I always let the water temp warm up to 110 degrees before I start driving. Between 110 and about 150 degrees, I feel the car surging under normal acceleration and driving. After about 150 degrees, it goes away. The only mod I have is the Blackwing. What do you think?

 

I believe the reports of surging with the Blackwing involved the cold air cover/cut shroud seal. If you're not using the cold air cover, check your connections for possible air leaks.

Jim

 

No cover, I'll check tonight.

 

123Gone,

Take a look at that thread as well. I have only seen the cold air cover not being secured tightly, or the Blackwing coupler being a little loose, cause what you speak of, everything else being equal.

Recent Idle thread:
http://forums.corvetteforum.com/zerothread?id=214659

RG

 

I have the cold air cover on securely and still have surging.....What's the deal?

Tony

 

I recently installed three Blackwing air filters (not all on the same car) and no problem with any of them. I think you problem is elsewhere, maybe a loose connection from unplugging the wires.

:flag

 

If you don't find leaks, try a pcm reset as well by removing the negative battery cable for a few minutes and putting the computers to sleep for a little while. Wake them up and do the idle relarn and then check it out.

RG

 

Well I'm a little confused, the computer should adjust itself in a matter of miles anyway so why reset. I don't have any leaks either. What exactly do you get when you reset the computer anyway? Won't the problem come back in time? I'm just a little skeptical when it comes to computer resets or idle relearn procedures. Can it be turbulance that causes surging as some vendors claim? I heard many reasons but none seem to support my issues. If you guys have any ideas on what to try please let me know.....

Thanks,
Tony

 

You may have gotten something on your MAF wires. You may have a loose MAF connection. You may have a loose temp sensor connection. You may have an air leak. You may have not connected or have a loose connection with the hose that plugs into the drivers side of the air box. These are the only things I can think of. I seriously doubt that it is turbulence there is just no where it could come from.

Jerry

 

Hi all,
123gone, I cut my shroud and put a cold air intake on my car a while back. Did the PCM relearn and started getting the surging you mention. My surging was only when the car was coasting, between no throttle being applied up to about 20% throttle. I put up with it for a few months, then got sick of it and changed back to stock setup. The surging instantly ceased, and I mean INSTANTLY. I can't help but think that it was from what Tabbruzz mentions about the turbulent condition created by the intake opened up to the exposed air. I did not have a cover over the air cleaner, so that might have caused a strange reading by the MAF when coasting(possibly a whirlpool of air in the intake due to closed throttle)? I DEFINITELY felt more power with the cold air installed, though!
Steve

 

No surging with the Vortex!!

:smash: :flag

 

Nor with many others' Blackwing. I'd be looking elsewhere if your Blackwing is secure. Good Luck

 

I am familiar with the Donaldson resulting in surging with the '01 only when the shroud is opened which allows additional air, whether or not a cold air cover is used. My understanding is that the computer installed on '01's and later limits and does not allow for the excessive amounts of air entering the 01 & 02 MAF and will result in an inappropriate air/fuel ratio. This lean condition will result in inconsistent and random readings in the various cylinders and can be easily verified by scanner readings. I removed my cold air cover and completely covered the cut-opening in the shroud on my '01 and all surging went away. I then experimented by allowing an ever-increasing amount of air in my previously cut shroud until the surging appeared. I didn't have to wait long for the surging to reappear, a hole of approximately 2"x2" had a profound effect on the A/F ratio. End result, cold air cover installed in garage cabinet, ugly cover patch on cut shroud, replacement shroud on order, and Donaldson filter installed in place of factory unit. No more surge.

 

At this point, I'm wondering if the problem is either 1. Too much air for the MAF or 2. Too much turbulence for the MAF or 3. Both 1 and 2. As an experiment, I might wrap the Blackwing with some cardboard so that most of the air enters the Blackwing from the furthest most point from the MAF. That way, we have reduced the air intake surface area and reduced potential turbulence. The Blackwing would still provide more air to the engine than the stock unit. What do you think?

 

From what Life's Sweet said, does that mean that cold air induction would be a problem on my 2002 Coupe? :confused: I'm thinking of installing the Vortex Rammer, but if the computer can't handle the cold air, I may be wasting my time and money.

 

Steve,

We seem to be on the same page here as I had the same issues when coasting. I tried a few things and here is what I found. With a conical filter and cut shroud(no cold air cover) I got surging. I was told to cover the cut shoud and the surging did go away(still no cold air cover). Now I heard and read many possible reasons for this Here they go:
1) Turbulance- because of two air flow directions confusing the MAF

2) Air intake temp confusing the MAF due to hot air from engine(remember i did not put on the cold air cover yet) and the cold air from the cut shroud.

3) Car may be running lean due to amout of air flow.

All sound logical, but what's the correct answer. I tested some more but this time with a donaldson and cold air cover. Mind you there are no loose connections anywhere as Mikie C and I took our time and really sealed the cold air cover. Of course I have the surging back. By doing this I ruled out # 2 above because the cover is perfectly sealed. I ruled out # 3 because I have a MAFT and autotap and my car is set to run rich. That leaves # 1- Turbulance or maybe the aftermarket MAF(Pro-Auto Tech's MMAF) is the culprit. This I plan to test next.

Tony

 

Hi all,
Hey Tony, sounds like your doing some excellent detective work! I have some to add to your investigation, also. I re-installed the stock setup, except that I didn't put the cover over the air cleaner, but used some cable ties to secure it onto the airbox. I left the opening cut in the shroud to let air come in for the intake to use. I have had ABSOLUTELY no problems whatsoever with this setup since I put it back this way. The only reason I could think of why the surging was occurring was the turbulent condition created by movement plus the throttle being closed, creating a type of backlashing whirlpool effect with the air in the entrance to the MAF area. I never had this while idling, only moving at any speed with the throttle between 0% and about 10% . It did accelaerate MUCH faster with the intake on and the pedal slammed to the floor! I wonder if you had a type of intake to bring ONLY outside cold air(maybe though some sort of pipes tapped into brake cooling ducts) in to an enclosed area that is larger than the pipes themselves creating a "Larger room" for the whirling air to settle down and then be "used" by the intake at it's own pace? :crazy: I think I'll try some experiments :smash: :D

Steve

 

What do you mean by surging? I've had a ProfFlow+ on my car for 3 years and never noticed any surging of the engine RPMs with constant throttle.
I have an autotap. What symptoms does the autotap show when the surging starts.

 

Hi MMarquez,
My particular situation was when I was moving(seemed like it was between 30-60 MPH) and let off the throttle,down to between about 10% and 0%. I would get a condition that felt like someone was tapping the brakes in quick intervals. It wasn't so bad that it jerked the car, just slight taps to feel noticable. I NEVER got surging when I had the throttle open from about 10% and up, and the car accelerated MUCH better with the mod'd air cleaner. I just couldn't take the surging anymore. I haven't had mine autotapped for the condition, though.
Steve

 

Steve,

Are you using the stock MAF?

Tony