Running lean Harrop Supercharger

codes :
P0171 System too lean (bank 1)
P0174 System too lean (bank 2)
P0230 Fuel pump primary circuit

Fuel trims : (idle)
stft bank 1 : 20.312%
ltft bank 1 : 12.5%
stft bank 2 : 20.312%
ltft bank 2 : 13.281%

Fuel pressure : (idle)
at inlet hose on drivers side : 50~ psi
passed fuel pressure regulator on passenger side : 20 psi

does anything here look off or does anyone know a common cause?

Truck has Harrop supercharger, DW 650cc injectors, tune from D3performance, fuel pump hardwire kit from DW

The truck idles rough but won't die in most cases, this causes issues when shifting and decelerating mostly. It has run fine for about 20k miles since installing SC then it started blowing the fuel pump fuse which was found to be caused by a loose fuel rail. in the process of fixing the fuse issue I replaced the Fuel pump (DW 340LPH, same as comes with the Harrop kit) and ran the DW hardwire kit to the fuel pump. Because of this I also get the code for fuel pump primary circuit.

If anyone has next steps for troubleshooting or a guess at the root cause it would be much appreciated!

 

Short term fuel trims are extremely high, long terms are probably higher and blowing the codes which usually go off around 25% out of wack. Are you saying it's at 20psi after the regulator, or that the passenger side rail is only getting 20psi?

Do you know what your fuel trims were before? There's a chance the tune is off and just didn't get triggered until the fueling changed a little.

 

I do not know what my fuel trims were previous to the hardwire kit, what would have changed the fueling? The pump should be running the same it did before the hardwire kit to my knowledge, and it was AFTER the regulator so the passenger and driver side rails should be very similar in the 50 psi range, but i was only able to measure the drivers side.

will contact the tuners and see if theyre willing to data log it and see if its something there.

 

Obviously something changed in the fueling, which is why I was asking. Might just be different performance with the pump or something and if the tune was on the edge of throwing a code to begin with maybe it was enough to push it over the edge? I've seen a number of tunes where the fuel/MAF variables aren't tuned well and people end up throwing codes when they drive to a different elevation or change something minor. The other alternative is the pump can't actually keep up despite showing 50psi. Even if the fueling trims were off by a lot it's weird it would be so far off it'd have issues just idling. Do you have any way to monitor the fuel pressure with the truck running and see if it's maintaining 50psi at idle?

 

And you didn't touch anything else? You said you had a loose fuel rail, are you sure the rails are all properly seated and all the hoses are good? Maybe there's a vacuum leak somewhere and that's why it's running lean.

 

I will check for hoses, there is a whistling sound coming from somewhere but i thought it was just the pulley,

the fuel pressure was measured with truck off/pump on and then with truck on and at idle and i put it at redline to see if there were any sudden drops but it was at no load completely stopped, pressure guage was bouncing between but didnt drop

on the loose fuel rail, it was the passenger side rail, front bolt, both rails are now snug and i have visually inspected the injectors to ensure they are properly seated but i have not fully removed the fuel rail to reseat/clean them which will be the next step after i hear back from the tuners about the expected ltft and stft

 

Yea that'd be my two things, try to verify there's no vacuum leak anywhere and see if you can get a datalog to D3 and see what they say. I would start with figuring out why the idle is bad and that will probably also fix whatever else. The fact it maintains pressure would seem to indicate the fuel system is physically fine, so in my mind all that leaves is air getting in or the tune doing something weird.

 

So d3 verified the tune wouldnt do anything weird just for a new fuel pump and the hardwire kit would not affect this,

vacuum leak it is, will try to find it later today and take it somewhere for a smoke test if i cant find it physically

still need to call harrop to verify what fuel pressure should be since the regulator is modified by them, stock claims to be 38-44(i think?) so mine is high but i dont see how that could cause a lean code, will update later tonight

 

Without D3 seeing a datalog I wouldn't rule them out. There was another member a few days ago with a truck freshly tuned by D3 and he was getting a code for being too rich (https://www.tundras.com/threads/general-supercharger-thread.85513/page-288#post-3204883), though granted he didn't have 20k successful miles on his tune. IF you don't find a vacuum leak, I would talk to D3 and see if you can send them a datalog and see if that reveals anything or can point you in a direction.

 

It was a vacuum leak.
When i removed one of the vacuum lines during the whole fuel pump fuse blowing issue to fix a coolant line too close to the belt i put them back in the wrong order so the vacuum line was being pulled a little bit causing it to leak, putting the hoses back correctly fixed it, thanks for the help!

didnt notice at the time since it was having the fuel pump fuse issue assumed they were related.

 

Had the same issue if you look at my previous post. Turns out one of my workers didnt swap the oring spacer over during the fuel pump swap. Engine was not getting sufficient fuel pressure.