what to do?
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From: Portland, Oregon
what to do?
Alright well here's the problem. I posted a tread because i was having problems with my fd cuz it made a spatter/studdering noise when i was on the highway and i was sort of gettin on it. On my 93' RX-7 i have a full xhaust system 3" all the way. I don't have a upgraded e.c.u or a boost controller, nor do i have a boost gauge. I was told from this site that i might be hitting the feul cut deffenser. I was suggested to go put on my stock main cat and get a boost controller and pfc before i do anything, well that's if my engine wasn't messed up. So i just got back a tuner shop i go to and a guy there said that i don't need a pfc or a bc because the stock e.c.u can handel it, and that theres no way i hit the feul cut because feul cut comes in at high rpm's not mid range. He said the cause of my problem was because i had blown my primary turbos. He suggests i just replace the turbo's, but i dont really trust him because everyone on this site is telling me otherwise. I need your guy's feed back.
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Joined: May 2001
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From: S.F. Bay Area, CA
Run from that mechanic, he know's nothing about FD's. That much is obvious.You may want to consider the following: 1. get a boost controller asap. 2. get an aftermarket ecu. 3. reinstall the main cat.
If you don't like those choices your looking at a blown motor, which is going to cost you much more than all those mods I listed above put together.
If you don't like those choices your looking at a blown motor, which is going to cost you much more than all those mods I listed above put together.
Originally Posted by Rmagic13b
Alright well here's the problem. I posted a tread because i was having problems with my fd cuz it made a spatter/studdering noise when i was on the highway and i was sort of gettin on it. On my 93' RX-7 i have a full xhaust system 3" all the way. I don't have a upgraded e.c.u or a boost controller, nor do i have a boost gauge. I was told from this site that i might be hitting the feul cut deffenser.
"Fuel Cut Defenser" is an aftermarket tool that does a similar thing. It's practically useless to add to an FD. Just so you know when you add 'defenser' it takes a different meaning.
I was suggested to go put on my stock main cat and get a boost controller and pfc before i do anything, well that's if my engine wasn't messed up.
1) Get a boost gauge and put the main cat back in. Ensure the boost doesn't exceed 11psi.
2) Get a boost gauge and put a restrictor plate in. Ensure the boost doesn't exceed 11psi.
3) Get a boost gauge, boost controller, PFC, and port your wastegate. Get the PFC tuned for 11-13psi of boost. (For higher than 12psi, I recommend fuel system upgrades too)
So i just got back a tuner shop i go to and a guy there said that i don't need a pfc or a bc because the stock e.c.u can handel it, and that theres no way i hit the feul cut because feul cut comes in at high rpm's not mid range.
He said the cause of my problem was because i had blown my primary turbos. He suggests i just replace the turbo's, but i dont really trust him because everyone on this site is telling me otherwise. I need your guy's feed back.
Dave
These cars will cut the fuel supply at any RPM if your boost pressure is too high for too long (although it is mostly encountered above 4,500 RPM), and I think there is also a fuel cut if your RPMs are over redline. Your "expert" may have been thinking of the over-rev fuel cut and didn't know about the over-boost fuel cut.
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From: King George, VA USA
Unfortunately, I've encountered fuel-cut myself. It usually happens around 6,500RPM on the highway in 3rd, 4th, and 5th gear (though I never go THAT fast).
From what I'm reading it makes sense. Too much boost for too long, or just too much CFM for the stock ECU to handle at that high of an RPM. It's only in 3rd+ gear at high high rev. Even though I may only be boosting 9psi or so, it still makes sense that I would hit fuel-cut at that high of a rev in the later gears.
I've running intake, dp, main cat, and catback. Running non-seq right now too, and only boosting 8-9psi. I plan to at least install a MBC to get rid of an overboosting/boost creep problem I'm having, and just get it running a solid 10psi.
Next step is alluminum AST and Power FC; fuel-pump too. I'd like to run 12psi on that setup for a while.
I do plan on going FMIC and upgrading to a Fluidyne radiator. Possible Koyo, if, after some more research, I decide that fitting won't be an issue. Price is a factor too. hehe.
I think I've got my head in the right place, so far. :P
From what I'm reading it makes sense. Too much boost for too long, or just too much CFM for the stock ECU to handle at that high of an RPM. It's only in 3rd+ gear at high high rev. Even though I may only be boosting 9psi or so, it still makes sense that I would hit fuel-cut at that high of a rev in the later gears.
I've running intake, dp, main cat, and catback. Running non-seq right now too, and only boosting 8-9psi. I plan to at least install a MBC to get rid of an overboosting/boost creep problem I'm having, and just get it running a solid 10psi.
Next step is alluminum AST and Power FC; fuel-pump too. I'd like to run 12psi on that setup for a while.
I do plan on going FMIC and upgrading to a Fluidyne radiator. Possible Koyo, if, after some more research, I decide that fitting won't be an issue. Price is a factor too. hehe.
I think I've got my head in the right place, so far. :P
Last edited by YoshiFD3S; Dec 2, 2005 at 04:46 PM.
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See this site for info on overboost fuel cut http://www.fd3s.net/fuel_cut_info.html
"Fuel cut is a function of absolute manifold pressure vs. RPM, regardless of what gear the car is in."
"Fuel cut is a function of absolute manifold pressure vs. RPM, regardless of what gear the car is in."
Thread Starter
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Joined: Nov 2005
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From: Portland, Oregon
yea thats wut i thought he was like yea i had a fd and i know these things thru and thru..but i had a weird feeling of this guy and think he just wants to **** me over, but i belive you guys. i'm going to get a boost controller and boost gauge asap. I dont care wut this guy says this guy doesnt know ****. thank you guys
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From: San Lorenzo, California
Originally Posted by YoshiFC3S
From what I'm reading it makes sense. Too much boost for too long, or just too much CFM for the stock ECU to handle at that high of an RPM. It's only in 3rd+ gear at high high rev. Even though I may only be boosting 9psi or so, it still makes sense that I would hit fuel-cut at that high of a rev in the later gears.
What the heck have you been reading? Nothing posted on this forum from anyone knowledgable, that's for sure....
If you are truly only hitting 9 psi, you are NOT hitting fuel cut and the stock ecu is still extremely safe and rich. You have another problem.