free website stats program '03 FLHTCUI running lean | Page 2 | Harley Davidson Forums

'03 FLHTCUI running lean

glider said:
38 lbs will just run at idle but will not be enough to run at any more than idle on a good day.


Have you checked the filter ? You may have a bad pump too.
Click to expand...

38 psi is pretty low IMO that could be the whole issue
 
Glider & Jack have you covered. That low press relates to the quantity of fuel delivered. No way out of that. Get that squared away before going any further.
 
coop85 said:
I replaced the filter and wouldn't be surprised if I managed to cause the low fuel pressure by not getting the clamps quite right. However, swapping out the filter had no effect on the way it runs. It misses at idle and will eventually quit. The bike accelerates pretty well up to highway speeds, although not quite as well as it used to.
Click to expand...

If you are pulling all that stuff back out of the tank again, replace the fuel pressure regulator too.

TQ
 
all good info, but I still have to wonder if a leak or pressure regulator wouldn't also be evident during the first 34" of running? I can ride it warmed up at highway speeds, squeeze the clutch, turn off the ignition, restart it and ride for 34" just fine at highway speeds before it pops again???????????
 
coop85 said:
all good info, but I still have to wonder if a leak or pressure regulator wouldn't also be evident during the first 34" of running? I can ride it warmed up at highway speeds, squeeze the clutch, turn off the ignition, restart it and ride for 34" just fine at highway speeds before it pops again???????????
Click to expand...
Immediately after start, there is a period of enrichment that occurs, until the engine is warmed up, tapering off as the engine warms up. I can't help but think that what you are seeing is a brief enrichment period, as the ECM samples engine temperature, normalizing the initial engine temp readings until determined to be reliable and stable. The enrichment/temperature algorithm is not published, so we can only guess. I do know that many things that could be detected with a single sample, are not reported for some period of sustained issue, like injector connection issues. This is likely so that sampling glitches can be ignored.

During the enrichment period, injector 'on' times are extended, providing more time to get enough fuel for combustion into the cylinders, temporarily compensating for low fuel rail pressure, which you DEFINITELY have, according to your previously posted measurements. I suggest that you fix what you already KNOW is wrong, then see if there is more to fix...in that order. These machines are VERY sensitive to fuel rail pressure, with fuel mix based upon that pressure. The symptoms you describe are definitely consistent with low fuel rail pressure. There may be more contributors, as I have discovered with my own ride, but you can only address them as you discover them. Right now, low fuel rail pressure is likely dominating your symptoms.

These are my suggestions, and are based on the presumption that previously posted fuel rail pressure readings are reliable. It is your ride. You decide.

Enjoy,
Rich P
 
You must log in or register to reply here.
Back
Top