loss of power at 5000rpm under boost

[starfish]

I'm having this weird problem.the car makes lots of power up to about 5000rpm then it feels like there is nothing left.If I shift the car befor the motor hits 5000rpm it runs great ,but I cant let the motor hit 5000rpm or it kind of cuts out,the boost drops,and I'm lookin stupid behind these hondas!I took eveybodys advise and set the car up right and I can't figure this out.255 walbro,12:1 blox fmu,Blox map bypass,t3/t4 turbo,intercooler,HKS bov,38 mm wastgate 7psi spring,new ECM,new fuel filter,plugs, wires,coil pack.If any body knows why it does this or what could be causing this please help.thanx

 

[LD25Delta9]

Couple different possibilites...It sounds like your ECU could be retarding the crap out of your ignition timing due to knock. Are you using the highest octane gas you can find? Here in Indiana there are Sunoco stations that have 96. Try not to put anything lower than 93 in. Even if it means you have to drive another 1/4 mile to the "expensive" gas station. It's cheaper than the alternative...(blowing your engine up) Also, did you make sure to get one range colder spark plugs? That could have a lot to do with it, too. You are going to want to get NGK BKR7ES Part #6097
One more thing, Get performance wires or at least the best the 'Auto Zoo" has to offer.
Without more detailed desciptions of symptoms or a video, that's the best I got for ya. Hope it helps.

 

[bullettdsm]

Try a BLT before anything.

Stock injectors?

MB

 

[starfish]

My injectors are stock.I allways use premium gas.I'm not sure what plugs are in right now but I know they are some sort of NGK,probably what the stock 420A calls for.I gutted out my muffler to get my turbo breathing better. The motor is making more boost ,I was able to get up to 6000rpms then she started poppin and cracklin and lost all power.when I let off the gas it was ok again.I'm not getting any nocking or pinging at all.Is this fuel cut?

I just order the FCD.Hopefully this will fix this crazy shit!

 

[bagged420a]

My injectors are stock.I allways use premium gas.I'm not sure what plugs are in right now but I know they are some sort of NGK,probably what the stock 420A calls for.I gutted out my muffler to get my turbo breathing better. The motor is making more boost ,I was able to get up to 6000rpms then she started poppin and cracklin and lost all power.when I let off the gas it was ok again.I'm not getting any nocking or pinging at all.Is this fuel cut?

I just order the FCD.Hopefully this will fix this crazy shit!

What do you mean its making more boost? As in over 7-8 psi? If so there is your problem, your running lean and hitting fuel cut do to the extreamly high fuel pressure. Your fuel system needs an overhaul if you want to run anything higher than 8psi

 

[LD25Delta9]

What do you mean its making more boost? As in over 7-8 psi? If so, there is your problem, your running lean and hitting fuel cut do to the extremely high fuel pressure. Your fuel system needs an overhaul if you want to run anything higher than 8psi

Fuel cut is usually a pretty violent occurance... There would probably be more to it than just crackling and popping. But you are right about needing more work done to run higher boost. There are some guys getting away with 9 and even 10lbs on a stock fuel system, but that's pushing it.

OP: It sounds like you are having the same problem I was. It was my wires. I had some MSD wires but 2 of them were messed up somewhere and caused the same symptoms you are describing. I replaced them with some premium auto zoo's and it completely fixed my problem.

 

[starfish]

at first I was only getting 5 psi boost,and couldn't find no boost leek .so I thought it was my muffler,so I gutted it out.then my boost went way up to like 10 psi so fast that my cheap godspeed boost gauge over sprung and got all fu--ed up.IT was pretty nasty sounding.poppin and cracklin.felt like I dropped a anker.So I ordered a treadstone FCD hopeing the problem was fuel cut.I dont think my wastgate is workin right. Its a cheap ebay tial nockoff.They gave me 2 extra springs.I'm not sure which one was allready inside the WG.Wil the FCD fix this problem?I was planning on keeping stock injectors.Also my fuel pump my be screwed up from the bad gas that I got from the gas station.Their insurance company is sending me a check for $798.YA HOOOO

 

[bagged420a]

Do you not have the FCD installed already? If not then that is your problem more than likely. Unless it accured while you had the bad gas

 

[rstare]

Do you not have the FCD installed already? If not then that is your problem more than likely.

Fuel cut is usually a pretty violent occurance... There would probably be more to it than just crackling and popping.

I agree with Delta, it doesn't sound like fuel cut. Fuel cut is usually decribed as hitting a brick wall.

If your boost stops increasing at some point, then your wastegate is working. Otherwise, as the engine RPM's increased, the increased airflow would cause the turbo to keep creating more boost. So, if your gauge stops at 8psi, or whatever, then your wastegate is working.
Since you think there is a chance something could be wrong with your fuel pump, I would try changing that first. Check your fuel filter, as well.
Do you have a wideband?

 

[LD25Delta9]

Now that the OP has described it a bit more, it does sound like what our cars do when they hit "fuel cut." It's not as bad as what I've heard described by the 4g63 guys, but it is bad none the less. Exactly as you put it though, "hitting a brick wall."

OP: It sounds like you are just hitting too much boost. You may have fixed your original problem by gutting the cat, but you have created a new one. I would put the weakest spring in your wastegate, then use a Manual Boost Controller to up the boost from there. It's hard to say which one is right from my side of the computer, but press on the springs and find the weakest one. If the weakest one is still too much, take the spring to your local hardware store and find one that is similar in size but not in strength and go from there....or get a new wastegate.

 

[bullettdsm]

I would put the weakest spring in your wastegate, then use a Manual Boost Controller to up the boost from there.:

OP, what Adam is getting at, is to set your car up so that the boost controller is what allows you LOW control over your set-up. Try to get it down to like 6psi and THEN check and see if your psi holds (and how she does above 5k at that point). That's part of trying to get a "baseline" of your set-up (part of the reason I asked about stock injectors. To get a baseline of your set-up. Also the reason others are asking about the FCD - to get a baseline of your set-up). If that works then you can bring it up incrementally.

You, apparently, also have other fuel issues that need to be dealt with. IDK what was wrong with the gas (are we talking fluid/water, or pieces of crap in the gas?), but you need to address that problem fully before you can attack another one (because that may be the cause). If we are talking just water in the fuel, then I can't see how your pump would be bad (but I could see how that would cause fuel problems).

I guess what I am getting at is being sure that you have the basics down/installed and fixed before you move on.

MB

 

[starfish]

Yes I have a wideband.when I punch it to the floor.The boost will go up to about 7 psiish.Then she snap,crackle.and pops,the wideband goes all the way lean to were there are just lines goin across the gauge.Feels like the fuel is cuttin out.as far as the bad gas,I emptied the tank,wiped it clean with rags real good.I didn't change the filter (it was only 2weeks old when this happened).sucked acan of seafoam up my vac line ,changed the oil,filter.used lucas fuel treatment.Car seemed to run better than ever eccept when I get to about 5000rpms or when I put it to the floor.Is it bad to drive the car like this(without goin full throttle)?

 

[bullettdsm]

Yes I have a wideband.when I punch it to the floor.The boost will go up to about 7 psiish.Then she snap,crackle.and pops,the wideband goes all the way lean to were there are just lines goin across the gauge.Feels like the fuel is cuttin out.as far as the bad gas,I emptied the tank,wiped it clean with rags real good.I didn't change the filter (it was only 2weeks old when this happened).sucked acan of seafoam up my vac line ,changed the oil,filter.used lucas fuel treatment.Car seemed to run better than ever eccept when I get to about 5000rpms or when I put it to the floor.Is it bad to drive the car like this(without goin full throttle)?

I'm guessing you're not going to want to continue to do this because you will probably burn the sides off your pistons . Yup you are running out of fuel but you'll want to know why. Too much boost? Too much air? Not enough fuel? Bad readings?

All kinda the same things but different reasons. See what happens when you set the boost controller to 5 or 6psi. Again, check for boost leaks (see if she can hold 20psi on a blt). I know its hard to keep the boost down that low, but see if you can. This will help you to diagnose (keep an eye on the wideband).

As for driving it around, that would be up to your self control. As long as you stay out of boost and the wideband says all is good, then you should be fine. But it will be your discipline to keep her out of boost.

FWIW, I am now driving my GSX around without a wastegate on a FP Green (just haven't gotten a deal on a wastegate yet - I'm cheap as h*ll). All it takes is self control.

MB

 

[rstare]

It doesn't seem like fuel cut to me. (Of course it's hard to tell over a computer) I've experienced fuel cut and it produces a jerking when under boost. Full power to none, instantly.
"Fuel cut" is an act where the ECU senses something is wrong so it cuts all fuel. Not allowing combustion to occur.
What you're experiencing (as bullet as said) is simply too little fuel. Which is different from fuel cut. It causes a lean condition which leads to a much hotter burn and in the end, detonation. That's why Mark said you'll be melting the side of your pistons.

Bullet, he filled his tank up with methanol, btw.

I've never believed that the Walbro255lph hp pump could really keep up with pressure required by the 12:1 FMU at 7 or 8psi. I know a lot of people do it, but I'm just skeptical. So, in my opinion, you're experiencing one of a few things.
One, the methanol damaged your fuel pump, it works, but it's not able to produce the higher pressures.
Two, the methanol damaged your fuel filter and it's not allowing the correct amount of fuel to flow through it.
Three, you're experiencing the fact that the fuel pump isn't able to produce the pressures demanded by the 12:1 FMU. This would be my last guess, because so many people run this setup.

Just to clarify, you do have the Walbro 255lph High pressure pump, correct?
If "yes", then as Adam said, turn down your boost. Bring it down to 5psi and see if this still occurs.
If that doesn't work, move to the fuel filter.
We'll move on from there.

 

[starfish]

I spoke to Chris at Horsepower freaks and found out that the fp that i bought is a 255 lph ,NOT A HP.He said that with using stock injectors a HP pump wouldn't work.Is this true?The car really does jerk.It feels like its suckin fuel under boost like crazy,then like its gettin no gas at all.when I let off the throttle and give it a little gas it goes back to normal.I can drive around with half throttle all day and it feels fine ,but as soon as It gets up to around 7 psi it cuts out again.I just got my check from insurance com. today so what do you think I need to fix this problem?I already ordered FCD from treadstone.

 

[bullettdsm]

I'm out . Good luck.........

MB

 

[nosdsm3]

I am having a very similar problem, I just finished my turbo install last week and have taken my car for two short runs. The same thing happens to me with the odd popping and rumbling when I come into boost. Did your car back fire at all? I am using a missing link manual fcd and about a week ago also ordered the treadstone fcd. It feels like fuel cut to me I was hoping that I would have the part by this weekend to try and fix but it has not come yet. If mine comes before yours I will post my findings.

 

[starfish]

do you have a wideband?does your car olso run lean at idle?

 

[nosdsm3]

My wide band is in the mail still not sure how lean or rich I am running that is why I havent really driven the car. With it not running right I was afraid that I was running it lean.

 

[starfish]

It does backfire and feels like my fuel shuts off all at once.I definatly feel that I'm gettin fuel cut at 4500rpm.When my car is still cold,at idle I'm reading about 15.5-16.3 then when the motor reaches operating temperature the gauge is showing 16.5-17.1 at idle.And when I'm driving ,when I start makeing boost I'm around 10.5 - 11.1 ish ,but when I shift and take my foot off the gas my wide band goes to like 17.1 to --- .I'm not sure if its suposed to do that when you lift off the throttle when you are driving.When my FCD gets here,I'll hook it up and keep you posted on how it works out.Are you set up simaler to me? T3/T4 turbo,intercooler,Missing link,12:1 FMU,walbro 255lph

 

[rstare]

You have several threads on the same topic....
You must have a High Pressure pump in order for this setup to possibly work.

 

[starfish]

Thanx,thats the info I needed to know.The guy I spoke to when I ordered the first fp,asked me if I was using stock injectors.He told me that I couldn't use the HP 255 with stock inj. But I guess he doesn't know what he was talking about.I ordered a HP,hopfully it will fix my problems.

 

[LD25Delta9]

Wow...you guys ran Mark off....maybe you should try listening to him.
It's not fuel cut. If it was, you wouldn't even hit boost. Your MAP sensor would read positive pressure and the ECU would shut down your injectors. If the fuel shuts down in boost, you are maxing out your injectors or in this case, you just are not getting enough fuel to them and I'll put money on the fact that you haven't put the proper spark plugs in. MAJOR NO NO! Do you like detonation? Cause I'll guarantee you're causing some. You have to install an HP as Rstare said. HAVE TO! This will supply your injectors with the proper amount of fuel. You'll run a little rich all the way to almost lean if you have it all setup properly, so what I want to know is why would you even buy a Wideband if you don't know how to read it? You know some numbers flash across it but do you know what they mean? "I don't know what it does, but it sure does do it!" If you ever get into a way to control fuel or spark then, yeah, that wideband will be a Godsend. Until then, you get a few uses: You can use it to tell when your plugs are getting burned up, that you might have put the wrong Oct. gas in...or to remind you that you should've paid someone who knows what they are doing to properly plan and build your car.

I'm with Mark. Deuces.

 

[starfish]

I know what the #s mean I just couldn't figure out why they were like that.I really don't know too much about these cars thats why I listen to YOU guys for advise.There set up alittle differet from my 69 charger!But how do I know which guy is giving me the right advise.The guy from Horsepower freaks is the guy who told me not to buy the HP.You would think he new what he was talkin about.Every fudgin part I bought on this motor was from the advise from YOU guys!Accept the pump!the car doesnt detonate at all untill I hit boost aroud 6-7psi then it feels like the car shuts off(it makes like one pop and throughs me forword),feels like it stalls out,and the A/F gauge shows ---.My map sensor shouldn't read boost with my blox map sensor bypassvalve,should it?Ive tried 3 sets of wires,2 sets of plugsNGKs and irridiums(the ones that the motor calls for)both gapped .045,2 different coil packs,and I got a new ECU.so can the injectors get maxed out with the 255lph(low pressure),under only 5-6psi boost?Its hard to tell which guy knows and which guy thinks he knows because I definatly dont know but I'm trying to learn!

I thought this site was for helping each other out!Not for puttin people down for what they dont know!

 

[rstare]

No, your injectors won't be maxed out. It your fuel pump that supplies the pressure and it's your fuel pressure increasing that's getting you more fuel. The duty cycle of the injectors arn't increasing at all from being NA. So, if your fuel pump can't supply the correct amount of flow at the pressures the FMU is demanding, it's not that you're outflowing your injectors, rather your fuel pump. The HP pump allows slightly higher pressures, which should suffice. At least it has for many of other people.

The guy you were talking to at horsepower freaks, or whatever, probably thought you had a 4G63. You need an AFPR when putting in a Walbro 255 for the 4G63.