Hi, I am new to the EVO's, so not sure what the problems are (have always had American muscle cars but thought I would give this a try, not sure if I will ever go back now). Anyway I have a 05 MR with a Vishnu stage 1++ kit on it (probably reflashed for 91 octane, but I put 93 in). I bought it from a guy in Cali. and I live in Illinois so there is quite a temperature difference. Once it got cold at wot the car would just cut off for a second and then slam back with all the power before you could basically let off the pedal. Doesn't seem to do it in 1st and 2nd. Any help would be greatly appreciated!! Thanks

 

You hit boost cut. Try turning down the boost alittle. I had the same problem. Welcome!!!

 

it boost cut. your car hit over boost limit setup in the ecu. what psi are you running???

 

Vinshiu dosent remove the stock boost cut in there reflashes? Thats weird, my custom flash covered that, race gas and 27 psi is a good thing.

 

Not sure what psi I am at (just what ever Vishnu puts it at I guess). I don't have a boost controller to turn it down. All I know is the my MR boost guage is tapped out!!!

 

So should I just get a new reflash and do it on 93 octane and with a test pipe (was thinking about getting one)?

 

It's fuel cut, not boost cut. The ECU doesn't know what boost you're running, and it doesn't care. What it does care about is how much air is crossing the MAF. In cold weather, the air is much denser, so even at the same boost levels, we are flowing much more air, which can put us beyond the built-in fuel cut threshold. Usually, this feature is removed with a tune, but maybe Vishnu doesn't (or didn't) do that.

If you're pegging the stock gauge, which maxes at 21.75psi, then your boost is too high. It may be spiking higher due to the cold weather and whatever they do to the boost lines (remove restrictor pill maybe) to help with controlling boost through the ECU.

Your best bet is to head down to the Vishnu forum and ask them directly. You could probably use a new map for 93oct and lower boost (if possible). You could also get a simple $85 MBC and control boost directly...

 

I assume you are running an Xede? This problem can be easily resolved with an Xede flash which will remove the fuel cut as well as raise the rev limit slightly. Most people who follow the Vishnu route do the Xede flash when they do cams because of the increased air flow -- I guess the previous owner never sent in his ECU


Warrtalon is completely correct in recommending the Vishnu forum
Lots of good information and you will probably get a faster response to similar questions

 

I've been having this same problem, only in 4th and 5th. I have a turboback exhaust with text pipe, an o2 housing and a drop in filter. When I put the cat-back section on it started doing this..i've been trying to figure out what the problem was. My service engine light comes on when that happens too. I dont have a tune yet...was planning on getting one when i get cams...i figure that will fix it

 

You guys are hitting fuel cut in the higher gears because the car will run higher loads in those gears, and that is what the fuel cut is based on.

 

Thanks for all the help! I will check out what Vishnu has to say about then..... Thanks again! Is it hurting my car right now then or is the fuel cut protecting it?

 

Same thing happened to me! That scared the hell out of me!!!!! LOL

Fuel Cut!

 

Not a good idea. It makes no sense to add a full exhaust without a tune or an MBC. first of all, it's pretty expensive and makes little-to-no power by itself. Secondly, it causes overboosting on some cars (like yours), which will cause fuel cut especially in higher gears with more load (that's expected). It also doesn't make a lot of sense to wait for cams unless you're going to get cams right away. You should at least get a base flash or e-flash now to keep your car running well and not hitting fuel cut - successive times hitting fuel cut causes the CEL that you're seeing.

You should get an MBC to have full control over that boost. I'm afraid also that you don't even have a boost gauge, which is a GRAVE MISTAKE. You should never, EVER modify your Evo without installing a boost gauge. What you're doing right now is driving around with mods that make no sense by themselves while potentially hurting the car with no clue how much boost you're running. That is an awfully strange thing to do to a car you spent 30k+ on...

 

Uhhh I have a boost gauge, fuel pressure gauge, and oil pressure gauge.

It would be cool if I could afford to buy everything at once but I can't. It makes more sense to get the exhaust before a tune, than a tune before an exhaust and then another tune. I'd rather just get one tune for it all...mbc will solve this problem for now. I just ordered one so we'll see