Strange Mapping Problem

[blue_vl_t]

I have been in the process of upgrading the whole exhaust

removed the turbos and all the gear to replace the dump pipes,

Reassembled everything, then disconnected the battery to tack a few parts of the exhaust underneath the car with a TIG.

Now its all going, only thing changed is the exhaust(all of it), but the engine is running richer than ever before, like 13.0:1 @2000rpm in the shed, and as you back off to get closer to idle, it goes off the scales rich and obviously dies.

Looked at AFM voltages, they are;

ENGINE NOT RUNNING

AFM-1 --- 0.44

AFM-2 --- 0.50

ENGINE @ 1500rpm

AFM-1 --- 1.60

AFM-2 --- 0.75

I removed the afm's cleaned them out and removed the cover from the top, checked the solder joins, they look good, they were new AFM's not long ago..

reassembled and checked again,

same results,

removed AFM's and swapped top one for bottom,

same results, and the voltages stay as is/similar.

I'll take a video and see if that helps too

any help appreciated

Edited November 20, 2011 by blue_vl_t

[SargeRX8]

Intake leak will cause the car to run rich as hell, you have measured air coming in and being given fuel for but lost before it gets to the engine. I forgot one tiny vacuum hose, it was enough to make my car idle with black smoke coming from the back. Check every single silicone connector, hose, seal, everything which helps the air stay in the intake.

Edited November 20, 2011 by SargeRX8

[blue_vl_t]

well i had looked a few times,

but i shoved some air in the intake this time and blocked the other, and what do you know, one air leak, i'll fix that, hopefully its all the problem is.

not sure why i always think a problem is something more complicated......

[blue_vl_t]

fixed the intake leak, but its running just as bad, like so bad i cant keep it running unless using 1500+rpm, took it for a drive around the block, stalled like 4 times, af mixtures are just going crazy, all over the place.

it will most likely be something simple, a matter of finding it....

[DVS JEZ]

What ecu? Can u check injector ms time and see if its excessive.

Try disconnecting th 02 sensor and see if anything changes.

[zebra]

Not something silly like the AFM plugs back to front, though shouldnt affect them as they will still be reading air

[blue_vl_t]

ecu is PFC pro, z32 afm's

o2 sensors are removed and bunged up, also turned off on the PFC.

The wiring to the rear AFM is only just long enough to reach, so wouldn't reach the front one.

Im just making up some caps for where the afm connect to the pipework, see if there is anymore leaks, pressurize the system

[Lithium]

Any chance one of the turbos randomly failing at the same time all this happens could cause these symptoms?

[zebra]

seems odd that the AFM voltage is so different between the 2, there is normally a bit of variation between them, but not that much.

I would be focusing on that area, melted wire, bent pin etc

[blue_vl_t]

Just pressurized the system with 5-10psi, looped the rocker cover breathers together, so it pressurized the whole motor, sump and all, its dead silent, no leaks, until the dipstick pops out, lol

so intake leaks, none.

I'll have to see about metering out the afm cables to the ECU, see what i come up with.

[GTScotT]

I recently had a similar problem with a Z32 that was meant to work..

I have a strange suspicion the body earth for that one is sensitive and may give a crazy effect... Mine was idling at 3.7v, yet i suspect the AFM will work fine when put into a known working case (will test tomorrow).

[blue_vl_t]

when using map tracer, in the shed, free revving the engine, if you hold the rpm at 2000rpm and gradually lift the throttle from the floor, the below lovely ms paint diagram shows approximately the path of the map tracer, ie which cells are being used.

Edited November 21, 2011 by blue_vl_t

[blue_vl_t]

At idle, 950rpm, the map traced usually hovers around the P03 / N02 area,

so for some reason the ecu thinks as i'm backing off the engine has more airflow, hence dumps heaps of fuel

[zebra]

blow off valves hooked up and working?

though you did pressurize the intake...

if the are atmo ones are they opening up under vacuum

[blue_vl_t]

blow off valves hooked up and working?

though you did pressurize the intake...

well, i haven't touched them, the car was running fine about a week ago, just removed exhaust side and reassemble with new exhaust.

as you said, pressurized intake, nothing was leaking......

Stock gtr BOV's

Edited November 21, 2011 by blue_vl_t

[blue_vl_t]

just metered out the wiring and plugged the ecu back in, and now its all good

[zebra]

do I get a prize for mentioning wiring in my (semi)educated guesses?

lol

[blue_vl_t]

a prize.......

i'll take you for a spin, you live close by to Kalgoorlie, lol

I actually could not find anything wrong with the wiring, and i'm an electrician.

but the plugs on the r32/r33 model is quite crap in design, you have to push the plug in further the the bolt will pull it in.

but i recon it is was just a matter of unplug the ecu and plug it in, kinda thing. lol

I do think i will have to install another muffler, the 4" is kinda loud, i am only able to find the Magnaflow ones off the shelf, anyone know if they will do much, or someone to build one custom etc??

[RB30TI]

? drive Tonyt then? Haha yeah the exhaust was very loud the other nite.

Does it go much Better with the 4in and no 2.5in gasket? haha

[blue_vl_t]

it should do, but my crappy superwizz turboteh bleed valve has a stripped thread, loose connection, which is probably why it was running more boost than i thought it was, i removed it, and its now running a massive 12psi, woo hoo.