RB25DET S2 Injector voltage

[Dev RB25]

RB25DET S2 Injector voltage

RB25DET S2 Injector voltage

need some serious help. car went in for a metal gasket job and ffp install. injector harness was extended, battery moved to the back. On the first day it started, the was a slight miss at idle. and when we hit 5k rpm, it hesitates and misfires, as you release the throttle , it idles like a impreza for a few seconds and then its back to normal.

Changed to bcpr7eix and another set of coil packs (wreckers), now the problem is at 6k rpm. taped coils up, applied dielectric grease.... if on 2nd gear at 6k rpm on boost it hesitates and misfires. IF on 3rd or 4th gear at 6k is just feels flat and empty...it just wont go past 6k and holds. you can feel like there is a slight miss-ish but not misfiring, i dont hold it too long that way worried im gonna blow something.

During this entire time, afr is at abt low 11's high 10's. timing up top has been set from 21 to 18 to 17 and stll doesnt help.

injector duty is at 65%.

MAF at abt 4.8v . the airflow load point in the map is at P15 (11k )

TPS been adjusted and this happens at any throttle Voltage it happens. i tried holding it at partial or WOT. so i doubt its the tps. at wot its 4.4v.

Batt Voltage reading 13.8~13.9

Im kind of lost and loosing hope here. Car was mint before the job. now it just doesnt want to run right.

Things ive checked are also for boost leaks, vacuum leaks, CAS timing (set at 15) crank and cam timing(all on correct markings). The car holds boost just fine, and at lower revs all the way to 5.8k it pulls hard. at 6k it just goes F*&&ed. makes no power whatsoever.

I even went to the extent of buying another set of bkr6 0.8mm to try it and its the same thing.

Car Spec :
RB25DET
Stock turbo
3"exh
fmic
walbro pump
fpr 3bar ( no vac)
stock coils
0.8bar boost
cometic 1.3mm metal gasket
power fc with fc edit
aem wideband

what do you guys think it is ? Wiring issue for the injector harness? battery moved to the back ? if it was injectors, i should be able to detect it on the log right? if it was fuel pump, shouldnt the afr be super lean before or when it happens? if it was maf the voltage should either be maxed out or suddenly drop? Could it be the coil pack harness? Please help. any suggestions or pointers will be great. any troubleshooting ideas . sorry for the lengthy post

When i checked voltage for the injectors, i noticed i was barely getting any voltage on the 12v wire,  its only abt 0.3-0.5v but on the ground with key on engine off, im getting 12-13v.  is this normal? shoulldnt i be getting 12v on both sides with key on ?

 

Edited October 6, 2016 by Dev RB25

[89CAL]

How are you measuring voltage on the injectors? If you are measuring from one side to the other on the injector then you will get next to no voltage. You need to measure between power into the injector with one probe and chassis ground with the other. Remember that the injectors earth through the ECU to fire and only do so when the CAS signals for the injectors to fire.

With the key on, engine off you should have - 12V between injector power and ground and nothing (or close to) if you probe either side of the injector (there is no ground so the voltage is not going anywhere and the injector cant use any of it, this means you potential difference voltage accross the injector is 0v)

Ive never tried spinning the CAS while testing injector voltage, but that may work, however the pulse may be so quick that the multimeter cant react quick enough

I think this is why people use noid lights, but having never really had any injector dramas myself I dont have much experience in this area