tloh

Ok... This is my first 240sx and sr20 motor so kinda in the dark about some stuff, but the general issues are has follows...

I have 2 ecus with the injecotrs to go with it
1. jim wolf ecu tuned for 555cc injectors, z32 maf, unknown turbo used
2. RS-Enthalpy tuned ecu for 740cc injectors, z32 maf, gt2871r turbo.

both ecus are in good working condition and with a good tune on them.

Motor mods are as follows
redtop
intake manifold isis
the injectors(555cc and 740cc)
the ecus
isis z32 maf
gt2871r .86
255 walbro
isis fpr
fmic
hks(real) ssvq (atmospheric)
bkr6eix-11 gapped at .35

Bunch of other small stuff, but this is the general idea.

Things I have checked
TPS voltage (.42 at idle in ecutalk and calumsult)
MAF is new
checked spark via holding coilpacks out and turning it over
BLT'd at 25psi no leaks
ecu voltage is above 12v on both black/white wires
timing has been checked and cas is set (the advance/retard is not set, kinda in the middle where it was previously)
all grounds have been checked
o rings on injectors on both sets have been checked.
new fuel pump gasket
other stuff as well, just can't think of it all.
fixed vac leaks, and made the car run worse (go figure)

The car runs in the low 10s afr wise no matter WHAT I DO. The slightest bit of throttle makes the fuel pressure jump 10psi. and I have even dropped the fuel pressure to 20psi at idle and STILL at wot with 555cc on a gt2871 hitting 18 psi.... it STILL hits 10.0-10.3, which should not happen at that psi with those injectors. The slightest throttle with fuel pressure idle set at 20psi makes the fuel pressure jump to 40+.

I can use #2 ecu with the 740cc injectors and same issue and the lowend driveability takes a HUGE decline. For a couple of days the 555cc and jim ecu was working decent lowend, but now recently has developed a idle drop issue when you push in the clutch when coming to a stop and revs alittle when pushing the clutch in. I adjusted the throttle cable and it helped for maybe 40 mins and was back doing it again and the adjustment hasn't moved.

The car runs lean (low 17s-18.0 at idle) and mid range is about 14-16 depending on the fuel pressure, which is decent. As soon as you go over about 45% throttle it just dumps fuel and starts going toward afr's in the 10s. By about 4k-5k at wot the car sits at 10.0-10.2. I can low the fuel pressure alot and will get 10.6-10.2, but at stock fuel pressure the car won't even run at wot as it hits 10.0 hard and starts choking.

I have tired the 740cc ecu with the 555cc injectors to try and force a lean issue and it does stay very lean, to make sure it wasn't a faulty new wide band.

Not sure where to start from here. This has become my daily now and i have been just staying out of boost and hoping to find the issue before something big messes up.

nismolvr

this might help, i did for me . A while back i upgraded to Z32 maf. mine was also running dog rich. found out it was my MAF wiring the maf has 2 grounds. pins C and D are grounds for the MAF , JIm Wolf wiring directions are wrong , It states to connect both grounds together. if youve done that thats probably why , your running rich. Disconnect pin C and connect that to chassis ground , i bet it will run better.close to stoich.

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tloh

I have the maf wiring with one going into the harness and one ground to chassis. I'll recheck voltage again though, thanks.

tloh

black/white 12.42
white .432
grounds are good.

nismolvr

ok , i see...

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inopsey

have you tried another maf? not sure i would trust a isis maf; and check your voltage at the fuel pump and injectors

Croustibat

How to solve your problems:

1/bin the ISIS stuff
2/use oem stuff (OEM intake mani, OEM Z32 MAF, OEM FPR)
3/ bin the blow off valve or recirc it, you have a MAF system. Or convert to MAP + IAT.
4/ get the thing mapped. A real map i mean, not an off the shelf tune.


ISIS is rebranded chinese junk, you dont want that on your car.

tloh

I think the intake manifold is a good idea. we flow tested the fpr at a shop and it was good. Plus I don't think running a stock fpr with 740cc injectors and a 255 walbro wouldn't be smart. and the ecus are tuned for the bov. I have ran dsms fine with out recirculating.

Croustibat

I am running 1000cc's with a real walbro and a stock sr20 FPR, so i dont "think" it works, i know it works. I dont know why zilvia boys are all crying about how a walbro "overfuels" the stock fpr, but it seems to only happen in the US ...

Now as far as "ecus are tuned for BOVs" go, well ... you CANNOT tune a MAF system correctly with a BOV, simple as that. A BOV is just a variable random leak in the system. If you dont understand what this implies, then you dont understand how a MAF based engine management works. you cant account for it. Yes it can run, randomly. But it does not run fine, and it goes pig rich every time the BOV opens at WOT, and sometimes go lean when it leaks at idle.
2 solutions: recirc, or bin.
Actually there is a 3rd : go MAP + IAT. But that is a pretty expensive and complex fix.

tloh

Ill try and recirc. it and see. or go ems and map it

tloh

got recirc kit for hks today and didn't fix the problem. tired a friends oem z32 maf and didn't change anything either.

tloh

The turbo wasnt preloaded by previous owner enough. Issue fixed. Also the isis stuff works perfect and as does the vent to atmosphere.

Zzz89

Can you explain turbo preloading? I'm kinda having the same problem thanks.

tloh

Google/search preloading a turbo theres tons of videos, i wouldnt recommend doing this unless you have checked for boost leaks becuase new gaskets are required as you have to take the turbo out. Its unlikely someone doesnt preload the wastegate when they switch wga's. Just wiggle the wastegate arm and make sure its super tight in closed position and you should be good. Mine was loose causing a huge leak at idle and above.

RalliartRsX

Sooooom the turbo was not preloaded, its that the wastegate wasn't preloaded. No such thing as "preloading" a turbo

However, this begs the the question. If the wastegate arms wasn't correctly tension, wouldn't this be EXTREMELY evident just by simply glimpsing at the boost gauge and realizing what little boost you are running?? Also, the tune isn't capable of running a little less boost that set for?? Sounds like it was only a wideopen tune.........

tloh

Wastegate is part of the turbo if its internally gated, don't be that guy, google it either way still comes up. And no i could not see a diff on the gauge becuase everyone said the .86 hotside on these motors spool super slow. So i figured 20psi at 4.4k was ballpark. Now its 20psi at 3800. But i think the ebc was helping cover the issue too.