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Boost Solenoid wiring for G35 and idle issues


TranzerZ
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Hi everyone and Happy New Year! I just had my 2004 G35 rebuilt with single turbo and Link G4X and am excited to learn everything about it. I have not brought it in for dyno tune yet and so I wanted to install the 3-port boost solenoid beforehand. I did search and only found 1 topic on this but it was for the R33 and so I wanted to make sure specifically for my 2004 G35.

So 1 wire of the boost solenoid goes to a switched +12V supply and the other wire taps into the LINK ECU's Ign 7 or 8?

My other question. My mechanic did a basic tune to get the car started and running but there is one issue. When I'm driving and let go of the throttle, say at 2000 rpm or above, and when the needle drops, it seems the engine cannot catch itself and would stall half the time. I would need to feather the gas pedal to catch itself to normal idle. There were times when it stalls like that, the ECCS fuse blows. Is that something related to the "Zero Demand Table" and is that something the tuner can fix?

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For the boost solenoid you need switched 12V on one wire and the other wire connects to an aux output preferably.  The easiest option in your car would be one of the original front oxygen sensor wire bundles - there will be a +12V and aux output going to the O2 probes that you wont be using so connect the boost solenoid to one of them instead.  It will be either or Aux 7 depending on which bank.  Aux 6 should be blue/yellow and Aux 7 blue I think. 

For the idle issue you will need to post a log and tune.

For the fuse blowing issue, check your firmware is up to date.  There was a bug in early firmware where a coil could get a long dwell time during a stall event and blow the ign fuse.  

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21 hours ago, TranzerZ said:

My Aux 6 & 7 are occupied, connected to CAN-Lambda

I cant see why anyone would connect CAN lambdas to aux outputs, are you sure about that statement?  What is the intent of that?

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I am not sure about that statement and the mechanic was the one that installed everything. I think maybe it was just assigned to the Aux 6 & 7? I'm just reading off of what the configuration is saying. I've been doing much research and learning what I can about Link. The CAN-Lambda L and H wires should just connect directly inside the ECU via 4-pin connection? So maybe the stock O2 sensor harness is just hanging out somewhere in my engine bay?

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I believe I figured out my stalling problem :D. It seems my Tial BOV's 11 psi spring is too weak so it would still flutter open even at idle and doesn't stay close. I added 3 washers in there to tighten the spring and it helped immensely. The engine will catch itself faster and stabilize and sometimes it's just normal. I stalled only once, rather than a million times. I wonder if it's a faulty BOV or just installed in the wrong location for my setup. I initially want it installed right before the MAF but there was no room, so the mechanic installed it between the turbo and intercooler. Maybe better between the intercooler and throttle body?

I haven't gotten a chance yet to install the boost solenoid so I'll give an update when I'm done.

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No, the BOV will not have any effect on the idle or stalling with the link ECU since the link doesnt use the MAF.  Only the ecu's which use a MAF get affected by an open/vented BOV as that type of system assumes all the air that has been measured by the MAF enters the engine, but with an open BOV some of that air is lost to atmosphere.  So you end up to much fuel injected for the amount of air that is entering the engine.   

In contrast, with most aftermarket ecus you are using manifold pressure to determine the mass of air entering the engine, since the leaking BOV is before the manifold, it doesnt effect manifold pressure, therefore doesnt cause incorrect determination of the air flow.

So if you want to fix the actual problem that is/was causing the stalling you would be best to do the log that I asked for earlier.  

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I did forget to mentioned that on a couple of my cruises, the VDC and Slip lights came on and stayed on. The SES light during those 2 trips were already on due to my error when I replaced the coil packs and forgotten to plug the MAF sensor plug back in. When I did plugged it back in, the SES light were still on but I did not have a laptop and Link software to clear the codes. So not sure when the VDC and Slip lights came on, if the SES light would of came on as well with it. If so, those 3 lights would indicate a faulty camshaft position sensor?

And another question that is off subject. Do I really need a MAF sensor when Link can just run off of the MAP? My mechanic told me to buy the aftermarket one and so I purchase the PMAS HPX MAF for $280. I'm starting to think I just wasted my money on this.

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Correct, you dont need a MAF, it will not be used at all. 

The stall issue is a mix of various settings that I suspect havent been tuned.  It looks like it needs more dashpot offset, try increasing that to about 1.5, it might need even more.  And for the oscillation you need less actuator integral gain, that should typically be around 0.05.

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I don't see an IAT sensor installed anywhere so is Link ECU reading the IAT temp off of the MAF sensor?

Also, a few days after I got my car back from the mechanic, one of my O2 sensors went bad. I noticed he reused my stock wideband sensor with the CAN-Lambda instead of the LSU4.9 that Link recommends. I changed just that faulty one that I was able to easily access in the engine bay but I haven't checked the one underneath. If that one is not an LSU4.9, would that be related to my issues? 

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One more thing. I connected the boost solenoid as you had suggested. One wire to the red/black (tested with my voltmeter confirmed 12V when car is on) and the other wire to blue. I assigned it on PCLink to Aux 4 and as open loop but how would I know if Link actually recognizes the solenoid? 

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16 hours ago, TranzerZ said:

I don't see an IAT sensor installed anywhere so is Link ECU reading the IAT temp off of the MAF sensor?

You will need to fit an IAT sensor, a MAF air temp is certainly not acceptable for a boosted engine.  

 

16 hours ago, TranzerZ said:

Also, a few days after I got my car back from the mechanic, one of my O2 sensors went bad. I noticed he reused my stock wideband sensor with the CAN-Lambda instead of the LSU4.9 that Link recommends.

Are you sure?  The nissan sensor wouldnt even have the correct plug would it?  Even if the factory sensor was a LSU4.9, you cant change the plug as the factory calibration resistor is molded inside it.  

 

14 hours ago, TranzerZ said:

One more thing. I connected the boost solenoid as you had suggested. One wire to the red/black (tested with my voltmeter confirmed 12V when car is on) and the other wire to blue. I assigned it on PCLink to Aux 4 and as open loop but how would I know if Link actually recognizes the solenoid? 

In the boost control settings just below where you have set aux 4 at the output, you will have an "aux 4 test" setting.  Set this to PWM at 20Hz and you should hear the valve clicking.  

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I am definitely sure about the mechanic using my stock O2 sensor lol. See attached pic of the O2 connector I pulled out. This sensor and the CAN-Lambda were both plugged into my stock harness. Maybe that's why PCLink said the O2 was faulty because it never detected it in the first place? Or maybe there was an O2 extension-like in my stock harness?

I'm shopping around for an IAT sensor. I see that there are a couple of 2 different sized thread fittings already welded on my intake tube near the MAF sensor. I see Link has the IAT1-8 but a bit on the pricy side. Is the Haltech or AEM ones good? Or maybe the Fast-Response GM Delphi? What do you recommend? And I'll need your help again on the wiring =D. Maybe use the MAF connector? 

20230110_063407.jpg

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3 hours ago, TranzerZ said:

See attached pic of the O2 connector I pulled out.

So how was this plugged in to the Link CAN lambda?  It does not have a plug that will mate with that sensor.

 

The IAT sensor needs to be in the manifold or in an intake pipe close to the throttle body, there is no point measuring air temp at the MAF before it has been heated by the turbo.  AEM & Haltech sell the same 1/8 sensor as Link.  The GM ones work fine too assuming you get a genuine one, many fakes around so buy from someone reputable.   Yes you can connect the IAT to the MAF connector.

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The Bosch square connector wideband o2 is also a LSU4.2 and not a LSU4.9 if I'm not mistaken.  Did the mechanic change the connector on the can lambda?  That would be a terrible idea.

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4 hours ago, koracing said:

The Bosch square connector wideband o2 is also a LSU4.2 and not a LSU4.9 if I'm not mistaken.  Did the mechanic change the connector on the can lambda?  That would be a terrible idea.

IKR! But good thing he didn't change the connector on the CAN-Lambda. This is what I saw and what I think the mechanic did. The stock O2 was connected to the stock harness. When I follow the stock harness a foot back, I see a LSU4.9 connector harness branches out and connects to the CAN-Lambda. I'm guessing, instead of buying a new LSU4.9 O2 sensor, he McGuiver-ed it to work with my stock one. Probably found an old LSU4.9 lying around, cut the sensor off, and use the wire to tap into my stock harness...geez.

I haven't had much time to work on my car but I'll post my updates when I can. 

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19 minutes ago, TranzerZ said:

IKR! But good thing he didn't change the connector on the CAN-Lambda. This is what I saw and what I think the mechanic did. The stock O2 was connected to the stock harness. When I follow the stock harness a foot back, I see a LSU4.9 connector harness branches out and connects to the CAN-Lambda. I'm guessing, instead of buying a new LSU4.9 O2 sensor, he McGuiver-ed it to work with my stock one. Probably found an old LSU4.9 lying around, cut the sensor off, and use the wire to tap into my stock harness...geez.

I dont think that is the case at all.  The CAN lambda comes supplied with the correct 4.9 in the kit, what would be the point of spending extra time finding a used sensor to get the plug from, then splicing it on to the nissan sensor etc, when the supplied one just plugs straight in?.  The CAN lambda would not work at all with a non LSU4.9 or a different connector.   Can you show us this faulty sensor that you think was plugged into the CAN lambda. 

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38 minutes ago, Adamw said:

I dont think that is the case at all.  The CAN lambda comes supplied with the correct 4.9 in the kit, what would be the point of spending extra time finding a used sensor to get the plug from, then splicing it on to the nissan sensor etc, when the supplied one just plugs straight in?.  The CAN lambda would not work at all with a non LSU4.9 or a different connector.   Can you show us this faulty sensor that you think was plugged into the CAN lambda. 

That is what I saw and that is what I pulled out (the prior pic I posted). I'm not kidding lol. And yes, it was probably never working because once I was able to get my hands on a laptop, PCLink, and connected to the ECU, I immediately noticed the error. So I purchased a new Bosch LSU4.9 and connect it directly to the CAN-Lambda. I even took saved the Screen shot of the error and sent it to my mechanic. He did not respond to me on it. 

Screenshot_20221230_001203_Gallery.jpg

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None of what you are suggesting makes sense hence why I keep asking questions.  So how was that sensor in your pic that still has the stock nissan connector on it actually connected to the CAN Lambda?  If the mechanic had changed the mating plug on the CAN lambda, then how did you later connect the LSU4.9 that you replaced it with?  Did you change the connector again yourself?

The Aux 6 fault in your screenshot has nothing at all to do with the CAN lambda or its sensor, or even the factory wideband sensor.  Aux 6 is just to "turn on" the heater circuit in early model 350Z's that had narrowband front sensors.  CAN  Lambda faults are viewed in the runtimes screen under Lambda 1/2 status and Lambda 1/2 Error.

 

 

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I'm glad you guys keep questioning me =D

So I went to dig a little deeper and started poking around. It's very tight with a turbo setup but I figured it out for sure this time lol. I have THREE O2 sensors! Two O2 sensors near each of the headers which connects to the CAN-Lambda and the one on top is the stock O2 connected to the pipe of the turbine exhaust gas outlet. One of the LSU4.9 wires were tied to the stock harness to keep it neat so I was misled when I ran my fingers to feel where it was leading.

Sorry guys! LOL. But what is the purpose of the stock O2 sensor?

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Absolutely no purpose of the stock O2 sensor in this case, if you have one or two working and correctly configured CAN Lambda modules in the headers.

From the brief screenshots you've shared, I wouldn't think much is properly configured...

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