This just started happening and before I start tearing into things I thought I would see what people thought.

This seems to happen in all gears but you can really notice it in 3rd, 4th & 5th.
Unless I am mistaken it our turbos are set up to be very linear in the power delivery. It's not like the nothing...nothing...and then holy sh*t like the Evo 9 or 8.

Well lately I have noticed that if I am driving out of boost everything is fine...but as soon as I step on it a bit at around 5 lbs of boost...it almost pauses...like it hasn't spooled up and then if you remain on the gas then full on boost and away you go. And this will happen if I floor the pedal or just gradually push it down. You get a hesitation before boost comes on. It's almost like a dip.

Very much like my old SRT-4 in a sense. You'd step on it and it would hesitate a bit till boost came on and then everything was fine. But that was how the car was designed. The Evo is sort of doing this only it has never done it before.

Any ideas of what it could be?

As a note I am running a ETS cat-back with cobb stage 1. Stock intake. And these mods have been on for about a 2 years running fine.

 

Turbo lag?

 

Either turbo lag or a Fuel cut. How much boost are you getting up too?

 

I don't think it's fuel cut, would be very violent and noticable. I bet you it's something like a loose wastegate arm or something, where it's opening up a bit at low boost. Just started all of the sudden? No mods or service or anything?

 

You could be feeling timing getting pulled really hard.

It wouldn't be a bad idea to datalog, rpm, boost, knock, and timing


Also makes me think, if you're feeling timing getting yanked it's likely due to summer heat + heat soak + crappy fuel

 

Yeah my first thought was turbo lag...but this is the first I have noticed it and it only happens at around 5 lbs of boost. Once you get past 5 pounds then it is fine up to about 20 taper to 17 or so. It's almost like hitting a speed bump. Once you get past it...it is fine.

 

Yeah I would think the same on the fuel cut. Like I said above it will do it if I slam the gas down or just go half pedal and feather it. It almost seems like something might be stuck and then it finally gives. Like I said above it happens at right around the same spot on the boost gauge. Right around 5 to 8 pounds of boost. Right when it starts to open up.

 

check your plugs

 

I know exactly what you are talking about. I had this same phenomenon on my car. I could never figure it out.

Soon after this started happening I changed plugs, installed a 3 port, and got tuned. The problem was no longer there. I assume it was either the stock boost solenoid or something related, or plugs that were causing the issue.

-Ryan

 

plugs

 

Agreed..check ur plugs

 

Have you ever changed your spark plugs? I had a similar problem and i brought it to my tuner (full bolt ons and a tune on pump). I thought it was a problem with the tune but he ran the car on the dyno and noticed things were off. The plugs were changed, the tune was untouched, and car was back on the dyno. Problem solved. I forgot what Rick (Rallinspired) told me about the plugs because it was over a year ago when this happened. Even though our spark plugs are rated to 60k, I think that is a bunch of bull especially if your tuned. As preventative maintenance, I change my plugs every year or every 15k miles. Its just an extra $50 a year to protect your investment.

 

I've been experiencing this too over the last couple of days. I checked my plugs and they look fine, if your tuned and still running with the OEM boost solenoid? the boost might be spiking too high and it could be "boost cut" thats causing the hesitation. I spoke with my tuner about my issue and thats what he stated, he suggested getting a 3 port and another tune will probably cure the problem.

 

I change the plugs out a while ago around 10K...the car has 21K now. It seems like everyone thinks its the plugs. I'll have to pull them this weekend and I'll let you know.

 

Did you check the plugs...?



Just kidding - The Evo X plugs are funny as they, at least on mine, can look great and yet be on their way out. They are finicky enough that we change them about 4 times per season. Usually, for me, when they are failing they cause a high rpm stumble or hiccup, which sounds somewhat different then your issue but it's a good place to start.