TOTAL loss of VTEC, Feels like Fuel Cut, please help
06-10-2020, 08:42 PM
#1
Thread Starter
TOTAL loss of VTEC, Feels like Fuel Cut, please help
Hey everyone, I’m currently extremely frustrated with my car and am EXTREMELY lost as to what I need to do now. Here’s the story and everything anyone would need to diagnose the car.
Build: 2002 Honda S2000
F20c
ap2 retainers
ap2 banjo bolts
stock motor other than that
Hondata Kpro V4 with all of the sensor conversions
Sheepey Vband turbo kit with gtx turbo
FIC 2150CC injectors
walbro 525 hardwired
ethanol
tial 44mm gate
AEM fuel pressure regulator
fuel pressure gauge
CC stage 4 six puck
oil relocation and oil cooler
All work is done by me
Story:
I bought the car last year in June 100% stock. Shortly after I redid the clutch with the popular act oem combo and sprayed a 75 shot of nitrous. I also upgraded to a walbro 450 and id1050x. Car made 199 base, 236 NA on ethanol and 305 with 75 shot. This was all possible thanks to hondata install which went smoothly. No issues in 2019 at all.
Winter of 2019/2020 I begin my turbo install. Changed out my injectors from the ID1050x to FIC2150. Changed out my fuel pump from a walbro 450 to a 525. Changed my fuel pressure regulator to the aem bolt on one and added a gauge. Changed my clutch to the CC stage 4 6 puck.
My first tuning session... car got on the dyno and I had a MAJOR boost creep issue due to a poor manifold design. I made well over 400whp and was only able to rev to 7500ish rpm. The boost creep was the only issue I had the entire time. So I went and bought a brand new Sheepey manifold and put a 14lb spring and ran on wastegate for around a week. PERFECT boost control and decided it’s time to go back to the dyno. (I had 0 issues)
Dyno session 2:
I’m the first person on the dyno and we notice that my fuel gauge is reading all wonky and my fuel pressure was EXTREMELY low. Turns out the fuel pump came loose from the hangar in the tank. Easy 1 hour fix. Here is where things get extremely wonky. I get back on the dyno and have perfect fuel pressure. The tuner begins tuning and every time vtec engages the car instantly cuts out. It’s like if you were to punch the car before reaching operating temp you get a nasty fuel cut. The car falls on its face instantly. here is what I’ve tried so far
I have 80/90’psi of oil pressure
i tested the solenoid, works
replaced the solenoid, no difference
tested continuity from ecu to solenoid, had it
completely ran a new wire from ecu to solenoid, still nothing
i noticed my car was only reaching 2/3 bars for operating temp so I replaced the coolant temp sensor, still no difference and this shouldn’t matter because the map allows vtec to engage at 141 degrees
At this point I have NO idea what to do. Tomorrow I will have a GoPro monitor my fuel pressure regulator when I drive. ALSO things to note. My idle is funky. My tuner said it almost like the fuel pump is surging at times. At idle the afr will randomly change from 14-17.5+ and just keep moving around. I’m sure I’m forgetting a few things but let me know if you have any questions or any ideas regarding what this could be.
Build: 2002 Honda S2000
F20c
ap2 retainers
ap2 banjo bolts
stock motor other than that
Hondata Kpro V4 with all of the sensor conversions
Sheepey Vband turbo kit with gtx turbo
FIC 2150CC injectors
walbro 525 hardwired
ethanol
tial 44mm gate
AEM fuel pressure regulator
fuel pressure gauge
CC stage 4 six puck
oil relocation and oil cooler
All work is done by me
Story:
I bought the car last year in June 100% stock. Shortly after I redid the clutch with the popular act oem combo and sprayed a 75 shot of nitrous. I also upgraded to a walbro 450 and id1050x. Car made 199 base, 236 NA on ethanol and 305 with 75 shot. This was all possible thanks to hondata install which went smoothly. No issues in 2019 at all.
Winter of 2019/2020 I begin my turbo install. Changed out my injectors from the ID1050x to FIC2150. Changed out my fuel pump from a walbro 450 to a 525. Changed my fuel pressure regulator to the aem bolt on one and added a gauge. Changed my clutch to the CC stage 4 6 puck.
My first tuning session... car got on the dyno and I had a MAJOR boost creep issue due to a poor manifold design. I made well over 400whp and was only able to rev to 7500ish rpm. The boost creep was the only issue I had the entire time. So I went and bought a brand new Sheepey manifold and put a 14lb spring and ran on wastegate for around a week. PERFECT boost control and decided it’s time to go back to the dyno. (I had 0 issues)
Dyno session 2:
I’m the first person on the dyno and we notice that my fuel gauge is reading all wonky and my fuel pressure was EXTREMELY low. Turns out the fuel pump came loose from the hangar in the tank. Easy 1 hour fix. Here is where things get extremely wonky. I get back on the dyno and have perfect fuel pressure. The tuner begins tuning and every time vtec engages the car instantly cuts out. It’s like if you were to punch the car before reaching operating temp you get a nasty fuel cut. The car falls on its face instantly. here is what I’ve tried so far
I have 80/90’psi of oil pressure
i tested the solenoid, works
replaced the solenoid, no difference
tested continuity from ecu to solenoid, had it
completely ran a new wire from ecu to solenoid, still nothing
i noticed my car was only reaching 2/3 bars for operating temp so I replaced the coolant temp sensor, still no difference and this shouldn’t matter because the map allows vtec to engage at 141 degrees
At this point I have NO idea what to do. Tomorrow I will have a GoPro monitor my fuel pressure regulator when I drive. ALSO things to note. My idle is funky. My tuner said it almost like the fuel pump is surging at times. At idle the afr will randomly change from 14-17.5+ and just keep moving around. I’m sure I’m forgetting a few things but let me know if you have any questions or any ideas regarding what this could be.
06-11-2020, 12:34 AM
#3
Wow! So many unknown variables added to the equation! 
So, you are saying the car goes into limp mode, when you hit VTEC RPM range? 
So, you are saying the car goes into limp mode, when you hit VTEC RPM range?
06-11-2020, 03:32 AM
#4
Thread Starter
I do trust the tuner as he’s tuned a few of my buddies before and a bunch of people from the Midwest recommended him. He might not be the absolute best but a lotta people stand by him. Thanks for including my other thread.
The car does not go into limp mode, but that’s what it feels like. It’s only when vtec attempts to engage at 4900/5000 rpm. The car simply falls on its face completely. When I look at the wideband it becomes filthy rich < 8.5 afr when it happens
The car does not go into limp mode, but that’s what it feels like. It’s only when vtec attempts to engage at 4900/5000 rpm. The car simply falls on its face completely. When I look at the wideband it becomes filthy rich < 8.5 afr when it happens
06-11-2020, 05:02 AM
#5
Did you change the cams?
06-11-2020, 05:41 AM
#6
Join Date: Nov 2007
Location: Illnoise. WAY downtown, jerky.
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Do you have enough oil in it?
and does the car still have a catalyst? If so...is it clogged?
and does the car still have a catalyst? If so...is it clogged?
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06-11-2020, 07:42 AM
#10
Can't the ECU be programmed to correct the richness problem?