Fuel Cut at 9psi with DDP

[MassSupra89]

So I just installed my BIC DDP and Test Pipe, and took it out for a spin.
It's great, spools fast, pulls hard, but I hit max boost around 9psi, 10 in some higher gears. I thought I remembered it raising people up to 12psi hitting fuel cut. Well I wasn't going too hard on it, just the occasional open of the wastegate then I'd shift (riding around town, didn't want to cause a scene)

So I found an empty road and took it WOT to about 4,500rpm in 3rd, kept a steady 9psi, no boost creep, and it hit fuel cut briefly.. I don't have any boost leaks unless its a very small one that I can't find, and I've got a full 3" exhaust.

And input? this happened to anyone else with the DDP at such low boost?




...Also when I was leaving the gas station a kid stops looking at me and goes "That is the coolest car I've seen in my life"
I don't agree with him but it was nice to hear, then I let the wastegate open alittle leaving the parking lot and I heard a "What the FUCK!?" lol.

 

[kwnate]

Same thing was happening to me, I never discovered a boost leak until I removed the stock intercooler. It had a dent and small hole that was siliconed over... I'd inspect all the piping top to bottom, taking pieces off to inspect. Hope you figure it out, fuel cut is so annoying...

 

[MassSupra89]

Yea it is. I've got 2.5" hardpipes and a Spearco rep. IC.
I'll go over all the pipes tomorrow and try again. Glad to know I'm not the only one it's happened to. really think its a small Boost leak?

BTW Nate(derailing my own thread) I read through all your recent Build thread stuff at work and trying to get your video's to work and I just can't get my computer at work or mine to play them:icon_mad: . Congrats on everything though, I love the pic of the Highest powered non CT award and the broken strap haha.

 

[koulee]

on stock afm, you should hit fuel cut between 11 and 12 psi. I'd check the IC and the bov.

 

[suprra_girl]

enjoy fuel cut, you will hit it with those mods
get a fcd, dyno make sure fuel is all good, then don't tutu with boost and you should be good

or you can.... lexus 550's bla bla bla

i been there and done it
max boost = 9.6psi
fcd required as i hit fc at 8psi wot haha

 

[MassSupra89]

Before the DDP I had MBC set to 10 with the occasional 11psi on the highway, (hit fuel cut before at 12+psi) I took the MBC out when I installed the DDP because most people have said they hit around 12 psi with the same exhaust mods. The thing is it hit 9psi around 2,800... sustained 9psi until it got to about 4,500 then hit FC, but never spiked. It held 9psi fine for around 4 seconds until randomly hitting FC-boost never exceeded what it had been previously hitting.

I don't want to go the FCD route without a way of monitoring AFR's, and I plan on getting a wideband when I go Maftpro anyway. I just want a steady 9-10psi for the time being, I'm not wanting to boost the hell out of a stock turbo. But fuel cut should not be kicking in so early.

 

[bigaaron]

Before the DDP I had MBC set to 10 with the occasional 11psi on the highway, (hit fuel cut before at 12+psi) I took the MBC out when I installed the DDP because most people have said they hit around 12 psi with the same exhaust mods. The thing is it hit 9psi around 2,800... sustained 9psi until it got to about 4,500 then hit FC, but never spiked. It held 9psi fine for around 4 seconds until randomly hitting FC-boost never exceeded what it had been previously hitting.

I don't want to go the FCD route without a way of monitoring AFR's, and I plan on getting a wideband when I go Maftpro anyway. I just want a steady 9-10psi for the time being, I'm not wanting to boost the hell out of a stock turbo. But fuel cut should not be kicking in so early.

The Cressida 7m-gte we built was hitting 11psi with the BIC ddp, maft with 550cc, 57trim ct26, 3" exhaust, and no boost controler!

 

[MassSupra89]

Hmm I figured I'd be around 11 with just the DDP, I could have sworn reading things like "raised boost to 12psi, and gained 29whp over standard 3"DP.

But I guess all engine's do act differently... maybe mine just doesn't want me to go over 9psi for more than 5 seconds.

 

[Jayhall]

throwing any codes?? mine did this at suprafest and it turned out to be the AFM

 

[tonysupra]

Hey Mass. To play the videos, press on the link and click on the SAVE button instead of the OPEN button. Then click OPEN FOLDER instead of OPEN. After, RIGHT click the folder and select OPEN WITH. Use Windows Media player because it wouldn't work for me on Realplayer. I'm assuming you do have Windows Media Player. Hope it helps.

 

[JustAnotherVictim]

I hit FC when I was running hard on the highway but otherwise it was fine.

 

[MassSupra89]

throwing any codes?? mine did this at suprafest and it turned out to be the AFM

Just code 34, Turbo boost signal, which would be fuel cut. I replaced my AFM electronics about 2 months ago.
I drove the car to work and gave it a hard 4th gear pull, hit about 8.5psi and brought it to 4,500rpm, no fuel cut. I'll have to try it in 3rd and maybe a 5th gear highway pull to see what results I get.

Hey Mass. To play the videos, press on the link and click on the SAVE button instead of the OPEN button. Then click OPEN FOLDER instead of OPEN. After, RIGHT click the folder and select OPEN WITH. Use Windows Media player because it wouldn't work for me on Realplayer. I'm assuming you do have Windows Media Player. Hope it helps.

Yea I tried that, I only play stuff with WMP too, i get some pop-up then it Buffers for awhile and never plays. I'm at work I'm gonna try again when I get home with other players. thanks.

 

[billspreston01]

I had my mbc set to around 12psi and I only hit fuel cut in second gear (and I wasn't getting anywhere near 12psi in second). But that same day I made a 4th gear pull on the dyno with no fuel cut It's a mystery system. Check the coupler to the throttle body.

 

[MassSupra89]

I had my mbc set to around 12psi and I only hit fuel cut in second gear (and I wasn't getting anywhere near 12psi in second). But that same day I made a 4th gear pull on the dyno with no fuel cut It's a mystery system. Check the coupler to the throttle body.

Ya it's a tricky one. All my couplers are good, I specifically checked that one thoroughly.
I haven't hit FC since that one first time... maybe it was just a fluke type thing... It was unlike the normal FC as well... it was almost like a short one, the CEL came on only for about a second, it was almost like a half assed FC.

 

[JustAnotherVictim]

Did it seem like it cut then acted like nothing happened?

 

[MassSupra89]

I let off and put it in neutral right when it hit FC... but yea I guess.

 

[JustAnotherVictim]

When I had my ddp running straight to the tanabe probably around 8 or 9 psi it acted like it hit fc but then continued like nothing happened. It might have been the half assed fcd job the guy had left in there. But I have no idea. I was laying on it in 5th at the time and I was pulling on a guy in his new Benz on the highway.

 

[MassSupra89]

I've got no fcd, I'm the second owner and car was bone stock when I got it. I'll keep that in mind if it happens again... So did it cut out and slam you forward at all? or just keep accelerating?

 

[JustAnotherVictim]

It cut for maybe a second and I had that feeling like I let off the gas even though I didn't. It did that maybe three times but it was never complete power loss. It was almost like the car was going to die but kept going.

 

[Insidious Surmiser]

i'm pushin about 12 psi before cut @130 in 4th... stock everything but drop-in k&n filter, no egr, no pvc, and the exhaust of course... my cut's very violent on the other hand.... feels like hitting a wall at 130... and of course the "POOOOOW" coming from the exhaust