The hunt for the vacuum leak!

[dikidera]

Power robbing to the wheels, sure, but airflow is still airflow I'd reckon.

Also I have the bifuel model(B5244SG), so my first cat is integrated in the exhaust manifold the second is downstream past the flex pipe.

And yes I do plan to buy either Volvo fluid or find HFM, but HFM is currently only available on ebay.


My main catalytic converter and the other piece https://www.skandix.de/en/spare-parts/e ... r/1041615/

[vtl]

Power robbing to the wheels, sure, but airflow is still airflow I'd reckon.

Also I have the bifuel model(B5244SG), so my first cat is integrated in the exhaust manifold the second is downstream past the flex pipe.

And yes I do plan to buy either Volvo fluid or find HFM, but HFM is currently only available on ebay.

The system is power on demand. It does not produce more power than it is commanded for. Don't diagnose problem by looking at the air flow alone.

How does your exhaust manifold look like? We don't have SG here in North America.

[dikidera]

Oh I was definitely commanding it for max power. I've attached pics above about cats.

I've done many logs so far and have not managed to achieve max airflow and thus peak power at 6200rpm even.

For reference, here is a post comparing not an S60 but a V50(the difference is it's lighter in weight)

I just looked at my primitive OBD data logger and i got peak 135g/s at 96km/h falling to 129g/s at 105km/h (rpm limiter at 2 gear) - it's P1 V50 but it doesn't matter - engine and ECU is the same as yours Smiley
I don't have engine rpm at saved log only GPS speed (you can easilly calculate rpm from that) and MAF because this is some basic demo version app that i randomly use for basic diagnostics.

[vtl]

Do you need to reset your bi-fuel adaptations or something like that? I know bi-fuel V8 Toyotas need that every so often, otherwise the adaptation drifts, vehicle looses power and finally throws error.

[dikidera]

I have personally reset ECM adaptations via CAN commands, but very often I am working on the car and leave it without the battery for a whole day. I also drive primarily on petrol as the bifuel distributor is giving me problems.

Another thing worth mentioning is that acceleration in lower gears high rpm is slower than high gear low rpm. Since it's a ULEV car like I said, the gearbox tries to upshift as soon as possible, so often time even at 60kmh I' am at 5th gear 1100-1200RPM and at 80kmh a couple of hundred above that, depending on torque converter behaviour. So, let's say I am in 4th or 5th gear, the speed in km/h increases faster than if I am at a lower gear. Which coincides when the engine is operating at higher RPM, where it should be producing more power, but if there is a backpressure or vacuum leak it would make sense the power is less at higher RPM as the problems becomes more pronounced, at least this is what I think.

And like I said before, I have had many situations even very recently where low HP cars such as Peugeot Boxer or Renault Master buses, most of which while having higher torque have less horsepower but still managed to accelerate faster uphill and even overtake me whilst I was not able to accelerate much(I have not observed clutch slippage). Most of these vehicles including the lada are between 100 and 120hp. Particularly the lada granta which I could not catch up to.

[vtl]

AW55 has torque limitation in the first and second gears, it allows a full torque only starting in third gear.

These cars are all ULEV.

[dikidera]

When I said lower gears I of course only meant 3rd to 5th. 3rd gear acceleration is just as bad even when it's not limited. Also in the quote above which was directed to me, you can see that the V50 170hp auto(AW55) with same torque limit still managed to produce peak airflow whilst I have not been able to. Now even if we didn't care for airflow, it's very apparent my car is not producing the power it should in the high RPM range or does it very slowly

Anyway, I will re-torque the intake manifold AND I was given a suggestion to drive with the Oxygen sensor off removed from the exhaust manifold, so if there was backpressure it would escape more easily and I should see improved performance(in open loop mode). The only thing I don't like here is the hot exhaust gas escaping in the engine bay or firewall. It just sounds like a fire hazard.

[dikidera]

@abscate it sure isn't possible. I tried, the 1/4 is about to strip the head of the bolt, because I cant insert the cup further in. And I really hate mucking with the thermostat housing, I will have to apply a new sealer on it.

20230905_182657.jpg (183.41 KiB) Viewed 277 times

[vtl]

Your tools selection is poor You need a short socket on a 3/8" U-joint and a variety of extensions. It is actually not that painful with the proper tools.

My arm is also barely long enough to reach that bolt with a wrench under the manifold. PIA, but I did it that way a couple of times.

[dikidera]

Under the manifold is my BIFUEL CNG distributor. It's bolted onto it. I am using the same tools though. But my swivel is I guess thicker.