Cam Issue?
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Cam Issue?
Working on a 1996 4x4 excab long box Pstroke, Auto Tranny. Started stalling a couple months ago but would always restart - after a couple weeks, stalled and wouldn't restart. I got the truck to my shop in non running condition. I've been working through the crank but no start flowchart, Didn't seem to have good fuel pressure so I put a new lift pump in it. Still wasn't getting good pressure - so I blew air through all the lines from both tanks to the lift pump inlet, no restrictions on either tank. Hooked the fuel pressure gauge up directly on the outlet of the top of the lift pump and was still getting less than 10 psi. Wrote it off to a bad new part - pulled it out, took it back, got another one, installed it now - still less than 10 PSI at the lift pump outlet. So - has anyone had a problem with the cam that has caused the lift pump to stop working? Is there a brand of lift pump that is just a huge no no to install? The 2 'new' (probably reman) ones I have put in the truck are Airtex brand from O'Reilly's.
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Joined: Aug 2009
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From: Michigan
the outlet of the lift pump is low pressure. the pump is a 2 stage pump half lift pump half high pressure pump. the place to check the pressure is the side of the fuel filter can where the fuel pressure regulator is.
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It was around $100 and it is an airtex.
It does fill the bowl - w/filter, it takes 50-60 seconds of cranking to completely fill. I have a video of the first 10 seconds of cranking with empty bowl, haven't figured out how to attach it yet.
Both tank 100% full with diesel.
Flashlight to see lobe? Please elaborate - I assume you mean with the lift pump removed - and just looking for a smooth surface all around?
Screen is clean.
I'm aware that it is low pressure on the high side - it should still be 20psi out of the lift pump I would think? I get less than 10 psi at the shrader as well.
It does fill the bowl - w/filter, it takes 50-60 seconds of cranking to completely fill. I have a video of the first 10 seconds of cranking with empty bowl, haven't figured out how to attach it yet.
Both tank 100% full with diesel.
Flashlight to see lobe? Please elaborate - I assume you mean with the lift pump removed - and just looking for a smooth surface all around?
Screen is clean.
I'm aware that it is low pressure on the high side - it should still be 20psi out of the lift pump I would think? I get less than 10 psi at the shrader as well.
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Elder User
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From: Northeast Ohio
Haha well yea with it removed and if its missing a chunk or something it's going to be pretty obvious though I doubt it's the cam
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Posted the fuel bowl fill on youtube for now -
VIDEO0008 - YouTube
I don't think a chunk is missing out of the cam - when I removed the lift pump that had been installed briefly and only ever cranked on, the wear pattern on the bottom of the 'foot' didn't seem irregular. I just didn't know if there was a known issue that would cause a good lift pump to not provide enough fuel. It seems strange to have the same symptons with 2 different 'new' lift pumps - same pressure readings at the shrader and the outlet of both lift pumps.
VIDEO0008 - YouTube
I don't think a chunk is missing out of the cam - when I removed the lift pump that had been installed briefly and only ever cranked on, the wear pattern on the bottom of the 'foot' didn't seem irregular. I just didn't know if there was a known issue that would cause a good lift pump to not provide enough fuel. It seems strange to have the same symptons with 2 different 'new' lift pumps - same pressure readings at the shrader and the outlet of both lift pumps.
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CPS is new - Was replaced when truck started stalling, did not change symptoms. It could need replaced again, but that wouldn't effect fuel pressure - would it? I feel like I need to get 20 + psi at the schraeder before further diagnosis.
Broken spring in fpr? would I just need to replace the fpr or the whole fuel pressure assembly to the driver side of the bowl?
Broken spring in fpr? would I just need to replace the fpr or the whole fuel pressure assembly to the driver side of the bowl?
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Pulled that spring out and it was not attached to the triangular piece behind it - My spare assembly these two pieces did seem attached, threw the spring in from the spare assembly and its still not building fuel pressure while cranking.
We've actually had 3 CPS ' s in the truck since it started acting up - the new one I purchased was off brand, the new one the owner had purchased I'm not sure where it came from. I'll get one from ford tomorrow and try it, if the off brand ones are so notorious for being garbage. Keep in mind, when the truck would run but stall constantly, the symptoms were identical with all 3 CPS's.
Keep the ideas coming... much appreciated...
We've actually had 3 CPS ' s in the truck since it started acting up - the new one I purchased was off brand, the new one the owner had purchased I'm not sure where it came from. I'll get one from ford tomorrow and try it, if the off brand ones are so notorious for being garbage. Keep in mind, when the truck would run but stall constantly, the symptoms were identical with all 3 CPS's.
Keep the ideas coming... much appreciated...