Okay guys, on friday as i started up the truck, there was this loud buzzin sound coming from the front end, then faded out. Truck ran fine on the way to work. At the end of the day, same noise, same result, but truck started to stall out. Any feedback would be appreciated.

I would check for codes first. But with out hearing it or knowing where on the front of the truck it came for it could be just about anything. Give us some more detail as to where you though it was coming from.

I would check for codes first. But with out hearing it or knowing where on the front of the truck it came for it could be just about anything. Give us some more detail as to where you though it was coming from.

trying to nail it down from feedback from the forum before i give out assumptions. almost sounds like a june bug or bearings going out.

--- Update to the previous post...

trying to nail it down from feedback from the forum before i give out assumptions. almost sounds like a june bug or bearings going out.

so i took a video and it almost sounds like a tapping sound. do you all think i might need a valve adjustment?

It wouldn't hurt to do a valve adjustment. http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/121-valve-lash-adjustment If you do it, it would at least help eliminate where the noise is coming from. You might check the idler pulley as well. It is an easy replacement if that is it. Keep us informed.

It wouldn't hurt to do a valve adjustment. http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/121-valve-lash-adjustment If you do it, it would at least help eliminate where the noise is coming from. You might check the idler pulley as well. It is an easy replacement if that is it. Keep us informed.

Performed the valve adjustment this weekend. Noise is still there, but now clearer. It sound like the stock lift pump when you initially turn they key on before start. The loud noise goes away once the truck has idled for a couple of seconds. Additionally, tapping sound can be heard. checked all gaps and all is within specs. any ideas? In regards to write-up, torque specs seem to be very high. Are these values from Haynes manual or manufacturer? I did not tighten to the torque specs due to not wanting the bolt to succumb to hoop stress.

:ahhh:truck died on the way home yesterday. just plain shutdown . just before it shut down, the truck started to sputter than it drove normal than . I checked stock lift pump by opening up testing port at the VP44 and bumped the motor to activate lift pump to verify if i was getting proper fuel delivery after the filter:thumbup2:. Than i cranked open injector line 3 & 4 and started to turn over motor. i observed fuel dribbling out initially, stepped on the gas peddle irratically until i finally observed the fuel shooting out of the injectors, continued to step on the peddle till it finally started running:hyper:. Tightened down the fittings and got home as quick as i could. What a mess!!!Gas gauge was almost at 1/2 a tank. I looked in the haynes book and noticed the PCM wiring diagram has an automatic shut-down relay. Does anybody know what this is for? Does this act as a protective device?Any and all comments are appreciated.

I would check for codes. You will need a code reader for your truck, Key trick will not work for that year. What is your FP at idle and WOT? When was the last time the fuel filter was changed? The stock pump could be DOA.

I would check for codes. You will need a code reader for your truck, Key trick will not work for that year. What is your FP at idle and WOT? When was the last time the fuel filter was changed? The stock pump could be DOA.

I will check this weekend and keep you updated. Additionally, narrowed down what the noise is. There are two locations. One is the boost and the other is that i think i might have a blown valve. My symptoms closely resemble what JohnFak was troubleshooting. Turned out to be a blown valve. thanks JohnFak for your details. this saved me a lot of time. I was wondering, would i do any damage driving the truck long distances with this issue?

I will check this weekend and keep you updated. Additionally, narrowed down what the noise is. There are two locations. One is the boost and the other is that i think i might have a blown valve. My symptoms closely resemble what JohnFak was troubleshooting. Turned out to be a blown valve. thanks JohnFak for your details. this saved me a lot of time. I was wondering, would i do any damage driving the truck long distances with this issue?

Any pics ?? Not sure what you mean by blown ...... my understanding is if its bad enough it could result in chunks of the valve dropping into piston ...... that cant be good. But if its just cracked am sure you have some time before it does .......

Any pics ?? Not sure what you mean by blown ...... my understanding is if its bad enough it could result in chunks of the valve dropping into piston ...... that cant be good.But if its just cracked am sure you have some time before it does .......

No pics. Just observations. Poor choice of words on blown. One or many valves may be going bad. Without knowing where themajority of the failure points have occured, I would need to remove the head. Did you drive your truck around? Any ideas on failure point locations?

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No I don't think you can really diagnose it without pulling the head. Did you check for leaking/cracked manifold as well as missing manifold bolts also ? I drove it for around 1 moOnth from the time it started till the time I had it in the shop and fixed.

Did you try to follow what ISX recommended as far as checking the valves again? No visual damage to valves when I did the valve adjustment. Update on fuel pressure readings: Idle: 12 psi @55 mph= 10 psi WOT(3000 rpm)=8 psi Filter change-+1 yr. I think I may need to clear codes. Still having engine missing. When engine misses, no drop in fuel pressure. At idle guage fluctuates. Any ideas?

: Update on fuel pressure readings: Idle: 12 psi @55 mph= 10 psi WOT(3000 rpm)=8 I think I may need to clear codes.

Do you have codes? If so, what are they? Your signature says your VP has less than 1000 miles on it. With the psi's that your running your VP is going to go south on you. The VP needs good fuel pressure to cool the computer down. Most of us are running a minimum of 14 psi and upto 20 psi. Have you tried to do a compression test on the cylinders? That would help tell which cylinder is bad.

no codes. three key trick works on my truck, only p-done. Signature needs to be rev:shrug:ised, actually have +20, 000 miles. today i simulated apps failure by unplugging harness. i cleared codes again just in case. i reset APPS and Now the gage reads 14 psi idle and 10 psi wot(3000 rpms) any ideas?

My truck will pull codes with the key trick but it has not always pulled all the codes. several times in the past I have found more with a scanner. Not always but sometimes. Enough to make me doubt what I am seeing.

three key trick works on my truck, only p-done. i reset APPS and Now the gage reads 14 psi idle and 10 psi wot(3000 rpms)

On some 2001 trucks when you do the key trick you only get 1 "done". There should be 2 "done". I would retry the key trick and wait to make sure you get 2 "done"s. If you don't you will need to get a code reader to have it done. If you're only getting one done then only one computer is being read. Did you rev the engine upto 3000 rpm while it was in park? Or did you do it while driving?

On some 2001 trucks when you do the key trick you only get 1 "done". There should be 2 "done". I would retry the key trick and wait to make sure you get 2 "done"s. If you don't you will need to get a code reader to have it done. If you're only getting one done then only one computer is being read. Did you rev the engine upto 3000 rpm while it was in park? Or did you do it while driving?

only getting one p-done. i have an obd-ll(inova). when i diconnected the apps, i did the key trick and did get the p1693 and p0122. i hooked back in, and erased the p0122. do i need to erase p1693? i thought this code went away once i erased p0122 code. i did it while in park. i took it on highway, as soon as i got to a steady 70, it quicklt stalled, pressure dropped to 8psi, then jumped back up to 12 psi. scratching my head here.

Your reply is not clear. You read your codes from a code reader? Clearly you have a FP problem. You need to get a better fuel delivery system on your truck. You can check all of your lines to see if you have any kinks in the fuel lines, check the fuel tank to see if it is getting clogged from there as well. But, I would be looking at a Fass, AirDog, or Raptor fuel system if I was in your shoes.

Your reply is not clear. You read your codes from a code reader? Clearly you have a FP problem. You need to get a better fuel delivery system on your truck. You can check all of your lines to see if you have any kinks in the fuel lines, check the fuel tank to see if it is getting clogged from there as well. But, I would be looking at a Fass, AirDog, or Raptor fuel system if I was in your shoes.

On some 2001 trucks when you do the key trick you only get 1 "done". There should be 2 "done". I would retry the key trick and wait to make sure you get 2 "done"s. If you don't you will need to get a code reader to have it done. If you're only getting one done then only one computer is being read.

only getting one p-done when i do the key trick. i have an obd-ll(inova), so hooked up the code reader and retrieved no codes. I decided to test the ECM by simulating an APPS failure and disconnected the APPS wiring harness. When i diconnected the apps, i did the key trick and did get the p1693 and p0122. i hooked it back in and erased the p0122. The CEL turned off for a split second and turned back on. I guess ECM did a check and found that there was still a problem with the APPS. I turned the key off, reconnected the APPS wiring harness, turned the key on, and erased the P0122 with code reader. Does the p1693 code automatically erase? i thought this code went away once i erased p0122 code.

Did you rev the engine upto 3000 rpm while it was in park? Or did you do it while driving?

I did it while in park. i then took it on highway, as soon as i got to a steady 70, it quickly stalled, pressure dropped to 8psi, then jumped back up to 12 psi. scratching my head here. This morning i turned key on to activate pump, pressure was at 15 psi. When i started the truck, pressure went down to 14 psi. drove to work monitoring pressure. At take-off, pressure would drop to 12 psi and stay there while i was driving. The gage would be 14 psi at idle. I am scratching my head wondering why the pressure is fluctuating so much on a daily basis. if you read above psi was initially at 10 psi idle and now its at 12 psi. I am going to check tank. I need to replace fuel sending unit anyhow, due to the truck shutting down at 1/4 of a tank and eliminate that as a possible issue. thanks ya'll for your input and i'll keep ya'll updated.

only getting one p-done when i do the key trick. i have an obd-ll(inova), so hooked up the code reader and retrieved no codes. I decided to test the ECM by simulating an APPS failure and disconnected the APPS wiring harness. When i diconnected the apps, i did the key trick and did get the p1693 and p0122. i hooked it back in and erased the p0122. The CEL turned off for a split second and turned back on. I guess ECM did a check and found that there was still a problem with the APPS. I turned the key off, reconnected the APPS wiring harness, turned the key on, and erased the P0122 with code reader. Does the p1693 code automatically erase? i thought this code went away once i erased p0122 code. I did it while in park. i then took it on highway, as soon as i got to a steady 70, it quickly stalled, pressure dropped to 8psi, then jumped back up to 12 psi. scratching my head here. This morning i turned key on to activate pump, pressure was at 15 psi. When i started the truck, pressure went down to 14 psi. drove to work monitoring pressure. At take-off, pressure would drop to 12 psi and stay there while i was driving. The gage would be 14 psi at idle. I am scratching my head wondering why the pressure is fluctuating so much on a daily basis. if you read above psi was initially at 10 psi idle and now its at 12 psi. I am going to check tank. I need to replace fuel sending unit anyhow, due to the truck shutting down at 1/4 of a tank and eliminate that as a possible issue. thanks ya'll for your input and i'll keep ya'll updated.

Update! so i am able to increase my speed over 70mph. I replaced the fuel filter and therefore the stock pump does not to work as hard. I noticed that on the highway that at 70 mph i was doing okay at 12 psi for about 15-20 miles and then when i looked at the fpg, the needle hade dropped to 7 psi:shrug:. any thoughts? My pressure is still fluctuating as the day goes by. In the morning i get 15 psi at idle and the lift pump is really loud, at WOT i get 13psi. I get a 2 psi drop at noon when i go to lunch, therfore i idle at 13 psi with lift pump really loud, at WOT i get 10-11 psi. When it is time to go home, at about 6 and truck has been sitting in the sun, i get 9 psi at idle with lift pump really loud, i try not to operate the truck at WOT, but as soon as i get halfway home i notice that the fpg starts to climb, eventually getting back to 12 psi. I am going to switch out stock pump this weekend.

The stock lift pump is most likely the culprit. If you plan on installing another one try reading this http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/25-fuel-system/32-stock-lift-pumps