2004 Misfiring when idle. MAS
#1
2004 Misfiring when idle. MAS
Hello, My 2004 Accord is almost stalling when stopped. Originally, there were no error codes, even though it was having slight intermittent misfires. I cleaned the mass air-flow sensor with the proper cleaner, but I think I did not let it dry enough before putting it back.
When I put it back, the misfires got worse, and all cylinders reported misfires, in addition to codes about Mass or Volume AirFlow Low Input, and Intake AirTemp Circuit High Input.
I changed the air filter and cleaned the housing, and cleaned the MAS again, and it got a little better, but still same problems.
I ordered a new non OEM MAS and installed it, but problem persists, and now it comes even closer to stalling, so I put the old MAS back.
Engine will do a pretty big misfire on a strong acceleration, so I've been avoiding that.
Similar thing happened about a year ago, and the problem was a loose spark plug. All plugs are tight.
Appreciate any guidance with this problem.
These are the current codes:
P0102 Mass or Volume AirFlow Low Input
P0113 Intake AirTemp Circuit High Input
P0300 Random Misfire
P0301 No. 1 Cylinder Misfire
P0302 No. 2 Cylinder Misfire
P0303 No. 3 Cylinder Misfire
P0304 No. 4 Cylinder Misfire
When I put it back, the misfires got worse, and all cylinders reported misfires, in addition to codes about Mass or Volume AirFlow Low Input, and Intake AirTemp Circuit High Input.
I changed the air filter and cleaned the housing, and cleaned the MAS again, and it got a little better, but still same problems.
I ordered a new non OEM MAS and installed it, but problem persists, and now it comes even closer to stalling, so I put the old MAS back.
Engine will do a pretty big misfire on a strong acceleration, so I've been avoiding that.
Similar thing happened about a year ago, and the problem was a loose spark plug. All plugs are tight.
Appreciate any guidance with this problem.
These are the current codes:
P0102 Mass or Volume AirFlow Low Input
P0113 Intake AirTemp Circuit High Input
P0300 Random Misfire
P0301 No. 1 Cylinder Misfire
P0302 No. 2 Cylinder Misfire
P0303 No. 3 Cylinder Misfire
P0304 No. 4 Cylinder Misfire
Last edited by Frank2004accord; 05-27-2018 at 01:56 PM. Reason: updated verified codes -bold text
#4
Attached are diagnostics.
You don't have to slavishly follow diagnostic, but rather determine if fault is 1) sensor, 2) wiring or connector, 3) If sensor, connectors, and wiring are absolutely good, then by default the ECM is fault.
good luck
You don't have to slavishly follow diagnostic, but rather determine if fault is 1) sensor, 2) wiring or connector, 3) If sensor, connectors, and wiring are absolutely good, then by default the ECM is fault.
good luck
#6
The SULEV had a MAF/IAT sensor. It is a combined sensor.
#9
voltage
With ignition in II, fuse #18 reads 12V on both sides.
Confirmed again that no voltage is present at pin 5 of unplugged MAF/IAT harness with ignition in II.
Is there supposed to be 12v there?
Confirmed again that no voltage is present at pin 5 of unplugged MAF/IAT harness with ignition in II.
Is there supposed to be 12v there?
Last edited by Frank2004accord; 06-03-2018 at 01:56 PM. Reason: addition
#10
Yes, there is suppose to be battery power at terminal pin number 5, Blk/Yel wire with the ignition switch in the ON or START positions.
The Blk/Yel wire runs from the back of the under-dash fuse/relay box through a couple of junction connectors and connector to the MAF/IAT sensor.
Junction Connectors are used to split/distribute power and/or ground from source(s) to various components. Terminals grouped together are connected by the same bus bar.
C556 is a junction connector located inside the cabin, under-dash area it initially goes through.
Then the Blk/Yel wire goes through terminal no. 5 in Connector C201. Take a visual look at the wiring at Connector C201, you can also test for power at terminal no. 5 here.
Then is run through a junction connector, C102 before it reaches the MAF/IAT sensor connector:
The Blk/Yel wire runs from the back of the under-dash fuse/relay box through a couple of junction connectors and connector to the MAF/IAT sensor.
Junction Connectors are used to split/distribute power and/or ground from source(s) to various components. Terminals grouped together are connected by the same bus bar.
C556 is a junction connector located inside the cabin, under-dash area it initially goes through.
Then the Blk/Yel wire goes through terminal no. 5 in Connector C201. Take a visual look at the wiring at Connector C201, you can also test for power at terminal no. 5 here.
Then is run through a junction connector, C102 before it reaches the MAF/IAT sensor connector: