MAF maxxed out?

[rockethound]

Ok,
I just finished putting the "92 SS back together, I installed a TD04 and v1 slanty I/C, coffee cup mod,desnorked it and ran an abs pipe cold air inlet from the RH foglight socket to the remaining half of the snorkus outlet. Now, bearing all of that in mind, here's my issue: under full throttle conditions, the car pulls hard to about 3500-3800 rpm then it jumps like an auto transmission downshifting into passing gear. The boost stops at 11psi but the car continues to accelerate. I usually let off the throttle at this time 'cause it just doesn't feel right. I don't think it's fuel cut because It's still accelerating, does this sound like a MAF issue?
I haven't dialed the mbc back yet, that will probably be my next step. I have a 5 speed so it has the Hitachi MAF, if that is the problem, would the Jecs MAF correct the condition or should I just turn the mbc back down? The car runs like a rocket other than this issue if it is an issue and not paranoia setting in.

Jeff

Try to be inconspicuous, conspicuous objects draw enemy fire...and speeding tickets

[dzx]

The JECs MAF has a wider range, but you need something to tune the car with after installing one. If I remember correctly it runs a little leaner? 11 psi shouldnt be making the car do that though. Especially with a small turbo like the TD04. Have you installed a fuel cut defender?

[555BCTurbo]

All turbos have Hitachi MAFs

[rockethound]

The JECs MAF has a wider range, but you need something to tune the car with after installing one. If I remember correctly it runs a little leaner? 11 psi shouldnt be making the car do that though. Especially with a small turbo like the TD04. Have you installed a fuel cut defender?

No FCD yet, probably my next step. I'm trying to decide between
Vikash's electronic FCD and the mechanical check valve from Mcmaster-Carr. probably do that sometime within the next week.
I'm also going to try a couple of things with my cai in the foglight socket to see if maybe it's creating enough turbulence through the K-N panel to disturb the maf, though I doubt that's the issue.

Jeff

[beatersubi]

rockethound,
I'm at about the same stage you are.
Just completed the 22t swap with a td04 and v2 slant mount, and I'm experiencing the same thing. The boost spools up real quick (fully spooled by 3k rpm), but feels like it loses power shortly after.
I wonder if it isn't fuel cut. Let us know how that works for you.

[skid542]

Fuel cut is controlled by the boost pressure. And from what I understand, it's like hitting a wall.

I pressume you've checked for codes? You could also wire in Vikash's scan tool and check the MAF voltage.

[dzx]

I have a 3" cold air intake in the fender of my car. I really dont think the turbulence is causing the problem. That usually only affects the idle.

Yes, Fuel cut is like hitting a wall. What you're describing sounds kinda like a boost leak somewhere or vacuum leak.

Is your knock sensor in good condition?

[rockethound]

Oh bugger...the knock sensor did have a crack in it, I forgot about it when I was installing the i/c. Thats going to be fun to get at.

[rockethound]

I don't have Vikash's scan tool. I guess I'll have to build one.

[rockethound]

well, I just read the two cheap fcd sticky posts in the turbo forum, (there's a lot of pages there ) now that I have a better understanding of the situation, it does sound like fuel cut issues. So, it looks like there is an fcd in my future.

Jeff

[dzx]

If your knock sensor is bad, it will pull timing after you hit boost so you will experience a loss of power but keep accelerating.

[rockethound]

yeah,
my existing k/s has a crack in the plastic, I was going to swap a different one in but got all wrapped up in trying to get my bpv to fit and spaced the k/s. So, now we'll se if it can be swapped without having to remove the i/c. I guess I might have an excuse to install the '04 i/c and the '05 scoop.

jeff