Diesel Place banner

6.5 Diesel Rough idle, Stalling, etc..

5K views 24 replies 5 participants last post by  OkDually 
#1 ·
Hi everyone I am new to this page and I’m seeking help. I have a 2000, Chevy K3500 Rack Body with a 6.5 Diesel (134,000) miles on it.
The problem all began with water in the fuel. We changed the tank, flushed out the diesel, and put a new injector pump right off the bat. After all that work the truck still kept stalling because not enough fuel was reaching to the fuel housing. The sock on the sending unit kept getting clogged and the truck would stall. We removed the sock and some how there was still debris on the bottom of the new tank. We ended up returning the new injector pump since it got dirty and put a new one in, as well as brand new injectors. The PMD has been relocated to the front of the truck under the bumper 5 years ago. The truck starts, when it gets warm it begins to idle and the engine shakes, and when I take it for a spin and slam on the pedal the truck would just shut up. If anyone can help me that would be great, thanks for your time.
 
#2 ·
Welcome to DieselPlace
I moved your post over to the 6.5L section for better views and answers to your issue.

:thumb:
 
#3 ·
Air in fuel so when you fix it, there are still some leak or the debris still clogging.
Nothing you can do except putting a filter somewhere.
Did you replace the Lift Pump also?
 
#5 ·
Yes I replaced the lift pump as well, should I get new lines? I don't understand why it stalls either. Maybe the PCM is bad again.
Did you replace the tank sock?
Have you checked and cleaned the inside of the Fuel Filter Manager?
down inside of the bottom of the fuel filter housing is a small screen filter that can get clogged.
 
#6 ·
I left the sock off and put a 3/8 clear filter to catch any crap from the tank. Inside the fuel filter housing I cleaned the bottom and when ever I check it after the truck stalls, there seems to be only a quarter of diesel inside there. When I prime the pump, diesel begins to fill up inside the fuel housing, I just don’t know if it’s not getting enough diesel and why the engine idles rough and stalls. Very stressful, many hands on this truck and still can’t run right. Thanks for the feedback guys.
 
#7 · (Edited)
I left the sock off and put a 3/8 clear filter to catch any crap from the tank. Inside the fuel filter housing I cleaned the bottom and when ever I check it after the truck stalls, there seems to be only a quarter of diesel inside there. When I prime the pump, diesel begins to fill up inside the fuel housing, I just don't know if it's not getting enough diesel and why the engine idles rough and stalls. Very stressful, many hands on this truck and still can't run right. Thanks for the feedback guys.
I would apply a 12v. jumper wire to the lift pump relay to force prime the fuel system and see if it improves.
( as shown here): https://www.dieselplace.com/forum/6...l-mins-5psi-0psi-shutdowns-2.html#post6910025

If it improves then I would look into replacing the OPS ( Oil Pressure switch) and test and or replace the lift pump relay located in the fuse box under the hood.
Go through all grounds as well

Also, install a piece of clear fuel line on the return side of the Injection Pump to help locate any air in fuel gremlins:
https://www.dieselplace.com/forum/6...-5l-td-pmd-resistor-settings.html#post7305306
 
#8 ·
Which Lift Pump did you put on?
May be there is not enough power with the addition of fuel filter?
 
#9 ·
I bought a $55 lift Pump from autozone. I bleeded the fuel housing air and bled the air out of the t valve 2 days ago. Today I drove the truck for an hour without it stalling, although I wasn't giving it gas all the time, i was keeping a steady paste (2,000rpm) My mechanic told me I should get new lines that way the fuel can travel faster to the fuel housing and there will be more diesel to feed the injector pump. I feel that not enough diesel gets to the fuel housing when I gun it, so the truck shuts off because there isn't enough fuel reaching. Im not sure why there isn't enough diesel reaching to the fuel housing, possibly bad line? cracked rubber hose in lines? What do you guys think I should do?
 
#10 · (Edited)
The OEM setup is quite sufficient for a stock engine. (As far as fuel delivery is concerned)

I only skimmed ^^^ all that up there.

You have the correct fuel cap? The incorrect cap can strain fuel delivery.

I would have left the correct diesel tank sock. The lp is designed for that. Lift pumps push better than they pull.

If you have or you suspect you have major debris or corrosion in the tank you should pull the tank. Empty it. Rinse it out and let it bake in the sun to dry (if the tank is recoverable) if not replace the tank.

Disconnect line to fuel filter housing. Disconnect return line. Disconnect lift pump on both sides. Blow all lines out with compressed air while tank is dropped.

Install a new fuel filter in the ffm if you have not already.

With the truck running... open the air bleed valve on top of the filter. Does the engine struggle to run? Stall? Or does it pump fuel out just fine. Use a clear hose and a Jerry can so you can see if you have air bubbles present and if they are constant or if they go away.

If the engine stalls or has trouble running when the bleed valve is open the lp is weak and failing or was never strong enough to begin with. I always recommend the delco lp.
 
#11 ·
JNL, OP is adding an extra filtration before the LP.
So, that is why I said the stock LP may not be sufficient.
The 93 model year LP is a bit stronger than 00 model year.
Get an ACDelco LP.
 
  • Like
Reactions: jnlperformance
#12 · (Edited)
The best way is to measure the pressure (even volume if possible).
First at the t-valve, you need around 4 psi at idle steady not average.
Then somehow, measure the pressure when the problem happens, not sure if that is all the time.
 
#13 ·
I have bought a new tank with new sending unit. I never replaced fuel lines / return lines. Also the back tank is disconnected (which is plastic). I have a Delphi Lift Pump currently on it. When we blew threw the hose last time there was debris inside them. Not sure if it’s preventing the diesel from reaching the fuel housing. When I stalled the other night I kept priming the fuel filter until it was full, than the truck started right up. I’m not sure why not enough diesel is being lifted to the housing when the truck is on.
 
#15 · (Edited)
If you start the truck and then open the T Valve for a minimum of 30 seconds, you should see a healthy stream of fuel flowing out of the drain line and the engine continue to run..

If you see no fuel flow from the drain line and/or the engine dies then your lift pump is too weak.
 
#16 ·
Not sure if this is it but have you checked to see if you install the LP in the correct direction.

I think it flows one way and it is very easy to reverse the LP.
 
#17 ·
I believe jnlperformance's reply is absolutely spot on. I had similar problems and after dropping the tank, flushing it out and replacing the entire fuel pickup assembly including the OEM sock, Brunhilda runs fine. Don't skimp on cleaning the tank, take the time to do it right. This was after replacing the LP, which only brought temporary relief.
 
#18 ·
I have cleaned the tank and sucked out the old diesel and particles. I believe the particles keep reappearing In the new tank because of the old return line and fuel line. Therefore, I put a filter to catch the debris until I get new lines. The lift pump is on correctly, the fuel housing just doesn’t stay filled like it’s suppose to. Something is preventing the fuel from reaching to the fuel housing to stay full, not sure what it could be, I just put a brand new lift pump. My next step is to try replacing the return and fuel lines. People have told me the rubber hose could of gone bad, or that hard line is corroded inside. My next step is to blow out these old fuel lines, and try again.
 
#19 · (Edited)
I have cleaned the tank and sucked out the old diesel and particles. I believe the particles keep reappearing In the new tank because of the old return line and fuel line. Therefore, I put a filter to catch the debris until I get new lines. The lift pump is on correctly, the fuel housing just doesn't stay filled like it's suppose to. Something is preventing the fuel from reaching to the fuel housing to stay full, not sure what it could be, I just put a brand new lift pump. My next step is to try replacing the return and fuel lines. People have told me the rubber hose could of gone bad, or that hard line is corroded inside. My next step is to blow out these old fuel lines, and try again.
Try disconnecting the fuel line, pre lift pump and attach a can of fresh fuel to the lift pump via a hose and start it to see if things improve..
 
  • Like
Reactions: jnlperformance
#20 ·
The truck starts running bad as soon as I take it for a spin and warm it up. Than the truck begins to shake like not enough fuel is getting to all the injectors. I changed the oil today and sometime this week will change the OIL pressure switch. I feel the LP is working but i don't know if its working when Im pushing the gas. The truck only stalls when I give it gas. I will update you guys what happens after I replace the OPS. Truly running out of options, the OPS is the last thing to switch, hopefully it resolves all my problems with this truck.
- Thanks for the feedback guys!
 
#23 ·
Make sure you get ACDelco OPS.
Although on a 2000, unless the Oil Pressure shows 0 psi, it probably does not matter in terms of the ability of lift pump to run since the relay is running the LP.
The OPS problem exist for 93-95 model year where the OPS runs the LP when engine is running.
 
  • Like
Reactions: jnlperformance
#24 ·
I replaced the OPS and the truck does the same thing as an as it warms up. The psi comes out Normally (according to my mechanic). We are going to replace the PMD next. I’m not sure what is causing the truck to surge and idle so roughly, the whole truck shakes. Let me know what you guys think. I drove it today and after stepping on it, it stalled on me. That’s why I think the PMD could be bad.


Sent from my iPhone using Tapatalk
 
#25 ·
I replaced the OPS and the truck does the same thing as an as it warms up. The psi comes out Normally (according to my mechanic). We are going to replace the PMD next. I’m not sure what is causing the truck to surge and idle so roughly, the whole truck shakes. Let me know what you guys think. I drove it today and after stepping on it, it stalled on me. That’s why I think the PMD could be bad.
Be sure to go through all grounds.
Clean each one and replace any that are in bad or questionable shape:
https://www.dieselplace.com/forum/showthread.php?t=163087
 
  • Like
Reactions: jnlperformance
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top