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Author Topic: 11 psi.... and fuel cut??  (Read 1227 times)

Offline Eric Mathews

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11 psi.... and fuel cut??
« on: April 09, 2005, 02:15:20 am »
ok well tonight i was at misson AWESOME TIME!! it was alot of fun, love the awd eheh, but anyway i could only run my car at 10 psi cause if it was even at 11 i would get fuel cut, now i know i should do the fule pump re-wiring kit thing, BUT!!!! should i have to do that to boost 12 psi without fuel cut? ... and im pretty sure my boost leaks are fixed... maybe a little one on one of the injector seels.   WHY AM I GETTING FUEL CUT!!!!!... please if someone could help eheh.  oohh and i logged my car ( at stock boost not 10) and i didnt get any knock above like 10 or something at full boost and eveything seemed ok ... thanks again guys

Eric
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Offline Andreas Zervas

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« Reply #1 on: April 09, 2005, 02:17:21 am »
FUEL
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Offline John Hartman

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11 psi.... and fuel cut??
« Reply #2 on: April 09, 2005, 09:04:50 am »
once again, fuel cut has nothing to do with your fuel.  You can put 1000cc injectors and dual Walbro 255HP pumps in, and if you don't fix whats causing the cut, your car will still have fuel cut.

If its fuel cut you are actually getting.
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Offline Eric Mathews

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11 psi.... and fuel cut??
« Reply #3 on: April 09, 2005, 01:44:56 pm »
hmm.... ok thanks john that clears thing sup a bit , what do you think could be the problem?
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Offline John Hartman

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11 psi.... and fuel cut??
« Reply #4 on: April 09, 2005, 02:11:03 pm »
more airflow in than the ECU thinks it has fuel for.

Kinda odd tho, I had my hacked maf, nice intake pipe, K&N, 2.25" upper IC pipe,2g exhaust manny and a full 3" exhaust and I never hit fuel cut even at 17 psi. And sometimes it would creep to 19. No cut, just some ugly knock.
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91 Eagle Talon TSi 5spd awd.  GT-12, TriFlow Cams, 850s, Tial, JIC, Jackal, sticky rubber.
86 Merkur XR4Ti 5spd, rwd, turbo, 91,381km.  Original paint, heated leather. intercooled, big VAM, Full 3" exhaust, Cossie sway bar, 16" tires.
06 Mazdaspeed6 6spd awd, DISI turbo, heated leather HIDs, Corksport, Cobb, Konig, Centric...
2018 VW Golf Alltrack turbo Tornado Red, 6mt, some free mods

Offline Kimyee Lai

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11 psi.... and fuel cut??
« Reply #5 on: April 09, 2005, 02:48:27 pm »
Well, the hacked MAF will delay fuel cut.  ECU doesn't see as high of an airflow.  Fuel cut is basically an airflow limit that is programmed into the computer based on the stock fuel system limits.  If the ECU sees an airflow that the mitsu engineers deemed above what the stock fuel system can handle, it cuts fuel.  

If you put in fuel pump rewire, whinebro etc, fuel cut will NOT be affected...the ECU doesn't know/care that you did these things.  Now if you put in a bigger injector, and use an SAFC to compensate, i.e. lower the airflow so you lower your injector DC to account for the size increase, you will effectively move fuel cut back as the ECU sees less airflow than there actually is.  Similarly a hack MAF, a post MAF, pre turbo air leak, will delay fuel cut.  It will also go lean, perhaps dangerously so, if the air bypassing the MAF isn't controlled.
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Offline Miles Frederick

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11 psi.... and fuel cut??
« Reply #6 on: April 09, 2005, 02:54:47 pm »
At what RPM in what gear does it occur ?

Perhaps it's not actual fuel cut.  Jesse Williams had a problem awhile back where it turned out to be a faulty Throttle Position Sensor.  It kind of felt like fuel cut, but at much lower rpm / load.  It might be worth doing the resistance check on the tps

http://www.geocities.com/MotorCity/Downs/7678/dsmtests.html
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Offline Edson Ng

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11 psi.... and fuel cut??
« Reply #7 on: April 09, 2005, 05:52:38 pm »
Could be a boost leak? The MAF  measures air going into the turbo while the boost is measured after the turbo so lots of air is going through the MAF to the point of fuel cut and yet little of it is getting to the engine (low boost reading).
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Offline Eric Mathews

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11 psi.... and fuel cut??
« Reply #8 on: April 09, 2005, 07:05:51 pm »
ya im pretty sure i dont haev any boost leaks, i checked and stuff but im gonna be checking it again this week... i just dont get why i could be getting it... cause my maf is hacked as well.... and its only 11 psi :S... could it be my maf its self?? and i need a new/different one?
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Offline Chris Andrews

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11 psi.... and fuel cut??
« Reply #9 on: April 10, 2005, 12:42:46 pm »
Quote from: "Edson Ng"
Could be a boost leak?


From the information so far provided, this is the most likely scenario.  Pressure test your intake,   my guess is that something is starting to leak around 10 psi........

Eric, please do a better job of checking your spelling...... :!:
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Offline Eric Mathews

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11 psi.... and fuel cut??
« Reply #10 on: April 10, 2005, 01:53:02 pm »
sorry i spelt "have" haev im trying though :P.  ya im gonna check for a boost leak and i was reading that it COULD be the ECU, but anyways thanks alot guys :D
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Offline Mitch Delmer

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11 psi.... and fuel cut??
« Reply #11 on: April 11, 2005, 10:44:42 am »
Are you sure its fuel cut?  cause i was having the same problem, kinda but at 14lbs, and it turned out to be going lean and misfiring.  It felt the same at fuel cut, and happened at higher rpm's. Installed a walbro 255 and fuel line upgrade to the rail and it went away, now i hit the real fuel cut at 23 lbs.  Oh and while this was happening my o2 voltage showed .88 so it should have been fine, but it must have been #1 that was going lean and misfiring due th the restrictive stock line from the filter to rail.  Hope this helps. Could even be a plugged fuel filter, stock ones are crap.
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991 AWD 5speed 6/4
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Offline Eric Mathews

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11 psi.... and fuel cut??
« Reply #12 on: April 11, 2005, 04:15:47 pm »
hmm ya i had never even thought of that... good point.  did that happen all the time or just WOT? ya cause my air fuel gauge is telling me im getting lots of gas, and i think im running rich too.
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Offline Mitch Delmer

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11 psi.... and fuel cut??
« Reply #13 on: April 11, 2005, 09:45:27 pm »
mostly at wot, but if i brought it up to 14lbs at part throttle uphill it would do it too.  you just cant trust those oxygen sensors since they read the mixture from all 4 after the turbo.  and they are horribly inacurate anywhere other that stoich.
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991 AWD 5speed 6/4
Holset HY35, Kinetic Tubular manifold, 3"turboback, RMT FMIC, 255walbro, 780's, Maffless!!,  AEM wideband, Eprom ecu with Speed Density chip...
11.40 @ 124mph-- 1700ft elevation  
DSM's---->>>Burnin gas and haulin ass

RMT Modifications
Shop phone-->250 833 5724

Offline Ryan Hobbs

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11 psi.... and fuel cut??
« Reply #14 on: April 29, 2005, 09:28:11 am »
Have you figured it out yet Eric?  I am having a similar issue and am also trying to track it down.

Ryan
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