I have done 16v with megasuirt. 20190802_205854 I used corrado 16v automatic throttle body with TPS, VR crank sensor 60-2, FPR 4bar with vacuum. One person did me rolling maping, he is Honda guy, but has experience with maping. Everything was fine until I went to track day and had problem with car. After I realease throttle to pass stopping area of cones and when press accelerator full or similar engine stops, wideband shows out of range lean. This happens when revs drops below 5000. Is this mapping or fuel pressure problems? or bad vacuum?
If the fuel pump was struggling, lifting off the accelerator shouldn't cause it. But naturally the car will run lean off throttle.
I have changed fuel pump under the bottom. Fuel pressure still drops from 3.5bar to 3 bar when I increase rpm. If I unplug FPR hose, pressure gauge shows 4bar. Lift pump pumping about 1,5-2l in 40s. I dissconnected fuel accumulator, nothing changed. Maybe stock pumps can't handle 4 bar pressure?
what pump are you using? oem digifant is rated for 75 l/hr @ 3 bar, the kjet ones are rated for 127l/hr @ 5 bar. If the gauge shows 4 bar with the vacuum line to FPR off surely that means pump is fine though, maybe FPR issue?
I have tried with another FPR (good one from other car). If I unplug vacuumline from FPR and increase suddenly rev engine fuel pressure drops. I ordered new lift pump. I will try to change it.
interesting, thats a B2 passat main pump, but it sits inside the fuel tank on those. what housing have you got it fitted into? looked up the spec and its about the same if not better than a mk1/2 pump so should be more than good enough so long as its in good nick. does the pump run loud?
First, the digifant pump is fine in something like that. I run the original 8v digifant fuel 1991 myself in my MK2 Golf on here JENVEE. I have had that car up to 190+ bhp on the rolls with no change of not achieving target AFR. I have mapped many cars with the same pump, in fact it is the same part on a G60. Only time those pumps go faulty is if you have a faulty/noisy lift pump When your car was mapped, did the mapper have a trace of AFR or Lambda with the pulls? If the car is able to meet target lambda of full load, you have other issues, including hardware and maybe the map.
Housing is original mk2 K JET fuel box (I have 2 pumps with this part number: one was fitted in EV '84 and other came from '87 KR). Fitted new main pump and lift pump. Increase rpm fuel pressure raises to 4bar so it's one good thing. Lift pump was tired, but old main pump was good. But pressure drops slightly when increase suddenly rpm (maybe gauge bouncing). I have done test drive and main problem when I start pushing max with 1st gear engine stops and after moment began to perform. Rolling drives from partial throttle and full throttle from 4000 rpm were fine.
ah ok, I was hoping you found a kjet spec pump that would fit a digifant housing. that could be handy to know
Can you also run s a log of what is going on with mega logveiewer? I usually use a 3 bar map to set these up, but 4 bar should be fine.
