My 03 evo viii has some mild mods on it from turbo back exhaust and stage II clutch/flywheel with a short throw to 272 cams, AEM stand-alone ecu, and true boost controler. last dyno in Colorado showed 332/331 so not too shabby. I've only had the car about a month now and I've run into some major problems. Going thru the gears one day and when I let off near the top of 4th at mayb 6800 rpm something went wrong. Started running crappy like on 3 cylinders so I pulled the plugs to find the #4 cly plug gap completley closed. Being optimistic I put a new set of plugs in and she ran perfect for a week then similar thing happened but the plug gap is only mostly closed. With new plugs car idled fine but as soon as the revs came up to maybe 3 could start hearing a clicking tapping sound which I'm afraid is the piston hitting the head. closed the plug gap a lil again. The plug from the second incident has little tiny ticks taken out on it on the bottom rim of the threads as well as the electrode tip too. Did a compression test to find 125,125,125,75. Not good obviously. I haven't started the car again as I am hoping to not continue damaging the head if it is getting hit with a piston. Does anybody have any good advice for me or alternative explanation other than a rod bearing is toast and I'm looking at a rebuilt engine? I live in Montana and I've found somebody who is able to rebuild locally but nobody in the state will touch the AEM ecu. I'm looking for answers to why this happened, what should I do now, and what am I looking at cost-wise for rebuild. Should I just take it back to Co. where they will tune the ECU after repair or try to make the stock ecu work here. Literally nobody in Mt has an AWD dyno by the way.

 

You're definitely having an issue with #4. Is the engine making any abnormal noises? It could be a bearing, but could also be rod bolts. When you take out the spark plug, shine i bright light down into the plug hole and see if you see any pits/scaring on the piston crown.

You also could have broken the ring land and or ring and it's bits are bouncing around inside there. Several things could be happening. You would need to pull the head to really see what's going on. By the sounds of the low compression on #4, i think it's the latter or similar.

 

You are looking at a rebuild with those compression numbers. I would not drive the car any longer if something finally lets go you could end up costing yourself a lot more money. As for the AEM it is overkill for your set up. Personally i would go back to stock ecu and sell the AEM to fund some of your rebuild.

 

how many miles on the car?

 

thanks for the replies. Yes like I had said I can hear a tapping/clicking sound when I raise the revs up to mayb 3k . Other than that no I don't think anything weird. And NO I'm definately not driving the car at all as I'm hoping the head will be useable still. Car has 23k miles on it and I just bought it maybe a month ago. I feel like I got screwed.

 

sorry to say but you may need to rebuild this engine. even if all 4 cylinders were 125 it seems a little on the low end but 75 on the 4th is definately an issue.

 

Well update time. Found a shop in town that is competant to work on my car and a quick bore scope showed my piston had a large chunk chipped off of it which was caused by detonation. He said it is quite obvious that the motor was running very lean and in his opinion the whole thing was the result of really crappy tuning...... So needless to say I won't be taking it to Co. for a rebuild cause thats where it was tuned. Looking into getting a shortblock and we will see what kind of condition the head is in on teardown..... Probably has a chunk of piston imbedded in it. Any opinions on the best place to get a strong shortblock? Oh and i'll be putting the stock ecu back in by the way so the AEM is going by by. hopefully I will be able to find somebody who wants it.

 

honestly I would just buy a stock shortblock if you have no intentions of going over 500 horsepower/400 ftlbs of tq. They are reliable when tuned properly and it will cost you way less money cuz you still have a good block and crank you can sell.

 

if you dont have one already buy a wideband you might have been able to prevent this issue by seeing if it was running lean.

 

that sucks man, hate to hear this sort of thing, that chunk of piston was beating up the spark plug and likely the valves too.

 

Yes the head came off today and at least it should be useable still. Will need valves obviously but the crappy news for the day is that that chunk of piston made it to the turbo and my mechanic says its toast..... he wants me to get and evo 9 turbo. any input???? He also suggests using slowboy guys to get a shortblock. Clean the head, do valves and use the stock ECU. I will keep the 272 cams. Any input on whether the 2.4 shortblock is the way to go for another $400. He quoted me 5500 for the 2.0 installed not including the head work or turbo. Grand total I'm prob looking at 7500 I'm thinking. He hasn't given an estimate on the turbo yet tho.

 

JMO, but if you go the 2.4L route, then the stock IX turbo will be too dinky. Better to do an FP Red if you wish to stick with a stock appearing turbo.

 

Sorry to hear man sounds nasty, did u have plans to do a build eventually? If so instead of spending your money twice just upgrade turbo now bbk/ fp green-red. I realise it must be hard financially with a big hit like this tho. 2.4 with a red would be nasty.

Goodluck

 

Wait wait, the #4 piston has a broken ring land and the engine builder wants you to buy a complete short block? Why not just use your good crank and probably good block, maybe do an over bore if necessary, buy some pistons, rods, head gasket, and what not from Chris@nolimitmotors and rebuild it? If the head is damaged get a stock replacement head on the cheap from the forums and go from there. If you have no plans to build a 450whp+ street monster you will be fine with good quality stock replacement parts. I have all kinds of spare parts in the garage, (no cranks though) so let me know if you need any help. I keep them around incase I blowup my engine but now I'm thinking I want bigger so I may be able to come off of some of it.

Josh

 

BTW when and if you go back to the stock ECU get Chris (Mellon) to tune it for you. He has done some amazing things with the stock ECU.

Josh