Sup guys, I recently just switched from a P73 with a VAFC to a P28 with s100. Got the car tuned last Wednesday.

I was driving around this weekend and I was on the throttle taking it through second gear and right at 5200 when VTEC should engage, my fuel cuts, completely. And the RPMs drop to 0. CEL comes on until I let off the gas... then the CEL goes off and the fuel comes back.

If I downshift I can hit VTEC and it pulls through just fine. Since this happened the first time it randomly keeps happening. Sometimes VTEC engages just fine, sometimes I get thrown against my sealtbelt from the fuel cut. It's lot's of fun.

My only thought is that since I still have my VAFC hooked up it is causing a problem. It doesn't have any fuel adjustments on it, but the VTEC crossover is still active, my tuner had to set it to 5200 along with the hondata, or the vafc was overriding the hondata. Should I just unhook my VAFC? Ya it's pretty much worthless at this point, but the throttle position monitor, rpm meter and neat-o red light when VTEC engages were reason enough to leave it in for now.

Just to add, this is a RANDOM problem. Sometimes VTEC engages, sometimes it doesn't. But it doesn't even stay on the low lobe, it actually CUTS fuel. Very frustrating and I've never heard of anyone else having this problem. BTW the motor is a 82X89mm ls/vtec.

 

Take the car back to your tuner for inspection.
It sounds like your tuner may have left the vtec pressure switch enabled when you don't have one etc...

 

Remove the VAFC....it is going to interfere with your ECU.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mtber &raquo;</TD></TR><TR><TD CLASS="quote">Take the car back to your tuner for inspection.
It sounds like your tuner may have left the vtec pressure switch enabled when you don't have one etc...
</TD></TR></TABLE>

Thanks, I called my tuner and am waiting for a call back. So you don't think the VAFC would cause the fuel to cut like that do you?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spunkster &raquo;</TD></TR><TR><TD CLASS="quote">Remove the VAFC....it is going to interfere with your ECU. </TD></TR></TABLE>

werd. Sell it.

 

/sigh.

I love how I get 2 people saying "remove the VAFC It'll interfere with your ecu" yet they offer no explanation of why or how. ALL the VAFC does is cross the cam over, there is no fuel adjustments. How can it "mess up" my ECU?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2LEM1 &raquo;</TD></TR><TR><TD CLASS="quote">/sigh.

I love how I get 2 people saying "remove the VAFC It'll interfere with your ecu" yet they offer no explanation of why or how. ALL the VAFC does is cross the cam over, there is no fuel adjustments. How can it "mess up" my ECU?</TD></TR></TABLE>

It's not going to "mess up" your ecu, but if the settings are adjusted at all, it will alter the settings that the car was tuned with. As with all software, there are chances that issues will arise, hence two people with a ton of electronic software recommend removing it. Also as with what mtber said, do you have a JDM ITR motor? If so and you are running the P28 ecu, it is looking for a vtec pressure switch unless you bypassed it.

 

My cousin has a white ek with a b20 vtec jrsc in it with a p28 and the same hondata you have. He has some problems with it sometimes too sometimes when he tries to smash on it, it would just jerk real hard. Iono if it is the same for you but the problem for his is the wire connecting the hondata to his ecu gets loose inside the ecu and all he does is push it back in. Make sure the red light on your hondata is on. This could be or might not be your problem, but it wouldn't hurt to check.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blown90hatcH &raquo;</TD></TR><TR><TD CLASS="quote">

It's not going to "mess up" your ecu, but if the settings are adjusted at all, it will alter the settings that the car was tuned with. As with all software, there are chances that issues will arise, hence two people with a ton of electronic software recommend removing it. Also as with what mtber said, do you have a JDM ITR motor? If so and you are running the P28 ecu, it is looking for a vtec pressure switch unless you bypassed it. </TD></TR></TABLE>

ty for input, there is no settings on my VAFC at all anymore. While I understand the effect of having two tuning devices fight each other for control, the VAFC is ONLY crossing over the cam. I still fail to see how this is making my fuel cut out. USDM LS/VTEC motor, I'm not sure about the pressure switch but I would think if it was something like that it would be a consistant problem, not one out of 5 times.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jerryyay &raquo;</TD></TR><TR><TD CLASS="quote">My cousin has a white ek with a b20 vtec jrsc in it with a p28 and the same hondata you have. He has some problems with it sometimes too sometimes when he tries to smash on it, it would just jerk real hard. Iono if it is the same for you but the problem for his is the wire connecting the hondata to his ecu gets loose inside the ecu and all he does is push it back in. Make sure the red light on your hondata is on. This could be or might not be your problem, but it wouldn't hurt to check.</TD></TR></TABLE>

ya, red light is on and it doesn't jerk so much as just fall flat on it's [freak]ing face. It is always at 5200 rpms and it never happens twice in a row.