Zound
///Member
Ever wanted to know what happens when your DISA/Resonance flap pin falls out and is ingested by your engine?
I'll explain exactly what happens.
If you have read my 330i thread you will know that I attempted to fix my failed DISA. (I'm calling it a DISA for simplicity, although it is actually a resonance flap)
The hex shaft had been completely worn out and thus the flap was never in a controlled position. I decided to epoxy the flap to the worn out shaft.
After about a month of driving I decided to see whether my repair had been successful. I quickly pulled the airbox and removed the DISA. To my surprise, everything looked fine. The flap was still held firmly in place, and the component operated fine. Additionally, the pin was also flush with the mounting surface.
I was chuffed with the result and continued to put the car back together.
About a week later, driving back from a 21st at about 2am, doing about 40km/h in the Irene area, my car suddenly stutters and throws an engine warning light. I immediately switch off the engine and coast for about 400m to a safe zone for inspection. Opened the bonnet to look for any obvious problems, checked underneath the car for oil, fuel or any sign of component failure.
At that point I was low on fuel, had about 50km left in the tank, and having had previous problems with fuel starvation when fuel was low I immediately thought it was fuel filter or fuel pump letting go.
I started the engine again to see if the problem would re-appear and immediately the hesitation had become a full blown misfire. Switched engine off and pulled out my bluetooth OBD2 dongle and ran the TORQUE application on my phone.
Scanned for errors/fault codes and came up with misfire on cylinder 5 and a MAF/Mass Air volume issue. Called Dad for a tow.
Next morning pulled DISA immediately, fearing the worst. Guess what, Pin pissing. I then cursed, stomped my feet, and banged my head for about 10 minutes knowing what had just happened to my beloved car.
Tears running down my face I got stuck into it. Pulled spark plug from cylinder 5 and the thing was completely disfigured. Then pulled Air intake manifold and the tappet cover and valve cover gasket.
Then used a long necked flexible shaft with magnet at the end to fish out the contents of cylinder 5. Two mashed and disfigured pieces were retrieved.
Performed a leak-down test with surprisingly no noticeable air leakage from the intake or exhaust valves, done at 3 bar.
Then did a compression test and the damage was revealed. All cylinders at 10.5 but the battle scarred cylinder 5 was sitting at 8.5.
Have put the car back together, with a new spark plug and a temporary DISA fix with a self tapping screw. Will assess drivability for now so to determine how to or whether to proceed with further repairs.
Have run the car once and monitored the smooth running values for the damaged cylinder. The ECU seems to be adjusting sufficiently to allow the car to operate with no substantial hiccups/hesitations/backfires or associated symptoms. Power delivery seems acceptable for now.
Will continue to monitor via the OBD2 diagnostics port as well as monitoring oil and fuel consumption.
Pictures to follow.
I'll explain exactly what happens.
If you have read my 330i thread you will know that I attempted to fix my failed DISA. (I'm calling it a DISA for simplicity, although it is actually a resonance flap)
The hex shaft had been completely worn out and thus the flap was never in a controlled position. I decided to epoxy the flap to the worn out shaft.
After about a month of driving I decided to see whether my repair had been successful. I quickly pulled the airbox and removed the DISA. To my surprise, everything looked fine. The flap was still held firmly in place, and the component operated fine. Additionally, the pin was also flush with the mounting surface.
I was chuffed with the result and continued to put the car back together.
About a week later, driving back from a 21st at about 2am, doing about 40km/h in the Irene area, my car suddenly stutters and throws an engine warning light. I immediately switch off the engine and coast for about 400m to a safe zone for inspection. Opened the bonnet to look for any obvious problems, checked underneath the car for oil, fuel or any sign of component failure.
At that point I was low on fuel, had about 50km left in the tank, and having had previous problems with fuel starvation when fuel was low I immediately thought it was fuel filter or fuel pump letting go.
I started the engine again to see if the problem would re-appear and immediately the hesitation had become a full blown misfire. Switched engine off and pulled out my bluetooth OBD2 dongle and ran the TORQUE application on my phone.
Scanned for errors/fault codes and came up with misfire on cylinder 5 and a MAF/Mass Air volume issue. Called Dad for a tow.
Next morning pulled DISA immediately, fearing the worst. Guess what, Pin pissing. I then cursed, stomped my feet, and banged my head for about 10 minutes knowing what had just happened to my beloved car.
Tears running down my face I got stuck into it. Pulled spark plug from cylinder 5 and the thing was completely disfigured. Then pulled Air intake manifold and the tappet cover and valve cover gasket.
Then used a long necked flexible shaft with magnet at the end to fish out the contents of cylinder 5. Two mashed and disfigured pieces were retrieved.
Performed a leak-down test with surprisingly no noticeable air leakage from the intake or exhaust valves, done at 3 bar.
Then did a compression test and the damage was revealed. All cylinders at 10.5 but the battle scarred cylinder 5 was sitting at 8.5.
Have put the car back together, with a new spark plug and a temporary DISA fix with a self tapping screw. Will assess drivability for now so to determine how to or whether to proceed with further repairs.
Have run the car once and monitored the smooth running values for the damaged cylinder. The ECU seems to be adjusting sufficiently to allow the car to operate with no substantial hiccups/hesitations/backfires or associated symptoms. Power delivery seems acceptable for now.
Will continue to monitor via the OBD2 diagnostics port as well as monitoring oil and fuel consumption.
Pictures to follow.
