Backtrack for a minute to electrical. Pump is supposed to prime at key on and key off. If I turn key back on in less than 10 seconds after turning it off, the pump doesn't prime/no voltage to pump. I'm guessing this is by design. Correct me if I'm wrong. But now I'm noticing it sometimes does this at key off...no prime/no power to pump. Test light at fuse box shows no power to prime terminal at all these times. Maybe there is more electrical issues and not just a fuel pressure problem. Or is there some sort of limit that's controlled by ecm, as to how often or how many times power is sent.

I should probably start a new thread. This egr post has morphed into something completely different....

 

I do not know if there is a limit function on repeat calls for priming. The proper test is fuel pressure at key on, the measured leak down and if you are concerned, fuel pressure while cranking or running.

George

 

Update. New fuel pump fixed the problem. Glad I bought that Delphi 10 years ago. I also learned all the things to do wrong while changing a fuel pump. I should write a book on what not to do lol. Now after that huge speed bump, someday I'll get back to the EGR stuff 😂

 

Also I think you were right about 11v being plenty, for a healthy fuel pump. Mine was just too weak. I know I started the Jimmy many times through the years with less than a perfect battery 😁

 

Glad your fixed up

George

 

So can we get back to original post for P0404? Yesterday I tried cleaning the ports since I hadn't done that before. Used a bicycle brake cable with frayed end on a drill (read that somewhere here on the forums). Before attaching to the drill I just tried to push the cable into the ports and seemed to hit a dead end on both, not very far in. With the drill and cable I also hit a wall then suddenly broke through the right side passage. Same on left. First question is, how long are these passages? I went quite a way in and did it several times, but nothing came out of the holes when I started it to blow them out. Should I have sprayed carb cleaner in first and let it sit before cleaning? It's still throwing the P0404 code.

 

My blazer does not have an EGR valve so I’ve never had to deal with this before. Maybe somebody else can give you some guidance.

George

 

Oh OK. I thought you were the one who was helping me with all the electrical testing on EGR before my fuel pump failure sidetrack. I've seen people mention removing the egr and blocking or bypassing the passages. I guess that's what you've done? Will start a fresh thread for passage cleaning question. Thanks.

 

Yes I was helping you and Istill can help but just not with physically cleaning the ports as I have never seen the set up.

George

 

So does anybody know....is it ever just actually the EGR valve that's gone bad? Still seeking that definite conclusion. 🤔