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Engine doesn't idle smooth

Chevydually said:
Ok checked the fuel no bubbles as far as location of pmd I might put it back on the pump because this trouble started after I moved it in the first place pmd went the first time ten years ago when I looked on the net everybody said my location was good. As far as parts go 99%of all parts come from same supplier regardless of the parts dealer even from GM
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Rebuilt pumps come from diffrent places. Some re-paint krap and send it to you. Some actually rebuild and test them. 2 diffrent companies make PMD's. I do not like the current low quality parts because I hate doing a job over. There is always time to do it over - why can't they take the time to do it right the first time?

Why is there only one battery? -yes it will run. No, it's not helping you with troubleshooting. You are dealing with fussy computers and trusting the positive connection laying loose in the tray to be good. That connection supplies the computer and dampens alt noise. Low voltage, say from that connection, to computers causes them to go NUTS! This is why we say take apart grounds and clean them - because it fixes a lot of things. Positive cables that are coroded also cause problems.

Things go real crazy when you loose the batteries with the engine running. Like a cable falls off...

The PMD is a high thermal load bad design that just added to the bad rep of the 6.5. 10 years ago most ignored heat kills electronics esp heat cycle fatigue and put the heat sink on the intake. This solved bad heat sink contact to the IP and no extension cable was required. Many learned later that a cool location on the bumper lasts longer than the underhood oven. Air coming off the engine fan is near 200 degrees. Dodge also had trouble putting electronics in the dammed hot IP.

I would check for codes, borrow a second battery, then disconect the optical sensor plug. It's the one on top of the IP. See if things run better. It will have a long crank. Then plug it back in and discount the CPS, crankshaft position sensor, and test again. The CPS is on the front of the engine on the timing cover.
 
Husker6.5 said:
That's way high.
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I wonder if this has a high idle switch?

Otherwise I would suspect temp sensor reading cold. A intermittent short could read normal then cold causing the ECM to kick up the idle because it thinks its suddenly cold. A scanner would confirm.
 
I have tried unplugging opticsensor and the crank sensor no change what should it run like will it smooth out or still run rough as far as one battery in it it was borrowed to something else you can have two three or four in it still runs the same.now as far as the pmd who do you recommend my self i prefer stanydin that who made the original.to the guy who suggested the temp.sensor tried that to unless it could farther up the harness I did have a problem that when you did unplug that it would run better but wouldn't shift into overdrive it shifts into overdrive and stays
 
Most diesel shops with good reputation won't rebuild them the very first pump I put in I bought in Jasper Wy I picked it up.in person he scanned told me.pump.was sold me a new one and said throw the old one away put that pump had different issue then now that was 13yrs ago.i changed my self in Reno Nevada in a truck stop parking lot
 
So optic sensor is out of the equation by the test.

Have you done the clear IP line to look for air? At this point I would disconnect fuel lines and run from a 5 gal pail. No water or gasoline smell in your fuel? Possible the fuel stop solonoid is sticking closed. Or loosing power and closing.

Time to wiggle the harness and see if you find a spot that changes.

This engine missing at idle? I can't tell from the video except it runs horrable. Then sounds like it hits all 8. ECM could be giving it more fuel to bring RPM up and it runs away when all 8 hit.

I really suggest a scanner to see what the ECM is seeing. Bat voltage, temp, air temp etc.

I am lost on what parts are "new". How many miles on them? Specificaly the PMD is it brand new or been run awhile? I would not throw parts at it.
 
WarWagon said:
So optic sensor is out of the equation by the test.

Have you done the clear IP line to look for air? At this point I would disconnect fuel lines and run from a 5 gal pail. No water or gasoline smell in your fuel? Possible the fuel stop solonoid is sticking closed. Or loosing power and closing.

Time to wiggle the harness and see if you find a spot that changes.

This engine missing at idle? I can't tell from the video except it runs horrable. Then sounds like it hits all 8. ECM could be giving it more fuel to bring RPM up and it runs away when all 8 hit.

I really suggest a scanner to see what the ECM is seeing. Bat voltage, temp, air temp etc.

I am lost on what parts are "new". How many miles on them? Specificaly the PMD is it brand new or been run awhile? I would not throw parts at it.
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Pmd has 100miles on it ECM 40miles
 
When ECM goes into default will it smooth out if it is getting fault signal when I get back home going to try out of five gallon can should hook in before the lift pump or run on a siphon to the IP I drive truck won't be home until weekend to work on it again
 
Yes did the clear line test no bubbles yes that does sound like the problem from the days of running a mechanical pump
 
When I do drive it down the road and stand on it it becomes a mosquito fogger it does smooth out until you let off the throttle when it does smooth out still no power
 
When this started this time it was winter about 10below 0 it acted like it was gelling up put 911and changed filter and the lift pump I could not here it run I changed it out with one that I no pumps fuel. Question if the pickup sock is collapsed and causing fuel starvation and the getting aslug of fuel
 
Since no bubbles at all, get the fuel pressure gauge on there after the ffm and before the ip. That will end any guesses about pickup in tank, end lift pump guesses, etc. the cost will pay for itself when liftpump dies and it shortens ip life- you will know immediately and fix rather than wear out the pump.

I am leaning towards injectors at this point. Maybe pull the glow plugs, and crank it over. Watch the misting as it compares between cylinders.

Another option is crack injector nuts one to bleed any air that could be trapped in the injector lines but not showing up in return lines- can’t imagine this is the case, but is free and takes 10 minutes.
 
Will L. said:
Since no bubbles at all, get the fuel pressure gauge on there after the ffm and before the ip. That will end any guesses about pickup in tank, end lift pump guesses, etc. the cost will pay for itself when liftpump dies and it shortens ip life- you will know immediately and fix rather than wear out the pump.

I am leaning towards injectors at this point. Maybe pull the glow plugs, and crank it over. Watch the misting as it compares between cylinders.

Another option is crack injector nuts one to bleed any air that could be trapped in the injector lines but not showing up in return lines- can’t imagine this is the case, but is free and takes 10 minutes.[/QUOl
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Will L. said:
Since no bubbles at all, get the fuel pressure gauge on there after the ffm and before the ip. That will end any guesses about pickup in tank, end lift pump guesses, etc. the cost will pay for itself when liftpump dies and it shortens ip life- you will know immediately and fix rather than wear out the pump.

I am leaning towards injectors at this point. Maybe pull the glow plugs, and crank it over. Watch the misting as it compares between cylinders.

Another option is crack injector nuts one to bleed any air that could be trapped in the injector lines but not showing up in return lines- can’t imagine this is the case, but is free and takes 10 minutes.
Click to expand...
 
Tried cracking the lines before didn't change anything but will try again it is free I posted earlier about about sock collapsing starving for fuel making a suction would that cause parts in the IP toact this way. Like I have stated this is the fourth time this has occurred.seams to happen in the winter months and generally I am not the one driving.this time it started out like it was gelling up or starving for fuel.now when I changed IP last time it did not change until I changed pmd out with a bad one.that worked a couple of time this time but now it won't hopefully the I post what I have done will help you all give me different ideas to try at this point I am ready to get my mechanical pump off the shelf and put it on and say s----w the elecrelect one
 
Yeah, I get it. I won’t own another ds4 6.5. If I get one it quickly becomes db2. I feel for ya.

I have said for years that this engine should require a fuel pressure gauge. Coolant temp#1, oil pressure #2 fuel pressure#3.
 
when you unplugged the optical sensor it went into limp mode to start with it unplugged. The only thing I'm hearing is this seems to be linked to the PMD. I would change out the harness on the IP and verify all connections related to it are good. Member mrmarty51 has used dental files to clean terminals and solved his electrical gremlins
 
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