CM871 fuel pressure delivery

[Skinny6]

I have a 2009 389 with an ISX600 cm871 in it I have been getting the "fuel pressure delivery" warning on dash and when it comes on the truck runs like it has a big cam in it. It will also when going down the road go limp like taking foot off accelerator for 3 to 4 seconds with red shut engine light and amber engine light on then they go out and truck runs normal again. The truck is hard to start as in just cranks and cranks and now to the point of needing a little ether sometimes to fire up. Any help would be appreciated I have had it in a couple shops and nobody has been able to help much as it does it at no specific intervals except for the hard start which is regular now

[tree98]

Bubble test your injectors for starters

https://youtu.be/Wu_WN8BA-LA

Can you hear the fuel priming pump come on and run for 2 minutes when you turn the key on?

There's a check valve on the isfm to keep fuel from draining back, they do go bad.

You could monitor fuel pressure with insite while driving, maybe the pumps dropping out intermittently from a broken shaft or ??

What did the shops do to try to figure out the problem besides drive it around and wait for it to act up?

[Skinny6]

I can hear the pump running yes and as for what they did they said they tested pressures but did not tell me what they were as in key on and when starting and running. I can also say that now after starting and it running then shut it down for as little as 2 or 3 minutes it still has to crank alot before starting as where it use to start normal other times after the first start of the day.

[Skinny6]

I can hear the pump running yes and as for what they did they said they tested pressures but did not tell me what they were as in key on and when starting and running. I can also say that now after starting and it running then shut it down for as little as 2 or 3 minutes it still has to crank alot before starting as where it use to start normal other times after the first start of the day.

[Rawze]

if it is losing its prime or getting air in the fuel system, the sound of the electric pump will change ad the air goes thru it.

You should listen for the electric pump changing pitch or sound... getting louder.softer, etc. as it runs for its 2 minutes with the key on and engine not running.

your issue could be air in the fuel, the gear pump starting to go bad, or possibly even the shut-off solenoid not operating correctly.

Could even be just the fuel pressure sensor.

you did not mention the exact fault codes that come up in insite when its acting up. Without this, its also anyone's guess too. You need to find out what codes it is throwing exactly.

all things to think about.

Like others have said.,. you need to also do an injector leak test on it. This ensures that the fuel system components are not getting hammered by combustion gasses, due to a leaky injector.

[Signature620]

Could be a long shot but check this out. I've come across 2 trucks lately with this exact complaint that we're sucking air intermittently through the test port before the gear pump. A quick check is have a look and see if the inner section of the fitting is sitting below the surface of the rest - It should be flush. If it's receeded, run the engine and put your finger over it. You'll feel it pulsing.

   

[Skinny6]

Quick update I am taking to get the codes in the morning and check pressures I did run the pump like said to and listened trying to see how to post it on here and now it will not start without a little help from starting fluid.

[Skinny6]

At about 30 seconds the pump kinda bogged down for about 3 seconds or so then picked back up and

[Rawze]

(01-13-2022 )Skinny6 Wrote:  At about 30 seconds the pump kinda bogged down for about 3 seconds or so then picked back up and

When the pump bogs down, it is getting fuel. If it only did this briefly then it is sucking way too much air.

Check your fuel water separator.. might have the gasket installed wrong, or is sucking air, etc.

The older models that have the glass (plastic) bowl that hangs down are notorious for sucking air if the gasket is not installed exactly right or if they are getting worn out.

The Davco style however have the glass bowl mounted upright, and will show no fuel on the fuel up on the filter if it is sucking air.