Fuel cut? Boost cut? Rev limit? Bad tune? Idk..
Oct 19, 2011, 05:38 PM
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Fuel cut? Boost cut? Rev limit? Bad tune? Idk..
I'm sure this is a question that has been asked alot, but I assure you, this is one to think about.*
My car is an Evo 7. Short ram, eBay tbe, grimmspeed Mbc, walbro 255 fuel pump and tuned by tach motor works. Launch control set to 5k if I'm not mistaken.
Two weeks ago, I decided to relocate my Mbc inside the car for easier access. At the same time, I pulled the radio to kill dead weight and remove the giant system in the trunk.
I extended the lines from the wastegate and turbo about 8 feet into the cabin on the center console where the cigarette location was. Everything went well until I test drove it for the first time.
Cold start up, it idles above 2k which is normal. Then after operating temps, idle is perfect.
Redline is 7k for us, but as soon as it reaches 6k or a little after 6k it rev limits. It's not fuel cut because I used to own an r32 gtr with a BeeR rev limiter. More like red line or launch control. It feels like it just cuts out and im about to shoot fireballs from the exhaust. It does it in every gear in the same spot.*
It idles fine, boosts perfectly and holds it u til it reaches that rpm. It's not the wastegate because it wouldn't boost at all. It's not the tune because a tune doesn't just go bad. Fuel pump is close to new, and fuses have all been checked.
I even ran the lines back to the stock solenoid. Nothing.
The Mbc is installed CORRECTLY.
I figured something went wrong because my odometer stopped working too. So I decided to relocate the Mbc back in the bay.
Here's what I have done so far:
Iridium spark plugs gapped to .24
Tightened all hoses
Sold a hallman Mbc thinking it was faulty, but nope. Lucky guy got it for 20 bucks.
Relocated the grimmspeed Mbc back in the bay with lines smaller than 1foot in length
Pulled the radio and tested ... Nothing.
Vacuum and boost leak checked .. Nada.
What I noticed:
Car stalled one time from a quick decrease in speed when rpm's dropped way below idle level. Never did it anymore after that.
After testing the "rev limit" in all gears the check engine light flashed for a misfire or knock. Replaced the plugs and it still does it.
It's still doing it and I'm dumbfounded. I feel like I'm wasting money fixing **** that doesn't need to be fixed ...
Any ideas? I may have left alot of information out, but feel free to ask.
My car is an Evo 7. Short ram, eBay tbe, grimmspeed Mbc, walbro 255 fuel pump and tuned by tach motor works. Launch control set to 5k if I'm not mistaken.
Two weeks ago, I decided to relocate my Mbc inside the car for easier access. At the same time, I pulled the radio to kill dead weight and remove the giant system in the trunk.
I extended the lines from the wastegate and turbo about 8 feet into the cabin on the center console where the cigarette location was. Everything went well until I test drove it for the first time.
Cold start up, it idles above 2k which is normal. Then after operating temps, idle is perfect.
Redline is 7k for us, but as soon as it reaches 6k or a little after 6k it rev limits. It's not fuel cut because I used to own an r32 gtr with a BeeR rev limiter. More like red line or launch control. It feels like it just cuts out and im about to shoot fireballs from the exhaust. It does it in every gear in the same spot.*
It idles fine, boosts perfectly and holds it u til it reaches that rpm. It's not the wastegate because it wouldn't boost at all. It's not the tune because a tune doesn't just go bad. Fuel pump is close to new, and fuses have all been checked.
I even ran the lines back to the stock solenoid. Nothing.
The Mbc is installed CORRECTLY.
I figured something went wrong because my odometer stopped working too. So I decided to relocate the Mbc back in the bay.
Here's what I have done so far:
Iridium spark plugs gapped to .24
Tightened all hoses
Sold a hallman Mbc thinking it was faulty, but nope. Lucky guy got it for 20 bucks.
Relocated the grimmspeed Mbc back in the bay with lines smaller than 1foot in length
Pulled the radio and tested ... Nothing.
Vacuum and boost leak checked .. Nada.
What I noticed:
Car stalled one time from a quick decrease in speed when rpm's dropped way below idle level. Never did it anymore after that.
After testing the "rev limit" in all gears the check engine light flashed for a misfire or knock. Replaced the plugs and it still does it.
It's still doing it and I'm dumbfounded. I feel like I'm wasting money fixing **** that doesn't need to be fixed ...
Any ideas? I may have left alot of information out, but feel free to ask.
Oct 20, 2011, 09:39 AM
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So let me get this right... you are hearing the "popping" when you get to that sweet spot while shifting? Correct?
Mine does the same thing but that's when I hit rev limit...
Sounds like the same with your case, and if so, yes you're wasting a lot of money on things that dont need fixed
and a evo 7 you say? Nice
Also... I'm sure you will hear the same noise if you are rolling slowly and you push the clutch and rev it all the way up. Correct?
Mine does the same thing but that's when I hit rev limit...
Sounds like the same with your case, and if so, yes you're wasting a lot of money on things that dont need fixed
and a evo 7 you say? Nice
Also... I'm sure you will hear the same noise if you are rolling slowly and you push the clutch and rev it all the way up. Correct?
Last edited by Pssst; Oct 20, 2011 at 09:45 AM.
Oct 20, 2011, 10:15 AM
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So let me get this right... you are hearing the "popping" when you get to that sweet spot while shifting? Correct?
Mine does the same thing but that's when I hit rev limit...
Sounds like the same with your case, and if so, yes you're wasting a lot of money on things that dont need fixed
and a evo 7 you say? Nice
Also... I'm sure you will hear the same noise if you are rolling slowly and you push the clutch and rev it all the way up. Correct?
Mine does the same thing but that's when I hit rev limit...
Sounds like the same with your case, and if so, yes you're wasting a lot of money on things that dont need fixed
and a evo 7 you say? Nice
Also... I'm sure you will hear the same noise if you are rolling slowly and you push the clutch and rev it all the way up. Correct?
Where was your MBC installed previously? Did you have to remove or relocate anything to get to it or relocate it?
Have you checked to see if its throwing any codes, or have you logged anything?
Oct 20, 2011, 02:08 PM
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the mbc was a hallman installed and mounted near the intake with 2 connectors to the wastegate and turbo nipple as instructed and the solenoid capped off.
as i extended the lines with 2 more connectors and longer gauged lines, thats when the problem occured.
i bought a grimmspeed now and i even shortened the line, still doing it.
no check engine lights and i havent plugged it in for accurate readings.
im buying a wastegate from a buddy so i HOPE its just a faulty wastegate.
heres my classification: if a wastegate is "faulty" and wont "open" the car will overboost. and if its overboosting, the car's "failsafe" would kick in and fuel cut. makes sense right?
as i extended the lines with 2 more connectors and longer gauged lines, thats when the problem occured.
i bought a grimmspeed now and i even shortened the line, still doing it.
no check engine lights and i havent plugged it in for accurate readings.
im buying a wastegate from a buddy so i HOPE its just a faulty wastegate.
heres my classification: if a wastegate is "faulty" and wont "open" the car will overboost. and if its overboosting, the car's "failsafe" would kick in and fuel cut. makes sense right?
Oct 20, 2011, 02:29 PM
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the mbc was a hallman installed and mounted near the intake with 2 connectors to the wastegate and turbo nipple as instructed and the solenoid capped off.
as i extended the lines with 2 more connectors and longer gauged lines, thats when the problem occured.
i bought a grimmspeed now and i even shortened the line, still doing it.
no check engine lights and i havent plugged it in for accurate readings.
im buying a wastegate from a buddy so i HOPE its just a faulty wastegate.
heres my classification: if a wastegate is "faulty" and wont "open" the car will overboost. and if its overboosting, the car's "failsafe" would kick in and fuel cut. makes sense right?
as i extended the lines with 2 more connectors and longer gauged lines, thats when the problem occured.
i bought a grimmspeed now and i even shortened the line, still doing it.
no check engine lights and i havent plugged it in for accurate readings.
im buying a wastegate from a buddy so i HOPE its just a faulty wastegate.
heres my classification: if a wastegate is "faulty" and wont "open" the car will overboost. and if its overboosting, the car's "failsafe" would kick in and fuel cut. makes sense right?
Oct 20, 2011, 02:34 PM
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same thing. connected it to the solenoid and same thing happens. then i connected the lines together running on wastegate pressure, and it boosted but VERY little i forgot if it was less than 10psi.
i'll try to take a video to better explain my issue.
its like the car made its own limp mode at 6k lol best way i can explain it haha
i'll try to take a video to better explain my issue.
its like the car made its own limp mode at 6k lol best way i can explain it haha
Oct 20, 2011, 02:38 PM
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same thing. connected it to the solenoid and same thing happens. then i connected the lines together running on wastegate pressure, and it boosted but VERY little i forgot if it was less than 10psi.
i'll try to take a video to better explain my issue.
its like the car made its own limp mode at 6k lol best way i can explain it haha
i'll try to take a video to better explain my issue.
its like the car made its own limp mode at 6k lol best way i can explain it haha
Maybe one of the guru's will chime in.
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Oct 20, 2011, 04:37 PM
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I thought that. Maybe my odometer was actually inaccurate and WAS infancy hitting redline... But is there any other measurement device that I can plug in that will measure or tell me if my speedometer is broken?
I don't want to buy a wastegate actuator tomorrow ...
I don't want to buy a wastegate actuator tomorrow ...
Oct 20, 2011, 04:43 PM
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When you say odometer do you mean TACHometer? Because thats going to be a problem. lol.
Oct 20, 2011, 08:19 PM
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I apologize for my specification, it reads my RPM's, but it doesn't measure my speed or miles traveled. Everything else works besides those 2. The wheel speed sensor might be bad, so I'm going to take care of that this weekend
Oct 21, 2011, 07:56 AM
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a tune doesnt go bad doesnt it? its just like the brain of the car regardless if the car is off, the tune is still there..
Oct 21, 2011, 08:31 AM
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the car was tuned months ago. worked fine, launch control was set to 5k and i always reved a little passed 6500 when ripping the car. **** started happening and now im baffled
a tune doesnt go bad doesnt it? its just like the brain of the car regardless if the car is off, the tune is still there..
a tune doesnt go bad doesnt it? its just like the brain of the car regardless if the car is off, the tune is still there..
I have never heard of a tune going bad per say... I know in the VW world companies would let you "Demo" their tune and after X amount of time it would revert back to stock...
I cant think of anything else though.. I know weather effects boosting but I see no reason why it would effect your rev limit
