Vanos Rebuild Start Hesitation

[jamesfoley]

Please don't turn on the AC for the test. Do hot idle again to confirm MAF is around 4g/s at idle and not 6.
The cold log proves that the precat sensors are working perfect -- deep low during extra air from the SAP running, and switching normally after that.
I was hoping the cause of fuel status 8 was due to bad MAF of 6g/s at idle, until seeing that the AC was on.

If MAF is indeed around 4 at idle, then it will be a challenge to find out the cause of status 8 but blaming the leaking injectors.
What is the injectors history?

We have proved it’s not MAF though.

No history with injectors, installed at factory and been there ever since is my guess…

Annoyingly you can’t buy genuine injectors at the moment due to them being unavailable, so my only option would be to pull injectors and send them away to be cleaned which leaves the car unusable which would be a pain 😅

Buying bigger injectors and having them mapped in is an option, but an expensive one.

[sapote]

We have proved it’s not MAF though.

No history with injectors, installed at factory and been there ever since is my guess…

Then it's time to check injectors leaking and flow rate.

[jamesfoley]

Then it's time to check injectors leaking and flow rate.

I do have a fuel pressure tester arriving in the mail in the next day or two, so plan on getting some solid readings on video of what that looks like.

Issue I have with doing injectors is it disables the car for a few days which I'd love to avoid if I can.

Might sound like a dumb question, I know leaking injectors can richen the mixture which would cause negative LTFTs, but why would they cause the fuel system to go into open loop fault? I would have thought things would have to be bad enough to throw a code.

The only other small things I've noticed with the car is that I sometimes feel like it surges if I put my foot down going from a low RPM cruise to pick up speed, almost like there is a lag in throttle input for some reason. The other is that when going up hill at low speed and low RPM, the car feels like it is doing a load of tiny surges, it just doesn't feel smooth.

But apart from the above, regular cruising around, getting up to speed, and wide open throttle all seem perfectly fine.

Faults wise I've had "094 Inlet VANOS adaptation" which was the VANOS being a tooth out on the inlet side and was resolved with having the VANOS timing re-done. I've also had "P0174 System Too Lean" when I re-fitted the new MAF, which I cleared and never saw again.

The following shadow codes only appear in P.A.Soft BMW Scanner and I have no idea if they are legit or not

• 089 Internal Fault
• 099 Internal Fault
• 050 Ignition coil, cyl. 4
• 025 Ignition coil, cyl. 1
• 143 Electronics-box fan

The above errors just appear randomly, sometimes they are there and sometimes they're not. Also the Ignition coil errors don't make much sense as I've had these codes both before and after I put a whole new set of coils in, and the code doesn't follow the coil if I move them around, unless these are the cylinders which have bad injectors? I can't find anything online about the internal fault codes though.

Just to keep a log it's worth mentioning that I pulled all the connections from the DME (with the battery disconnected) to check for oil in the plugs, but the DME box and all connections are dry as a bone.

Determined to get to the bottom of this...

[Slideways]

What about trying another DME?

[jamesfoley]

What about trying another DME?

Could do, what's involved in doing that? I'm assuming there are EWS and mileage things to sort?

Flashing my DME to a newer firmware version was a route I was going to go down also, unless its safer to leave my DME as it is and get an updated one to try just in case something breaks...

[sapote]

Might sound like a dumb question, I know leaking injectors can richen the mixture which would cause negative LTFTs, but why would they cause the fuel system to go into open loop fault? I would have thought things would have to be bad enough to throw a code..

The fuel status 8 events is a very short time, and so I don't think it forced into the open loop control. I want to know what sort of problem leading to status 8.

[jamesfoley]

The fuel status 8 events is a very short time, and so I don't think it forced into the open loop control. I want to know what sort of problem leading to status 8.

I've been trying to find information on the MSS54 and its fuel status but I can't really find much. The DME must have some conditions that need to be met which is causing the status to change and it would be awesome to know what they are.

[Slideways]

Could do, what's involved in doing that? I'm assuming there are EWS and mileage things to sort?

Flashing my DME to a newer firmware version was a route I was going to go down also, unless its safer to leave my DME as it is and get an updated one to try just in case something breaks...

After disabling the EWS, it should just be plug and play with another DME.

[jamesfoley]

After disabling the EWS, it should just be plug and play with another DME.

So I could get another DME, have the EWS removed and it will just work?

Does the milage / VIN / FA coding not matter? Not doubting you, just trying to understand what data is stored in what modules

[Slideways]

So I could get another DME, have the EWS removed and it will just work?

Does the milage / VIN / FA coding not matter? Not doubting you, just trying to understand what data is stored in what modules

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/195737-dme-ecu-swap-change-process

[jamesfoley]

Please don't turn on the AC for the test. Do hot idle again to confirm MAF is around 4g/s at idle and not 6.

Warm log with no accessories turned on: https://datazap.me/u/jamesfoley/e46-...s?log=0&data=2

The only thing I can see is the status 8 peaks are around the times where the pre-cat o2 sensors are below 0.1v, or 0v

[sapote]

On the post cat sensors: as soon as the rpm was over 2000rpm, the cats seem not able to treat the exhaust gas and the sensor signals dropped below 0.5V -- a sign of aging cats?

On the fuel status 8 bad open fault, it is hard to trouble shoot as the open loop is just a short moment and so no error codes. I would expect that during status 8 -- open loop should cause rich mixture but then why the pre cat o2 switched to lean, below 0.5v?

[sapote]

On the same log, looking at the pre cat sensor switching pattern, notice the during the high rpm that the sensor seems to switch less often than during idling instead of faster proportional with rpm. I think this is caused by the slow sampling of the reader, as if the oscilloscope was used then the switching frequency should be faster during higher rpm. This means we cannot tell what mixture that the sensor sensed during the higher rpm with fuel status 8 -- rich or lean.
You might want to look at the sensor signal with a oscilloscope.

[jamesfoley]

On the post cat sensors: as soon as the rpm was over 2000rpm, the cats seem not able to treat the exhaust gas and the sensor signals dropped below 0.5V -- a sign of aging cats?

Aging cats is a possibility but not really one I’m too worried about right now. As far as I know the post-cat sensors have no influence on the mixture, and it’s currently passing emissions so it can be a problem for another day.

On the fuel status 8 bad open fault, it is hard to trouble shoot as the open loop is just a short moment and so no error codes. I would expect that during status 8 -- open loop should cause rich mixture but then why the pre cat o2 switched to lean, below 0.5v?

At this point I honesty have no idea what could be wrong here, every Google adventure I go on just gives me the usual E46 fuel pump stuff. Being a fuel status error it kinda makes sense it’s fuel, and the last link in that chain is injectors, so will probably get those checked. However what doesn’t make sense is that fuel trims and pre-cat o2 readings look “normal”. Oil does smell kinda fuel contaminated, though I’ve been to a couple of places now that have told me it smells fine 🤷

On the same log, looking at the pre cat sensor switching pattern, notice the during the high rpm that the sensor seems to switch less often than during idling instead of faster proportional with rpm. I think this is caused by the slow sampling of the reader, as if the oscilloscope was used then the switching frequency should be faster during higher rpm. This means we cannot tell what mixture that the sensor sensed during the higher rpm with fuel status 8 -- rich or lean.
You might want to look at the sensor signal with a oscilloscope.

I could pull all PIDs apart from pre-cat, fuel status, and rpm? Would result in a higher resolution log in theory.

I don’t currently own an oscilloscope, though I’m happy to buy one of the cheaper 40MHz ones from Amazon and back probs the O2 sensor plugs. Just not 100% sure how I get readings from those while driving the car…

[sapote]

"Just not 100% sure how I get readings from those while driving the car…"
No need to drive as the fuel status 8 will show up with rpm higher than 2000.
This seems to be an nice digital storage scope for less than $70. max input voltage is 35v perfect for car electronic. The o2 sensor signal is a slow signal, way below 20Mhz of this scope bandwidth. Which scope that you're looking with 40Mhz?

I use a Pico scope 3000 series and like it, but it's more expensive.