HPFP irratic reading at high RPM

This started a few weeks ago with a slight "miss" at high rpms like above 5k. It didnt happen all the time. I completed a boost leak test and found no leaks. Pulled battery and let it go for a week or so and made a couple pulls with no issues. Yesterday on my way home I got on it and it missed again, and i noticed my HPFP reading was irratic from like 1860 falling just for a second to like 180 so i stopped running it hard and eased it home. It did drop pressure a couple times and stumbled around like it didnt wanna run on the way. Did the PRV test and when I turned the engine off the pressure never went up it only fell. Pulled HPFP and cleaned everything last eve also. It seems to me the PRV is bad? its only a year old. but i have another one laying around. any input ? should i just swap it out?

 

PRV swapped and seems to be working via the prv test. I replaced the fuel pressure sensor a year or 2 ago.

 

Cold engine koeo fuel pressure 57psi

 

2008 Speed 3, hks bov, aftermarket intake and turbo inlet pipe, grimspeed boost control solenoid, stock downpipe then straight pipe from there, front mount intercooler, tuned by justin at freektune been running 33% E85 for about 8 months, new turbo isntalled 7k miles ago. auto tech hpfp internals. i will get a datalog this evening and post.

 

boost leak test showed a tiny leak , fixed that and cleaned spill vavle. seems to be back up and running ...

 

So it's normal again? What oil and fuel are you running?

 

33% E85 mixed with 93. mobile one 5w30 if if remember correctly. yes it is running correctly now.

 

Maybe I should add that its been on this E85 mix for about 10 months and there was very little carbon build up and no "black death" going on in the HPFP.. lol just a little dirty..

 

If that's not a DEXOS oil, you may be in for some hard times. What did you use to clean and lube the HPFP? Specifically, what liquids?

 

Ummm... non chlorinated brake clean to clean everything. Then lubed with the clean on before my change..

 

Clean oil. This

 

Pull the HPFP again, clean it with lighter fluid/naptha. Only need to do the internals and spill valve though.
Lubricate the parts with Redline injector cleaner (can use a small bottle, it will last a long time). When you put the pump back on the car, make sure the spill valve is only finger tight. Take the spill valve back off, fill the pump up to the bottom/lowest thread you can see (with Redline), then fully reinstall the spill valve.

Despite being a Dexos oil, it may not be handling the ethanol well.

Edit: Fill the pump up using Redline injector cleaner to the bottom thread.

 

Ill.get on this next oil change. Daily driver. Hundreds of miles a week. It'll only be about 2 months. Thanks for the heads up