Fuel Cut at 8-9 psi with MAF-T basic, injectors, FPR....

[mk3-4-me]

Wow this format is different, i like it. LOL

Anyways i just got done throwing my new precision turbo in and im hitting fuel cut at 8-9 psi. I had this problem before my newer turbo was put in as well. So i figured it would of been a boost leak in the IC piping, and i knew i was taking it apart soon so anyways so i just left it. Now that i got it all back together, it still hits fuel cut (code 34). I dont think it could be the IC piping as i just redid them.

MODS TO MY 7M:

JE .20 over
Eagles
aeromotive AFPR - 40 psi with vac hose off.
560cc evo injectors
AEM cam gears (not adjusted)
Desno FP
Precision 6152
IC
Greddy BOV
MHG
ARP's through out
GM 3in sensor with MAF-T Basic I'm blow through mode
1 pc DS
3 in turbo back
AEM UEGO WB

Now it could be the tuning i did with the MAF-t, but the AFRs look good. I didnt really set the basic tune as per manual. I.E used my WB instead of the VF meter. Im gunna redo the basic tuning with a multimeter soon, but with the RPM tuning, it looks good. Under boost i start at 12:0 creeping down to around 11:5 in like 2nd gear, then its pretty much around 11:0 the rest. when i hit FC it goes to 10:0 which is the most it reads.

The car pulls great untill it dies. So idk what it could be. My ISCV hose isnt clamps down and its kinda loose at the port and im gunna clamp it down 2morrow, but i dont think that would cause it. But im not saying it wont! lol

So im just wondering what you guys suggest i do, or if you guys ran into this with using MAF-t basic.

thanks!

 

[CajunKenny]

Are you running the Maft in AFC or Speed Density mode?

Can you post up a log?

 

[Nick M]

Now it could be the tuning i did with the MAF-t, but the AFRs look good.

That code is only generated by having the air flow meter generate a signal fast enough to the ecm. Either there is no resistance (intake leak) or more is being pulled through from the larger turbocharger.

 

[CajunKenny]

Nick, you just made me think of something. If he's running the Maft in Speed Density, code 34 is stored because the Maft doesn't come on quick enough.

 

[mk3-4-me]

Sry forgot to mention it's in blow through. And it's just a MAF-t basic, so no AIT sensor.

 

[Nick M]

I don't use either version of MAFT-T. They both have to clamp the signal or 34 is generated when the boost is cranked up. So I have no comment about the tunning aspect generating the 34. But it is generated because the Hz is fast enough to trigger it.

 

[mk3-4-me]

What do you mean clamp the signal??

 

[mk3-4-me]

There's a setting on the tuning device that you set fir the size of the GM sensor you are using. Could it be that I have it on a smaller sensor setting so it reads different, causing it to go over the HZ it can read?

I'm pretty sure I have the right setting.

And there's a setting for Hz frequency I think, maybe should I try adjusting that?

 

[mk3-4-me]

So what's clamping the signal?

Idk what it could be that's causing the FC!

 

[Nick M]

If the meter is small, the signal will be faster making the engine think more air is entering the engine. Clamping just means you set how fast the Hz signal is.

 

[mk3-4-me]

Do you know how I would go about setting the HZ Signal speed?

And I'm pretty sure I have a 3 in sensor so that's the setting I have it on. So theoretically, if I had a 3.5 and it was set on a 3 in setting would that fit the problem I'm having?

My sensor Is the black plastic one, which from what I've read is the 3 in and the metal sensor is a 3.5??

I'll measure it when I get off work.

 

[Nick M]

Do you know how I would go about setting the HZ Signal speed?

I have no comment about tuning a MAFT-T. Or Pro.

 

[mk3-4-me]

I'm gunna retune it with a VF meter this time and see if it was just a bad base tune.

 

[forcefedsupra]

I have the metal sensor and it's a 3". My MAF-t has always been fairly sensitive as in it would start FC when the temps would drop and such. If you are positive you don't have a boost leak, then retuning it will probably fix it, but I've always had to readjust it fairly often.

 

[mk3-4-me]

So the actual sensor where you plug into is metal? Or just the pipe it's in? Cause mine is black plastic in the middle. I thought the plastic was a 3.0 and the metal was a 3.5...? Maybe I did have it wrong.

I think it was my base tuning. Because I never did that with a VF meter, just my WB for tuning. And after I retuned it last night using a VF meter for the basic tune, my wastegate stuck open (old starting to rust ss auto wastegate) after I punched it, so must be close cause I've never built enough boost to open it before.

 

[forcefedsupra]

The sensor itself is plastic, I have seen some that are all plastic. I always used a WB and never did the multimeter thing and I'm not sure if that would work better or not.

 

[supraguy@aol]

I think i've mentioned to you before that I have almost the exact same setup as you, right down to blow-thru mode and 560's.
I would simply check for boost leaks, as that it the most common cause of FC. I have not pushed my boost past 16psi, but I have yet to hit FC at that level.

 

[supraguy@aol]

ps- I just noticed that you're using a bigger turbo.
I'm on a stock CT(for now).

 

[mk3-4-me]

Loo ok well I retuned it to get my VF better at cruising speeds. Around 2.7. And I'm boosting now! Break the tires loose when it comes to 10 psi. But I'm running 15 as of now.

Ya my VF was at 4.9 cruising before I retuned it. So I think it was just already using alot if fuel for normal driving, that when I needed even more for boost, it just laced out.

But it is boostin 15 lbs great now! It just breaks My fresh 245s loose wen it gets to about 10 psi!!

Goin to the track this weekend hopefully and see what I get.

Thanks!!