986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Diagnostic help needed! Hot film MAF and low oxygen adaptation.

Danimal · 01-29-2024, 10:13 AM

Update. I smoked the intake through the AOS connection on the plenum. I only had a leak at one of the boots for plenum that I reattached after cleaning the throttle body and a tiny bit from the top of the resonance tube hinge once I cranked the PSI up a bit on the smoke machine. Fixed the boot and reattached the AOS.

Then I smoked through the oil filler tube, but had a hard time sealing it off with plastic bags, rubber bands, and tape. I didn't see smoke come out anywhere.

After making sure everything was connected, I disconnected the battery for 10 minutes and did the e-gas learning sequence. Then it started right back up no problem.

However, while the SAI was running there was an exhaust rattling type sound that went right away as soon as the SAI kicked off. At first I was pretty worried, but it ran/idled perfect as soon as the SAI kicked off...so I'm a little less worried.

The only other issue is that the oil smelled a bit like gas. I'm not sure if its a leaky injector or just from the car running rich based on the error code. but it you put your nose over the filler tube, you get some stink. You have to get pretty close to smell it.

I took it on two 20 minute test runs around the neighborhood and highway. No error codes yet but I know it's too soon to tell if I am in the clear. There is definitely something going on with the SAI/exhaust. There is no exhaust smoke on start up or during driving.

I'm out of diagnostic time for a bit while we work on our house, but here is my current plan.

1. Back the car on race ramps, start it cold, climb under to see if there is something obvious going on with the exhaust.
2. Remove the engine cover, start it cold, and see if there is something obvious going on with the SAI.
3. Test the fuel pressure to see if the fuel pressure regulator is going bad. This is what caused similar fuel trim codes in of the "arrowhead garage" videos on youtube. He's got some helpful videos.
4. Possibly remove and clean the fuel injectors....does not sound fun, but could be good to do anyway.

Sorry, no time for pics right now, but I took a bunch.

01-29-2024, 10:13 AM	#21
Danimal Registered User Join Date: May 2023 Location: Oakland, CA Posts: 195	Update. I smoked the intake through the AOS connection on the plenum. I only had a leak at one of the boots for plenum that I reattached after cleaning the throttle body and a tiny bit from the top of the resonance tube hinge once I cranked the PSI up a bit on the smoke machine. Fixed the boot and reattached the AOS. Then I smoked through the oil filler tube, but had a hard time sealing it off with plastic bags, rubber bands, and tape. I didn't see smoke come out anywhere. After making sure everything was connected, I disconnected the battery for 10 minutes and did the e-gas learning sequence. Then it started right back up no problem. However, while the SAI was running there was an exhaust rattling type sound that went right away as soon as the SAI kicked off. At first I was pretty worried, but it ran/idled perfect as soon as the SAI kicked off...so I'm a little less worried. The only other issue is that the oil smelled a bit like gas. I'm not sure if its a leaky injector or just from the car running rich based on the error code. but it you put your nose over the filler tube, you get some stink. You have to get pretty close to smell it. I took it on two 20 minute test runs around the neighborhood and highway. No error codes yet but I know it's too soon to tell if I am in the clear. There is definitely something going on with the SAI/exhaust. There is no exhaust smoke on start up or during driving. I'm out of diagnostic time for a bit while we work on our house, but here is my current plan. 1. Back the car on race ramps, start it cold, climb under to see if there is something obvious going on with the exhaust. 2. Remove the engine cover, start it cold, and see if there is something obvious going on with the SAI. 3. Test the fuel pressure to see if the fuel pressure regulator is going bad. This is what caused similar fuel trim codes in of the "arrowhead garage" videos on youtube. He's got some helpful videos. 4. Possibly remove and clean the fuel injectors....does not sound fun, but could be good to do anyway. Sorry, no time for pics right now, but I took a bunch. __________________ 2001 Boxster S \| Triple Black \| Stock 17s \| Bilstein PSS9s \| BAD Shifter \| 6x40w Cabrio Amp \| 986.2 muffler "Sixty percent of the time, it works every time!"