Yeah it's your SAFC, it just isn't tuned right. Good Luck

 

Gap the plugs smaller. Meaning 22-24. If that works go from there and adjust them out. Solved my problem and I tried about everything.

 

hey guys, i had the same problem after I got rear ended. Got a walboro put in few months ago and after I got reared it sta rted stuttering or hit boost cut like at 7-9 psi. So we changed the plugs and pump and still same problem. My car wasnt tuned yet, Im sending my ecu in to al tomorrow and I think that should fix my problem, do u guys think it will? Man getting my car repaired and not driving right after a freaking month sucks ***, im really tired of this crap and hopefully the flash from al will make it a nice ride again 8- )

 

His S-AFC is untuned and that is most likely his problem.

 

Its not the safc doing that. I just switched to mag wires and ngk bpr7es and my car is doing the same thing. it was great for about 3 days and then started misifiring in the upper rpms but the car would still accelerate. I've had a walbro pump and TT reflash for about 3 months now without a problem. I changed the plugs and they were fine for another 3 days up until this morning.

 

The plugs get fouled real easy on our cars.. I am inclined to think that our coils aren't producing "sufficient" output under boost..

When I first started modifying my car, I had a misfire that I was convinced was fuel cut, I dropped the boost, checked fuel pump pressure, adjusted my tune, watched for minor knock and excessive MAF readings or boost spikes..

Then I decided to change my plugs with NGK BPR7ES gapped at .026 and it completely went away for a few months.. Plugs just don't last very long on our cars if your boost is higher than stock. Its not that the plugs are bad, but under boost you are literally quenching the spark or combustion and not getting a complete burn...

Two things you need to be aware of, first, its not the plug wires, but the boots that may be giving you trouble, so just changing the wires may have two of your plugs covered, but the other two boots attached to the coils (I think) still are stock, correct?

The other thing is, the Evo's coils are IDENTICAL to every other normally aspirated 4G coil used on DOHC apps with dual coils/wasted spark.. I am convinced they don't produce very good output and are therefore very sensitive to any defect in the ignition components..

The other thing to look at is the indexing of your spark plugs, I realize a DOHC motor that it likely doesn't make much of a difference, you want to at least improve your chances of the plugs electrode facing away from the direction of the intake valves. My theory is the turbulence could be affecting a weak spark.. I personally haven't noticed any difference, but my problem was solved with new plugs.

I wish I could suggest a bolt-on replacement coil that was inexpensive plug and play, unfortunately you'd need an expensive box, but I'd like to see someone who has this as a persistent problem, and plugs hasn't helped, to try it.

HIgh output coils and CDI ignition boxes help because at idle, you don't get the misfiring that can quickly foul your plugs and make them less efficient at ionizing (the point just before a spark jumps) and more difficult for a complete hot spark. Plus the additional energy allows the plugs to fire even when somewhat fouled, effectively 'self cleaning'

Thats why Iridium plugs are so popular, they have a tiny electrode with very little surface area so the spark always occurs in the same place on the electrode, and stays "Clean" in that area... the problem is that even though they last longer than any other type of plug, their expensive to change every 3000-10000 miles...

I would recommend changing your plugs at EVERY oil change if you have higher than stock boost and lower than stock heat ranges on your plugs.

 

Oh, and carbon buildup in your combustion chamber could also cause this symptom, if nothing else helps, try using some sort of detergent additive to clean the combustion chamber, and have your fuel injection system cleaned.. sometimes that helps, it can't hurt.

 

cause my car wasnt tuned. You guys think that the tuning is my problem? Because I changed my plugs, then put gas in the car first time a month after my accident, and the car drove fine. Took it to the shop and they test drove it, changed pump, changed plugs once again cause they said the car was stuttering again like hell, checked all the maf readings, checked air and fuel etc., but still didn't find anything. To me, the shop said its a 100 percent a fuel problem, but when I took it to mitsubishi they only looked at my car for 30 min and considered it as a bov or wastegate problem LOL. So im thinking that I need tuning, maybe once I get my car ecu dynoflashed I should be good hopefully. If this doesn't fix it, how do I check if my coils have gone bad. I know how to change my plugs and stuff but I dont know where the coils are. Also, what do u guys mean by gapping and how do I gap then properly?

 

if it's sputtering.....like "pax pax pax"..then it's either plugs or tuning

 

i had a turbo talon as well as my gf. both were severly modified and had ngk bpr7es with magnecore wires and I never had a problem. I would change the plugs whenever I felt like it but i never had this problem. I left the gap stock on the plugs (around .30-.32) so maybe i'll try less of a gap this time around. but I still think this is crazy. my plugs shouldnt be fouling out twice a week.

 

Subscribing. I also am trying to isolate a misfire/stuttering problem. Mine is most prevalant after the car completely warms up. It stumbles badly at around 3500 to 4500 rpms at PARTIAL throttle. I've changed the plugs which helped for a week, then it returned and I changed them again, but this time it didn't help. I just swapped out my coils and wires for a friends to see if that was the issue, but it still does it. It is not my tune because it does it on both my 91 and 100 octane maps.

I'm now going to look at the following: a possible loose wire, my Walbro fuel pump going bad, my o2 sensor on my O2 housing being fouled from running leaded race fuel, ic piping being damaged or partially popped off???, or a vacuum line somewhere being off.

 

Switzer Ignition anyone?

 

Hi all,

Thank you for all the input and ideas.

First, after swapping my wires back to the stock ones, car runs perfectly.

The stock wires are thin, but they attach to the coils very securely. The Magnecors are beefy, but don't slide onto the coil that great. I had a zip-tie on there with the Magnecors trying to secure it, but I guess it wasn't cutting it.

Regarding the SAFC "tuning", I hear you on the necessity of a real tune with wideband O2 and a dyno. I have very subtle changes (-1% upto -3-5%), in an attempt to not hurt anything, heh. Also, my car was actually running pretty good after switching to BPr plugs, so I wasn't really worried about having messed anything up.

Interesting that several people had fuel pump problems. I don't think that was the case for me anyway.

I agree about our cars fouling plugs on a regular basis, lol. Car seems pretty sensitive to the plugs. If I continue to have probs, I may try a lower gap as the other poster mentioned.

Thanks again,

FB

 

Hi,

Yeah, I have had way more luck at .025/.026. I had tried Denso Iridiums in the past which come at .028 and they fouled. It does seem crazy, but it seems to be a quirk with this car?

As for gapping, you can adjust the gap between the electrode. I use the circular gapping type tool to close the gap, then open it so approx .025" or so. If you are changing plugs without gapping them, you don't know what the gap is set to, right? They may not necessarily be at the right gap for your car. Warning with the iridium plugs, it's a friggin pita to gap them, and I've ended up breaking 1 or 2 which is a real bummer. NGK coppers are fairly simple to gap.

Interesting to see so many people having similar probs. I have not had a CEL btw. Also, do check for vacuum leaks, switching to Samco hoses with tbolt clamps helped me in the past (until the plugs fouled again, lol)

Take care,

FB

 

I had the same thing happen to me on my GST eclipse. Ran race gas about 4 different times at the track and it caused the BRAND NEW O2 to give improper readings. It didn't throw a CEL, but the car sputtered around 4000 rpms. Changed it out with a new one and the car ran great.