Thanks for the heads up mike!

Don't worry, as much money as i have in this damn car, i have no intention of f'ing it up!

 

Ok so i think i have narrowed the problem down to either being the ECU or the FCON. Is it possible for a error to occur in either of these w/o a throwing a SES light?

 

yes, i set this up usually when the customer adds in a knock amp with the build. its the only wideband i trust not to go crazy after it leaves. so its not utilizing it with the innovate that he has. thats not the issue though.

i have a feeling it is his stock computer for some reason or in the wiring harness. we had a car do exact same thing a few times and after messing with the harness, we found a weak point in one of the wires that went to the cam sensor and caused it to act weird. it was heat dependent too that caused the wire to mess up.


im sure it wont be a hard thing to figure out chris. let me know if you need anything...

 

i had a factory computer go crazy and the only thing it wouldnt do correctly would be let me scan the codes. even though it was throwing them, it wouldnt let me scan it at all....

 

i guess gettin it back to the installer to fix is out of the question huh? IME electricl problems are never easy to nail down, esp if you dont even know where to start!

Good luck! must be something pretty uncommon if it snuck past one of the top VQ guys.

 

Diagnostics (ECU).

 

you mean diagnosis??? It could be the ecu but i am not sure because it isn't throwing a code or SES light

 

Hey Chris we have a 2003 maxima in the shop right now that we are trying to figure out.It has no cel light and cranks fine but we have no comunication from the ecu and we believe the ecu is toast.Ill let you know what we find.

 

can a water temperature sensor do this issue if its not reading properly??

 

Unlikely that it would not throw a code. And chances are it would put the car in limp mode (rpm limited), rather then just shutting it off altogether. The backfiring also does not seem to be a symptom that could be linked to a faulty coolant temp sensor.

 

thanks for the replies guys!


This is deff temperature related. I reset the ecu yesterday and let the car run in the driveway and it runs perfecto for about 20 mins. I then think that maybe we are on to something so i get in and start driving it around the block a few times w/o issue. I even boosted it a tad (2.5psi) and it runs fine. I then pull it in the driveway and continue to let it run for another few mins until i hear it start to stumble and then cutt off.

Like i said it is weird because i don't know how long it would have run in the driveway w/the hood up because it isn't getting hot enough (i think).

I JUST WANT TO FIGURE THIS OUT SO I CAN DRIVE MY ****ING CAR I JUST SPENT A *** LOAD OF MONEY BUILDING

 

have you done any logs when it starts to stumble? like watching air temp, water temp, timing, fuel pressure, vacuum, etc

something has to be acting funny. maybe help narrow it down? raised temps could cause a solenoid/valve etc to stick, not open etc.

good luck

 

Sometimes the OEM ECU will throw a CEL without turning the SES dash light on.

Have you tried checking with an OBD-II scanner or Cipher?

 

i had a few hundred miles on the motor and hours of sitting there running, i also tuned a full standalone which takes a couple days on the dyno. then i drove it all around for a couple days and no issues. chris then drove 8 hours all the way back to LA with no issues at all. the next night is the first time it happened. i wish i could keep every car for a week or two after its all finished up but people really want their cars back. i fully understand why though cause 720whp is definitely something to get excited about....

 

thats what sucks man, i can't log any of the sensors from the fcon. I mean i can log my stock sensors w/ a cipher, BUT i am not sure that the stock sensors are the root of the problem being as i am not getting and CEL nor am i getting any codes.

A LOCKED EMS SUCKS

 

Yea man i tried to get the codes pulled and there were none to be found. The light isn't on nor are there any codes

 

I guess you don't have the navigator? even though you can't datalog you can at least see the inputs into the Fcon and see if any look funny. But really only inputs that would affect the Fcon that the ECU wont see are Boost, Air Temp (if you have that HKS sensor) and Air Fuel if you have air fuel feedback.

It almost sounds like a bad map sensor, have you verified that the boost/vacuum is ok when it goes crazy? I assume you at least have a boost gauge?

 

boost and vaccum are ok when idling fine, but obviously vaccum goes down when it starts to stumble. I get these readings from my hks evc VI.

I don't have the air fuel feedback hooked up. Jeremy says he only uses this feature when using the knock amp and i am using the innovate.

 

ok, so this is only happening at idle? otherwise the car runs fine?

 

it runs fine at idle and when driiving regardless of driving style. The determinig factor is when the car gets heated up. If i drive it around it warms up faster. If i let it idle in the driveway i can let it run for awhile. Like last night it ran for over 20mins sitting in the driveway till i decided to go drive it around. I drove it around for a few mins in the neighborhood and then parked it in the driveway where i let it run for a few more mins until it crapped out again. Once it died i tried starting it up and it cranks right up but immediately starts to sputter for a few seconds till it kills.