Help! car goes lean after 10 min.

[klefroid]

Starting a new topic because it's getting confusing.

Car: ROW 1977 3.3 (mod. 1978)
Mods: Cams, Turbo, adjustable WUR, AFR gauge, headers and muffler.
New parts: Green wire, rotor and cap dizzy, spark plugs and wires, coil, injector blocks
hoses an vacuum lines, o-rings, battery, original fuel pump up front and
044 in the rear, air metering plate
Checked: boost and vacuum leaks, race clamps used, waste-gate ,inter-cooler
pressure test, Wur, ignition timing, fuel pump relay's

SP: 6.2 bar
CCP: 2.2 bar
WCP 3.75 bar

Car is a bit low on power but not much. NO AIR FILTER used for testing.

At this point I have 2 issue's left:

1 On cold start up afr is +- 11 and going up to 12.2 fully warm on idle.
on the road: cruising at +- 13.3 boost +-11.2
But after a few pulls IDLE goes lean even up to 17! (If I stop while driving and set the fd more rich (allen key) makes her making less power)

2 Strange sound while going off the throttle https://youtu.be/2clYanR0iUI

[speednme1]

The strange sound.....sounds like a blow out valve that is open to the atmosphere...that's the only sound that I hear.

[klefroid]

The strange afr curve is found... Problem in the wur.
Boost enrichment gets stuck sometimes... So I'm letting my Wur rebuild by Brian if hes willing to do.

Car looks like it almost has it's full power when playing with the wur.

Can that sound be created by running with no air filter and housing?

[JFairman]

Noise does sound like a blow off valve venting to open air.

If your miserable old worn out and obviously out of adjustment CIS ever goes too lean just open the hood and pull the 12 volt wire plug off the WUR.

In 10 to 15 minutes it will be running richer. Probably a little too rich at idle and around town but you'd be a lot better off if driving hard on a track and you can take a second and plug it back in anytime.
You'll learn things while doing it.

[bpu699]

When mine did that it was a bad relay. When it ran on one pump it went super lean... Then it would correct. Happened on th road an scared the crap out of me, as I had spent the prior 2 years chasing a rich condition...which turned out to be a cdi issue... I think...

When it happens, pull one relay... If it doesn't die, that's the bad relay. Or, just swap relays...

[T77911S]

if you are venting your BOV to atmosphere it is probably opening at idle and letting in air making it run lean. when i vented mine before i had very strange AFR readings.

jim
i may test mine this afternoon to see what the AFR does when i vent mine. pulled tranny on mercedes last week.

[RarlyL8]

Unfortunately many things can cause the symptoms you describe. To ferret out the culprit you need to catch it during the failure. A set of pressure gages will help.
Typically a malfunctioning BOV will manifest during boost events.
Typically a WUR will malfunction rich.
Fuel pump pressure check during this event would eliminate that as an issue.
Worn/old fuel distributor can also cause these symptoms but is more difficult to diagnose.
I would verify system pressure is stable first, then warm pressure, then isolate the component.

[T77911S]

remove and plug the vac line to the DV and see what it does. RUF removes the DV completely. it may not hurt it but you may want to limit boost.

[klefroid]

I'm a bit confused... I mean the re-circulation valve...
There is going air past the piston internally if I put pressure to the throttle body
It's not stuck open but there is a fair amount of air passing the piston... I still have full boost but maybe that sound is coming out of the intake (no air filter box used)

I have got a good wur from a friend that I can use it until mine is rebuild... car drives very good!! But she is building up boost a little later then before 3200 rpm (before 3000)

[T77911S]

the sound on the video sounded like a valve vented to atmosphere.
is the stock valve in the pic above is open at idle it would not go lean because that air has already been metered.

i would suspect an air leak on the pressure side but then not sure if you would get full boost, depending on how bad it is.

[klefroid]

I closed off exhaust and oil vent. Intake metering unit and put in 0.8 bar and no airleaks to be found. I will put on the air box and see if it still sounds the same. Thanks

[T77911S]

i take it you have the cast iron FD, 009 injectors?
same as me.