OK i just finished building a brand new b18c5 type r motor, Motor has been in my car for about 5 days now. At first all seemed well, i have not taken it over 3500rpm until i break in the motor. Last night i figured i would see if vtec was working because everything was working fine in the lower rpm's.

So i start to rev out the motor as soon as i get to the vtec rpm X-over the motor falls flat on its face, it stumbles and has no power. There is absolutely no power until the rpm's fall below the vtec point and then it runs fine again. I did get a CEL one time, code 22 vtec pressure switch. So i swaped the pressure switch from a known good motor. So far no more code 22 but the problem still remains, the motor falls flat on its face at VTEC.

I tested the vtec solenoid, while parked i reved the motor to 5000rpm and ran a power wire from (+) batt terminal to vtec solenoid, the second the vtec solenoid clicks the motor Sputters and stumbles until i cut power to the solenoid.

So far i have removed the cams to see if there was a plug missing and or i had installed the oil orifices backward for the rocker shafts, but they are in correct and they look ok. All the rocker arm pistons are in place. So far everything seems to be there.

Its really getting on my last nerve, im ready to buy a gallon of premium and burn the whole F'in thing.

But before i do that are there any suggestions as 2 what could be causing the problem.

Currently running
motor has only 250 miles since first start up
Had a chipped P28 Ecu with jun p73 program running it,

Switched to a stock p28 because of no vtec problem, same thing happens
obdII to obdI harness
blox stage 3 cams
full endyn port and polish
0 miles stock b18c5 block Purchased direct from acura Preassembled

ANY HELP GREATLY APPRECIATED

 

I would have personally broke it in more aggressively. Try getting it tuned and see what happens. Do you have fresh gas?

Try the all motor forum.

 

i have been driving the motor for a couple of days, gas is as fresh as i can get it,
just no vtec

 

Something suggests to me that there may be a problem with your harness adapter.
Got an OBD2 ECU you can swap in to check it (i.e., w/o the harness adapter.?

 

i think its your ecu or your jumper.....try to switch it with a friend...i prefer you find a person with p28 with a skunk program... it just a suggestion...

 

i had the same vtec dying problem before...it turns out my car was low on engine oil...

 

well, if you are running a stock p28 with a C5 that might be a problem...most p28 ecu's come from a SOHC 1.6 VTEC, this might be a fuel map problem.

 

sounds to me that your vtec is coming in too early. try putting it at 6400.

your low cam lobe is huge now, remember that

 

A shot in the dark... Not enough fuel pressure?

 

Do you have a VAFC? I do and was having the same prob. If not I'd be willing to bet that it has to do with the wiring somewhere. Is this a stock wiring harness? ITR chassis? What are the other details?

 

My hondata-tuned car does a similar thing if it's not perfectly warmed up and decides not to go into VTEC. It's so rich (I think) at that point it just stutters like it's at a rev limiter.

So it's probably a combination of the OBD1 ECU and something (VTEC Solenoid, wiring) that's the problem.

I would try to figure out why it's not in VTEC first. That's probably why it stutters, so ignore that for now.

 

My setup is as follows
Stock itr chassis wiring harness
engine harness is off a 1995 gsr
obdII to obd1 conversion harness
stock injectors, stock fuel pump, stock fuel regulator
I did have a problem with my distributor so a new one is on the way
I don't have a vafc but i can try to borrow one from a friend to monitor the vtec

Thanx for the help

 

Its got to be a wiring malfunction. Follow your vtec wires back as far as you can go and check for shorts. Also check the adapter harness.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bbasso &raquo;</TD></TR><TR><TD CLASS="quote">A shot in the dark... Not enough fuel pressure?</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by R-Type R &raquo;</TD></TR><TR><TD CLASS="quote">... stock injectors, stock fuel pump, stock fuel regulator ... </TD></TR></TABLE>

Seems Rob might have been onto something here.
But not just fuel pressure!

 

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

Seems Rob might have been onto something here.
But not just fuel pressure!</TD></TR></TABLE>

I take it you dont think its getting enough fuel???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by walker111 &raquo;</TD></TR><TR><TD CLASS="quote">I take it you dont think its getting enough fuel???</TD></TR></TABLE>

Yes, for a number of reasons ... including the lack of at least 310 or 440cc injectors, FPR, pump and appropriate ECU tuning/management. JMHO

 

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

Yes, for a number of reasons ... including the lack of at least 310 or 440cc injectors, FPR, pump and appropriate ECU tuning/management. JMHO</TD></TR></TABLE>

I'm not doubting, just learning.

 

I'm in total agreement about the fuel issue. This tends to be a trend when larger camshafts are installed. I had the exact same problem when I first put my motor together and then I got it tuned.

Then when I changed exhausts same thing happened again. My 3" exhaust required a 6 point addition of fuel at 5500 on the VAFC just to pull past VTEC.
Sounds exactly like the problem you are having. Try 310cc Injectors at the very least. And please, don't do any full throttle pulls until you have it tuned!
240cc's is way too small for the amount of air you are drawing in.<U>PUT IT ON A WIDEBAND!</U>

 

Sounds like you need more fuel. Mine did the same thing with almost exact same setup except JUN III's and a Mugen P28. It kinda feels the same way if you are getting too much fuel too. Drive it around and check your bumper for black soot. Or have someone drive behind you and tell you if you are pouring soot outta your exhaust pipe when you hit the mad tite vtec. Of course that just to get you headed in the right direction. You should really take it in to your local dyno tuner though.

EDIT: Damn homie! I just saw that you are running stock injectors. What are you thinking? Why would you increase the air with the P&P and cams and not bump the fuel. The ecu alone ain't gonna cut it!

 

msg Kenji, he might be able to help you for the ECU part
good luck

 

does it pick up if you keep flooring it? my b16 would fall flat at vtec and then pick back up around 6500 rpms. turned out my fuel pressure was way too high and i was dumping too much fuel at vtec x-over.

 

what kind of gas are you putting in it. unleaded, super, plus

 

I agree that it might be a fuel issue,
I will definetly try to get some larger injectors
The new Dizzy is in but same problem
I use only 93 super
Do you think a adjustable fuel pressure regulator will stop the hesitation?
Again thnx for the help

 

All Motor forum would know this.