[JCart]

What brand mechanical pump? I yanked mine as soon as practicable and went with DIY E-fuel and have never looked back. Full power to RedLine, idles nicer too. Order a new SD spring and see what happens or track down a very small machine screw and nuts from hardware store, while waiting for new spring. Then do a bunch of research on DIY E-fuel systems on here.

 

[FarmerBrad]

What brand mechanical pump? I yanked mine as soon as practicable and went with DIY E-fuel and have never looked back. Full power to RedLine, idles nicer too. Order a new SD spring and see what happens or track down a very small machine screw and nuts from hardware store, while waiting for new spring. Then do a bunch of research on DIY E-fuel systems on here.

Unfortunately I was at a weak moment lol and purchased a NAPA part for my truck and told myself next time I would just go efuel but here I am in the winter again with no shop not wanting to do the conversion but sometimes your better to one and done.
I was thinking of ordering a replacement spring tomorrow just to see so Ill go with your advice and order a SD one any specific year?
Ill definitely start doing some reading on DIY efuels looks like a lot of good threads on the forum

 

[JCart]

Bugman reference the part number above is what I’d try.
Cheers

 

[97F250HDXLT]

This is the lowest price I see, before ~$11 shipping & tax:

Valve Assembly - Pressure Regulator F6TZ-9K061-AA | TascaParts.com

F6TZ-9K061-AA - Valve Assembly - Pressure Regulator

www.tascaparts.com

 

[FarmerBrad]

I tried the BB mod years ago and it didn't do that much for me. I then went with the California spring and it helped quite a bit.

Here is the part number for the spring kit. F6TZ-9K061-AA

Bugman reference the part number above is what I’d try.
Cheers

This is the lowest price I see, before ~$11 shipping & tax:

Valve Assembly - Pressure Regulator F6TZ-9K061-AA | TascaParts.com

F6TZ-9K061-AA - Valve Assembly - Pressure Regulator

www.tascaparts.com

Got the updated spring on order and will install and recheck pressures when it arrives sometime late next week
Appreciate your guys input and will update with results.

 

[FarmerBrad]

Well after a little bit of a wait as my part had to travel from Tennessee it finally came in and I had a chance to get it installed.
Definitely seems to be more firm of a spring and it shows as my pressure is within spec now.
I have attached a picture of the old spring with the bb and new one, also a video of the truck showing fuel pressure

 

[Grassfed]

Brad,

There is a gentleman on the 99+ forum named Tugly, who has mentioned this problem and potential fix. His theory was that as the injectors age they run better with more injection pressure which is why they will run smoother when cold because the injection pressure is higher than when the engine is warm if that makes sense. His remedy is/was new injectors If I am remembering correctly. This problem is widely documented but with no apparent fixes. Most of the threads just fizzle out. I think with enough of us tracking this down we might be able to make headway. I am inclined to agree with Tugly as I have seen many of his posts and appears to know a thing or two.

That being said, I have the same exact problem as you and have searched high and low for answers and have done numerous fixes and nothing has taken away that slight RPM hunt at warm idle. I have done E-fuel, new UVCH and pigtails, high pressure crossover line, re-oringed IPR, new ICP, CPS. I too pass the contribution test and buzz test without a problem. I'd hate to throw more sensors at it, even though at this point I'm really down to MAP, replacing entire IPR, and EBP sensor as far as what affects fueling and ultimately affects our problem. It is possible I have an injector or two that aren't performing up to snuff. I wish there was a way for me to tell beyond what I have done already. I talked to Jim at Rosewood Diesel some months back, and he explained how destroyed most of the plungers and tips are at this age. He replaces them with tungsten plungers and some other updates I think. It is definitely tempting to go this route but would hate to go through the money and time to be stuck in the same position. Of course, larger injectors are tempting, but more than anything I would just like a smooth running motor. Even with stock injectors and performance tunes these trucks are plenty fun to drive for me. In any case, I am here to try and help how I can and hopefully we can all learn something through this trial and error.

I should add too that recently the truck sat in single digit to negative temperatures for almost 4 days and on the fourth day, still in single digits, and after a couple slower than usual cranks it fired up on the first try after waiting about 20 more seconds after the Wait to Start light went out. I know this is more of an indication of Glow Plug Relay/ Glow plugs and battery performance, but thought it might add to the story a little as I would imagine if my injectors were really bad it would have had a harder time.


One thing I need to try is to get it up to temperature where it would start to rear its ugly head, take off the drive belt to rule out any funny business on that end.

Great trucks, have been blessed with many adventures with mine and plan on many more.



1997 F350 E-fuel, New ICP, CPS, Superduty pig tails and UVCH. 3" downpipe for reference.
AB injectors 170,00mi

 

[FarmerBrad]

Brad,

There is a gentleman on the 99+ forum named Tugly, who has mentioned this problem and potential fix. His theory was that as the injectors age they run better with more injection pressure which is why they will run smoother when cold because the injection pressure is higher than when the engine is warm if that makes sense. His remedy is/was new injectors If I am remembering correctly. This problem is widely documented but with no apparent fixes. Most of the threads just fizzle out. I think with enough of us tracking this down we might be able to make headway. I am inclined to agree with Tugly as I have seen many of his posts and appears to know a thing or two.

That being said, I have the same exact problem as you and have searched high and low for answers and have done numerous fixes and nothing has taken away that slight RPM hunt at warm idle. I have done E-fuel, new UVCH and pigtails, high pressure crossover line, re-oringed IPR, new ICP, CPS. I too pass the contribution test and buzz test without a problem. I'd hate to throw more sensors at it, even though at this point I'm really down to MAP, replacing entire IPR, and EBP sensor as far as what affects fueling and ultimately affects our problem. It is possible I have an injector or two that aren't performing up to snuff. I wish there was a way for me to tell beyond what I have done already. I talked to Jim at Rosewood Diesel some months back, and he explained how destroyed most of the plungers and tips are at this age. He replaces them with tungsten plungers and some other updates I think. It is definitely tempting to go this route but would hate to go through the money and time to be stuck in the same position. Of course, larger injectors are tempting, but more than anything I would just like a smooth running motor. Even with stock injectors and performance tunes these trucks are plenty fun to drive for me. In any case, I am here to try and help how I can and hopefully we can all learn something through this trial and error.

I should add too that recently the truck sat in single digit to negative temperatures for almost 4 days and on the fourth day, still in single digits, and after a couple slower than usual cranks it fired up on the first try after waiting about 20 more seconds after the Wait to Start light went out. I know this is more of an indication of Glow Plug Relay/ Glow plugs and battery performance, but thought it might add to the story a little as I would imagine if my injectors were really bad it would have had a harder time.


One thing I need to try is to get it up to temperature where it would start to rear its ugly head, take off the drive belt to rule out any funny business on that end.

Great trucks, have been blessed with many adventures with mine and plan on many more.



1997 F350 E-fuel, New ICP, CPS, Superduty pig tails and UVCH. 3" downpipe for reference.
AB injectors 170,00mi

Thanks for the response Grassfed,
I remember reading thru quite a few threads of his aswell (don't remember if it was here or elsewhere) and seems like a smart guy and the theory makes enough sense.
I've replaced injectors on different diesels engines for various problems but these HEUI Powerstrokes are new to me and like you said don't want to end up in the same spot after replacement just because I didn't do my homework and diagnostics.
Wouldn't be surprised if that's the route I end up going down as previously stated seeing what was in the filter bowl these injectors probably aren't in good shape and are wore out however they do seem to perform well still making it not super high on the priority list as of now just didn't want to start replacing other components trying to remedy the issue.
Although I'm glad my fuel pressure is within normal range now it still hunts occasionally like it did before.
Your right it's unfortunate that most of the threads just get left hanging dead with no real result on what fixed the problem but that's just the nature of the internet lol.
However funny you mention taking off the drive belt because one of the next projects I intend on tackling is the LPOP and balancer replacement as the seal is leaking on the front and looks to me like that pulley has some runout that wouldn't be helping anything for that matter so I will update if that helps with idle as I'm sure its not gonna hurt any.