mjones89

i am a newbie when it comes to anything about car engines, i recently bought an 03 evo and i think i got played. the car was working fine when i got it in may, but for the last two months i have been having a problem. when i accelerate everything is fine up until about 5000 rpm's, at that point the car starts bogging, almost like a popping noise. any ideas about what it could be? please help

Brsox10288

The spark plugs might be fouled out... boost leak.. check both asap

buchnerj

iTrader: (19)

+1 on the plugs. It would cause a popping noise and cause a good bucking in the acceleration of the car. Pull the plugs, see what they look like and what they are gapped at. If they look pretty fed up then replace and gap them. What mods do you have? If youve increased the boost a good bit .022 or smaller.

mjones89

i replaced the spark plugs about a month and a half ago and gapped them at .032 (thats what the mitsu dealership said to gap them at) i thought that might have been it but still continues. i dont have a boost guage and i dont kno how to manually turn it down so i dont kno what it is set at

mjones89

not sure what mods are done

mjones89

i also took wd40 and sprayed all my vacuum lines and didnt notice a bog or bubbles or anything

buchnerj

iTrader: (19)

Does the car appear to be clearly modified? Its hard to answer your question. If you have a bigger turbo, or the boost is turned up than you need to gap them a good bit lower than .032. I have mine gapped to .020 because I am running 30psi on E85. Do you see a manual boost controller under your hood? Take a picture of it and post it, get a good close up and a couple shots and im sure we can find something. But those would be my two guesses, especially if you hear a popping noise, does it continue to accelerate after you hear the pop? If you just go WOT and hear a pop and it won't go any further, that could be symptomatic of a fuel cut or something fuel related, but if there are just a few bogs on the way to redline than that sounds ignition related to me, for sure.

dxbtune

vacuum line bubbles?...wd40 is oil based what you spraying that for i bet the engine bay looks real pretty now...
use some brake cleaner instedd and you will get an rpm increase w/ a leak... gap ypur plugs to .022 and start over

Armyevo2003

iTrader: (2)

Well as far fetched as it might seem...what BRAND of plugs did you replace them with? I have tried using bosch, champion and ac delco and they always messed up for me at higher rpm. In my experience I only use NGK as they keep working at all rpm's for me.

mjones89

friends say that it looks like it has a bigger turbo, hard piped, custom headers, and an aftermarket exhaust but i have no idea cuz like i said im a noob, i'll take some close up pictures of the engine so you can see for yourself. i sprayed wd40 because a friend told me that i would hear a difference in the motor if there was a leak. the bog is a sufficient decrease in acceleration but it doesnt go away, havent pushed it to redline once i hear the bog i shift (dont want to mess anything up), i have no idea what a boost controller looks like so i couldnt tell you if i have one or where it is. i do kno that i am running lean (lots of blue smoke at bogging point) but it also backfires, dont kno how i can be lean and rich at the same time?

mjones89

spark plugs are ngk iridium tip

buchnerj

iTrader: (19)

blue smoke... wtf? What are your AFRs? You need to get a wideband and take a log of this asap. Take a picture and post it up, get a few and we will be able to tell if its a diff turbo and if the vacuum lines off the wastegate are going to a MBC or just to the stock boost controller. I know you choose to back off, which is probably a good thing when the bogging starts, but it could narrow your symptoms, if you honestly can't push past it then it might be fuel, if not than I think its ignition related. You need to either find a friend with a tatrix cable and evoscan and ecu flash or get to a tuner and a reputable garage asap. Post up the pics and well see what it looks like.

mjones89

yea blue smoke meaning im burning oil, i dont have an afr gauge havent had the money lately, tomorrow i will continue accelerating at the bogging point to see if maybe it only bogs for a few seconds or if its continuos, i'll try to post some pictures tomorrow also thanx much

Brsox10288

Replace your plugs with ngk iridium plugs if you dont have them in already. Evo's are very sensitive when you put things on them that they dont like!

mjones89

i just put a new set of ngk iridium plugs in about a month and a half ago