New to owning an evo here. (2003 VIII) first off, let me say that even with the engine completely crippled right now, It's still sending the Scoobies home crying when I pull around a corner.



since i've had the car, I've been plagued with CEL codes, and fuel cutoffs. I haven't had the full "evo experience" since i've owned the vehicle.


Last week I kept throwing P0300 and an EGR malfunction code.
I searched The forums and found the infamous loose vacuum hose. (triple ziptied that sucker.)
I also Changed the spark plugs (did the job myself... which was probably stupid. I didn't mess up the threads or anything, but I have no idea what spacing the gap means and what it involves. I bought the plugs from the dealer, and installed them into the engine.)
I had the computer reset and drove it for about 40 miles. Cel came back with P0300. I search the forums and found that I should WOT it. (because of carbon buildup or something like that....) I did a WOT and BOOM! I hear a loud pop and smell burnt exhaust. I check the engine codes this morning and now i'm getting a P0234. Overboost or wastegate/actuator malfunction.

My question is: would the gap spacing of the sparks cause me to get a complete fuel cutoff at around 5K? Not sure what the next troubleshooting step is for getting rid of the misfire code as well. If push comes to shove, I'll replace the Wastegate actuator, but after searching the forums it seems that it COULD be the sparks or something else causing my issue.

It should be noted that the car has a modified exhaust and AMS Short Ram intake. Both were there before I got the car. I don't believe it has an aftermarket BOV or anything like that. Any help is greatly appreciated!

 

You need to get the car tuned to get rid of the P0300 CEL. Also you need to have the car tuned for those modifications. Spark plug gap is set by using a feeler gauge and will be able to set the gap exactly where you want it to be which will improve drive-ability and power.

As for the loud bang look for loose couplers on the intercooler piping. You should perform a boost leak test for loose couplers.

It would also help to know what boost you have the car set at and what the air fuel ratio is while going open throttle.

Not sure where you got the advice to floor it to rid your problem but that is terrible advice.

 

Thanks. I will have that done. I'll also check for loose couplers. I'm not sure what the boost is set at, unfortunately I don't have a boost gauge yet. I am assuming that it's stock boost (because there is no boost controller installed) but the previous owner may have made other modifications that i'm oblivious to.

Thanks again.

 

If you don't know how to set spark plug gap, I would probably take the car to a reputable shop to do a tune up and full look over of the car.

 

Oh man

 

if everything under the hood is good (couplers). get new plugs, gap to 25 and bring it to a reputable tuner and get that thing tuned. you can only do either exhaust or intake without a tune but you need a tune with both. might as well get all the bolt ons before tuning then.

 

Well this is weird. The p0234 is gone. the p0300 remains...even after 2 CEL resets, the mechanics told me that the sparks don't need to be gapped (they're straight from mitsubishi so that makes sense I guess.) It has AEM Intake and some aftermarket exhaust they were on there before I bought the car. I'll get it tuned next... Do I go into the stealership and just tell them to tune it. Or would it be better/cheaper to take it to my mechanic?



I will admit though, this is frustrating. I've had the car for a week now and thought it would be minor. I'm reading different threads about the issue, but no one ever posts what they did to actually FIX it. I've heard everything from 5th gear synchro, to spark plugs, to wires, to coils, to flywheel, to tuning. @_@ I'm not sure what to do next. I guess I'll do the tune, if that doesn't fix it This thing is going back to the dealer and i'll wait for a decent 06 to pop up.

I've also read that it could be the stock plastic blow-off valve. What do you guys think?

 

not the dealership! someone help this guy out. please.... any tuner.

 

It's always good to check the gap. Not everything that comes from a parts department is what it says it is.

 

Alright first things first, the plugs from the dealership are going to be iridium plugs. They do not need and should not be gapped. they are preset from factory. only copper plugs need to be gapped.
The exaust and intake is enough to be making your car strike higher load cells and hit fuel cut. like said before here you need to get a boost controller and have it tuned by a tuner, dealerships won't do that. While at the tuner spend the extra money and make sure they inspect and boost leak test it before, and talk to them about the problems you are having.

Or my best suggestion is take the exhaust and intake off, throw on some cheap OEM ones someone is selling and enjoy the car as it was originally engineered with less problems.

 

What ^ said.....I have an 03 8 too, I have been plagued by the p0300 problem for a while too....there's a few things that can trigger it.....a tune will help, and they can adjust the fuel and timing to keep that from happening.....personally it is probably your couplers...if your on stock piping and plan to be for a while get your hands on a set of t bolt clamps and some hairspray and spray on the piping right before sliding on the new clamps.....that should ensure a tight seal, bought a set 2nd week in....haha mine popped at throttle body 3 times in a day......any other questions ask away.

 

^Sounds legit. I will definitely go down this road if I can't figure this issue out soon. I was told by a former mechanic that I should check/replace Mass Airflow Sensor and Idle Air control sensor/valve. He says that it's definitely Airflow related, and after reading your post I have to agree.

This DID happen to me, but It was after I was messing around with the EGR valve's new hose. So It was probably my fault. I thought I had blew the engine : / but I popped it back on and tightened the coupler as best as I can and it was fine. I'll do the hairspray thing tonight with every single coupler that I can find.


lmao! I appreciate everyone's help on this, it's just when you drop that kind of cash on your dream car, and it runs like a nightmare....you want to yell at someone. *Points to the salesman's picture on my dart board*

Thanks guys. I'll report back after I redo couplers and have the shop check for boost leaks. I'll ask them to tune it but they seem to think that theyres NOTHING wrong with it and that "it's an evo" so that means that It can drive through walls and magically fix itself with it's pixie dust powers of pixie awesome...

-___-

 

Okay, I just took it for a spin and went to auto zone. NOW i'm getting a P0420 fml... Either faulty cat, faulty sensor (which would make sense I suppose), or exhaust leak.

They guy at auto zone seems to think that the misfiring is throwing off the cat. I think it's the other way around... To top it off, I just noticed a rattling noise when coasting in gear. Is it wrong to want to smack a baby at this point? haha.

I'm still gonna check for boost leak and see about getting a tune today after work. I hope one little oxygen sensor caused all this. That's something that is cheap AND I can do myself. *crosses fingers*

 

The last time, well only time, I installed iridium plugs they needed gapping. The reason for the no gapping advice is the delicate center electrode and the soft platinum coating on the outer electrode. So, you have to be gentle. If you think the gap is going to be correct you have more faith than me.

 

Where do yoy live? Maybe we can find you a reputable Evo tuner to help you.