum never dissipates, it holds onto my finger for 5 minutes (probably longer, but I didn't want to wait any longer haha)

So that brings me to the EGR solenoid, which I don't know how to diagnose. I have tried going to the junk yard and getting a different one, but it made no difference it seems. I have tried shaking it, and it doesn't rattle. When I turn off the engine though, you can hear the EGR solenoid humming. The humming is because it seems to be dissipating vacuum. I listened to a friends truck (same truck) turn on and off and his didn't hum. I thought okay, probably the solenoid, but both solenoids I got from the junk yard did the same thing. So I am unsure.

If it makes any difference, it usually happens when its a bit cooler outside, typically when I drive to work in the morning.

I have replaced my vacuum canister, EGR valve, and EVP sensor all within the last year. They are all brand new components.

Any ideas, boys? Any chance there is a whole in the diaphragm of both solenoids I picked up? Any ideas on code 556?

Vehicle in question is a 1994 F150 5.0L 5SPD 4X4 with long box and duel tanks

 

Sounds like there may be a short in the solenoid wires.

 

Ill be sure to check that out. What about the solenoid dissipating vacuum though? This happens regardless of whether or not the solenoid is plugged in or not.

 

That's why I think there's a short.

 

Hmm, can you elaborate? I would think the solenoid wouldn't dissipate if it was unplugged. If it does dissipate while unplugged, does that mean even with the truck off the ECU is still applying a voltage to the solenoid?

 

Alright, you made me break out the book. The solenoid will always have vacuum in, and it keeps vacuum after shutdown because of the vacuum canister. The only time the solenoid should bleed off vacuum is if the solenoid stops vacuum to the EGR, then the vacuum at the EGR bleeds off but not any vacuum from the source. So now I'm thinking that you did get two bad solenoids. See if your friend will let you try his solenoid on yours or try one of yours on his truck and see what happens.