Hi All,

I'm out of ideas for troubleshooting and about to turn over the car to my tuner. Before I do that, I'll ask the forum for additional ideas.

The car is running rich under load above quarter throttle. It idles at a fluctuating 14.0-15.0 AFR. Cruises and drives fine even under heavy load - just goes to full rich 10.0 and holds. No new modifications have occurred since the tune. Issue was not seen during tuning so my assumption is something has failed on the car.

A bit of information:
2004 350z
Vortech V3 - SCi with 3.12 Pulley
Tuned with UpRev 3000 miles ago
UpRev GT MAF
NWP Throttle Body
DW600 injectors
Walboro 255 pump
NGK Iridium LFR6AIX-11 plugs (.034" gap)

What has been tested with no success:
Verified wideband as accurate on local dyno. Still made good power.
No boost/vacuum leaks (-24" vacuum and builds boost properly)
MAF cleaned
MAF swapped with friend's UpRev GT
OEM throttle body installed
Fuel Pressure is 52psi at idle
Spark Plugs replaced (passenger side appeared darker)
Tune reuploaded
Full Tank of 93
No oil consumption
No CELs

Today, I have sent out my injectors to DW for flow testing and cleaning. Thoughts are that the injectors could be dirty and not atomizing fuel properly. Besides that, I have no other ideas and an open to your thoughts. Car does not misfire and drives with no issues, just runs rich under load.






Video of Car Running Rich under load:
https://www.youtube.com/watch?v=A2QK...ature=youtu.be

 

Can you post up a data log? At idle and when it happens. Guess you'll have to wait for those injectors

Rpm, load, throttle position sensor, throttle pedal position, short and long term fuel trims, injector duty cycle, coolant temp, afr's, iat, intake cam sol %'s, target afr, ign timing

 

Definitely something wrong here Is it making boost? Does it break up or just rich? Who did the tune?

 

Will take a datalog once I get the injectors back.

Making boost just fine. Made it's normal 5psi at 4-5000rpm but I didn't take it higher. Also making good power which reinforces it making boost. If I overlay my original dyno graph and the troubleshoot graph (different locations - both dynojets), the numbers are similar.

Not breaking up at all. Only symptom is running rich. If I didn't have a wideband and didn't notice the black exhaust/tips, I never would have noticed. Car was tuned by Vince at RT Tuning and made 409whp. Ray, its the same guy who tuned Craig's previous setups. I'm confident the tune was proper as he's quite good and the car made proper power.

 

in for answer want to learn since i’m putting on my vortech soon

 

Update: Injectors "balanced in spec 'like new'". So I'm rather lost. I'll data log upon their arrival through snail mail.

Air: No boost/vac leaks.
Fuel: Pressure is good to the rail. Injectors are good. Fuel rail?
Spark: Plugs replaced. Odds of all coilpacks going bad at same time without misfire is low.
Tune: Reuploaded.
Misc: No oil consumption. Proper power to 5000rpm.

Open to ideas at this point

 

Got the car back together last night - still the same issues. Was able to get some datalogs for anyone that wants to take a look.

Attached Datalogs:
Idle
Acceleration (Normal acceleration, goes rich at partial throttle around 3000rpm)
WOTs (3 brief WOT accelerations: easing into WOT, starting below 3000rpm and starting above 3000rpm)

Any ideas are appreciated as I set an appointment up with my local shop.

 

How are your short term fuel trims at idle?

 

 

Sounds good. should be within 3% of 100 at all times

 

I don't know if this helps at all, but before I went standalone my Uprev Vortech tune would tend to shift and start running rich....almost to the point of needing a re-tune once a year...not sure what to attribute it to...