Did my VP go too?

[Shainer]

Have to be methodical and start proving systems out one at a time.  If the symptoms are repeatable at idle you can crack injectors to try and figure out how many cylinders are impacted and try correcting the the injectors on those holes.  If that doesn't change things or it seems like there is no consistent issue on specific cylinders I'd probably look for air in the fuel by adding a section of clear line.

 

Actually walk through BlueChip's guides.  No sense in me re-inventing the wheel.  Only thing I will add is that in my experience issues tend to be related to components and systems a person has messed with.  They make the assumption everything was done right, and never prove them out.
https://www.bluechipdiesel.com/troubleshooting-1

 

Edited March 11, 2018 by Shainer

[Marcus2000monster]

I’m going to try to crack each injector individually today if I get the truck out and it does what it’s been doing. So if I crack an injector and it starts runnin crappier that means that injector is A ok? And if it don’t change idle quality it is malfunctioning? 

[dripley]

That's pretty much it, providing the problem is in the injector.

[Marcus2000monster]

3 minutes ago, dripley said:

That's pretty much it, providing the problem is in the injector.

Going to do as @Shainer said and rule out what I can. Injectors are first on  the list. I can’t understand why I didn’t have this problem until after the Airtex died unless it’s the VP? Surely if injectors were at fault the symptoms would have been present before the lp failure. 

I’m thinking I want to pull the connector tubes out and inspect them as well. I read a thread on here by @Mopar1973Man about a miss in his truck and it turned out to be connector tubes....

[dripley]

It's a process of elimination. The fuel system is pretty simple except for the VP and it's internals. I like you dont think it's an injector but it could any connection in the system. It seems 9 times out of 10 the issue lies in what you worked on. It does for me any how.

[Marcus2000monster]

8 minutes ago, dripley said:

It's a process of elimination. The fuel system is pretty simple except for the VP and it's internals. I like you dont think it's an injector but it could any connection in the system. It seems 9 times out of 10 the issue lies in what you worked on. It does for me any how.

Well that’s very true because it certainly didn’t come from the lot running like that! Lol. If injectors and tubes check out I’m gonna be pretty certain it’s VP time. All the symptoms I have a are Vp44 failure related. 

[Shainer]

Yup process of isolating the issue.  9 out of 10 times it is related to prior components being messed with... and one guy didn't complete the survey.  I look at it from the perspective of what if you replace the IP and the issue remains?  Are you better off?  Do you have more reliable data to isolate the issue, or did you add another handful of uncertain variables?

[Marcus2000monster]

Just now, Shainer said:

Yup process of isolating the issue.  9 out of 10 times it is related to prior components being messed with... and one guy didn't complete the survey.  I look at it from the perspective of what if you replace the IP and the issue remains?  Are you better off?  Do you have more reliable data to isolate the issue, or did you add another handful of uncertain variables?

Lots of truth there. I believe that the process of elimination should begin with the simplest and end with the most advanced. 

[Mopar1973Man]

Typically I work on a two smoking gun rule. I try to find two different test that could possibly fail the device. Basically, double checking your work.

[Marcus2000monster]

8 minutes ago, Mopar1973Man said:

Typically I work on a two smoking gun rule. I try to find two different test that could possibly fail the device. Basically, double checking your work.

?????

[Marcus2000monster]

If there was air getting into the system wouldn’t the symptoms exist with a cold engine as well as a warm engine?

[Mopar1973Man]

Depends on the air leak. Suction side leaks never drip and continuously pull air into the system all the time your driving. 

 

As for my comment above. Like I said find two different test that could possibly pass or fail the device you think might be failing. This way you get a double fail then you know you not spending money needlessly on a guess. 

[Marcus2000monster]

37 minutes ago, Mopar1973Man said:

Depends on the air leak. Suction side leaks never drip and continuously pull air into the system all the time your driving. 

 

As for my comment above. Like I said find two different test that could possibly pass or fail the device you think might be failing. This way you get a double fail then you know you not spending money needlessly on a guess. 

Must not be a suction side leak then. Only idles shitty not at wot or anything above 1500 rpm. Talked to the folks that the po ou truck had replace the injection pump and they said they have their pumps done by industrial injection so I know that they’re a certified rebuilder andnits not likely that a bad pump is their fault... What would you suggest for tests on the Vp44?

[Mopar1973Man]

Injectors wore out? Pop pressures low or pissy?

[Marcus2000monster]

4 minutes ago, Mopar1973Man said:

Injectors wore out? Pop pressures low or pissy?

Just installed 75s 2 weeks ago. Never had issues with them till the Airtex went out.

[Shainer]

What tests have you performed?

[Marcus2000monster]

1 hour ago, Shainer said:

What tests have you performed?

So far I cracked injectors and all seemed to make the truck idle strange so they check out.  I am going to get spray bottle with soapy water to spray around the liftnpump fittings and filter canister etc to look for air leaks. 

[Shainer]

I would not do that.  If air intrusion is suspected the last thing you want to to is suck water and soap onto the fuel stream and send that to the IP and injectors.  Besides you will never see a single bubble on any line under vacuum or pressurized fluid.  Read Blue Chip's section on long crank times.  He outlines air in fuel validation.

 

Lets talk about the replacement lift pump.  Is that in your signature?  It has air separation?  Where is the return line on the lift pump plumbed in?  Did you replace all the lines from the tank to the IP?  Quick connect on the tank?

Edited March 13, 2018 by Shainer

[Marcus2000monster]

Returned to the filler neck and it’s a yes to all the questions 

[Shainer]

Hmmm...  Did FASS switch over to mostly quick connect fittings?  You keep the factory fuel basket in the tank?  My bet is your issue is on the suction side of the lift pump.  The longer it runs the more aerated it makes the fuel.  I when it starts acting up the lift pump is probably getting noisy as well but you may not be able to hear it.  You could jumper the lift pump relay harness after the engine starts missing so you can listen to the pump with the engine off.  The alternative is to disconnect inspect, clean, replace any quick connects on the suction side.  Guys sometimes don't get the one on the tank seated, or while seating it get debris in it that allow air to enter.