running lean, low boost

[moalaska]

I just got done doing the following

Removed k26/6 installed vitesse stage 4 turbo
Lindsey 4" exhaust
Venturi delete
Cycling valve delete, mbc
Replaced every vacuum line
Repaired melted klr line
New manifold gaskets
Older second hand vitesse maf with chipboard 55# injectors 3 bar for
Boost guage and wideband

Car starts fine
Idle fluctuates and sometimes goes high and sticks for a bit around 2k
I had another throttle body it seemed that the plate doesn't close as good as my spare. Also put new orings in it

Tried adjusting idle per procedure but seems ineffective, it I don't think the throttle body wants to close all the way easily or there is some other issue keeping it from being stable

AFR at idle 17-20, way lean
Vac seems OK at idle
If I get it under a load past 2k AFR goes down some but still seems to want to go lean

Boost will not go past 4 psi, and bov sounds like it's stalling the compressor

Car seems to stumble and be starved for fuel

So.....

What could my idle problem be??
What is causing lean idle? I know I have a big turbo but it shouldn't affect idle AFR and should be getting more boost than I am.

Bad Wastegate?
Could my bov be blown and just letting the boost air back into the intake pipe?

I know I can adjust the fqs but don't want to do a band aid

And does anyone have examples of how John usually sets the dip switches. I left them how I got it which the po said was the normal set up. Should I only have one up or down at a time or could there be endless possibilities.

[RRRacing1970]

55# Injectors are stock turbo injectors... I wold start there with a new set of 75# to 78# LI Injectors... with all the stuff u have changed I can see why you are running lean...u think!
PS: I would call... Vitesse Racing Home of the Spooled Turbo an ask them about all the stuff u have changed and try to get them to give u a base line s/u for the "DIPPED... Switches"!
Good luck... Ron

[kdjones2000]

Ron, pretty sure stock injectors are 37#, not 55#.

You have lots of mods, so that makes it hard to offer many recommendations for your issue.

+1 on the calling Vitesse, although I have heard that Jon doesn't like to handle secondhand stuff very much.

Good luck!

[v2rocket_aka944]

Stock 951 is ~37#, yes.

Mo- try unplugging your Idle Control Valve and see if the idle AFR improves...

[RRRacing1970]

Sorry about that... what I meant to say with all of the mods he is running (not taking into account for the huge turbo) I'd be running the #55 injectors!
With that big of a turbo I would be on 75-78# injectors!
Ron...

[moalaska]

It may sound like a lot of mods but really the only thing that has change significantly as far as engine management wise is a larger Turbo and the maf setup. The maf has larger than stock injectors which should be able to keep up with the bigger turbo on lower boost settings. And the larger turbo shouldn't contribute to it running lean at idle when the engine is operating in vacuum and not boost. The amount of lean actually goes down a little at higher rpm, I'm not running it too much lean like that.

My throttle body plate doesn't seem to want to close all the way, it doesn't quite close all the way past the idle screw hole. I'm guessing that is contributing to making it difficult to set idle and air is leaking past. I have a, spare that operates smoothly I'll put it on today

And I have contacted John. I didn't expect much as it was a second or third or even fourth party Crossing of hands with the used set up. he cannot help with the dip switch settings because they are all custom for each set up. I would still guess that there is a general way that they are set up so I have an idea of which way to switch it to test the different Maps between ethanol or normal Or race gas. I'm recieved all the instructions just not the dip settings but the guy I bought it from said the way it was set up was for normal settings, pump gas etc. And knowing John's reputation with his products it should easily be able to run decently at idle or even moderate boost I would think, maybe not optimally but should be better than it is. And i wouldn't think the boost curve would be too much higher up in rpms, his turbos are known for improved spooling times even considering that it is a larger turbo. I don't think the problem is with the maf or supporting hardware, so I have underlying things I need to get figured out.

[RRRacing1970]

What kind of Waste Gate are you running?
Ron...

[moalaska]

Stock Wastegate. That is another consideration of something that could be failing. Need to figure lean issue first and isolate that as well as unstable idle. I understand stock spring could be weak or stuck open.

[RRRacing1970]

Lean Issues?

Hi mo...
Have you checked to see if the pressure line from the discharge turbo tube from the banjo bolt...( I'm assuming you are running the pressure line for your stock waste gate from the banjo bolt)... leak and or are you running a orifice sized down banjo bolt in order to reduce the pressure form the banjo bolt to the stock 951 waste gate... I have had these low to mid range problems before if the line leaks & or the orifice is plugged... also if diaphragm/spring in the stock waste gate is bad.... my engine wanted to lay down (run out of power (lean?)) in the mid range RPM about 2800- 3400 RPM with the gas pedal on the floor only in the upper gears...3rd,4th & 5th.

With the engine running at idle, disconnect the waste gate pressure line at the banjo bolt while @ idle (note what happens) (hopefully nothing but a small amount of Turbo discharge air coming out the banjo bolt hole. If u have a small air compressor... set it at 8-10 psi and put the air in your waste gate line to the waste gate u should hear nothing... now set 18-20 psi and do the same thing (while the engine is running at idle) now u should hear the exhaust going through the waste gate. Waste Gate is... (good or bad?)... solved... it works or it don't!
Ron...
I had a dual port Waste Gate Valve Pressure line get a piece of (RED-HOT) carbon blown back up into the silicone pressure line while running 19.5 PSI At the Manual Boost Controller.... (Burned a Hole Right through it) (see pic)

[RRRacing1970]

PS... Sometimes a a leaking WF Pressure Damper or Bad WF Fuel Pressure Regulator will cause unstable idle and lean conditions at higher eng. speeds? Are u running a manual adjustable WF Press.Reg. or a 3 Bar Porsche Reg.
Ron...

[moalaska]

I have the 3bar that came with the vitesse kit. I also have an adjustable one with guage from summit that I could put on in some point in time.

[moalaska]

Installed different throttle body today. The idle was more stable it seemed like, except for sometimes it was slow to come down but didn't fluctuate as much. When I first started AFR was spot on at 14.6. After about a minute it slowly started to climb to 17 19 then 20. Went around the block obvious choking not enough fuel or too much air. Went around corner really fast and AFR went down to 15 and stayed there for about a minute then when I kicked the throttle it went back up again. Tried fqs just for fun in position 1 and 3, little to no change. Next step I guess is check fuel pressure, I could always swap old injectors in to see if there is a sticky injector. I'll fiddle with it tomorrow. Maybe try cleaning up grounds. And bypassing idle valve. Something is causing it to go lean. It would be great if it was something simple like a clogged fuel filter.

[moalaska]

Oh yeah I Audi tried unplugging the stock oxygen sensor and when I did it made it even more horribly lean.

[RRRacing1970]

Just pull all the plugs and read them... that will tell u what injectors are pluged or sticking if u have some bad injectors & which ones are bad or good!
Ron...

[moalaska]

Tested fuel pressure at rail. It's at 36, which is low for the 55 lb injectors should be at 45 or so. I have the correct regulator so maybe the reg is bad. I squeezed the return line and pressure went to 100.

[moalaska]

Ok. I decided to pull the air filter off for some reason and found a rubber hose in there, the one that attaches the diverter valve to the Tube. It must have been in the air filter when it got shipped and it got sucked up against the maf element. Needless to say it made it difficult for the sensor to get an accurate reading. After taking it out afrs were in mid 13s at idle and much more stable. Will go around the block bin a bit and see how it does under load.

[DannoXYZ]

Originally Posted by moalaska

Tested fuel pressure at rail. It's at 36, which is low for the 55 lb injectors should be at 45 or so. I have the correct regulator so maybe the reg is bad. I squeezed the return line and pressure went to 100.

If that 36psi is with vacuum-hose connected, then that's correct pressure.