I have a 93 eg coupe, with a b16 i/h/e.
Basically everytime i hit vtec the speedometer goes retarded (goes from like 0-120 and back and forth) And sometimes when i hit vtec continuosly it gives a check engine light, but when i turn the car off and on its perfectly fine. I also have a small idle from like 1000-1500 when im at a light, or it seems when i turn off the ac/heat theres no idle.
Any help would be appreciated

 

when the CEL is on does vtec still engage?

 

i think it does? i didnt even get to check it but im pretty sure it does

 

sounds like two wires are exposed and touching somewhere. possibly the VTEC wire and the speed sensor wire.

 

bump? would i have to pull the engine to check this?

 

just trace the wires and look for exposed wires. the touching wires are going to be somewhere between the ECU and the engine/tranny.

 

have you tried to pull the cel or is your ecu not storing it

 

IDK? my cel is on only when i run vtec consistantly.. More like lets say 6-10 times.. Its not a huge problem because i still can DD it with no problem, but i still would like to know the problem.. When i do turn off the car and back on its off and its not throwing me any codes, just giving me the light.

 

change or check the wiring at the VSS on the tranny, if it is loose or bad that will cause your speedo to bounce crazy like that and if your in VTEC and your speedo has zero for a reading it will shut down ur VTEC causing it to throw a code

 

thanks ill try that buymp

 

bump?

 

i found out another problem, im idling 1-2 rpm, and im literally getting terrible MPG.. sum1 help me out.?

 

bump
tttt

 

why are you bumping this?
have you tried the suggestions? are you going to tell us if you've tried the suggestions?
it's hard to give more input when you don't tell us what has and hasn't helped.