ECU Fuel cut/boost cut under load
#1
ECU Fuel cut/boost cut under load
Running into an interesting problem with my 94 Civic turbo build. Under load, the car seems to hit boost/fuel cut 6500-6700RPM and shuts off all datalogging to the Hondata S300v2 unit I have installed. Of course, I can't log in to see what exactly it's doing on the ECU because it doesn't record the issue before it cuts out and restarts. My tuner says it might be a RF interference disrupting ECU signal? Does it only under load, and not at idle. It HAS to be under load. Also, I am overheating after a few pulls(heat soak), but I suspect that a higher flowing 12" fan could resolve this issue as I have burped the system and added Wetter Water before tuning. I have no water leaks and the thermostat is working normally. Current setup:
9:1 compression/81mm
LS stroke/manley rods/je pistons
ITR cams/springs/retainers
14psi spring in 38mm tial wastegate
650cc rc injectors
walbro 255lph
Top mount manifold
72mm Turbo
stock ignition system/vms 10mm wires/ngk copper plugs @ .045mm
2.5" piping
Things I have added/tried:
-Added one ground from intake -> strut tower (0g ground wire)
-Added thicker Thermostat ground
-Checked signal at dizzy(OK)
-Rechecked timing and reset (tuner found one tooth off on intake, jumped on dyno, reset)
-Check fuel(disconnected fuel feed line and checked flow rate, healthy)
-Check injectors(no leaks that I can tell, could use a cleaning though)
-New Fuel Filter
Things I have planned:
-Larger, Better cfm rated cooling fan for overheating issue
-Maybe more grounds/thicker grounds? (0 gauge?)
-Retime dizzy w/ mechanical timing
-check ecu for burned resistors/grounds/pins?
-Have a beer
Please, if anyone has had an issue like this, point me in the right direction, and let me know if I'm already headed that way. This is my first turbo build and I'm excited to see what I can accomplish in my driveway. Attached is a photo of my car.
9:1 compression/81mm
LS stroke/manley rods/je pistons
ITR cams/springs/retainers
14psi spring in 38mm tial wastegate
650cc rc injectors
walbro 255lph
Top mount manifold
72mm Turbo
stock ignition system/vms 10mm wires/ngk copper plugs @ .045mm
2.5" piping
Things I have added/tried:
-Added one ground from intake -> strut tower (0g ground wire)
-Added thicker Thermostat ground
-Checked signal at dizzy(OK)
-Rechecked timing and reset (tuner found one tooth off on intake, jumped on dyno, reset)
-Check fuel(disconnected fuel feed line and checked flow rate, healthy)
-Check injectors(no leaks that I can tell, could use a cleaning though)
-New Fuel Filter
Things I have planned:
-Larger, Better cfm rated cooling fan for overheating issue
-Maybe more grounds/thicker grounds? (0 gauge?)
-Retime dizzy w/ mechanical timing
-check ecu for burned resistors/grounds/pins?
-Have a beer
Please, if anyone has had an issue like this, point me in the right direction, and let me know if I'm already headed that way. This is my first turbo build and I'm excited to see what I can accomplish in my driveway. Attached is a photo of my car.
#2
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Re: ECU Fuel cut/boost cut under load
Sounds like it could possibly be a connection issue between s300 and the ecu itself. Check all the solder joints on the ecu where the s300 is installed. Was it soldered in by someone reputable?
#3
Re: ECU Fuel cut/boost cut under load
I'm not sure who put it together, as I bought it second-hand and didn't think about the soldering. I will definitely check that this next Saturday and get back to you about that. Lots of pics in store. Out running errands today, as I'm moving the end of the month.
#4
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Re: ECU Fuel cut/boost cut under load
You could try another know good ecu with s300 to rule out the ecu/s300 as being the issue for sure. If you had access to one that would be the easiest way to rule it out.
#5
Honda-Tech Member
Re: ECU Fuel cut/boost cut under load
I agree it sounds like either the s300 itself or installation could be the issue. Might be time for an upgrade to a v3
#6
Re: ECU Fuel cut/boost cut under load
Are you logging with the laptop connected or auto logging? sounds like you are auto logging, and if so, try it with the laptop connected to catch your issue. If you're relying on an auto log then download, the system wigs out and doesn't save your log; you miss little problems like this.
#7
Re: ECU Fuel cut/boost cut under load
Are you logging with the laptop connected or auto logging? sounds like you are auto logging, and if so, try it with the laptop connected to catch your issue. If you're relying on an auto log then download, the system wigs out and doesn't save your log; you miss little problems like this.
The dyno used was Dynojet and as far as I know was hooked up to the laptop using a new Hondata connection wire that was purchased about two weekends before. I will ask my tuner if he was autologging, but he's a bit cranky sometimes, so I might not get an answer there until I answer that one myself, lol.
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#8
Re: ECU Fuel cut/boost cut under load
The dyno used was Dynojet and as far as I know was hooked up to the laptop using a new Hondata connection wire that was purchased about two weekends before. I will ask my tuner if he was autologging, but he's a bit cranky sometimes, so I might not get an answer there until I answer that one myself, lol.
Ok, reading the other responses here, they are on the trail also of why it wouldn't be logging. Got it!
My follow up question is: What in the blue blazes is happening under load; fuel cut, or not logging?!
If any of this is occurring while tuning, I'd suggest finding another tuner. You're paying them to do this and a good tuner will help you get it done (either with or without an additional charge) and not just treat you like a number and try to get you in and out as quickly as possible.
#9
Re: ECU Fuel cut/boost cut under load
Woah.. This happened on the dyno? I didn't catch that part (don't think it was mentioned). And the tuner couldn't tell what happened? Is the tuner trying to figure out boost cut, or the Hondata not logging? Now I'm a bit confused. Referencing RF interference tells me he is trying to diagnose the log cutout, but the bullet point here references boost/fuel cut but unsure due to Hondata not logging,, **shrug**
Ok, reading the other responses here, they are on the trail also of why it wouldn't be logging. Got it!
My follow up question is: What in the blue blazes is happening under load; fuel cut, or not logging?!
If any of this is occurring while tuning, I'd suggest finding another tuner. You're paying them to do this and a good tuner will help you get it done (either with or without an additional charge) and not just treat you like a number and try to get you in and out as quickly as possible.
Ok, reading the other responses here, they are on the trail also of why it wouldn't be logging. Got it!
My follow up question is: What in the blue blazes is happening under load; fuel cut, or not logging?!
If any of this is occurring while tuning, I'd suggest finding another tuner. You're paying them to do this and a good tuner will help you get it done (either with or without an additional charge) and not just treat you like a number and try to get you in and out as quickly as possible.
Personally, I think the problem is hand-in-hand. The tuner said they're both happening at the same time. So its either:
a.) Boost cut is causing hondata to shut down(I've never heard of it)
-OR-
b.) Hondata is losing connection and cutting all fuel/spark making it seem like a boost cut is happening.
I hope this clarifies. I've checked my grounds yesterday and they seem fine. About to pull the computer next to check soldering.
EDIT: I have datalogging up until it hits the cutout around 6500 rpm @ 75%-100% throttle
Last edited by Vomit; 07-19-2018 at 09:54 AM.
#10
Re: ECU Fuel cut/boost cut under load
Gotta be something quirky in the soldering. When I first installed my Demon2 board, I had a solder issue and if anything bumped the ECU kick panel, it would go into limp mode. Similar issue since it would also disconnect and cause Neptune to crash; just like pulling the USB with the program running without properly disconnecting from the program. Forgot about this until now.
#11
Re: ECU Fuel cut/boost cut under load
UPDATE:
*Installed a better valve cover ground*
*double checked timing in Hondata and motor, set to 16° advanced at idle*
*installed high flow radiator fan*
*regapped plugs from .045 to .030*
*uploaded my tune from s300v2 to a new s300v3 borrowed from a friend*
Something happened when the file was transferred to the s300v3. The car wouldn't start at all with the original tune from the v2 on the v3. It acts like it wants to start, but blows fuel out of the exhaust and quits. Starts up every time with original tune on the v2, no problems. About to pull the ecu
today to check it out. Also messaging hondata about the issue.
*Installed a better valve cover ground*
*double checked timing in Hondata and motor, set to 16° advanced at idle*
*installed high flow radiator fan*
*regapped plugs from .045 to .030*
*uploaded my tune from s300v2 to a new s300v3 borrowed from a friend*
Something happened when the file was transferred to the s300v3. The car wouldn't start at all with the original tune from the v2 on the v3. It acts like it wants to start, but blows fuel out of the exhaust and quits. Starts up every time with original tune on the v2, no problems. About to pull the ecu
today to check it out. Also messaging hondata about the issue.
#12
Re: ECU Fuel cut/boost cut under load
Interesting. If it does well on the V2 but ***** the bed on the V3, think you've got your answer.
#13
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Re: ECU Fuel cut/boost cut under load
Sounds like your tune got corrupted when trying to transfer it from s300v2 to v3. You probably need to get the original tune file from your tuner and try uploading that to the s300v3 and try again. Also .045” plug gap is way too big for a turbo setup, .030” is probably pushing it, I typically start at .025” and only tighten it down if I run into spark blowout.
#14
#15
Re: ECU Fuel cut/boost cut under load
Thank you for the input, guys! I will re-gap to .025 and retest once more. Also, called the tuner, and he is going to email me a copy of the current tune. He mentioned the same thing as previously stated about file corruption.
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