Cats and MAF (P0102): Back on and off-road...
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12-01-2008, 11:51 AM
Join Date: Apr 2006
Location: Littleton, CO
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Cats and MAF (P0102): Back on and off-road...
My 99 Disco II had been sitting parked next to my house with failed emissions for some time now. Finally got around to cutting out and replacing the cats myself a couple weekends ago. All fixed, it was running well and passed emissions. Took it on a nice break-in trip to Rifle and did a little off-roading for the sake of getting to our destination, not just off-roading for the sake of off-roading.
Some 600 miles round-trip and it was running great. Then I left it with my little brother for a weekend while he was watching our house and dogs. Worked fine for him while we were gone, then started running really rough the following Monday morning. Misfires, backfires, idiot light (though that had been on for a while). I ruled out the Little Brother Factor, as it had no more mud on it than after the Rifle trip, bought an OBD2 scanner (INNOVA ScanTool 3130) and then started talking codes with DiscoMike.
Initially thought it could be a blockage in the exhaust and went through a few steps to check that out. Even seemed as if that were the case, as RPMs increased a good 500 or so (it had been a bear to get it above 2k) with the forward O2 sensors out. Removed the rear section of exhaust behind the Y-joint, but no difference in RPMs this time...
Went through a series of resetting codes, driving, re-reading codes, wash, rinse repeatand focusing on the consistent ones: P0102 (Mass or volume air flow low input) and P1884 (too many possibilities to name, according to DiscoMike). These came back every time, as well as a few P030x for cylinder misfires.
Then read pages 18-2-21 and -22 in the Rave guide:
In the event of a MAF sensor signal failure any of the following symptoms may be observed:
l During driving engine rev/min may dip, before recovering.
l Difficult starting.
l Engine stalls after starting.
l Delayed throttle response.
l Emissions control inoperative.
l Idle speed control inoperative.
l Reduced engine performance.
l MAF sensor signal offset.
These matched my symptoms exactly. Removed the MAF and took some MAF cleaner to it. Power restored fully! Check engine light OFF. Runs beautifully now. Unknown to me and according to Mike, the Bosch MAFs on D2's don't take too well to cleaning and I'll probably end up replacing it within the month, though.
In any case, I wanted to write this up so it's searchable to anyone else who encounters this and to thank DiscoMike publicly for all the help. I really appreciate taking the time to chat on the phone and being so accessible, though you still didn't really answer the beer/scotch/wine question. Let me know and I'll send something your way.
Thanks.
-C.
Some 600 miles round-trip and it was running great. Then I left it with my little brother for a weekend while he was watching our house and dogs. Worked fine for him while we were gone, then started running really rough the following Monday morning. Misfires, backfires, idiot light (though that had been on for a while). I ruled out the Little Brother Factor, as it had no more mud on it than after the Rifle trip, bought an OBD2 scanner (INNOVA ScanTool 3130) and then started talking codes with DiscoMike.
Initially thought it could be a blockage in the exhaust and went through a few steps to check that out. Even seemed as if that were the case, as RPMs increased a good 500 or so (it had been a bear to get it above 2k) with the forward O2 sensors out. Removed the rear section of exhaust behind the Y-joint, but no difference in RPMs this time...
Went through a series of resetting codes, driving, re-reading codes, wash, rinse repeatand focusing on the consistent ones: P0102 (Mass or volume air flow low input) and P1884 (too many possibilities to name, according to DiscoMike). These came back every time, as well as a few P030x for cylinder misfires.
Then read pages 18-2-21 and -22 in the Rave guide:
In the event of a MAF sensor signal failure any of the following symptoms may be observed:
l During driving engine rev/min may dip, before recovering.
l Difficult starting.
l Engine stalls after starting.
l Delayed throttle response.
l Emissions control inoperative.
l Idle speed control inoperative.
l Reduced engine performance.
l MAF sensor signal offset.
These matched my symptoms exactly. Removed the MAF and took some MAF cleaner to it. Power restored fully! Check engine light OFF. Runs beautifully now. Unknown to me and according to Mike, the Bosch MAFs on D2's don't take too well to cleaning and I'll probably end up replacing it within the month, though.
In any case, I wanted to write this up so it's searchable to anyone else who encounters this and to thank DiscoMike publicly for all the help. I really appreciate taking the time to chat on the phone and being so accessible, though you still didn't really answer the beer/scotch/wine question. Let me know and I'll send something your way.
Thanks.
-C.
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