Hesitation at high rpm...help

[KaosR_Eclipse_GsT]

i don't know whats wrong with my engine now...but its not as fast as before...every time when i Mash, the engine starts boggin at 4k and up...i thought it was the fuel injectors but when i took it too the shop they said nothing was wrong with the fuel system...

but one of friend said he had the same problem and it was just one of his pipping that wasn't on tight...could that be the problem?

i know its not the spark plugs because i had them replaced yesterday

but i notice, everytime when i remove the valve cover and place it back on, it starts running smooth again... but after a while it starts boggin again...please help

[WankelTII]

Get an air fuel guage, if you are running rich while its hesitating then you have a leak in your piping somewhere, if you are running lean, then you are over boosting your injectors. It should stay in the rich all the time at WOT.

[kjewer1]

Any leak in the intake piping after the turbo will cause you to run rich. This is what wankel was also saying. But another very very common problem is spark plugs and wires. Use only stock or NGK wires, and sometimes Magnacores work. Almost everything is is a big risk. Trust me For plugs on the turbo cars run only NGK copper BPR6 or 7 ES plugs. Platinum is no good with boost, but I havent tried the Iridium plugs yet. The regular NGK coppers are good though because they are cheap (<2 bucks) and on a turbo car you should be replacing the plugs every 10k miles at the latest. Also, its VERY important to have them gapped correctly. For up to 20-23 psi, use a gap of .028. 25 psi and up, you'll likely need to go a little smaller. I run .026, or the car wont run Hope that helps.

[EclipseRST]

Originally Posted by 95 GSXracer

Platinum is no good with boost, but I havent tried the Iridium plugs yet.

i have had the best luck with the Bosch Platinum+4 plugs, i'm not sure why but they seem to work the best for my car. maybe cause it isnt the 4g63, who knows...

[kjewer1]

If you run low boost platinum will still work Heres a quick lesson on turbo motors and plugs, for anyone interested. Platinum is used not because you get a stronger spark, but because it is much harder than copper and therefore lasts longer. The problem is it has higher resistance making it harder for the spark to jump the gap. Not an issue with a normal car, but lets look at the turbo car. By forcing more air and fuel into the same small combustion chamber, we raise the density of the mixture. The denser the mixture, the harder it is to get the spark to jump the gap. Combine that with the higher resistance of platinum, and you get misfires which which give you that stutter you feel/hear, and often foul the plugs requireing you to drive a couple miles before the car runs right again. I believe most poeple report trouble with platinum plugs over ~16 psi or so...

[EclipseRST]

oh ok i get it now... yea i usually run right around 13-15 psi daily and when i got done breakin the engine and turbo in i raced it once at 21psi with race gas and i didnt really notice anything so maybe just that one race didnt really affect it or maybe i just got lucky, hmmm i think i might just have to buy some new plugs now!! thanks for explaining it to me...

[kjewer1]

Some people do get away with it, and that one person will say dont listen to everyone else about platinums, they work fine, etc. lol. You're one of the lucky ones. I'm surpirsed they worked with the race gas. I have a hard time firing through all that lead with regular plugs. But its all relative. You might as well keep them in if they still work for you, but I wouldnt be surprised if the car did feel a little better with coppers.

[ashah000]

did u check your spark wires

[youngvr4]

if you have a boost controller, and its doing that then it could very well be that. my vr4 does that now, but for my car i just need the apexi super afc. you might need a hks boost cut remover or maybe the same thing i need. turn off your boost controller and if it stil does it then hell i don't know

[SpyderEclipseGst]

Originally Posted by EclipseRST

i have had the best luck with the Bosch Platinum+4 plugs, i'm not sure why but they seem to work the best for my car. maybe cause it isnt the 4g63, who knows...

Heh those were the first alturnative I used after I started misfireing. I used the bosh +4's. My Engine started acting all crazy, misfire hell.. then I tried the spitfires(no good) !!! I went with stock plugs and wires and walaaaa.. Fixed the problem and I felt a good ride and smooth performance. I agree for the gst's go stock..

[KaosR_Eclipse_GsT]

Originally Posted by ashah000

did u check your spark wires

yea i had them replaced with the 'ngk chopper spark plug' my car runs smooth...but its still jumpy when i mash...

when i step on the gas pedal all the way down and then when my rpm hits like 3k the engine starts boggin...'it goes and then it start boggin'

hmmmm....

ill have my spark plug wires and all the vacume hose replace tomarrow

ill be back and post up how it goes...

thanks

[WankelTII]

when i step on the gas pedal all the way down and then when my rpm hits like 3k the engine starts boggin...'it goes and then it start boggin'

that sounds more like you are running too much boost, i think you might need to get an apexi S-AFC and turn the fuel up some.