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When I press the gas pedal while listening to any radio station, the radio station starts to get very fuzzy and distorted until I release the gas pedal. I'm reading that this may be caused by the voltage regulator(embedded in alternator) being faulty. Also, my cheap ebay bought led tailights, license plate lights, and trunk dome light are blinking very fast when I turn them on(this further supports the possibility of the alternator/voltage regulator being faulty).
Someone else on g35driver.com had a similar issue, where the newly installed LED taillights caused his car acceleration to bog considerably(I'm looking for the original post now)
Also, here are some updates on the list of things I thought may be the issue below:
1)Faulty Engine Harness
2)Faulty IPDM Replaced, no difference
3)Faulty ECU have used one ready to replace
4)Faulty front wheel speed sensors Causing VDC light to go on when taking sharp right turns
5)Faulty/lazy upstream O2 sensor Swapped the drivers side sensor/odd difference. going to swap passenger side next
6)Faulty brake booster have this on my ebay watchlist
7)Clogged EGR(if that's even possible on this engine-PCV, cams control everything from what I've read) considering cleaning the charcoal canister, but I've never done so
8 )Fuel leak from...somewhere..(going to check fuel pressure under load-STILL HAVENT FOUND ANYONE THAT WILL DO THIS)
9 )the knock sensor or sub harness IS actually bad on the new motor causing the same exact issue as last motor????(displaying knock code on startup, even before closed loop)
-Disconnect main harness and follow FSM to ring out every sensor with a good digital multimeter.
-Disconnect all sensors, everything, megohmeter every wire to find a pinched wire.
-Take to dealership and pay a couple Grand for them to fix so it doesn't cost another motor.
OR
-Sell and buy another one.
Sorry you're having so many issues, I've been there on other vehicles and it sucks.
thanks for the advice bud, im just trying to logically understand how to isolate this issue other than giving the dealer my car along with tons of cash. so i will start probing the wiring harness asap.
im still thinking for some odd reason though, alternator right now... but would that make sense as to why the car performs well on the dyno, but not on the street??
Could always pull the alternator and have it tested by a reputable shop, preferably a shop that rebuilds alternators. My guess is you have a wire that pinches when the motor shifts due to torque, using a megger on the wires will find it, pretty sure automotive wire uses 250v insulation so that's the range I would use on the megger. Just make sure EVERYTHING is unplugged if you do megohmeter the entire harness.
Also might be a loose connection at a bolted lug or harness connector and unplugging and inspecting everything might pinpoint or simply correct the issue.
Still need to OBD2 scan first since that's the easiest.
Could always pull the alternator and have it tested by a reputable shop, preferably a shop that rebuilds alternators. My guess is you have a wire that pinches when the motor shifts due to torque, using a megger on the wires will find it, pretty sure automotive wire uses 250v insulation so that's the range I would use on the megger. Just make sure EVERYTHING is unplugged if you do megohmeter the entire harness.
Also might be a loose connection at a bolted lug or harness connector and unplugging and inspecting everything might pinpoint or simply correct the issue.
Still need to OBD2 scan first since that's the easiest.
That's a great idea, I might pull the alternator this weekend, and have it tested(or find a cheap used one on ebay and swap if that's gonna cost less time/distance traveled)
Interesting thought on the pinched wire during motor shifts due to torque.I will also look into a megger to scan the whole harness.
I have run multiple obd 2 scans on both the previous engine that died(still trying to find out why, I have the old engine completely torn down see picture below) The code I currently have is: "P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)". this code basically is telling me that my knock sensor is bad, or just sensing knock rather. However, the old engine that displayed the same exact symptoms under load, did not display this code after I installed a new oem knock sensor(driveabillity issues remained the same)
I'm guessing that something else is pulling timing(electrical short, bad module/sensor, etc) and that is causing the engine to protect itself by giving a high voltage knock sensor code(could be totally wrong here, just a guess)
Links to most recent dyno run switching through gears easily: (Car cannot even come close to doing this on pavement, and sounds more like a rusted honda civic with an ebay muffler)
Did you use new bushings\mounts when you put the motor in and are you sure that they are all tight and you didn't miss one when installing? Maybe the motor is shifting and banging against the unibody and causing the knock sensors to detect knock and back off power to prevent damage.
Does the engine rev freely in neutral or is that also weak?
Did you use new bushings\mounts when you put the motor in and are you sure that they are all tight and you didn't miss one when installing? Maybe the motor is shifting and banging against the unibody and causing the knock sensors to detect knock and back off power to prevent damage.
Does the engine rev freely in neutral or is that also weak?
Hey thanks for the input. I double checked the mounts and bushings prior to installing the new engine. There was nothing abnormal.
The engine is also weak in the lower rpm when free revving in neutral up to the same 4500-5000 rpm point, where it becomes responsive again(I mean honda civic to Ferrari difference here)
1) We found the source of the P0328 high voltage knock sensor code to ACTUALLY be true.Tom from Porsche stopped down the other day and probed the ecu, the engine bay, and just about every ground the car has(except for the antenna ground for the radio- get to that later) See picture below of the new knock sensor sub harness, that came with the new JDM engine I just bought with 52k miles on it. Yes, this sub harness, just like the sub harness on the last engine, also shorted out due to a slit in the wire causing the engine to retard timing to protect itself.
We have replaced this with the Z1 motorsports sub harness, and a new knock sensor. The code has disappeared, and there is a noticeable difference in power throughout the rpm band(much smoother, doesn’t want to fall on its face as much from a start)
2) We found the source of the “slip” light coming on around tight right turns to be the yaw/side G sensor. We have simply disconnected this module, and the car performs without traction control at this point, and no blinking “slip” light affects performance around turns anymore. SOLVED-ish.
3) We see an 86% voltage signal on the accelerator pedal position sensor when we fully depress the gas pedal. This may be a problem( or the problem) My radio signal is still completely cutting out when I press the gas pedal(only under load). Hopefully whatever is causing the 86 percent voltage signal, is also what is causing the radio signal to cutout whenever I press the gas pedal under load(This very may well be the voltage regulator within the alternator)The used alternator I found for $35 with 100k miles on it should be here today, and I will pop up in asap/update with any findings.
Again, thanks all for your input, it is much appreciated.
Also, I am very aware that this is 2 different VQ35DE engines with the same knock sensor sub harness issue. Nissan/Infiniti…shame on you for making this sub harness so shoddy, and allowing it to have such an adverse effect on drive ability when it becomes prematurely faulted. The amount of disgust I have right now for whoever engineered that harness is completely out of control. God bless.
This problem is almost nailed down at this point. As soon as we can get the engine to perform the way it does after 4500 rpm throughout the entire rpm range, this case will be closed.
I'm still at a loss how the car will perform on the dyno, but fall flat on its face on the street.,
Also where is the yaw/g side sensor module located? my car activates traction control and I get the slip light on hwy on ramps occasionally. and i'm not even driving it hard then.
I'm still at a loss how the car will perform on the dyno, but fall flat on its face on the street.,
Also where is the yaw/g side sensor module located? my car activates traction control and I get the slip light on hwy on ramps occasionally. and i'm not even driving it hard then.
Glad you finally getting to the bottom of this
EPIK, I am still at a loss as to why this car is falling on its face on the street as well...If I could solve that issue, this thread would be closed in a heartbeat...
The yaw/g side sensor module is right below the middle console(where the shifter is). You can get to it by removing that center console piece that is in between the seats with the shifter ****, and the sensor are right there, you can disconnect them and your vdc will be completely off at that point(still will have ABS though)
my symptoms are simply indicative of something like a weak fuel pump, faulty coolant temp sensor, bad ground, or low voltage output from alternator. There still isn't a logical explanation as to what is happening here.
Car performs perfect on dyno. (~280 whp- Mustang Dyno)
Car performs poorly on street. (~100 whp- butt dyno)
On a different note, I reached out to Z1 motorsports, and they told me that this car specifically (2003 G35 Coupe 6MT), has an insane amount of ECU repair requests, and active repairs ongoing. So with that being understood, and knowing the ECU died on the dyno when ECS was tuning it, I'm going to start chasing the possibility of the ECU being the problem.
I have another used ECU that I purchased, but it won't let the car turn on(NATS security light stays solid red when I insert key with the new used ecu plugged in), so I'm going to have the dealer reprogram my keys to the new ecu for 50 dollars, and prey to god that the low end wakes up, and the magical 4500 RPM wake up condition goes away... -even with the new ecu only having a stock tune.
Wish me luck ....(god I wish I could I close this thread already....what a mess)
BTW if anyone lives in the Albany, NY area...I am more than willing to meet with you so you can see this phenomena instead of just reading about it...
Okay, everyone, we have made some very interesting progress regarding the issues we are seeing from a start until 4500 RPM.
Tom found a very interesting tool within Osiris Rom editor that now allows you to see knock.
So yes you guessed it, knock is the issue(see attached data logs showing knock from 1500RPM-4500RPM, then knock disappears thereafter)
The engine is knocking until 4500-5k RPM where the "knock window" opens up, and the cylinder pressures heighten allowing the timing to neutralize/advance again.
This suggestion strongly supports why the power/responsiveness picks up just at the edge of that knock window around the 4500-5k rpm mark, and knock is absent the rest of the RPM range thereafter.
Just a bit of information for everyone:
-I do not have wideband 02 sensors installed, which would help a ton to dyno tune/street tune the car properly. (THIS WILL BE INSTALLED ASAP)
-The car was dyno tuned using a tailpipe wideband 02 sensor, but the High Flow Catalytic converter changes the ACTUAL AFR at the tail pipe (WIDEBAND 02 WILL BE INSTALLED UPSTREAM OF THE HIGH FLOW CATS ASAP)
-Target AFR at WOT starts at 11.9, and dips down to 11.47 for most of the pull (WE FEEL AS THOUGH THIS IS WAY TOO RICH FOR AN N/A SETUP, AND SHOULD BE RETUNED TO 12.25-12.5 AT MINIMUM)
05-24-2017, 04:27 PM
