LST2

I have just wired in the VTEC solenoid and pressure switch and I am running into a few problems. I have a 95 GSR head with ITR cams on a 95 LS block. I have a chipped (uberdata) P72 ECU. It seems my Vtec is engaging only intermittently. That is what I was thinking before b/c I had lowered my VTEC crossover to ~4K for tuning. However, it does not kick in until late 5Ks RPM. It is kind of like it kicks in at the butterfly crossover. I have an Edelbrock intake so I don't have the dual butterflies. I don't have any CELs.
It also makes a strange sound. I can hear a definite "click" when it engages and disengages but then it sounds like I hear some other ticking/clicking. Almost like valve noise or valve/piston contact. I double-checked my timing belt and it is still aligned.

I read somewhere that I had to wire the ground of the VTP to the ECU. So I wired it to A26, which looks like it is the IAB ground. Maybe this ground only works when the IAB is supposed to kick in which is in the high 5Ks as well.

I am running my vtec oil source from the oil pressure location on the back of the block along with the feed for my turbo.

I am going to change my oil today to see if that helps. I put in some "stop leak" and that may be messing with the vtec engagement.

Any other suggestions?

Thanks!

wantboost

iTrader: (2)

sounds like an oil pressure issue, did you setup teh vtec settings properly in uber?

LST2

Yea, I think so. I have vteck enabled and VTP enabled. I have the engagement set to 4,300 RPM but I am pretty sure it is not kicking in until much later.

I think it is probably an oil pressure issue as well. Wouln't I get a code on for the vtec oil pressure sensor? Maybe it is b/c I have the feed for the turbo and vtec in the same location... although I hear many other people use this.

wantboost

iTrader: (2)

i use the golden eagle sandwich thing. i use one port for head feed then i use the other one for the turbo feed

DaveF

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LST2 &raquo;</TD></TR><TR><TD CLASS="quote">change my oil today to see if that helps. I put in some "stop leak" and that may be messing with the vtec
</TD></TR></TABLE>

wtf ?????? isnt that **** for your radiator?????


also, take the ground for the vtec oil pressure and ground it right on the head, engine or trans somewhere. that is probly ****** you over too.

wantboost

iTrader: (2)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dturbocivic &raquo;</TD></TR><TR><TD CLASS="quote">wtf ?????? isnt that **** for your radiator????? </TD></TR></TABLE>
holy ****, i didnt even see that hw said that... im pretty sure thats a problem. its probably fucked your oil pump, bearings, pretty much the whole motor

LST2

Nah this is the stuff for your oil. It is the kind that look like hunny. I have 5w30 in their now and maybe with the 95* temps along with the turbo and LSVTEC my oil is geeting too thin. I am going to 20w-50 for a little while until it cools off.

LST2

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


also, take the ground for the vtec oil pressure and ground it right on the head, engine or trans somewhere. that is probly ****** you over too.</TD></TR></TABLE>

I think this may be the problem too but I have seen it here a few times that the P72 needs to be grounded to A26... anyone want to chime in on that?

DaveF

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LST2 &raquo;</TD></TR><TR><TD CLASS="quote">

I think this may be the problem too but I have seen it here a few times that the P72 needs to be grounded to A26... anyone want to chime in on that?</TD></TR></TABLE>

thats wrong info.

LST2

OK thanks. That has to be it then. At first I thought it was just intermentent VTEC b/c I had the vtec set low. It was probably comming in consistently at around the IAB activiation... 5,800 RPM. I'm going to change the ground to the thermostat housing and see what happens.

LST2

Well, I switched the ground and I don't think that fixed the problem. I just picked up some 20W-50 and I am going to see if that raises my oil pressure a little bit.

LST2

I just changed the oil to Royal Purple 20W-50. The Vtec does seem to cick in a little earlier (5,300 RPM). This is still not where I set it (@ 4,400 RPM). Also, it sounds like it is clicking in and out of Vtec as the RPMs go up. You know that clicking sound you hear when Vtec kicks in, well I hear those clicks repeatedly like the pins on the rocker arms are not staying in. Is this what is like if you have low oil pressure? Or does it usually just not kick in at all?

LST2

Anyone care to offer suggestions?

DaveF

put a mechanical guage on the engine and check oil pressures in and out of vtec.

LST2

I just checked the oil pressure at port next to the vtec solinoid and I am basically getting no oil pressure. I am not sure if you have to activate the solinoid to get pressure but I had lower than 5 psi with it unactivated... then I wired the solenoid to the battery to make it live and the pressure went up to like 10 psi @ 3000RPM. That is way to low.

I have not checked it at the block but the block should be getting enough pressure as my light has not come on. I am going to hook the gauge up to the block to check the pressure there.

I loosened the feed line to see if I was getting any oil from it and I was. It was comming out fast with it just loosened.

I do hear a click when I hardwire the solednoid to the battery but maybe there is something else wrong with the solenoid. I really don't think so as the Vtec does kick in there is just not enough oil pressure to keep it engaged.

What are my next steps?

dumpeDc2

I dident read all the posts but when I built my Ls-V I couldent get vtec to cross over and i was stumped for a while. It ended up being the vtec solinoid screen was clogged with metal shavings from braking in the motor. I hard wired the solinoid to the battery also and could only hear it click but not working and I also had low oil presure at the headwhen checked. its only 3 bolts so it couldent hurt to check it out.

LST2

I did check the solenoid. I hard wired it and it clicked. I also cleaned out the screen. There was a very small amount of debri covering the corner of the screen so I cleaned that out but that should not be enough to clog it. I read another in another thread that there are two places to check the oil pressure... one right above the coolant line on the head (10mm bolt) and another on the vtec solenoid itself (hex head bolt). I think the hex head tests the oil pressure at the head and the 10mm bolt measures it only durring vtec activation. That makes sense as the oil pressure changed a little on the 10mm bolt when I mannually activated it.
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turboLSvtec030

it seems that around 5200 to 5400 is the stock engagement point. are u sure your wiring is right on the vtec controller? plus theres a plug on the front of the head on the left above the exhaust, screw in an oil pressure gauge then jump your vtec sylenoid to the battery so the oil can enter the port at around 5000 for only about 10 seconds and check your pressure with the factory specs in a haynes manual, it also describes this technique inside, for gsr and so on.

LST2

That is what I did. I checked the pressure with the solenoid activated and it was pretty low about 10psi. I could not tell what RPM I as at though. I am going to check it again this weekend with someone else so I can check the RPMs. I will check it at the block, the top of the feed line, on the vtec solenoid (regular head pressure) and the port on the head (VTEC engaged only oil pressure). I'll post the results.

turboLSvtec030

also make sure your orfices are in the head, some head shops are bad about leaving these out, theres one on the intake side and exhaust right under the top rail to the right. mine was missing on the exhast side then i bought one and make shure it goes ito the hole in the rocker rail too. and maybe youre kicking a code, check to see if it is and see wich it is, maybe the sylinoid or the pressure switch is bad.

turboLSvtec030

my haynes calls for only about 7 to 10 anyway. it say around 3 to 5 without solenoid engaged hen when jumped should be around 8 to 12 at 5000 rpm held steady since thats close to the factory engagement.

dumpeDc2

if for some reason you dident put the dowl pin back under the #3 cam cap then Vtec might not cross over. also after I was doing the same thing as you by hard wiring the solinoid for an extended peroid of time I fryed the solinoid and had to replace it, so if you got a friend with a D or B series mabey try switching it if your outta ideas.

LST2

I'll check these. Thanks guys.

LST2

OK, it is defiantly an oil pressure problem. My oil pressure at the block and the fitting on the feed line where it attaches to the head is 70-80psi at 5,000 RPM... plenty. I then tested it at the VTEC test port while I was driving. I set the crossover low, at 4,200. I saw zero oil pressure until I hit 4,200 then I got 20psi. Then as I revved higher I heard vtec kick in at around 5,400 when I had about 30psi.. way to low. It is the low oil pressure that is causing it to "click" in and out of Vtec once it starts. So where do I start troubleshooting. I heard the following:
-Vtec Solenoid shot - Don't think so as I hear it "click" when I give it 12v and it is letting oil in where I set the crossover.
-Vtec Solenoid screen clogged - checked that, it was clean
-Dowel pins on cam journals... I'll have to research that, not sure what to look for
-Cam journal bolts loose. I know that one or two of them did not seem to tighten all the way when I put the head on.

One thing to note is that when I purchased this head the cam journals were pretty worn so I had a shop bore them back to spec when I put the new valve train it. It is possible that the dowel pins or something like that got screwed up.
More suggestions?

LST2

Bump for more suggestions...