SirRevvs

So tonight I've been trying to diagnose the problem I'm having with a mini swap. 1995 Civic EX B2 bottom end Z6 head no revving past 6500 rpm. I was going to test the VTEC selenoid (had a long day) and hooked up 12v to the VTEC press sensor blue wire instead of the green/whitte wire for the selenoid. Got a little puff of smoke at the selenoid. ECU threw a code 22 VTec press sensor so I replaced the sensor and the code went away. Went about testing continuity and the ECU for the VTEC wires no problems. THen I put in my Hondata P72 same problem with engine.

After that I went to plug the P28 back in and I get a sold CEL with ignition on. ZCode is a 21 VTEC selenoid. So I open up the ECU to find a burnt circuit/transistor. I searched on H-T to find out what the transistor is and I find out that the part that buned up Q31 is a common problem with switching the IAT and EVAP plug around which I haven't done so this must be from when the head was re-done previously. But now I have this solid code 21 and I've checked continuity and replaced the selenoid but still have the code. It's weird to cause it didn't do this right after I did the test wrong but after I plugged in my P72 and then the P28 againl.

So the two q's I have is would what I did fry circuit Q31 on the circuit board causing my code 21, and if this was previously burnt up on the circuit board could this also be causing the problem I've been having with the engine not revving past 6500 rpm?

PLease somebody chime in?

Aralliius

i also rev limit at 6500 wit a d16z6 and have a CEL but i cant figure out how to check it at home so imma subscribe to this and find out.

SirRevvs

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aralliius &raquo;</TD></TR><TR><TD CLASS="quote">i also rev limit at 6500 with a d16z6 and have a CEL but i cant figure out how to check it at home so imma subscribe to this and find out.</TD></TR></TABLE>

Well I didn't have a CEL before when this was happening but that's interesting that you do with the same problem. What code are you showing?

Syndacate

Since you're not running it through a fuse or anything it's possible you backfed the ECU when you shorted out the solenoid. That's what I'd place my money on, you jumped the wrong wire, it ate the VTEC solenoid, then fedback to the ECU where it ate one of the transistors.

So it's possible both are bad.

Try diff VTEC solenoid AND diff ECU.

I'm pretty sure the regular VTEC harness goes through a relay of some sort, but even if it doesn't, wires don't get mixed up from the factory .

THC07

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SirRevvs &raquo;</TD></TR><TR><TD CLASS="quote">
So the two q's I have is would what I did fry circuit Q31 on the circuit board causing my code 21?</TD></TR></TABLE>

No

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SirRevvs &raquo;</TD></TR><TR><TD CLASS="quote"> and if this was previously burnt up on the circuit board could this also be causing the problem I've been having with the engine not revving past 6500 rpm?
</TD></TR></TABLE>

No

is your p28 running in limp mode?

Aralliius

SirRevvs i have no clue what code im showing cuz i can seem to find that Grey jumper cable will i have to unplug it form something?

THC07

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aralliius &raquo;</TD></TR><TR><TD CLASS="quote">SirRevvs i have no clue what code im showing cuz i can seem to find that Grey jumper cable will i have to unplug it form something?</TD></TR></TABLE>

its in there. look above the ecu pannel. stick a jumper in ther, and count.

SirRevvs

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by THC07 &raquo;</TD></TR><TR><TD CLASS="quote">

No

No

is your p28 running in limp mode?

</TD></TR></TABLE>

Even before there was any cel whatsoever the engine still wouldn't rev past 6500 rpm. And yes if a put my P72 in with knock disabled it does not throw a code but still won't rev past 6500. The only circuit that is fried on the board is the Q31 transistor.I just don't understand why it didn't throw the code right away after I fried the selenoid. It took me switching the computer out several times to throw it.

Yes I also replaced the selenoid, press switch and vtec assembly. Can't get the code to go away. Is there a particular way the little circular valve with the off set hole in it underneatht the selenoid should be facing? I have the offset hole postioned underneath the oil passage in the selenoid.

SirRevvs

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Syndacate &raquo;</TD></TR><TR><TD CLASS="quote">I'm pretty sure the regular VTEC harness goes through a relay of some sort, but even if it doesn't, wires don't get mixed up from the factory .</TD></TR></TABLE>

I know wires don't get mixed up from the factory it was purely my mistake, and the last time I'll make it.

EDIT: I did not test the selenoid with the wire connected to the ecu. I did however put 12volts to the press switch wire while it was connected to the ecu so if anything I would have fried the press circuit but it not throwing a code for the press switch it throwing a code for vtec selenoid.

THC07

are the p28 and p72 both chipped?

making sure the wiring is right... getting another car to test both ecus with, might be a good idea. just make sure the evap and iat are correct. lol, so dude dosent get mad at you if you burn his.

Aralliius

THC07 i look thair above the ECU pannel and i see something that looks like it but it more or less under the dash above the ecu pannel, should i unplug it and try?

THC07

you should not have to unplug it. it may be in a rubber cap of some sort. but its not pluged into anything

what color are the wires?
there should be a brown wire and a black.. i think


ill go lookk at mine later and tell you for sure.