misfire in vtec

[weetabixhead]

My car has developed a misfire in vtec all of a sudden and it has me stumped. It revs fine up to 5000rpm and drives fine no sluggishness etc. Once above 5k and into vtec she misfires pretty badly. Ive changed the distributor plugs and leads so far, none of which has cured the problem. I also noticed that the car is idling pretty high even when warmed up.(approx 1100rpm). Im running out of ideas at the minute could it be a partially blocked injector or something else fuel related?? The timing on the engine was also double checked and is spot on. Any ideas people??

 

[ramboteamjon]

have you checked your oil level? check oil pressure, coolant temp all the usual, might need the vtec solenoid mesh cleaned or something silly like this

 

[dhdavectr]

I'd think injectors would give a rough idle, at least mine did.

Could be an earth issue, go round and check for surface rust between connections.

 

[aroon]

Might be worth seeing if you can borrow a dizzy to see if this cures your problem

 

[dhdavectr]

Did you double check for fault codes ?

 

[weetabixhead]

I swapped the dizzy off my other engine which was running perfect. Oil levels are spot on aswell. I double checked the earths and they all are ok too. I have yet to check the fault codes but i dont have an engine check light on... ill check them anyway

 

[weetabixhead]

Ill swap over the injectors also and see does it help the issue

 

[dhdavectr]

did you check your timing with a timing gun and short out the diagnostic plug ?

 

[weetabixhead]

Yeah i did and i got a mechanic buddy to double check it for me. Its spot on.

 

[Tsuchinoko]

Did you tried a known good ecu? Check the wires that goes to the alternator.

 

[ramboteamjon]

is everything working ok? ie coolant temp, speedo and oil pressure within spec? any trouble starting at all

 

[weetabixhead]

Yep everything is spot on. No check lights, oil level is ok, coolant ok, timing is set spot on, i checked plugs amd leads already all good so all the major stuff seems good so im assuming it is something simple that im missing. I did notice a small amount of oil in spark plug hole of cylinder one due to one of the rocker cover seal being perished but the amount is so small that it hasnt affected the spark. I will swap the seals out tomorrow but i doubt this is the source of the problem anyway. I havnt had a chance to check the injectors yet due to work but im hoping to get back at it tomorrow evening.

 

[weetabixhead]

Problem solved. Turned out to be a partially blocked injector. All is running perfect now again.

 

[dk11290]

nice, glad all is fine.. I hate stupid problems that ruin the fun! what did you do replace injector ? or run injector clean through the system ?

 

[weetabixhead]

Swapped them off another engine that i have which was running perfect.