scottkern3

Hello all!

I have an '05 Trailblazer LT inline 6.

The gas gauge was constantly showing E after a fill up and the pump seemed to be getting louder so I took it in and they said that the fuel pump needed to be replaced. Anyways, I replaced it myself and it runs and sounds great but...

The fuel gauge is now acting up again and I'm getting a P0452 error code (Evaporative Emission System Pressure Sensor/Switch Low Input). ???

I'm going to check all the lines going to the EVAP system (at the rear of the tank) to make sure that everything is snug but what else should I check? I did notice the the breather tube wasn't connected to anything when I took the tank out. The tube does have a quick connect at the end of it but I don't think that this has anything to do with the issues I'm having, or does it?

Any help or comments would be appreciated.

PS. I will also check the electrical connection to the pressure switch (on the top of the fuel pump)

rubrhammer

ll the tubes need to be connected. You missed one somewhere. That won't solve your gage problem though. I replaced a pump a couple of weeks ago and the new one had a bad gage sender on it so out it came again. The pickup on the rheostat is very flimsy and may not be making a good contact. Also, make sure the float arm has clearance to swing through its travel without hitting the side of the tank. I've seen replacements that weren't right.
Bob

scottkern3

Would you happen to remember where it connected to?

rubrhammer

I was working on a silverado so it might be different but here is what I had.
Vent to canister (approx 1/2" dia), vent to filler neck(approx 1/4"-5/16" dia) this line had a tee in it and vented 2 high points in the tank, one at the sending unit and another on the rear raised portion of the tank. Fuel delivery line 3/8" and return line 5/16".
Hope this helps,
Bob

scottkern3

I'm hoping to get under there tonight. I'll post what I find.

scottkern3

So I think I managed to fix it. The vent tube connected to a hidden port (not very visible) on top of the fuel tank. After connecting it I was still getting the check engine light (P0452).

I crammed my hand on top of the fuel tank, right above the fuel pump and found that one of the electrical connectors wasn't connected. I ended up having to loosen the fuel tank straps to drop the tank about 1/2 an inch... i really didn't want to drop the tank in the 30 degree weather we're having right now. I was able to connect it and it resolved my check engine light.

I'm hoping that I won't have the fuel gauge issues anymore, but if I do, I'll definitively post here.

Thank you for helping me rubrhammer!