Hey guys im having a problem with my newly purchased evo. Bought the car a few weeks ago and the car ran great, somtimes it would hit fuel cut under boost at WOT but I figured that was caused by the cold temps and was gonna get it retuned. Well when I was changing the oil I noticed antifreeze under the car checked everthing and cleaned it off and came to the conclusion the car was pushing antifreeze out of the overflow tank when under boost cause by the head gasket.

So this weekend I removed the head and put a new head gasket in with new arp head studs. I also replaced the water pump, timing belt, balance shaft belt, idlers, and tensioners. I also added a few parts an ebay o2 housing, new autolite iradium spark plugs, evo 9 bov, and a vibrant air filter from map performance. The car also already had a few mods done to it such as a 3 inch tbe, evo 9 turbo, AMS fmic, licp, hks 272 camshafts, 255 walbro fuel pump, and a street tune.

Now with my problem after finishing everything up the car starts and runs great and drives great. when i went for a drive I can boost up to 5-10 lbs then the car acts like its hitting fuel cut really bad and pops and backfires is this caused by the tune being off so far? Or am I forgetting somthing and hooked somthing up wrong.

I also notice with the evo 9 bov is much louder then the evo 8 bov and flutters alot under boost is that normal? im just baffled right now so im looking for answeres. if its the tune great I can get it retuned and planned on it soon anyways but I dont wanna drive the car 500 miles to get it tuned with somthing being wrong with it or getting there and they cant tune it cause of the problem. Any help with be much appreciated.

Thank you

 

could be a leak. try replacing spark plugs/wires?

 

Check the cam timing.

Josh

 

Take those out and put NGK Plugs in the car. That is most likely your problem. I would put a set of NGK BPR7ES in it. You can get them from Advance or Napa or OReilly's Auto parts.

 

The cam timing is right on checked it about 5 times before I put the car back together


also did a boost leak test everything seemed to be fine there


the car was running ngk bpr7es in it before but they looked pretty crappy so i got these oem specification autolite irdaiums but ill go get a set and try it in a few minutes before oreilly closes

 

+1 Yeah stick with ngk. They are cheap and effective. BPR7EIX for iridium if you wanted to go that route.

 

did you regap the plugs or just put them in the way they come?

 

Another +1 on the NGK plugs, I made the mistake of running autolite plugs, the ignition sounded like it was breaking up like crazy under boost. Put on NGK Iridiums and problem immediately went away.

 

yup only NGK or denso on 4g63's

 

I didnt make it up to the parts store for the plugs so ill have to get them in the morning what do you guys recommend the NGK BPR7ES or NGK BPR7EIX

and I gapped the autolites at .30

Anything else I should check out also?

 

Check for boost leaks

 

Either will work, but most people recommend the Iridiums. Modded/tuned cars sometimes run a half or full step colder depending on the power levels, and also how you drive.

In case you're wondering..

BPR7EIX = Stock
BR7EIX = 1/2 step colder
BPR8EIX = 1 step colder.

 

That gap seems pretty large, when it got cold I had to gap mine at .022 you might bring that gap down and try it, its worth a shot and quick.

 

Ok you hadn't mentioned that you changed the type and gap on your plugs. That's a good place to start. As mentioned earlier, I would run BR7EIX's lots of people recommend the BPR's but the non protruding electrode allows more heat to be transfered to the head and dissipated. Just my .02 worth.

Josh

 

This is funny because i just changed my plugs to BR8ES plugs which is what my tunner put in the car. I have the exact same mods as you except all buschur parts and buschur tune with an 03 evo 8 turbo.

I would recommend going with the BR8ES plugs and gapped 0.024". I assume you meant 0.03" before = ) Not 0.3"


Good luck and let us know what happens