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since 2001
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525 Posts
Discussion Starter · #1 · (Edited)
I have been fighting a detonation problem in my B13, which currently uses a t25 turbo, 370cc injectors, JWT ECU, and starion FMIC. AT WOT the techtom unit reads a "lean" mixture from the O2 sensor. From my experence, usually the JWT ECU program will be rich at WOT. Upon a WOT acceleration, the lean mixture usually starts at 4,000 rpm and last until redline. Most of the time, the motor will begin detonating around 5800 rpm where I immediately back off.

I have changed the following in attempts to solve the problem with no luck:

Replaced BB TMIC for a front mounted Starion IC
Installed a walbaro 255lph fuel pump
Changed FPR
Replaced o2 sensor
New temp 6 plugs
Adjusted TPS to correct voltage
Set timing at 15 degress
Reground MAF and disable EGR system completly
New fuel filter

I currently do not have a boost controller or guage on the car but have not seen the MAF voltage even come close to 5V. This same turbo kit ran flawlessly at 10PSI on my B12, so I am pretty baffled and desperate to find the cause of detonation.

Any suggestions or input would be much appreciated! Thanks
 

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Tired!
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10,149 Posts
Could be something as simple as bad plugs or maybe the WG is failing and you are running higher boost then you think. Get a boost gauge on there and check it out.

Brent
 

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Enemy of the stupid
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4,727 Posts
You didn't say if your running a walmart fuel pump? did you change the fuel filter before you added the turbo? try the filter 1st but if you don't have a upgraded pump then get one before you kill the motor.
 

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since 2001
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525 Posts
Discussion Starter · #4 ·
Yellow4g63 said:
You didn't say if your running a walmart fuel pump? did you change the fuel filter before you added the turbo? try the filter 1st but if you don't have a upgraded pump then get one before you kill the motor.
No, I am running a Walbaro Fuel pump, lol. I've replaced the filter with a 300zx TT unit as well.
 

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since 2001
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525 Posts
Discussion Starter · #5 · (Edited)
coach said:
Could be something as simple as bad plugs or maybe the WG is failing and you are running higher boost then you think. Get a boost gauge on there and check it out.

Brent
Changed the plugs to the platinum NGK temp 6.

I think the WG failing is a possibility.... anyone one know where to get a new one? On the other hand if the turbo was boosting past 12psi the techtom would show the MAF voltage maxing out wouldnt it?
 

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No soup for you
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2,266 Posts
Whats the compression of the engine in your car? I also like to run 7 range plugs gapped down to .028.

John
 

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593 Posts
my car did the same, i took the maf off, turned the car on and adjusted the air idle control valve, now as far as that being the correct way of doing things, i dont know. but my car does alot less bucking with that adjustment, but my problem still occurs.
 

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since 2001
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525 Posts
Discussion Starter · #8 ·
NismoDriver said:
Whats the compression of the engine in your car? I also like to run 7 range plugs gapped down to .028.

John
It's a JDM engine presumably with 9.5:1 compression with US intake manifold. I run temp 6 at the same gap as you. I have been considering switching to temp 7 in thoughts that the temp 6 maybe getting hot, causing pre ignition. It would explain the detonation I am hearing, but not the lean mixture.
 

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since 2001
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525 Posts
Discussion Starter · #9 · (Edited)
SR-SONIC said:
my car did the same, i took the maf off, turned the car on and adjusted the air idle control valve, now as far as that being the correct way of doing things, i dont know. but my car does alot less bucking with that adjustment, but my problem still occurs.
Could an inproperly adjusted IAC valve cause detonation? If it was adjusted improperly, would'nt the engine idle higher or does the ECU mask this?
 

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No soup for you
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2,266 Posts
The engine could very well be 10:1. With 91 piss water and a 6 range plug, it *could* be the problem. I could be WAY off to. Good luck finding it!

John
 

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since 2001
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525 Posts
Discussion Starter · #11 ·
NismoDriver said:
The engine could very well be 10:1. With 91 piss water and a 6 range plug, it *could* be the problem. I could be WAY off to. Good luck finding it!

John
When picking out the engine, I prayed it wasnt a 10:1. All I could do was stay away from the ones with tubular manifolds and get the one with japanese writing on it. I hope it isnt.

how are those temp 7 on a daily driver?
 

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No soup for you
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2,266 Posts
No problems out of the 7's. I use the BKR7E-11. Its a copper plug w/ extended electrode. Works great.

John
 

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Veritas
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6,205 Posts
Charles--

You did say platinum plugs? Try the 7-range coppers like John suggested. I'm thinking ignition is the culprit for the detonation, and maybe the plugs are too hot either as a result of heat range, or the fact they are platinums. JMHO.

As for running lean: I take it you've checked for boost leaks and what-not. Some air is getting in there from somewhere, or not enough fuel is being supplied. You've changed out most of the fuel stuff, so I'd lean (pun intended) towards the air side of things.

Your JWT ECU is 3 or 4 bar fuel? Bored or stock MAF?
 

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rollin 4 deep with JoeD
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1,410 Posts
hybrid D E T said:
When picking out the engine, I prayed it wasnt a 10:1. All I could do was stay away from the ones with tubular manifolds and get the one with japanese writing on it. I hope it isnt.

how are those temp 7 on a daily driver?
Yo Chuck,

Do a compression test homie, this should give you some idea what compression your motor is.

Or if you still have access to the auto shop at school, check out a boroscope.

10:1 turbo motor would be bad.
 

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Banned
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3,473 Posts
I run NGK BKR7E-11 gapped at .30 with stock fuel pump and TMIC with no detonation problems at 9psi.
 

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Guanaco Tuner
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3,049 Posts
So you guys have never had any problem with the 7-11 plugs? I remember back in the day people didn't like the extended plugs.
 

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sleeper
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5,445 Posts
i have the plat. 7's. no probs in over 40k miles and the car sees hard use. I'd try out some copper 7's as they're cheap and see if that fixes the prob.
 

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since 2001
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525 Posts
Discussion Starter · #18 · (Edited)
SERprise In WV said:
Charles--

You did say platinum plugs? Try the 7-range coppers like John suggested. I'm thinking ignition is the culprit for the detonation, and maybe the plugs are too hot either as a result of heat range, or the fact they are platinums. JMHO.
I am going to try the temp 7 plugs here in the next couple of days. If thats not it, I will hook up a boost guage. I suspect the WG may be failing and not functioning reliably.
As for running lean: I take it you've checked for boost leaks and what-not. Some air is getting in there from somewhere, or not enough fuel is being supplied. You've changed out most of the fuel stuff, so I'd lean (pun intended) towards the air side of things.

Your JWT ECU is 3 or 4 bar fuel? Bored or stock MAF?
I run the JWT ECU with 3 bar, 370 inj, and stock maf.

I'm not sure if I am in correct in saying this, but a leak that causes a lean mixture on forced induction engine could only be between the compressor and the MAF sensor (the suction side). In other words, air is being sucked in by the compressor that hasnt been calculated by the MAF. So perhaps I should examine here?

If a leak were on the pressurized side air would be blown out under boost, causing a rich mixture since a portion of the air calculated by the maf is missing.
 

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since 2001
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525 Posts
Discussion Starter · #19 ·
NismoDriver said:
No problems out of the 7's. I use the BKR7E-11. Its a copper plug w/ extended electrode. Works great.

John

I will pick up some of these plugs and give em a try. Frankie, you run these too?


and what the fuc% is this all about!? :eek:
 

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Veritas
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6,205 Posts
A leaking blow-off valve would allow air in that is unmetered as well, Charles. Just throwing stuff out there as it flies through my tiny little brain.

-GP-
 
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