More Dramas With The Car

[AzzurrA]

Hi All,

Well, more dramas with the car, after just waiting a month to get the bloody thing back from a simple 1/2 day turbo and intercooler swap!

Well, seeing as my turbo died (due to the heat recently i think ) i upgraded to an R33 unit, and also an R34 GTT intercooler...

Have barely driven the car since i got it back about a week ago, due to the hot weather.

I took it out and put it on the dyno today to check the AFR's, to make sure i wasn't running out of fuel/detonating with the hot weather we're having at the moment, and came across a bit of a shock when we found out that the car isn't leaving closed loop mode! (AFR's are at 14.8:1 from light throttle, all the way through to full throttle... i.e. it doesn't change like normal as it comes onto boost)

The workshop was busy, so they didn't have time to look at it/sus it out, but they suggested that there are only 3 things that control closed/open loop... these being:

AFM <-- I checked this, voltage readouts seem to be normal

TPS <-- Checked this as well, again, readouts seem to be normal

O2 Sensor <-- Now, im thinking this may have been damaged when the exhaust wheel of the turbo went kaput and ended up in my cat... The readouts are around 0.5 - 0.8v at extremely light throttle (i.e. just above idle) and then at much throttle at all, they drop rapidly, to around 0.02 - 0.05v.

Now, if anyone has any thoughts/ideas, they would be muchly appreciated...

Hell, even if someone has an O2 sensor i could borrow/try out, or an R32 GTS-t ECU that i could try plugging in to see if its the actual ECU, that would be great!

I Just want my car back on the road dammit!

[Spook's_Skyline]

well, im driving around with a totally kaput o2 sensor (no signal whatso ever)

its using lots of fuel, but drives fine

[AzzurrA]

Okay, just ran an ECU diagnostic test, and got code 55 (all clear)

[shanef]

If no one lends u an o2 sensor b4 thursday i'll be in brisbane with my car and we can test them then?

Or where bouts u live? Caus i work in toowong (opposite corner to teh regatta) and can bring the sensor with me n u pick it up?

[AzzurrA]

Well, i just did an O2 sensor test as outlined on the below site, and got no flashing LED's at all from the ECU....

http://www.overflow.250x.com/diagnostics.htm

Shanef, hopefully i'll have it all sorted by then, but if not, i might have to take u up on that offer

[predator]

o2 as stated will allow the car to drive fine.. just going from off-boost to on-boost is a tiny bit laggy as it goes.. "hmm, where's the o2 sensor, not there, damn, ok AFM time anyhow'. Been there, tried that.

There is something else going wrong.. possibly anything related (which narrows it down). Is there a clutch switch? maybe it thinks the clutch is still in/neutral and refuses to go out of closed loop? Stab in the dark

[AzzurrA]

okay, anyone else got any more ideas? nobodys still been able to figure this out, and i'm about ready to just burn the piece of shit...

Elite 32 came around (thanks mate) and we swapped the O2 sensor for a good one, and everything seemed to be okay....

for a bit....

We put the new sensor in and took it for a drive, and on my handcontroller we could see that it was coming out of closed loop mode (cycling between rich and lean at low load) and then going constantly rich when i stood on it... all sounds fine!

i then took it for a drive by myself, and it was still cycling between lean and rich at light load, but then when i stood on it it would go constantly lean....

I also spoke to a workshop (can't remember which one though, as i've called that many trying to get this resolved) and they basically called me an idiot when i asked them if there was anything like a neutral/clutch switch....

[85URK]

you have a really doozie there. go see sum1, and ask everthing they think it could be write it down then go try them all. one by one as a process of elimination. that is all i can say to do. bcoz one thing can seem like something but it is another.

[53XYN]

just courious .. wat colour sticker is on the AFM??... u say u upgraded to 33 turbo? .. try out a 33 AFM.. i know its bigger then the RB20 model .. even tho the voltages are same outputs etc.. as you have tested.. it might be it doesnt let enough air in for the turbine .. i mean i could be totally wrong here.. i know some series one 33s have green sticker AFM.. which is a lil restrictive.. 1.5/2 pink sticker afm flows far more then even Z32 TT airflow meter..hope u get it working soon...

[The Dan]

Don't swap the AFM. The green stickered series one AFM is the only one that will plug in anyway. It needs to have an exhaust gas analyser put up it's arse to find out exactly what ratios it's running. It could still be running slightly rich but the computer will read lean. When sam remapped my stock ECU he tuned it to run leaner than standard to increase combustion efficiency. It read lean on my Datalog but was still pushing 12:1 ratios. No pinging and no leanouts.

Remember with the new turbo and cooler on it will be flowing much more air at similar boost levels so the car should run slightly leaner due to this fact.

Just another thing....have you tried resetting the ECU?

Edited December 29, 2005 by 3lit3 32

[Rhinorebel]

[ Just another thing....have you tried resetting the ECU? ]

<{POST_SNAPBACK}>

You have mentioned this before.... How do you do it and what should it do??

Very curious as my ECU is retarding the timing at high revs due to a higher than standard boost level. Would 'resetting' the ECU cure this.

Dave

[The Dan]

It basically relearns it's timing, fuel and ignition curve on a minor level. It will advance timing until knock is detected then retard timing by 2 degrees, then advance by 1 degree continuously until knock is detected then it does it all over again. It will fine tune the ECU to your current mods. I'm not sure you want to cure a timing retardation do you? It is obviously detecting knock and therefore retarding timing for that reason. You should be running around 20-25 degrees btdc at WOT full boost 6000 rpm. What boost are you running? and what basic mods do you have?

[AzzurrA]

thanks for that guys, i checked fuel pressure on wednesday last week (have been on the coast since wednesday night) and found that at idle it was running around 2.5bar, and at normal driving it was running roughly 3bar... as soon as any throttle was given, it was dropping off to around 2.25 - 2.5bar.... looks like a new fuel pump and FPR is the way to go!

[Rhinorebel]

It basically relearns it's timing, fuel and ignition curve on a minor level. It will advance timing until knock is detected then retard timing by 2 degrees, then advance by 1 degree continuously until knock is detected then it does it all over again. It will fine tune the ECU to your current mods. I'm not sure you want to cure a timing retardation do you? It is obviously detecting knock and therefore retarding timing for that reason. You should be running around 20-25 degrees btdc at WOT full boost 6000 rpm. What boost are you running? and what basic mods do you have?

<{POST_SNAPBACK}>

I'm running 12 pound boost and mods are a FMIC, 3 inch exhaust with a Rob Bliss dump pipe, Pod filter (very large!!) and that is about it. It has a brand new AFM and TPS.

So how do I go about resetting the ECU? Just unplug it and plug it back in??

[Shaneo]

I'm running 12 pound boost and mods are a FMIC, 3 inch exhaust with a Rob Bliss dump pipe, Pod filter (very large!!) and that is about it. It has a brand new AFM and TPS.

So how do I go about resetting the ECU? Just unplug it and plug it back in??

<{POST_SNAPBACK}>

i believe disconnecting the battery for a while will reset it. unpluggin the loom from the ecu would have the same effect. off the top of my head i thin 15minutes is enough, but try overnight just to be sure.

[The Dan]

Nah, all you gotta do is disconnect the positive terminal and stand on the brake pedal for 1 minute. This is sufficient to reset the ECU.

Jason...how did you go about checking your fuel pressure?

2.5 bar(36.75 psi) as soon as you stand on the pedal is not all that bad. It's just when you get up in the revs you will need about 3.4 bar(50psi) rail pressure. Check fuel pump flow to make sure it's not just a blocked fuel filter or something silly like that. A blocked fuel filter will cause the same fuel pressure drop.

Edited January 2, 2006 by 3lit3 32

[AzzurrA]

borrowed an oil pressure guage (its all they had) from Option1, and they plumbed it in and told me to drive around the block and watch the guage...

And yes, as the revs rose, the fuel pressure dropped down....

i'm thinking i'll just change the pump and regulator and the filter while i'm there too, and that should net me the sort of power i'm chasing (after i get sam to tune it when he comes up)

[The Dan]

Well apparently they have the 040 pumps for sale for $220 in the business traders section of the forums....they are on discount. They usually retail for more than $100 more than that.

I would recommend using a nismo reg or something that bolts straight on to the rail like a SARD also. If not, you can get a malpassi 1:1 rising rate for around $180-$200 which will do the job nicely.

[AzzurrA]

yes, i believe it will probably be a SARD or Nismo FPR i use...

[AzzurrA]

yeah, i realised that after i posted it (i'm bloody tired at the moment) hence me editing my post, but u were too quick, lol