Ok So Here Is A Log Of My Surging Issue And Cold Start

[WogsRus]

Hi guys.

Well my car has had issues as per this post.

http://www.skylinesaustralia.com/forums/in...howtopic=169954

So basically last night i put on a whole new ECU and issue was still there no change. so i guess it's not mapping or anything.

The cold start as you can see sux, and i noticed a spike on the AFM, no idea what that means.

In the Surging log, you will see that the O2 sensor drops to zero half way though the boost building ie: airflow. and then comes back, fairly apparent in the first 10 runs. I have no idea what couses this, but on another ecu it did exactly thesame.

WHat could be causing this.

Can somone with some knolage have a look for me. PLEASE.

Wogs_Log_Files.zip

[Strik3r]

i dont have any software to read through all those logs, but ill recommend again to try yet another AFM just to tripple check thats not the problem. any chance you can also borrow someones AAC valve as those 2 would be the first things i'd be checking (even if you've already double checked them - once more wont hurt).

[WogsRus]

Hay mate, had to different AFm on it, and i have a NEAR new ACC valve, and it's not that.

Had a different computer sotck and mapped, and same issue.

Maybe i will try a new O2 sensor and remove the cat sensor.

[CEF11E]

just some of my observations...

1. you are maxing out your AFM and by the looks of it the wiring from the AMF has a bad ground as if it is earthing out somewhere. this is possible causing your surging.

2. you are running way to much timing at full boost possibly to much between 2000 and 2600 rpm.

cheers!

[WogsRus]

HAAAY MATE your my herrooo.

Ok so how do i check the wiring, i suppose just go through the whole loome?

How did you pick up the wiring earthign issue? so i can have some idea what to look for if i fix it?

I know the AFM is maxing out, but need to put up withit, will the maxing out couse a surge?

The timming has never been an issue before this started to happen. It worked fine for 6 months, and teh ecu is read only so i can't reprogram it.

Maybe beace the SAFC II i took out -10 on the fuel map, it is puting in too much timming. Humm will need to put that back.

OK so how do i actually fix the AFM thing, apart form an Z32 airflow meter.

Any reasdon why the O2 sensor drops out like it does?

[R31Nismoid]

You cant be maxing out the stock AFM with the stock turbo.

There is something wrong with the AFM if its maxing out.

[WogsRus]

it is pulling 217 rwKw plus so it might be possible. But i have put in 3 different AFM and they both show same values.

[Strik3r]

check the AFM wiring.. it could be shorting like ceffie said.. look for exposed wire or anything out of the ordinary.. if your AFM is doing anything wrong, it will throw out everything.. idle, power etc.

[WogsRus]

Ok well last night i go tin late, but i did manage to pressurise the FMIC and piping, minus the plenum, and all good, pressure at 50psi stable and holding, managed to blow up the end caps i was using though. LOL.

Put in new o2 sensor, still thesame. I have started with the wiring, but dam there is a lot of it. Hoping to do a lot more tonight with the wiring issues.

Follow the wiring diagram and go from there.

If you have any more ideas keep em comming.

Thanks guys, i know i seam a pain in the ass askling all the time, but here in tas there are no people who have a clue, yeah a mechanic will look over it, but have no idea what to look for on an imported car.

Thanks

[rob82]

Ok well last night i go tin late, but i did manage to pressurise the FMIC and piping, minus the plenum, and all good, pressure at 50psi stable and holding, managed to blow up the end caps i was using though. LOL.

Put in new o2 sensor, still thesame. I have started with the wiring, but dam there is a lot of it. Hoping to do a lot more tonight with the wiring issues.

Follow the wiring diagram and go from there.

If you have any more ideas keep em comming.

Thanks guys, i know i seam a pain in the ass askling all the time, but here in tas there are no people who have a clue, yeah a mechanic will look over it, but have no idea what to look for on an imported car.

Thanks

Sounds like you've got a leak under vacuum if the 02 sensor goes to zero before it gets to boost. Please dont tell me you've vented the rocker covers and havn't bunged the PCV vavle. Also if there is too much base timing then you can sometimes get an idle surge. remember the only proper way of checking the base timing is to do it with a nissan consult - bar none!!!!

[WogsRus]

I have Consult, and yeah the base timing is at 12 due to runing lower octane fuel.

The 02 sensors goes to zero WHILE on boost, that is the strange thing. No i acctually took the tubo outlett off and then the intake off. Then ganged one up and put a cap with a pressure line tap in the other and pressurised up to 50 psi. So it bypassed any of the PCV stuff.

I Have pulled the PCV off and checked and it was warking correctly.

The sure is not at idle, it just that it doesn't start properly, the surge is coming onto boost at low rpm but high TP.

[NewKleer]

where abouts in the log (and which one) shows it going to 0 on boost? most of the time i see it flat at 0 is when ur rpms have dropped? maybe i missed it

[rob82]

I have Consult, and yeah the base timing is at 12 due to runing lower octane fuel.

The 02 sensors goes to zero WHILE on boost, that is the strange thing. No i acctually took the tubo outlett off and then the intake off. Then ganged one up and put a cap with a pressure line tap in the other and pressurised up to 50 psi. So it bypassed any of the PCV stuff.

I Have pulled the PCV off and checked and it was warking correctly.

The sure is not at idle, it just that it doesn't start properly, the surge is coming onto boost at low rpm but high TP.

The timing will be 12 because you have too much bypass air around the IAC, screw it in until the base timing comes back to 15 deg.

[WogsRus]

no i have set the CAS to 12 deg base idle, the car was tuned on 98 plus, and i am running premium at the moment. I have gone back to 98 plus and it made no differance after i reset the timming.

Ok i will post a new log modified to show the things i am talking about.

[WogsRus]

Ok modified surging log, about 1/3 of the way in very obvious, when viewing load RPM, AFM, O2 and TP, and have a look you will see that the air is ramping up but the 02 drops out.

surgingcold.zip

[NewKleer]

ok i see it now, point 790, 970, 1240, etc

[WogsRus]

ok hang on i need to open datalogit

[WogsRus]

Look at about 12 seconds into this one and again at 22 seconds in and again at 33 seconds in

Surgingmod.zip

[WogsRus]

what datalog viewer software you use i have Datalog viewer 3

[NewKleer]

(im just using excel...i found the points, i edited post above)

after looking at that, the times it happens you either arent putting your foot all the way down, or ur TPS is very slow to react. maybe TPS needs adjusting/replacing

look at the blue line:

and notice the dutycycle drops off, ie the ecu is purposely putting less fuel in. my guess is that the drop seems consistent from switching from open loop to closed loop. TPS then only hits the full 4V after the ecu has decided to enter closed loop mode (ie cruising/14.7:1 AFR).

what happens if u run with TPS disconnected? (im not sure if thats a limp mode condition or not)