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6000 RPM no fuel issue

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42O

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6 November 2008
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HP Turbo Kit (stage III) finally installed on my 2003 acura nsx, and was at the dyno with tuner and mechanic who installed the turbo. 438HP at 8psi was the overall result. Problem is after a few dyno runs at around 6000 RPM the fuel seems restricted, and loss of power due to fuel cutting off.

They cleaned out fuel filter, checked fuel pump, and everything is fine the first dyno run, then when we do it again there is power loss and fuel cut-off it seems. What could be the problem here? I'm not a mechanic, I am the nsx owner, just trying to help the mechanic fix the problem quickly and effectively.
 
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Yes, brand new fuel pump was installed prior to dyno tuning. He is going to get larger fuel lines and install them tomorrow to see if that does anything. Seems to think that will solve the problem.
 
I learned that a z32 fuel filter has less restriction. I did this when i did my RB25DET swap into my 240. I did not do this for my car and you shouldn't have any problems pushing 450+ with just a walbro upgrade. The only reason i haven't swapped out my oe for the z32 fuel filter because i purchased a brand new one when i bought my x and turbo'ed a week later. What kind of fuel pump are you running? did you check fuel pressure with the pump running on high?
 
I had a similar problem with with Supercharge setup. Car was leaning out on higher rpm. Turns out to be an old/bad fuel filter. I would definitely try a new oem filter before changing the lines

Danny
 
If the shop that was tuning my car didn't have the instrumentation to monitor fuel pressure at the rail and at the filter inlet during a dyno run I'd take it somewhere where the technicians do more than shotgun the problem.
 
Mark911 said:
If the shop that was tuning my car didn't have the instrumentation to monitor fuel pressure at the rail and at the filter inlet during a dyno run I'd take it somewhere where the technicians do more than shotgun the problem.
Click to expand...

I totally agree... Without knowing what the fuel pressure is during the run, there's no way to know for sure if it indeed a fuel problem. A cheap B&M gauge on the fuel filter will do the trick.

Not to mention, if it was indeed a fuel issue (ie: not enough fuel), it would show this lean condition on the WB02... they are using one right?

I find it odd (coincidental) that it happens at 6k rpm and on the 2nd+ runs. Could be the VTEC solenoid not working and the engine is remaining on the low cam while the ECU is providing fuel/timing for the high cam.
 
One more thing... reread your post. Not entirely positive on what you mean by "fuel cutting off" at 6000-6500rpm, but I believe that peak torque is right around there. If the spark plugs were not gapped correctly or the wrong type of plug, it will miss/stumble as the spark is being blown out.

Did they change and/or regap the plugs? 0.032-0.030" ish for 8psi...
 
So im guessing you live in Hilton head....guessing that your the car with the red with the red black wheels....Im the one from the day with the black on black....
 
warren1205 said:
I learned that a z32 fuel filter has less restriction. I did this when i did my RB25DET swap into my 240. I did not do this for my car and you shouldn't have any problems pushing 450+ with just a walbro upgrade. The only reason i haven't swapped out my oe for the z32 fuel filter because i purchased a brand new one when i bought my x and turbo'ed a week later. What kind of fuel pump are you running? did you check fuel pressure with the pump running on high?
Click to expand...

I know a brand new fuel pump was installed, and I am not sure what brand it was, I believe it was the one that came with the turbo kit. I could be wrong, but my mechanic ordered a new fuel filter, larger fuel lines, and a few other things. He is pretty confident this will fix the issue, I just wanted other input.
 
C-speed said:
One more thing... reread your post. Not entirely positive on what you mean by "fuel cutting off" at 6000-6500rpm, but I believe that peak torque is right around there. If the spark plugs were not gapped correctly or the wrong type of plug, it will miss/stumble as the spark is being blown out.

Did they change and/or regap the plugs? 0.032-0.030" ish for 8psi...
Click to expand...

I am not quite certain on this, I will ask him tomorrow, thankyou. Also I am sorry I am not that great at explaining things. It just seems that there is massive power loss during dyno runs at 6000 RPM due to no more fuel being pushed through.
 
C-speed said:
I totally agree... Without knowing what the fuel pressure is during the run, there's no way to know for sure if it indeed a fuel problem. A cheap B&M gauge on the fuel filter will do the trick.

Not to mention, if it was indeed a fuel issue (ie: not enough fuel), it would show this lean condition on the WB02... they are using one right?

I find it odd (coincidental) that it happens at 6k rpm and on the 2nd+ runs. Could be the VTEC solenoid not working and the engine is remaining on the low cam while the ECU is providing fuel/timing for the high cam.
Click to expand...

Like I said I am not good at explaining things sometimes, but I have all the AEM guages in the car, and they had all kinds of computers and stuff hooked up to the car, and they knew what they were doing. I will get back to you guys after the new fuel filter, fuel lines, and a few other minor parts are installed, I am just going to hope this fixes the problem. I appreciate your concerns.
 
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42O said:
Like I said I am not good at explaining things sometimes, but I have all the AEM guages in the car, and they had all kinds of computers and stuff hooked up to the car, and they knew what they were doing. I will get back to you guys after the new fuel filter, fuel lines, and a few other minor parts are installed, I am just going to hope this fixes the problem. I appreciate your concerns.
Click to expand...

I hope so too, but I doubt its the fuel lines, nor the pump, nor the filter. :)
 
Well, we will see in a few days when those parts come in. I will ask about the spark plug gaps today to see if he made any adjustments there. He seems certain its a fuel issue though, him and the tuner. Thanks for your help.
 
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You mentioned that you have a 2003 NSX. Do you have any trouble codes indicated by a check engine light on your dash? This could point you in the appropriate direction to look - misfire detection, VTEC malfunction, MAP sensor fault, etc. If your check engine light is illuminated, have your shop use a scan tool to read the diagnostic information from the ECU.

If you area going to change to a NGK copper spark plug, DO NOT go with the NGK BKR7E-11 mentioned as the plug gap out of the box is quite large for boost applications.

NGK stock # 6097 is a straight BKR7E with a smaller plug gap more suitable for boost right out of the box - this is the plug a lot of the high HP NSX guys are running. Your shop should use a feeler gauge to confirm and possibly adjust the gap with brand new plugs. I would start with a .030" to .032" gap and work from there.
 
Devin@AEM said:
If you area going to change to a NGK copper spark plug, DO NOT go with the NGK BKR7E-11 mentioned as the plug gap out of the box is quite large for boost applications.

NGK stock # 6097 is a straight BKR7E with a smaller plug gap more suitable for boost right out of the box - this is the plug a lot of the high HP NSX guys are running. Your shop should use a feeler gauge to confirm and possibly adjust the gap with brand new plugs. I would start with a .030" to .032" gap and work from there.
Click to expand...

IMO (everyone can do as they wish), there is absolutely nothing wrong with the NGK BKR7E-11 plug. Yes, they are pregapped to 0.045" out of the box. however, there is nothing wrong with REGAPPING them. The NGK BKRE7E-11 plug is an EXCELLENT plug for FI applications and is very good an not fouling up and cold starts.

I've personally recommended this plug (and tuned them) on many FI vehicles from daily driven to high horsepower (900hp+) applications - yes on Honda's including NSX.

But again, do as you wish - it's your car :) the #6097 that Devin suggested works too... just wanted to make a point that the BKR7E-11 works too.

And I did state in my 2nd post (#10) in this thread to check the plugs and set the plug gap to 0.030-0.032" ;)
 
Tinker219 said:
I have to agree with Devin here, there is no reason to crush the sh*t out of a .045" gap to bring it down to .030". Why risk the chance of weakening the ground strap?
Click to expand...

No point in going OT on this, but its far from "crushing" - 0.0015" is around the thickness of 2-3 sheets of paper :confused: I'm sure if you did a quick search on Google, you'll find that this plug is used for *MANY* FI applications.

But again, do as you wish - there nothing wrong with either plugs.
 
whrdnsx said:
Just wondering what's wrong with the Iridiums in FI application?

I have them in my low boost turbo setup with no problems.
Click to expand...

I suppose I should clarify :) You can actually use Iridiums with FI, however platinum plugs perform VERY poorly under boost. They misfire, foul and are not very good at preventing knock. The problem is the cost per mile on the plugs. I suppose if you don't care about spending $10+/plug every 6-8000 miles, then sure, run the iridiums, but the coppers will perform the same if not better at 1/5th the cost - $2/plug.

:D
 
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I appologize for not being a little more clear in my post about the spark plugs.

The more "appropriate" copper plug if you were aiming for a .030 - .032 gap would be the #6097 BKR7E. No need to bend, smash, crush (or however you want to word it) a larger factory gapped plug down when you have a more closely matched plug available for the job.

420 - I hope some of the posts here have given you a few good ideas to take back to your mechanic/tuner.
 

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