Vtec intermittently not engaging

[FastFwd]

Hey all,

Last week i got a yellow so i got my external gate plumed back and i blocked off my Bov for the time being so i could get it over the pits, i went on a cruise last weekend and my car was running awesome until the Monday after i got a hole in my exhaust manifold so my turbo wasn't spooling to well and all of a sudden my vtec wasn't cutting in at the right times. 4 days later which is today i got my manifold fixed and i gave it a little on the way home and realized my vtec doesn't cut in until 7200 - 7500.

If i rev it up without giving it boost the vtec will cut in a 5800ish which i think is the correct timing. but if i put the foot down and let it boost to 7psi which i got the gate set to, the vtec wont cut in until 7200 - 7500.

does anyone have any sudjestions..sorry bout the life story...

[BlitZ]

this is the first time ive heard of anything like this..

check the Vtec solenoide connector first..

then if things are correct
place and LED or automotive elctronic lights off the VTEC wire just off the ECU in the foot well..

see if the light turns on normall at the 5600 engagement..

If the light goes on and the vtec doesnt sound.. you probabaly have a stuffed soleniode...

Well thats where i would start

[CRXer]

Maybe theres been a change in manifold pressure with the altered setup & your upper vtec boundary is out o whack.

What sort of management u runnin?

[FastFwd]

i have an ODB1 can anyone help my find this wire, or a link to a blueprint? I have a Vafc 2 connected and an Apexi Power FC, the Vafc 2 is only used for monitoring...

[CRXer]

If its cutting in consistently at the rpms u mentioned then the solenoid sounds fine(pin A4 btw).

Id take it to a tuner & get em to check your upper window boundary.

Unless someone on here can guide u thru it.

[FastFwd]

well its not cutting in that great...i meen it comes on but its not all that crash, it sounds kinda weird sometimes..

[CRXer]

i assume your oil is always well looked after in such a beast of a vehicle,so try what Blitz said but connect the low wattage 12V globe to the wire coming off the solenoid not at the ecu end.This will tell u if the wiring is consistent as well.

Preferably dont cut into the wire,but what i always do is depin the solenoid plug & wrap a thin wire around the end of the pin then reinsert the pin into plug. Then run the new wire back into the cabin,hook up to globe & ground other side of globe.

Then see if vtec engages consistently & at what rpms.
Dont leave this setup like this without properly fusing the wire from solenoid,if u must keep it.

[FastFwd]

Yeh always givin it a service every 5000 thou...even tho it has only done 6700k's since the full forged rebuild. done three full services so far.

well on the vafc 2 right....when the vtec comes on the button glows bright green....could this be the same deal to test???

If not, so i gotta run a wire from the engine bay side of the solenoid wire not the Ecu side? cos if i do it i might keep it a perminant LED on the dash for monitoring.

[CRXer]

connecting at the solenoid side just lets u know there are no intermittent bad connections in the wire between the solenoid & ecu,which usually becomes a prob with swapped engines due to bad joints.

If it turns out ok,there is no real need to keep monitoring the wire unless other probs occur,its just more unnecessary wiring in your car to short out & cause vtec probs.

Seen alot of poorly wired vafc's caose vtec probs with just bad joints made on the solenoid wire,so check this also.

but it all seems a little too coincidental that the probs arose when u started having manifold pressure variations to overlook this.

[FastFwd]

ok...

Im sorry to have wasted yours and blitz time, went outside to start the solenoid test when i thought i might just check the oil. it was missing about 750ml of oil. I not only feel like a newb but now i hope i havent caused any damage to my motor after the fresh rebuild ive done.

I took her for a drive after...vtec comes on fine now. i think that when i went on the cruise last weekend i was doing alot of thrashing (beating evo 6.5's :) ) that i completly forgot to check the oil after.

Which arises another question. I have a pressure guage... When should i be worried when i look at it? cos i know pressure goes up and down on Vtec's like a Show ride at a festival. do you know the ranges on how much is too much and how little is to little.

[CRXer]

:eek: how dare u treat that fine piece u got there like that:(

Think the pressure switch looks for about 60psi to engage vtec if that helps at all,not sure

[SKREMN]

it should never go below 50psi in vtec and idel around 10-20psi
shouldnt go over 80ish

[BlitZ]

ok...

Im sorry to have wasted yours and blitz time, went outside to start the solenoid test when i thought i might just check the oil. it was missing about 750ml of oil. I not only feel like a newb but now i hope i havent caused any damage to my motor after the fresh rebuild ive done.

I took her for a drive after...vtec comes on fine now. i think that when i went on the cruise last weekend i was doing alot of thrashing (beating evo 6.5's :) ) that i completly forgot to check the oil after.

Which arises another question. I have a pressure guage... When should i be worried when i look at it? cos i know pressure goes up and down on Vtec's like a Show ride at a festival. do you know the ranges on how much is too much and how little is to little.

Well its good to see that you are breaking in the motor the right way...:thumbsup:

Needs to be thrashed..:thumbsup: