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It sounds as though the shop you took it to obviously misdiagnosed the vehicle as to start with MAF measure air flow entering the intake.
Sensors that deal with altitude are MAP/BAP sensors.
How are you retrieving the code? Is it OBD1 or OBD2?
Quoted From Beefy:
No, mass air sensors gage how much air is entering the intake tube. They are usually backed up by a MAP or Baro sensor as a failsafe, and to judge altitude. Are you sure it’s not two codes rammed together? Like a 1 and a 33? Or 13 and 3? I’ve no idea what those codes would be. Guess I should look and get back to ya.
http://www.troublecodes.net/Ford/
I don’t see a ‘1’ on here. But a 33 is an EGR code. Did you ever eliminate the EGR system?
True they measure incoming air but not true that they are backed up by a MAP sensor as this sensor is not necessary to use on an engine that uses a MAF sensor. The system will either use a MAF sensor which measures the air going into the engine to calculate the appropriate fuel OR it will use a MAP sensor who’s readings are used to calculate the fuel mixture based on engine load (the speed density formula), you won’t see both on the same engine. Both can have a BARO sensor however as it is used to calculate barometric pressure, normally these are part of the ECU these days however so you really can’t ‘test’ them directly.
That said I think you need to find the code and follow the diagnosis for that code in order to have a successful repair.
Thanks for the replies, guys. As soon as I get some more funds to take it back to the shop, I will be driving it easy, and left to wonder IF Autozone gave me the right MAF sensor or one that was defective, AND why, with a 332 code–EGR system closed–the shop would find the MAF as defective and reading at 5000 ft., as none of my codes had anything to do with the MAF. All I am for sure on is during the diagnosis, they did find that I didn’t have any vacuum leaks or that the egr valve and sensor were not defective.
Quoted From EricTheCarGuy:
True they measure incoming air but not true that they are backed up by a MAP sensor as this sensor is not necessary to use on an engine that uses a MAF sensor. The system will either use a MAF sensor which measures the air going into the engine to calculate the appropriate fuel OR it will use a MAP sensor who’s readings are used to calculate the fuel mixture based on engine load (the speed density formula), you won’t see both on the same engine. Both can have a BARO sensor however as it is used to calculate barometric pressure, normally these are part of the ECU these days however so you really can’t ‘test’ them directly.
That said I think you need to find the code and follow the diagnosis for that code in order to have a successful repair.
My bad. I was thinking of a baro, not a MAP. I love this forum, because it keeps me fresh while I slog through the non-automotive classes until I finish my degree.
A lot of pre OBD 1 Fords came with MAF and BARO’s after the switch form Speed Density back in 86 i believe it was?
They placed there BARO sensor on the firewall.
Quoted From dreamer2355:
A lot of pre OBD 1 Fords came with MAF and BARO’s after the switch form Speed Density back in 86 i believe it was?
They placed there BARO sensor on the firewall.
Yea you can have a Baro sensor on both set ups but what you won’t see is a MAF and a MAP on the same engine.
Quoted From EricTheCarGuy:
Yea you can have a Baro sensor on both set ups but what you won’t see is a MAF and a MAP on the same engine.
You are, again, correct, Eric. My truck does not have map, just maf. And another thing the tech at the shop said was that there were no EGR codes!!! AAUUGGHH. He showed me where the old maf sensor was reading at 5,000ft. of atmospheres, and I asked him IF the maf I put on by myself was good–which he said they would test for FREE when I have time to bring it back–then he would look at the fan clutch as being a/the culprit, as my ac quit working a while back and they said my fan clutch was going. BUT an ASE friend of mine said that my truck would be overheating BEFORE it would start pinging if the fc was going. Gonna start pulling my hair out SOON!!!
Quoted From EricTheCarGuy:
Yea you can have a Baro sensor on both set ups but what you won’t see is a MAF and a MAP on the same engine.
Again, not trying to start an argument, but I looked up a 2001 Chevy Blazer 4.3 on that free Chilton’s manual, and it shows both a MAP and MAF. The only reason I thought to look as it is because Duane from realfixesrealfast is doing a video series on that era blazer, and he mentioned that the PCM is using the MAP to verify what it should see from the MAF.
Quoted From Beefy:
Again, not trying to start an argument, but I looked up a 2001 Chevy Blazer 4.3 on that free Chilton’s manual, and it shows both a MAP and MAF. The only reason I thought to look as it is because Duane from realfixesrealfast is doing a video series on that era blazer, and he mentioned that the PCM is using the MAP to verify what it should see from the MAF.
Also to add to this, a lot of Chevy vehicles do. Impala’s have MAP’s and MAF’s.
But again, this is why i love these forums, its very educational and there’s always that old saying, technicians never agree!
And back on topic, you don’t have any issues with your exhaust manifolds do you? The slightest hole/crack can create a ‘ping’ noise.
Weird, I was under the impression that if you had a MAF sensor a MAP was not necessary and the fact the a manufacturer would add something that’s not ‘needed’ strikes me as odd but I’m in no position to argue as I don’t know modern GM’s all that well, I look forward to learning though.
Back to the topic however and I believe we can rule out EGR which leaves engine and ignition timing. You might want to check the mechanical timing if you’re able and also the ignition timing as if one or both of those is off it can also cause an issue with ‘pinging’.
Come to think of it I THINK that still has a distributor on it and if that’s the case we can check the timing chain slack. You do this by bringing the engine up to TDC with the timing mark on the crank, it really doesn’t matter if it’s compression or exhaust. Then remove the distributor cap and observe the position of the rotor, then spin the engine counterclockwise till you see the rotor start to move then stop, check the timing mark on the crank, if you feel it went more than 7
Thanks for the response, Dreamer and Johnz. No injector leak down test or cleaning; he based his worn injectors on the shuddering starts when cold, and the computers rich condition because the injectors are not spraying like they should, and the mileage. Any thoughts?
Thanks for the response, Dreamer and Johnz. No injector leak down test or cleaning; he based his worn injectors on the shuddering starts when cold, and the computers rich condition because the injectors are not spraying like they should, and the mileage. Any thoughts?
[quote]Quoted From EricTheCarGuy:
Come to think of it I THINK that still has a distributor on it and if that’s the case we can check the timing chain slack. You do this by bringing the engine up to TDC with the timing mark on the crank, it really doesn’t matter if it’s compression or exhaust. Then remove the distributor cap and observe the position of the rotor, then spin the engine counterclockwise till you see the rotor start to move then stop, check the timing mark on the crank, if you feel it went more than 7
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