Secondary air mass from lambda bank 1

[Iyzmi]

Trying to track down the cause of my 27AF trouble code. The SAP, fuse, and relay all tested ok. Live data from the HFM intake hose sensor also looks good. Freeze frame data shows secondary air mass from lambda bank 1 and average secondary air mass to start at 0 kg/h - does anybody know what sensor this comes from? I recently replaced the bank 1 O2 to resolve code 2740, wondering if the new one is DOA despite no more O2 trouble code.

[Scrippy]

Suction hose that pops into air box elbow. The hose plugs into the intake elbow and travels down the drivers side of motor and plugs into SAP. Then SAP goes to Y-hose to each valve on back of heads by firewall. The sensor is at the back of the intake hose just before it plugs into SAP.

[Iyzmi]

Originally Posted by Scrippy

Suction hose that pops into air box elbow. The hose plugs into the intake elbow and travels down the drivers side of motor and plugs into SAP. Then SAP goes to Y-hose to each valve on back of heads by firewall. The sensor is at the back of the intake hose just before it plugs into SAP.

Isn’t that the HFM air mass flow, which is reading healthy at around 13 kg/h?

[Scrippy]

Originally Posted by Iyzmi

Isn’t that the HFM air mass flow, which is reading healthy at around 13 kg/h?

I recall that you would want > 19-20kg/h. To test you SAP, just remove that hose from the intake elbow and start car when cold. You should feel suction on that hose during a cold start for around 30 seconds. The suction should be pretty strong like a shop-vac. The SAP will only turn on during a cold start and not a warmed motor start.

[Iyzmi]

Originally Posted by Scrippy

I recall that you would want > 19-20kg/h. To test you SAP, just remove that hose from the intake elbow and start car when cold. You should feel suction on that hose during a cold start for around 30 seconds. The suction should be pretty strong like a shop-vac. The SAP will only turn on during a cold start and not a warmed motor start.

Would that process still work if I have cold start disabled in my tune?

[Scrippy]

Originally Posted by Iyzmi

Would that process still work if I have cold start disabled in my tune?

Nope

[Iyzmi]

Originally Posted by Scrippy

Nope

That’s what I’m having trouble understanding. The SAP shouldn’t be getting triggered in the first place. The HFM is providing a steady reading but 27AF will not go away and the SAP readiness monitor will not pass.

[Scrippy]

Originally Posted by Iyzmi

That’s what I’m having trouble understanding. The SAP shouldn’t be getting triggered in the first place. The HFM is providing a steady reading but 27AF will not go away and the SAP readiness monitor will not pass.

I would then assume the tune sucks to that point. How can you reach a readiness state when the whole process is not happening and the tune doesn’t fake out the cars DME? This is why DME tunes always cause smog problems. I would flash back to stock and see what happens to readiness once an actual successful SAS runs from a cold startup. It will take 2 for total readiness if successful.

PS:You should check with BPM Sport regarding their delete and what happens to CEL, Readiness and any other questions. Mike’s tunes come highly recommended.

[Iyzmi]

Originally Posted by Scrippy

I would then assume the tune sucks to that point. How can you reach a readiness state when the whole process is not happening? This is why DME tunes always cause smog problems. I would flash back to stock and see what happens to readiness once an actual successful SAS runs from a cold startup. It will take 2 for total readiness if successful.

It’s a BPM Sport tune that I’ve been running with no issues for over 5 years. The car is ESS supercharged with green giant injectors so I can’t really flash back to stock easily.

[Scrippy]

Originally Posted by Iyzmi

It’s a BPM Sport tune that I’ve been running with no issues for over 5 years. The car is ESS supercharged with green giant injectors so I can’t really flash back to stock easily.

lol I just added BPM Sport to that last reply. I think you should email them asking what’s best to do. Their stuff is pretty spot on.

[Iyzmi]

Originally Posted by Scrippy

lol I just added BPM Sport to that last reply. I think you should email them asking what’s best to do. Their stuff is pretty spot on.

I emailed Mike last week and followed up yesterday but still haven’t heard back. Fingers crossed he has the answers..

[Scrippy]

Originally Posted by Iyzmi

I emailed Mike last week and followed up yesterday but still haven’t heard back. Fingers crossed he has the answers..

He’s a busy Bee, he’ll get to ya I’m sure. I didn’t know you had those upgrades. I would wonder about fuel trims maybe. Your higher volume injectors might be presenting more quantities than expected downstream by the O2’s? Did you go through the website contacting him or personal means?

[Iyzmi]

Originally Posted by Scrippy

He’s a busy Bee, he’ll get to ya I’m sure. I didn’t know you had those upgrades. I would wonder about fuel trims maybe. Your higher volume injectors might be presenting more quantities than expected downstream by the O2’s? Did you go through the website contacting him or personal means?

Fuel trim issues seem unlikely given how long I’ve run this setup with no issues and passed emissions. With everything else checking out fine, I was really thinking the smoking gun is the secondary air mass from lambda bank 1 reading 0 kg/h. This doesn’t appear to be coming from the HFM sensor.

I contacted him through the website.

[Scrippy]

Originally Posted by Iyzmi

Fuel trim issues seem unlikely given how long I’ve run this setup with no issues and passed emissions. With everything else checking out fine, I was really thinking the smoking gun is the secondary air mass from lambda bank 1 reading 0 kg/h. This doesn’t appear to be coming from the HFM sensor.

I contacted him through the website.

That might just be a blocked port in the head. I had persistent 27B0 and it was in fact a clogged port. I have a thread on it with pictures. When I scoped bank 1 it was obvious.