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+--- Thread: 870 2006 fuel lift pump (/showthread.php?tid=4772)
870 2006 fuel lift pump - akwman - 07-09-2019
I checked the relay , its good . The unit acts like it has lost prime . I can not get the lift pump to get going , I played with the plug / another relay got it to work weakly sounding for 7 seconds , I heard it start to strain . It then quit . So my question is how long should it take me to change out the pump and what might I need to complete the task . Yes I have the pump and the gasket . All pointers appreciated .
RE: 870 2006 fuel lift pump - Rawze - 07-09-2019
Just some thoughts...
9 of 10 times someone changes the lift pump on a CM870 or CM871, it is not too longafter, the gear pump goes out. This is because the debris from the failing lift pump take its toll on the gear pump.
Also, the retaining screws for the lift pump, most of the time,.. are VERY VERY VERY difficult not to strip out, as they typically seem to be way too tight for their size. -- Use only a brand new tool that is of high quality on it,.. lots of down-pressure on it when breaking them free for the first time. Many people have reported having to remove the whole IFSM before its over with.
RE: 870 2006 fuel lift pump - Andre_The_Giant - 07-09-2019
I had to do the lift pump on my truck twice already. Im only 410k miles, I ended up running all new fuel lines after, assuming it kept sucking air? I wasn't aware that it caused stress to the gear pump when it happens. Should I just replace my gear pump too? or is there a way to test it? Thank you for the heads up Rawze
RE: 870 2006 fuel lift pump - akwman - 07-09-2019
(07-09-2019 )Rawze Wrote: Just some thoughts...
9 of 10 times someone changes the lift pump on a CM870 or CM871, it is not too longafter, the gear pump goes out. This is because the debris from the failing lift pump take its toll on the gear pump.
Also, the retaining screws for the lift pump, most of the time,.. are VERY VERY VERY difficult not to strip out, as they typically seem to be way too tight for their size. -- Use only a brand new tool that is of high quality on it,.. lots of down-pressure on it when breaking them free for the first time. Many people have reported having to remove the whole IFSM before its over with.
I just had that issue on the first , I am wondering if it is now a torque head or a Allen number 5?
RE: 870 2006 fuel lift pump - Rawze - 07-09-2019
(07-09-2019 )Andre_The_Giant Wrote: I had to do the lift pump on my truck twice already. Im only 410k miles, I ended up running all new fuel lines after, assuming it kept sucking air? I wasn't aware that it caused stress to the gear pump when it happens. Should I just replace my gear pump too? or is there a way to test it? Thank you for the heads up Rawze
Although you should be prepared for it, knowing now what may cause its untimely demise, . No sense in blindly replacing it if it does not need it yet. -- That is, unless you know for sure the electric pump got shredded, or maybe if it has a whole lot of miles on the gear pump, and your on borrowed time with it anyways..lol.
RE: 870 2006 fuel lift pump - Nilao - 07-10-2019
When I did mine I had to pull the ISFM as the Allen head bolts were starting to round out. A little heat and a pair of vice grips and they came right out.
Sti on my original gear pump, 994k miles, around 80k since lift pump was replaced. Still puts out 270psi rolling down the road.
RE: 870 2006 fuel lift pump - akwman - 07-10-2019
Lift pump replaced . New issue , power fades to and from pump won't stay on / swapped out relay , no change relay does click vibrate when power goes to it intermediately . Where to look next ? Is there another fuse or relay some where I'm missing on the fuse panel ? any help would be appreciated . Of course no start .I went to the battery box cleaned up some relay terminals , got it to work steadily until it timed out . I pressed the top of the rail valve above all the stuff with the end of the test light probe , I got fuel spewed at me . Great we got pressure but no start . Im thinking could it be , could it be an ecm .
RE: 870 2006 fuel lift pump - Chamberpains - 07-10-2019
You said you cleaned up some terminals at the battery box. Did you check the fuses back there?
RE: 870 2006 fuel lift pump - akwman - 07-10-2019
(07-10-2019 )Chamberpains Wrote: You said you cleaned up some terminals at the battery box. Did you check the fuses back there?Fuses checked /pulled. Went to power wire to ecm / yes . Checked power here and there . Pump now working overtime . Cycles fuel back to the tank . Truck now FIRES OFF , then dies . Could it be the gear pump. I think I can rule out the ecm .