Air Mass Meter Test
Having problems. Car stalls as soon as AMM is plugged in.
Does anyone have the schematic of the unit. Are there any resistance readings available for the different plugs.
Mine reads:
- 1 2 3 4 5 6 1 - 0 2.8 18K 19K 527 2 - - 2.9 18.7K 19.1K 527 3 - - - 18.5K 19K 530 4 - - - - 38K 19K 5 - - - - - 19K 6 - - - - - -
The numbers on the top are the terminal numbers as are the ones on the left side of the table.
I would like to make sue that the unit is aout of kilter before getting a replacement.
Also can anyone tell me what the screw is for just beside the plug. It has a cap protecting it.
Thanks in advance
Does anyone have the schematic of the unit. Are there any resistance readings available for the different plugs.
Mine reads:
- 1 2 3 4 5 6 1 - 0 2.8 18K 19K 527 2 - - 2.9 18.7K 19.1K 527 3 - - - 18.5K 19K 530 4 - - - - 38K 19K 5 - - - - - 19K 6 - - - - - -
The numbers on the top are the terminal numbers as are the ones on the left side of the table.
I would like to make sue that the unit is aout of kilter before getting a replacement.
Also can anyone tell me what the screw is for just beside the plug. It has a cap protecting it.
Thanks in advance
Has the AMM been connected and disconnected with the ignition ON? If so, it may have gone south.
Bentley says you should measure 3.5-4.0 ohms between pins 2 and 3. But I've seen readings outside of that range and work fine. So I don't trust that spec.
Anyway you should never connect/disconnect the AMM with the ignition ON. The ECU gets confused and it's hard on the AMM.
No spare?
Bentley says you should measure 3.5-4.0 ohms between pins 2 and 3. But I've seen readings outside of that range and work fine. So I don't trust that spec.
Anyway you should never connect/disconnect the AMM with the ignition ON. The ECU gets confused and it's hard on the AMM.
No spare?
That screw adjustment with the anti-tamper plug on it is for idle mixture control. The resistance between pins 2 and 6 of the AMM should vary between 0-1000 ohms with the screw adjustment, according to Bentley.
Thanks. Was thinking that there is noone out there. In the Haynes book it says that the resistance between terminals 2 and 3 should be between 2.5 and 4 ohms. That is for the LH 2.4. Then it says that for a LH 2.2 the resistance between terminals 2 and 6 should be 0 to 1000 ohms. There is no mention of what it should be for the LH 2.4. Is it the same??
So far it would seem that the resistance between terminals 2 and 3 is OK (2.8 on mine)(Heated wire). Same with the resistance between terminals 2 and 6 (if the given figures apply for the LH 2.4 as my readings are 527 ohms)(Idle mixture potentometer).
There should be values available for all the terminal combinations.
Not sure what functions the other combinations give. If could get that could then maybe deduce what is causing the running problem.
If start without the AMF then the car starts rough when cold. As the engine warms up the idle becomes smoother. When cold in this state engine is very touchy to any additional gas given. Once it warms up this problems disappears and can give the car gas and drive relatively OK.
Realy would love to get this old beuty of mine back on the road in a smooth driving state.
Is there anyone out there in ether land who can help with the diagnostics.
Thanks
So far it would seem that the resistance between terminals 2 and 3 is OK (2.8 on mine)(Heated wire). Same with the resistance between terminals 2 and 6 (if the given figures apply for the LH 2.4 as my readings are 527 ohms)(Idle mixture potentometer).
There should be values available for all the terminal combinations.
Not sure what functions the other combinations give. If could get that could then maybe deduce what is causing the running problem.
If start without the AMF then the car starts rough when cold. As the engine warms up the idle becomes smoother. When cold in this state engine is very touchy to any additional gas given. Once it warms up this problems disappears and can give the car gas and drive relatively OK.
Realy would love to get this old beuty of mine back on the road in a smooth driving state.
Is there anyone out there in ether land who can help with the diagnostics.
Thanks
"Was thinking that there is noone out there."
When there are multiple threads on different forums for the same problem it gets hard to follow.
As Tech suggested, if the car runs without the AMM, but doesn't run with the AMM, it's time to replace the AMM.
When there are multiple threads on different forums for the same problem it gets hard to follow.
As Tech suggested, if the car runs without the AMM, but doesn't run with the AMM, it's time to replace the AMM.
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John DeBrock
Volvo 240, 740 & 940
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Jan 10, 2006 08:18 PM




