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boost issues (just like a lot of jerks)

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Old 04-15-13, 04:10 PM
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a few updates. re confirmed that all my injectors are 550. after putting everything back together i decided for ***** and giggles i'd see how it ran if i unplugged the boost pressure sensor and it ran exactly the same. any chance that's a sign it's bad? would there be any change even with other issues or fuel/boost cut/whatever the butts is going on with this thing?
Old 04-16-13, 10:49 AM
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Stopping by my mechanic to get the cars fuel pressure checked as well as ser about boost leaks though I'm still doubtful on that. Update will be coming later.
Old 04-16-13, 02:40 PM
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new update. There are no boost leaks at all. just got back from testing. still have yet to test my fuel pressure. about to give in and by an rtek to see if that hoe will work in either my stock n374 or n370 (both of which only run the car on one rotor) oddly enough as does the s5 na ecu
Old 04-18-13, 12:56 PM
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does anyone know if just getting a standalone unit would help with this issue?
Old 04-18-13, 01:10 PM
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I'd also like to reiterate that i do have two stock ecus. the n370 that runs it only on one rotor and the n374 that runs it on one rotor. the only reason i use the knightsports ecu is cause it's the only one that runs it on both rotors and makes it drive-able at all
Old 04-18-13, 04:52 PM
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Guessing it's a JDM wire harness since the N370 doesn't work correctly either. As Bumpstart pointed out back in post #5, the JDM pinout is different from the US one and nobody really knows exactly how.

It 'should' work with the modified ecu, but now that it doesn't, you're stuck. You could try a stock N374 ecu, but it's better to actually identify the problem rather than throwing parts at it.

*If* everything else is in working order, then I'd swap in a USDM N370 wire harness and try the N370 ecu.

The people trying to give advice are stuck because you haven't identified the problem. All we know is it doesn't go like you want it to.

Is it bogging out because it is too rich or too lean?
Is it losing spark?
Is the timing correct?
Does it just have a poor ground?
Does it happen consistently at a certain rpm or throttle position?
Does your turbo have shaft play?
Old 04-18-13, 05:50 PM
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If you know Japanese and the KS ecu has some information on it you could contact them about the settings/rom tune.. You may be able to email them using google translate, be sure let them know you from USA..

Welcome to Knightsports Site

KNIGHT SPORTS ?RX-7????????

Konnichi wa!
Old 04-20-13, 01:15 AM
  #33  
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Guessing it's a JDM wire harness.

i believe i stated earlier that it was an NA harness but may have left out it has been modified to work according to some of the swap threads.


*If* everything else is in working order, then I'd swap in a USDM N370 wire harness and try the N370 ecu.


This is actually something i'm going to try next if a new ecu doesn't work.


Is it bogging out because it is too rich or too lean?
Is it losing spark?
Is the timing correct?
Does it just have a poor ground?
Does it happen consistently at a certain rpm or throttle position?
Does your turbo have shaft play?


out all of these the only thing i haven't cleared is if it's for sure running rich. everything else is in working order, grounded propperly, and so on.

also it doesn't matter the rpm. it only happens once the boost gauge hits "0"

Originally Posted by Nick_d_TII
If you know Japanese and the KS ecu has some information on it you could contact them about the settings/rom tune.. You may be able to email them using google translate, be sure let them know you from USA..

Welcome to Knightsports Site

KNIGHT SPORTS ?RX-7????????

Konnichi wa!
This is something I have been thinking about! I'll have to give it a try and try and find a registration number or something on it.


Thanks for the advice guys! I'll keep updating as I progress

Last edited by jakeishness; 04-20-13 at 01:21 AM. Reason: it looked bad
Old 04-21-13, 10:06 PM
  #34  
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1. We use non turbo S5 wiring harnesses with no major modifications all of the time on the S5 turbo swaps, along with Apec or Jspec ECU's, MAF, and MAPs. (there is a thread about 50% of the time the jap ecu's wont work for some unkown reason)

2. The JDM harnesses are missing one of the interior plugs that runs to the driver side behind the dash. Something to do with the RHDness. May or may not be fixable. I have always avoided trying to use them because of that tho.

3. Where are you getting this boost readings from? Are you sure your not overboosting? All of our turbo swaps never seemed to require a fuel cut defender, so be careful not to pop your engine from overboosting/detonating. Many low level aftermarket gauges end up being inaccurate. Like reading 1-10 PSI off, including Autometers and Garett brand gauges, but especially the china/ebay cheapies.
Old 04-23-13, 01:59 PM
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Originally Posted by First gen man
1. We use non turbo S5 wiring harnesses with no major modifications all of the time on the S5 turbo swaps, along with Apec or Jspec ECU's, MAF, and MAPs. (there is a thread about 50% of the time the jap ecu's wont work for some unkown reason)

2. The JDM harnesses are missing one of the interior plugs that runs to the driver side behind the dash. Something to do with the RHDness. May or may not be fixable. I have always avoided trying to use them because of that tho.

3. Where are you getting this boost readings from? Are you sure your not overboosting? All of our turbo swaps never seemed to require a fuel cut defender, so be careful not to pop your engine from overboosting/detonating. Many low level aftermarket gauges end up being inaccurate. Like reading 1-10 PSI off, including Autometers and Garett brand gauges, but especially the china/ebay cheapies.
this is the boost gauge i use.
Electric Boost Guage - Prosport Gauges Peak & Warning gauges
and i'm def not making boost. cause no go fast and i dont hear the turbo spooling that fast
Old 04-24-13, 10:53 AM
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Originally Posted by jakeishness
i believe i stated earlier that it was an NA harness but may have left out it has been modified to work according to some of the swap threads.
This is confusing because you modified an NA harness to work with an N370 ecu. But it doesn't work with an N370 ecu. So you swapped to a Jspec ECU?
It seems more likely there's a problem with the harness rather than two completely stock N370 ecu's. I'd revisit the harness.

Originally Posted by jakeishness
and i'm def not making boost. cause no go fast and i dont hear the turbo spooling that fast
Easy with all the technical mumbo jumbo!
Old 04-24-13, 11:13 AM
  #37  
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Ya Im using prosport oil and fuel pressures, so far they have treated me quite well.

Had to make sure, we've had alot of problems overboosting the stock turbo when using aftermarket exhaust.

It would be nice to get a wideband on it and see exactly whats happening under boost. Sounds like its rich for sure while cruising and idle from what you said, but do you think its hitting a rich spot or a lean spot at 1 to 2 psi?

And yes, usually standalones will fix all these sorts of problems, but usually bring some headaches getting setup correctly.

Is the walbro wired in to the fuel pump resistor relay?

And do check your fuel pressure.
Old 05-06-13, 01:26 PM
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So I got an rtek chip with the "no omp" selected as the rtek guy suggested to omit the omp from the computer to keep it from going into limp mode. Hopefully I plug that bitch in and everything is *******. If not then at least i know it's not the omp driver issue.

Originally Posted by RXSpeed16
This is confusing because you modified an NA harness to work with an N370 ecu. But it doesn't work with an N370 ecu. So you swapped to a Jspec ECU?
It seems more likely there's a problem with the harness rather than two completely stock N370 ecu's. I'd revisit the harness.


Easy with all the technical mumbo jumbo!
lol yeah my tech savey lingo does intimidate a lot of people! and also one was an n370 one was an n374 and one was an n350 and all of those ran it on one rotor. the ks n374 is the only one that runs it on two. hopefully not the wiring ... but if this doesn't work hopefully it is! XD i'll have my mechanic take another look at the wiring and do some volt tests if he can.
Old 05-06-13, 01:31 PM
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Originally Posted by First gen man
Ya Im using prosport oil and fuel pressures, so far they have treated me quite well.

Had to make sure, we've had alot of problems overboosting the stock turbo when using aftermarket exhaust.

It would be nice to get a wideband on it and see exactly whats happening under boost. Sounds like its rich for sure while cruising and idle from what you said, but do you think its hitting a rich spot or a lean spot at 1 to 2 psi?

And yes, usually standalones will fix all these sorts of problems, but usually bring some headaches getting setup correctly.

Is the walbro wired in to the fuel pump resistor relay?

And do check your fuel pressure.
i needs to get my *** a wide band here ... either way to be honest. And there is a good possibility that it's hitting fuel cut at atmospheric pressure. I was currious to think that it's just the secondaries not firing and the car being all "wtf?! where's my fuel?!" Also do the secondaries kick in even under 3500 like if i'm at wot. i can however keep my throttle low and rev past 3500. Basically wondering if secondaries kick on at any rpm at wot or at any time it tries to go into boost?

(ex: in 3rd gear at 5000 rpm and try to go into boost and secondaries supposed to kick in but car is in butthurt mode and doesn't fire?)
Old 05-06-13, 05:56 PM
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Secondaries kick in at 3800 rpm and above while the car is under load
Old 05-08-13, 03:21 PM
  #41  
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Ya the secondary's activate anytime the RPM is over 3.8k and I believe 0 psi or above. So ya if you light throttle up to 5k and then go past 0 they come on at that point.

I have seen two friends blow there engines while having secondary issues. Be very careful.

If you try to boost below 3.8 rpms it breaks up once you get to 3.8 rpms?
If you use light throttle to pass 3.8 rpms and then slowly roll on does it still breakup?

Be careful, the engine can only take a handful of those heavy breakups.
Old 05-08-13, 09:03 PM
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alright guys new update is I put in the new chip into the ECU for the an70 and everything runs perfect. the only weird thing is the chip was set so it has the Omp delete so I could rule out the omp all together but if having to run premix means then so be it. I'll just deal w it til I can buy a stand alone! Thanks for all the help and hopefully someone will find this helpful to them too.
Old 05-09-13, 06:37 AM
  #43  
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btw on that same n370 i opened it up and saw singe marks around the chip. probably why the guy sold it to me for 70 bucks and why it was only running one rotor. but now this thing rips! 11psi off the bat! so goooood!
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