2002 7.3 making tapping/knocking sound as rpms go up

jtgf250 · May 18, 2015

Well had a chance to work on the truck some before leaving for work today. All rods look good as far as I can tell and movement of valve train looks good. Did change cps as the o-ring was leaking on it but no change. I did notice the most pressure I could read using AE when I drove the truck was about 2400-2600 icp.

Had my father in law rev the truck up some while I was under the hood. Sound seems to be coming from the HPOP itself. If you hold the hpop lines, you can feel the pulse go right in time with the tapping. Faster and louder as you raise the RPM's. So right now I'm leaning towards the hpop.

lincolnlocker · May 18, 2015

jtgf250 said:
Well had a chance to work on the truck some before leaving for work today. All rods look good as far as I can tell and movement of valve train looks good. Did change cps as the o-ring was leaking on it but no change. I did notice the most pressure I could read using AE when I drove the truck was about 2400-2600 icp.

Had my father in law rev the truck up some while I was under the hood. Sound seems to be coming from the HPOP itself. If you hold the hpop lines, you can feel the pulse go right in time with the tapping. Faster and louder as you raise the RPM's. So right now I'm leaning towards the hpop.

did you pull all the push rods out and roll them on a flat surface?

live life full throttle

psduser1 · May 18, 2015

Might throw a mechanical gage on the hpo rail, see what your actually getting as you crank.
Either the pump is toast, as you said, or an oring or two has let go.
Pull both fittings at the heads, #5 orb, tee them together into a gauge, and see what your pressure is. If you can't build 500 psi, it's the pump.
If you build pressure with that setup, check each bank of injectors, individually.
If one side is dropping pressure, or can't build pressure, you'll be down to four injectors instead of eight.

lincolnlocker · May 18, 2015

psduser1 said:
Might throw a mechanical gage on the hpo rail, see what your actually getting as you crank.
Either the pump is toast, as you said, or an oring or two has let go.
Pull both fittings at the heads, #5 orb, tee them together into a gauge, and see what your pressure is. If you can't build 500 psi, it's the pump.
If you build pressure with that setup, check each bank of injectors, individually.
If one side is dropping pressure, or can't build pressure, you'll be down to four injectors instead of eight.

good post my man!!

live life full throttle

jtgf250 · May 18, 2015

Im not having an issue with starting the truck. It builds pressure lo and high and fires right up. The issue is the loud tapping when bringing the rpms up. Sounds like something in the hpop.

Arisley · May 18, 2015

Dude, if you can tell if all rods look good before leaving for work in the morning, my hat is off to you.

So you pulled the motor and broke it down, checked the rods for twist, bending and stretching before work. Sweet.

OK, I think you meant push rods. Did you pull them out and roll them on a known flat surface. Something like a mirror, slab of glass, pool table surface (although, if you checked push rod straightness on my pool table, we would have an issue".

Arisley · May 18, 2015

It is a pain to measure rods for straight in a truck. You would have to have something that would drop down in the glow plug hole or the injector hole with 100% repeatability. You would have to measure the total rise of the piston within .00015 accuracy. You cannot do that before work in the morning.

jtgf250 · May 18, 2015

Arisley said:
Dude, if you can tell if all rods look good before leaving for work in the morning, my hat is off to you.

So you pulled the motor and broke it down, checked the rods for twist, bending and stretching before work. Sweet.

OK, I think you meant push rods. Did you pull them out and roll them on a known flat surface. Something like a mirror, slab of glass, pool table surface (although, if you checked push rod straightness on my pool table, we would have an issue".

LOL, no bueno on the pool table. I got home at 7:30AM this morning and laid down. Got up at 1PM and started messing with the truck till about 4 when I cleaned up to come to work for a 12 hour shift.

I pulled out a few, not all the rods. And yes push rods. Im off til Friday after this night so have a few days to mess with it more this week. Gonna hop back on it first thing in the afternoon.

Arisley · May 18, 2015

K. I understand. Hard to help with partial info. The more complete you can give us, the more like it is I am looking under the hood.

I am not being an asshole here, but you gotta give us accurate info. Some people would have figured that you have you just verified that all the connecting rods have been verified straight. Some people would have felt you just verified all the push rods straight. None of us would have been right, and you would bash on us when you founs #2 exhaust rocker arm cracked.

jtgf250 · May 18, 2015

Arisley said:
K. I understand. Hard to help with partial info. The more complete you can give us, the more like it is I am looking under the hood.

I am not being an asshole here, but you gotta give us accurate info. Some people would have figured that you have you just verified that all the connecting rods have been verified straight. Some people would have felt you just verified all the push rods straight. None of us would have been right, and you would bash on us when you founs #2 exhaust rocker arm cracked.

No hard feelings. I understand what you are saying, not my first forum and no I'm not one of those guys to bash others. I guess I didn't say "push rod" and just said rod since that's what we were referring to earlier in the post. Sorry about the miscommunication.

I take all the help and knowledge I can get.

lincolnlocker · May 18, 2015

so you only pulled out a "few" push rods but still state that they are all ok as far as you can tell? pull them ALL out and roll them on a flat surface

live life full throttle

jtgf250 · May 18, 2015

As I stated before, I will this week as I will have more time.

Since my father in law was around today and able to raise the rpm's for me to hear the tapping/noise better while I was under the hood, it sounds to be coming from the hpop area. The few I pulled and rolled, are good so far along with the rocker arms.

mandkole · May 19, 2015

Try pulling the belt off-- a bad idler bearing can hammer pretty good.

jtgf250 · May 19, 2015

mandkole said:
Try pulling the belt off-- a bad idler bearing can hammer pretty good.

Already did that. No change

psduser1 · May 19, 2015

jtgf250 said:
Im not having an issue with starting the truck. It builds pressure lo and high and fires right up. The issue is the loud tapping when bringing the rpms up. Sounds like something in the hpop.

Gonna say it's not the pump then.

ghohouston · May 19, 2015

A broken flexplate in an automatic truck can make a nasty sound, and it can travel through the motor, and make you swear you have a bad lifter. Just a thought.

Arisley · May 19, 2015

Yes it does.

lincolnlocker · May 19, 2015

ghohouston said:
A broken flexplate in an automatic truck can make a nasty sound, and it can travel through the motor, and make you swear you have a bad lifter. Just a thought.

very true. once it gets to the poi t where it sounds like a handfull of marbles getting shook around in a metal coffee can then you know its way bad.

live life full throttle