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Thread: My first boosted ride.... whoooooaassss

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Posts: 71-80 of 176
2009-04-19 19:39:22
Originally Posted by Mr.sentra_specv
i would pull the iacv off and clean it out. get a fsm and use it to check out your air regulator as well. its hard to see but how close is your maf to your turbo? have you used a wideban o2 sensor to see what afr you are running? there is also the possiblity of an air bubble getting stuck in the iacv area and messing with that so double check the coolant and make sure its air free. as for calums ecu with cold start that part of the ecu doesnt get changed. the ecu that you had calum work on was it the ecu that was in the car originaly? did you swap any sensors over from the original motor or are you using the det's sensors?

They (Jen and DC Scotty and crew) have changed the IACV, the AAC, and all other sensors from his working DE motor that he pulled from the NX. The NX ran perfectly (almost TOO good IMO) with that motor. It was VERY impressive for a DE with cams.

The MAF is on a decent length pre-turbo intake pipe, looks like it was a CAI at one point in time. Filter is attached to the other end of the MAF.

The ECU was the original ECU that was in the car prior to the swap. It was sent to Erick to have the daughterboard and chips installed. Erick tried raising the base idle in the chips and reinstalled them, and it didn't really affect the base idle, though the IACV does PSUEDO affect idle.

Jen doesn't have a wideband bung, so we couldn't install one this weekend. I told him to go to an exhaust shop and have a bung welded in, with a plug temporarily until he can install a wideband.

Coolant temps were fine, no signs of overheating (although he's running TMIC with no vent to it.)
2009-04-19 20:13:16
the reason i am saying double check the coolant is because the FSM states the coolant goes threw the idle controll equipment and if any air gets there it would def not function correctly. what maf are they running? what size inj? i wonder if the ecu is possibly falsely detecting detonation and running on the nock tables. the fsm says the det sensor at idle should be 2.0-3.0v at pin number 27 on the ecu. check the voltage from the Maf it should be under 1v with the car off and idle should be 1.2-1.7v. there are some basic test we can do once they get a wide band hooked up to see if we have the correct K value in the tune and that would def mess with idle conditions if it is incorrect. have you guys checked the o2 operation?
2009-04-19 20:47:16
N60 MAF and 370cc injectors at 4bar. ECU programmed as such.

They did check the MAF voltages with consult and NissanDataScan. They didn't see anything out of the ordinary, no CEL, no issues with sensors being out of range. That's what is wierd about it.

As stated above, regarding o2 sensor. It's wierd. I remember Jen telling me that when the TPS is disconnected that the o2 operates properly. When they reconnect the TPS the o2 seems to get "stuck"
2009-04-19 21:13:49
hrrrm maybe a bad ground on the o2 sensor? is the grounding strap still on the exhaust? i know some people have had some issues with the n60 maf before with low speed and idle issues. what we can do is uncheck the o2 flag and nock flag in the calum ecu and see what that does.
2009-04-20 01:08:13
Originally Posted by Mr.sentra_specv
the reason i am saying double check the coolant is because the FSM states the coolant goes threw the idle controll equipment and if any air gets there it would def not function correctly.

I have seen that on Honda's alot, but so far not on a Nissan...That doesn't mean it couldn't happen though. Seems like a grounding or ecu issue to me though on this particular case. I will look at the schematics tomorrow if you don't figure it out by then to see if the tps and
O2 sensor possibly share a common ground or power wire. It may be a wiring issue and not a computer issue. Hmmmmmmmm, this is a good one.
2009-04-20 06:30:39
couldnt be a wiring issue since the wiring harness being use is the one from the car that worked. all sensors are usdm sensors except the knock. no codes on the data scan. the ground on the exhaust has been broke since i had the car. the weird thing about it is that the car didnt always do this when i did the swap. it seems like what ever we do to fix the car using the proper way the car gets worse. as u can see by reading my prior post it went from five grand to three then to the stupid thousand to seven flux. the next thing for me to do is change the maf. sometimes the idle will jump to the correct idle for a couple of seconds and slowly go down to stupid flux. im stuck guys
2009-04-20 15:58:42
it was almost impossible to start my car today. . .
2009-04-20 16:46:21
do you think you can try the stock tune and maf and try working up from there?
2009-04-20 16:53:56
like stock ecu and maf?
2009-04-20 16:57:13
that could be, but if you dont have it, try stock maf w/ the stock tune(@3bar) on your calum if thats what ur using. and work up from there to the tune you want. you never know.
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