View Full Version : Problems with primer on top of fuel filter??
BLACKDMAX
02-08-2010, 14:08
Has anyone heard of any problems with the manual pump on top of the assemble that the fuel filter screws onto not working to prime the system? I have an '02 Duramax with 150Kish miles and this winter I've had the thing not start 3-4 times. Each time I've gotten out, pumped that manual pump until tight and then it started right back up and hasn't been a problem until sporadically appearing again. Then this past Fri. this happened again, but I could never get the system to prime how it has in the past, and thus, I couldn't get it to crank. I live in SC so real COLD is not a problem. But coincidentally when this has happened, every time but 1, it was in the 20s and once in the teens. One other time it was 35. Do I need the block heater below 32? Is that causing the thing to not crand and/or lose prime? Doesn't seem right?? I recently had the fuel filter changed and noticed this filter was not even hand tight where it screws into this assembly I'm referring to with the pump on the top. Could this have let air in the system and the pump just doesn't work anymore? I took it back and they put another filter on it, but still couldn't get it to prime. It has been last spring since I had the fuel filter changed before and this problem showed up a few times before this last filter change. Anyone heard of cold causing this type problem, or Chevy having a problem with that manual pump going bad. Guy that got it running again said he had to disconnect air intake and hit with a little ether to get it to crank. Drove it. Sat over 2 hours then it fired right back up again. I've also changed the fuel filter myself before and I almost never got it primed back after that to crank. Took 20 minutes of pumping that manual pump with no resistance, and then it finally got resistance and then cranked. I'm scratching my head here. Hate to go back to the dealer and their labor rates without some insight. Anybody seen this or can help out. Tks.
First, don't let anyone spray ether in there! Glow plugs and ether just don't mix.
Second, yes, a loose filter will allow air in and the pump will not work. (Air pumps easier than fuel.) I'm assuming you are opening the bleed screw on the top of the filter housing, right? That makes it much easier to expel the air.
Bottom line is you seem to have an air leak somewhere on the suction side.
And no, you don't need the block heater.
May be a problem with the fuel filter housing. These are known to crack and leak air. May want to try replacing the housing.
BLACKDMAX
02-09-2010, 09:49
Tks. guys. Yes I have been using the bleeder screw on top but after 20 minutes of pumping the thing the other day, and the fact this problem continues to come up, I figured that housing may have a problem.
One of the best things that you can do for ANY Duramax is add a lift pump. This will also likely cure yor problem or at least force a leak where the air is getting in.
http://www.kennedydiesel.com/images/Twin_pumps%20_overhead_bracket.jpg
I've heard that the bleed screw (plastic!) can crack and leak air, too. You may wanna check that, too.
make sure the three screws that hold the priming pump to the housing are tight. seen a few of them back out and cause problems.
One thing to remember is that teh OE bleeder while it is a cheap lightweight piece of plastic is really not that bad. The only tool that should touch it though (except in emergency) is a 1/2" nut driver to break free the first time. From there I only use my fingers. You will find that the bleeder does not allow fuel/air to pass until backed out a fair bit. That is because it seals to an oring making seating pressure non critical.
I have a 06 and when I first start it up it will run for about 1 min then stall, out of fuel.
prime the pump with plunger, fuel leaks out from underside of plunger, i removed the 3 screws and cleaned all of the seal and I have put it all back together, does not seem to be leaking now, we shall see !!!!!!
the dealer wants 136 dollars for a replacement housing.
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