got new maf still have code 34
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Joined: Feb 2003
Posts: 412
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From: Windsor, Missouri
Car: 1987 Z28 Camaro
Engine: 305 tpi
Transmission: 700r4
got new maf still have code 34
ok, i got a MAF sensor from a person on this forumns, cause mine was bad, and i hooked it up, and the car ran SOOO much better, it quit blowin smoke, quit flooding, stalling, runs like i just bought it, however the check engine like is still on, is it a maf relay? and where is the relay located, and how much would they cost??? thanks
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Joined: Jan 2000
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87Z,
First, you need to clear the existing error codes and try it again. Disconnect the battery for about five minutes to completely clear error codes and V-RAM in the ECM. That's usually just long enough to clean the battery terminals and cables. If you have a Theft-Loc on your radio, make sure you clear the lock feature before disconnecting the battery. Once the codes are cleared, you will have a fresh slate and can analyze whatever errors remain.
The DTC 34 can be created by several problems. The LAST item on the list is a failed MAF sensor. A 34 means that the ECM is getting a lower than expected intake air flow signal at a given engine RPM and throttle position. The ECM calculates and assumes an acceptable range of signals based on RPM and TPS, so it is important to set the TPS voltage to 0.54VDC at idle.
The low signal can also be caused by poor electrical connections at the MAF, MAF relays, or ECM. Make sure the MAF connector is clean and fully seated in the MAF housing connection. Check the connector at the MAF power relay for corrosion, loose wires, and other damage. The relay contacts themselves may be failing and creating resistance, resulting in a lower signal level. You can either replace the relay or measure the resistance of the contacts, or measure voltage drop across the relay in circuit. If all that checks O.K., you may have poor connections at the ECM. Removing and reseating the connectors can help clean them and create a better connection.
Finally, even if everything electrical is in good condition, the MAF can report a lower signal if there are leaks in the duct work between the MAF and throttle body. This can include the bellows, resonator boxes, clamped connections, etc. Any vacuum leak can also lower the amount of intake air being measured by the MAF since it is not flowing through the sensor. These leaks include the EGR, brake booster, hoses, gaskets, and CCV system (which is why you should NEVER use a breather-type oil filler cap on a MAF system).
There have also been cases where a MAF sensor is altered by removing the inlet screens, causing intake air to be diverted around the sampling tube in the sensor body. If you're using a completely stock MAF, this shouldn't be an issue.
First, you need to clear the existing error codes and try it again. Disconnect the battery for about five minutes to completely clear error codes and V-RAM in the ECM. That's usually just long enough to clean the battery terminals and cables. If you have a Theft-Loc on your radio, make sure you clear the lock feature before disconnecting the battery. Once the codes are cleared, you will have a fresh slate and can analyze whatever errors remain.
The DTC 34 can be created by several problems. The LAST item on the list is a failed MAF sensor. A 34 means that the ECM is getting a lower than expected intake air flow signal at a given engine RPM and throttle position. The ECM calculates and assumes an acceptable range of signals based on RPM and TPS, so it is important to set the TPS voltage to 0.54VDC at idle.
The low signal can also be caused by poor electrical connections at the MAF, MAF relays, or ECM. Make sure the MAF connector is clean and fully seated in the MAF housing connection. Check the connector at the MAF power relay for corrosion, loose wires, and other damage. The relay contacts themselves may be failing and creating resistance, resulting in a lower signal level. You can either replace the relay or measure the resistance of the contacts, or measure voltage drop across the relay in circuit. If all that checks O.K., you may have poor connections at the ECM. Removing and reseating the connectors can help clean them and create a better connection.
Finally, even if everything electrical is in good condition, the MAF can report a lower signal if there are leaks in the duct work between the MAF and throttle body. This can include the bellows, resonator boxes, clamped connections, etc. Any vacuum leak can also lower the amount of intake air being measured by the MAF since it is not flowing through the sensor. These leaks include the EGR, brake booster, hoses, gaskets, and CCV system (which is why you should NEVER use a breather-type oil filler cap on a MAF system).
There have also been cases where a MAF sensor is altered by removing the inlet screens, causing intake air to be diverted around the sampling tube in the sensor body. If you're using a completely stock MAF, this shouldn't be an issue.
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