i have a gsr in a civic and it drives pefect until you goto cross over into vtec... It was fine (I dont drive this car). I changed MAP and TPS Checked voltage on both Perfect according to the book its dead on timing (ignition and valve) is dead on.

It almost sounds like vtec is kicking on and off really rapidly...Also sounds almost like a launch control while driveing... sometimes vtec will crack perfect in first only but in all the rest bucking and backfiring. Fuel pressure is 53psi at idle...lowered and raised it no different.

If the car idles its absolutly perfect.
Any driving under 4500 pulls hard and flawlessly but soon as it goes to hit vtec bam all the trouble...

Confused!!

Plugs are fine cap and rotor are new..

 

UPDATE::

If you disconnect vtec by unplugging the pressure switch it will rev all the way up fine you just get the cel for the pressure switch and of course no vtec..

Checked oil level its fine.....

 

pull the valve cover off and look at the middle cam lobe see if any are worn out

 

i will check i sure hope not cuz they are brand new skunk 2 cam that i broke in correctly and did a valve adjustment and were working just fine.. Ill pull it off tomaro wife is home from work now....

 

what ECU are you using?

My car did the EXACT same thing with a Hondata S300, when my laptop forced it to update the firmware on the ECU.

If you are running a Hondata system, I may have a solution for you.

 

chipped p28 deleted knock and 02 and iat. gonna put the ecu in my buddies gsr tomaro see whats up....

 

Checking stuff out now

 

ecu is good... battery is dead as ****.. going to put in another and see if it help. next is msd if that dont work

 

What kind of oil are you using like what weight?

 

castrol gtx 10w40
Not MSD Tried retarding timing same thing rewired for the vtec and pressure switch nothing.

its weird earlier it was hitting vtec in all gears then turned around hit vtec in 1st bucking **** in second but it you mess with the throttle a little it will kick vtec..
WTF??

Replaced map and tps set the tps to 4.8v at wot just like the book same ****... confused as hell. only thing i can thinkof is fuel..

im frustrated now so i am calling it quits for the day ill hit it again tomaro with a new walboro 255 but fuel pressure is at 44 at idle and 54 with the vaccum line simulating wot...

Fuel injector??

 

Get it tuned lol.

 

distributor?

 

its not turbo its pretty much stock. we found it running lean plugs are white we put the neww 255 in same thing has to be injectors but its lean accross the board... fp is still good...

 

Change your oil put 5w20 in it.
We see it all the time. (dealership)

 

i seriously doubt its the oil. people around here run 2050 in a b16 and have no issues. i can see maybe in a k20 it being a problem if someone would put in 1040 sae instead of 520 synthetic. its definatly a fuel system problem. somwhere after the pump. gonna replace the filter the line and injectors tomaro. ill let you know. its a new rebuilt engine alot of people use strait 30 to break them in and their fine.