Hitting boost cut I think

[mattsplat72]

I am pretty sure I am hitting cut.
I am hitting a wall at 13 and I am getting a code 34 turbo pressure .
I tried to search but the search engine omits " Cut" and gives me 500 threads I can't find shit any help anyone?? thanks

Mods
Safc2 ,
Stock IC and pipes
Boost controller
Apexi Intake
Stock afm with screw adjusted all the way out
Stock injectors
Stock Elbow and HKS all the way back

I am going to turn the boost down to 10. I want to return back to higher settings later . What steps do I need to address to get there?

 

[92TealSupra]

I am pretty sure I am hitting cut.
I am hitting a wall at 13 and I am getting a code 34 turbo pressure .
I tried to search but the search engine omits " Cut" and gives me 500 threads I can't find shit any help anyone?? thanks

Mods
Safc2 ,
Stock IC and pipes
Boost controller
Apexi Intake
Stock afm with screw adjusted all the way out
Stock injectors
Stock Elbow and HKS all the way back

I am going to turn the boost down to 10. I want to return back to higher settings later . What steps do I need to address to get there?

Hey there Matt. I ran over 13 pounds easy with a Lex AFM. All I had on my '87 was, Lex Afm: Apexi Intake: 550 Rc': SAFC: Walbro 225: Aeromotive FPR: 60-1 Ct-2:, and a 3" exhaust..

You are indeed hitting fuel cut. I am sure you hate every minute of it too.

 

[mattsplat72]

Yeah, The crazy thing is the massive jump in boost from going to a full unreestricted 3 inch from turbo back. I didn't touch settings and boost shot up from 8 to 13ish. I hit cut only a few times during quick freeway pulls and it bucked for a sec until I let off of the pedal. If I keep it at about 3/4 pedal it will sit right at 10 and be ok . So I am going to start after centralia on the 16th

If you find these parts lmk I will pick them up from you. I assume that I need

AFPR
550 injectors ( can I go a little bigger? like 600 )
a Lexus AFM housing

I have Fuel pump, Intake, and Safc2

After this, would the next step be the dyno. Hmm I think the best option is to wait and just enjoy the car till winter and go stand alone .

 

[ft413]

Yeah, The crazy thing is the massive jump in boost from going to a full unreestricted 3 inch from turbo back. I didn't touch settings and boost shot up from 8 to 13ish. I hit cut only a few times during quick freeway pulls and it bucked for a sec until I let off of the pedal. If I keep it at about 3/4 pedal it will sit right at 10 and be ok . So I am going to start after centralia on the 16th

If you find these parts lmk I will pick them up from you. I assume that I need

AFPR
550 injectors ( can I go a little bigger? like 600 )
a Lexus AFM housing

I have Fuel pump, Intake, and Safc2

After this, would the next step be the dyno. Hmm I think the best option is to wait and just enjoy the car till winter and go stand alone .

your getting 13 psi without a boost controller?

 

[mattsplat72]

I have a boost controller look at first post I just didn't repeat in my reply to 92 Teal sorry my pain meds were starting to kick in

 

[GrimJack]

Are you adjusting your fuel with the afc yet?

 

[mattsplat72]

Yeah a little bit. As the boost comes on it increases at a steady rate till I am in full boost . I also have it set more agressively for Hi THtl then I do for Lo THtl.

What is you input on this Grim? Any thoughts?

 

[kwnate]

Check your intercooler pipes and IC for cracks/leaks. I had a cracked IC and I was hitting fuel cut right after I did the downpipe and exhaust.

 

[92TealSupra]

Doesn't it need the electronics as well?

 

[kotu100]

nope, the stock electronics get used with the bigger housing. its the larger housing itself that fools the ECU allowing to run higher boost. the 550's allow you to drive the car and run higher boost safely. it can be done without the injectors using the safc to increase fuel where its needed, but the car will run vry lean until it gets tuned.

oh and right now im running 12psi, sometimes it shoots up to 14 real quick if i wot shift. only mods are 3" TBE, lex afm, afpr, and 550s. no fuel cut yet.

 

[mattsplat72]

Thanks Nate I noticed a tiny oil stain ( less then a teaspoon) on the cold side of the turbo directly under the joint from the little hard pipe and the rubber elbow. I am going to flour bomb every thing and see if I can spot any blow by.

Kotu
Totally interested in the Lex Afm PM a price. and thanks


Any one have a guess on time to tune it on the dyno?

So I suppose that I need 550's and the AFPR

 

[GrimJack]

Yeah a little bit. As the boost comes on it increases at a steady rate till I am in full boost . I also have it set more agressively for Hi THtl then I do for Lo THtl.

What is you input on this Grim? Any thoughts?

So, you're adding fuel using the afc? Do you know how the afc adds fuel?

It artificially increases the Karmen Vortex Hz signal to the ECU, so the ECU thinks there is more air coming into the engine, and adds more fuel to compensate.

So... you're essentially using the AFC to increase the Hz signal. Which will lower your fuel cut point.

The way around this (or ONE of the ways, anyway) is to add an adjustable fuel pressure regulator and / or larger injectors. Turn up the fuel pressure, remove fuel using the AFC, and voila, your fuel cut point moves higher. Of course you'll need a wideband to make sure you keep everything in one piece while setting it up.

 

[syty1]

WOW
Once again SM guys solved my problem...
I hit fuel-cut this morning and couldn't figure out why. I'm running an HKS PFC/FCON & FCD w/ stock injectors FPR and AFM. When I did my BHG, I found a leak at the resonator on my HKS 65mm exhaust....replaced it w/ straight-pipe.
Boost was only about 8 - 9 psi 'cause I've got it turned down till the engine is broken in more.
This site is a goldmine of info !
Thanx
David

 

[MKiiiturbodrift]

I think i may have the same problem as well. Except Im running stock boost...around 8psi. But occasionally when im into the throttle it just cuts and bucks really hard and then comes back pulling again. does this sound like a boost leak or a fuel cut?

 

[7mgte1988]

I may be wrong but the stock fuel pump will not allow anything over 12.7psi.I got the Lexus AFM and 255LPH pump and i can boost what ever but i iam currently at 14.5 to 15 with stock injectors

 

[GrimJack]

I think i may have the same problem as well. Except Im running stock boost...around 8psi. But occasionally when im into the throttle it just cuts and bucks really hard and then comes back pulling again. does this sound like a boost leak or a fuel cut?

Boost leak *causes* fuel cut. Yes, this is what it sounds like.

I may be wrong but the stock fuel pump will not allow anything over 12.7psi.I got the Lexus AFM and 255LPH pump and i can boost what ever but i iam currently at 14.5 to 15 with stock injectors

No may about it. You're wrong. Check your facts before posting in the tech sections - no guessing or "I heard" in here, please.

 

[kotu100]

oh forgot to ask do you have a boost gauge what kind, and where is the vacuum/boost T'd into?

its possible the boost gauge is inaccurate and you're actually pushing more boost than you think.

also not sure if this helps, but before i did the lex+550's, with only the tanabe exhaust and dump DDP i would hit fuel cut if i boosted under a load, or if i WOT shifted. it only takes a fraction of a second of too much boost to fuel cut.

 

[IBoughtASupra]

How Does The Tanabe Sound At Idle?

 

[92TealSupra]

How Does The Tanabe Sound At Idle?

I use to have one, there fine. Not very loud, but I liked my blitz nur spec a lot more.

 

[kotu100]

How Does The Tanabe Sound At Idle?

i love it, its got a nice rumble to it, but its very quite, even without a cat. living in Ma i need a quiet exhaust, and this is it. besides when the WG opens it unleashes HELL! :evil2: