Audi S1.5 [OEM+] - (10-valve turbo B3 Coupé)

[LeafBox]

You need to check the vac lines to the fuel pressure reg and the little vac valve screwed into the head, check the full throttle enrichment switch and solenoid isn't stuck.
If your feeling brave you can have a look inside the FPR and make sure the diaphragm isn't split. If it is though it would usually leak fuel out of the little breather hole. Because the mixture is controlled by fuel pressure on the top of the metering head, a drop in pressure or a leak in the control system will cause it to run rich ( which is counter intuitive)
It would be worth measuring the voltage at your fuel pump.

I threw the question out on other forums as well, and most of the responses was basically this^
However, there was one person who pointed out that the problem didnt' need to be too much fuel, but rather too little air, which got me thinking.

Long story short, my Bosch BOV couldn't hold tight during idle, which meant that every time I changed gear I was creating a massive air leak till the boost could build back up and shut the BOV close again.
I threw on an open BOV I had laying around and plugged the return. The car starts easier, I get way less "back crackle" while engine braking, and I can shift gear without it hesitating.

Only downside is that it sometimes don't manage to catch the idle while I clutch. But that could be due to the BOV having questionable orings.
I guess I'll tinker with it some more

[newsh]

K Jet doesn't like a normal DV
You can get one that's specially set up for it though.
Pretty sure Bailey make one

Have you pressure tested the inlet tract?

[LeafBox]

Motronic doesn't like a normal DV
You can get one that's specially set up for it though.
Pretty sure Bailey make one

Have you pressure tested the inlet tract?

Not yet no, It's on my list of things to do during the winter

[newsh]

Not yet no, It's on my list of things to do during the winter

A leak between turbo and engine will make it idle badly and run rich on boost.

[Arnout]

Just finished reading your through entire project. Very nicely and creatively done, while keeping the looks so stock. Nice to see a non B4 converted coupe. I admire your determination in thuis project. I still own my first car (Audi 80 from 1991) and since 8 years an RS2, however did not trust myself with these bigger projects with the fear of getting out of time or space. These cars need some determination to keep them running at this age. Really admiring your work on the suspension parts, mine are getting in need of such a treatment as well.

Have fun with the coupe!

[LeafBox]

Just finished reading your through entire project. Very nicely and creatively done, while keeping the looks so stock. Nice to see a non B4 converted coupe. I admire your determination in thuis project. I still own my first car (Audi 80 from 1991) and since 8 years an RS2, however did not trust myself with these bigger projects with the fear of getting out of time or space. These cars need some determination to keep them running at this age. Really admiring your work on the suspension parts, mine are getting in need of such a treatment as well.

Have fun with the coupe!

Thanks a bunch! Always fun to get all your hard work appreciated!
I personally prefer the B3 front end. I think the B4 looks a bit nose heavy.

Gonna drive it as much as possible!

[De80q]

I'm with you about the B4 front end, I prefer the B3 also. It's nice to see others working with the 10vt. I'm running my K24 at 20psi with EFI. It's quite fun!

[LeafBox]

I'm with you about the B4 front end, I prefer the B3 also. It's nice to see others working with the 10vt. I'm running my K24 at 20psi with EFI. It's quite fun!

The 10vt is where it's at! I would love EFI though... This K-jet is driving me up the walls
But there's no room in the budget for that stuff now, I have other projects looming. Also I've spent a bunch of time making the damn thing fit, so I'm reluctant to yank it out

[LeafBox]

Back at it again with more growing pains! Good thing I have you guys!
I've just realized that my oil-pressure seems a bit low.

Warm engine
Right above 1Bar @ Idle, ~3.5Bar while driving, AND when the boost comes on the oil pressure drops to ~2?

I've seen talk about some kind of pressure-valve in either the head or built in to the temp-sensor (which has the spring and stuff, but I have no idea what/why or how it works)
And the ETKA doesn't show anything useful so I don't know what I'm looking for.

[Arnout]

I recall that the oil pressure must at least be >2 bar when rpm is above 2k. My old 2.3 10V non turbo also did between 1 and 1.5 bar idle, however the gauge quickly rose to 4.5 or so before 2k rpm. Do the oil pressure switches trigger the warning light? Also, the gauge is not very precise, however I find it is consistent. My rs2 does around 2 to 2.3 bar idle with the oil at around 90 degC.

Assuming the sensor is not causing this, the relation between oil pressure and boost is strange. I might overlook something, however the only point at which turbo pressure and oil pressure might meet is at the turbo? Then you should likely have massive oil consumption as well. It might also be only rpm related. Did you try revving the engine higher under no boost conditions and look at the oil pressure? Then it would more likely point to the oil pump itself.

[LeafBox]

I recall that the oil pressure must at least be >2 bar when rpm is above 2k. My old 2.3 10V non turbo also did between 1 and 1.5 bar idle, however the gauge quickly rose to 4.5 or so before 2k rpm. Do the oil pressure switches trigger the warning light? Also, the gauge is not very precise, however I find it is consistent. My rs2 does around 2 to 2.3 bar idle with the oil at around 90 degC.

Assuming the sensor is not causing this, the relation between oil pressure and boost is strange. I might overlook something, however the only point at which turbo pressure and oil pressure might meet is at the turbo? Then you should likely have massive oil consumption as well. It might also be only rpm related. Did you try revving the engine higher under no boost conditions and look at the oil pressure? Then it would more likely point to the oil pump itself.

That's a good suggestion about revving without boost, I'm gonna try that. The light does not come on, but in all honestly I haven't checked to see if it works, gonna do that too.
Also there's no oil consumption what so ever, the level is at the same place it was at the beginning of the season. Might also swap the pressure-sender if all else fails.

[LeafBox]

Welcome to 2018!

Despite the complete snow disaster that hit the middle of Sweden yesterday, spring is not THAT far off, and it's time to get ready!

There's some stuff that needs fixing, some stuff that we need to think about some more, and ofc a couple of things we need to do just because we want
And one of the thing we just wanna do came in the mail today, and I'm way to excited and have to show someone

*****

[Nuvo]

Futuras! Are they the real deal or replicas? What size are they?

[newsh]

Nice!

[Kiku]

In with my experience. Really it doesn't matter if your oil pressure is 2 or let's say 1.5 or even 1 with original gauges. I struggled quite a lot when i did a rebuild on engine on the car right now. Oil pump went original NEW ect other details. Fired up the car(2 seasons ago) and oil pressure was 1bar on idle and ~90oil temp. Then changed the sensors back to old ancient ones, pressure changed at same conditions to 1.5. Defo something was wrong and when i got tired of the crap i manually checked the pressure with standalone pressure meter and it showed 1.8. Anyways going strong for 2 years for now. Realy what matthers is what does the pressure at rpm 2000 and so on. Friend of mine did whole rebuild at the same time as i did allso new oil pump ect and hi had ~1bar at idle. Go figure...

ps: friend allso tried the spoken "shims" in or on(how to say?) pressure valve and it didnt change nothing...