I was on my way up to tahoe and I was in 4th gear when I noticed an issue. At about 3500 rpms all the way to 7k the car kind of went and then hesitated. The best description would be having a circle and having a hump on the circle and hitting that hump. It would feel like its going then back off then do that consistently. I was guessing a fuel issue but thats just to take a crack at it.

I'll try to add better descriptions as I can think of them.

Any thoughts?

 

What elevation were you at? Is the car still doing it? Have you made any changes to the car?

 

not sure of the elevation, didnt think to check. I didn't drive home, I had my buddy drive home, I'll see if its doing it tomorrow. Haven't made any changes.

 

bump before the bowl!

 

I say either

-You're not pulling enough air in due to elevation
-Overboosting due to cold air
-****ty fuel (My car whenever I get ****ty fuel I pre-detonate right around boost (not peak) which is 3-3.5 for me VF23 spools slow compared to stock.

It's either backing off timing or fuel or air. Was it knocking or was it just sputtering? Also did it do the same lets say you're at 3500 in 4th and you dropped it into 3rd instead to accelerate the same rate?

 

I think it was the elevation, I did a couple pulls last night on the way to the sharks game in 3rd and 4th and didnt have any issues.. I had no idea elevation could do that. It was just sputtering but I wouldnt necessary call it sputtering. Kind of like it would lose the momentum for 1/2 a second every other second, it wasn't a dramatic difference either. I just pay attention to how my car drives and felt a slight different to how it should drive.

It did the same thing when I downshifted from 4th to 3rd *** well. When it was under load is when I noticed the issue.

 

My guess was that you were running too rich. You were not getting enough air in for the amount of fuel being sprayed. The MAF was still reading air but the 02 content was not enough for an adequate burn.

 

oh okay, good to know. thanks shayhan

 

Well higher elevation you go there's less air concentration hence why a turbo car actually is more efficient for it. Except when it runs way too rich and causes this.

 

Yay I think I was right one time lol

 

There is a sensor inside the ECU which reads barometric pressure (which changes with altitude), and the ECU uses the reading to make changes at elevation. So I don't think it's a fuel issue.

Could have been the boost controller making changes to reach the desired boost. Overboost throws a code so I'd say you weren't reaching boost and the car was trying to make changes. Really just guessing since there was no CEL thrown.

 

I could be running rich, I haven't gotten a protune yet, just slapped a crap forum map on it and ran with it after making sure I didn't have knock if you didn't already know that from lurking as much as you and I both do. haha


My car NEVER reaches boost ever since I put on different DP without a tune.. I was catless with an hks DP when I first flashed my car and was hitting 15psi, since switching to my invidia catted DP I am only hitting about 12psi. I am using the same exact map. Could that be an issue?

 

Yeah check all your vacuum and boost lines asap. Get that forum crap off and put the cobb OTS map back on, I don't like those but it is probably way safer than the tune youre on now.

 

Aaaahhh and the light shines in with illumination.

So the situation is more like

Got some parts changed my DP threw on an internet tune and went for it.

Not trying to be a smart ***, but yeah your ecu is probably limiting you pulled some timing. I dont think it would automatically pull boost though. Get an AP with an OTS that looks like it will match, or go to a shop that will tune opensource and just get a protune.

With how much motor replacement is on these I just prefer to always play it safe. I learned my lesson early about putting on parts without a tune, or putting on parts that my AP didnt like. I didnt pop a motor but my car ran pretty poopy with some of the stuff I did.

 

Very adaptive ECU but they definitely are picky. I'll be off of my mix or with a bad batch of fuel and... car hates me esp with a tune on 93. Also check your wastegate arm and make sure it doesn't need lube.