lean spot at 6k rpm
 

hi guys got a odd one

had my car on the dyno and they are saying the engine is getting a lean spot at 6k rpm. we have had haltech logged onto it for 2 hrs and they are saying all is good ecu side. we did have a lean spot at 2500rpm so i put a pulsation dampener before the primary rail and that fixed the issue. the car runs fine just on primacy injectors only and with secondary injectors only it will run perfect. both got 350hp. but when all 4 are plugged in it doesn't want to play. engine is running a in line fuel set up
engine is a jc cosmo 13bt. efr turbo, walbro 535 intank pump, -6 lines both ways, bosch 1650cc injectors, ffe fuel rails, all braided lines, haltech elite 1500
could it be im getting pulsations at the top end or you recon its something else like electrical
cheers

How long is the vacuum line running from your UIM to FPR? If it's got extra slack try removing a few inches of hose and see if it changes the rpm (pushing it higher) or fixes the problem.

Carlos shared this video a while ago and it sounds relevant to your problem.

https://m.youtube.com/watch?time_con...ture=emb_title

thanks for your reply
yes it is relatively long. I've got my boost solenoid, fpr and haletch vacuum sensor on ecu all on one line going thru the car. ill remove the fpr line and run its own line. that should make it shorter a fair bit. that's quite interesting that vid. thanks for that

Issue fixed! Not a 100% sure what the issue was from! But I installed a id750 fuel filter, radium fuel rails, pulse dampeners, cut 80mm out of vac line to fpr, went from 1x 535 to 2x 460 walbro pumps! But it’s all good now! Cheers