LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Had my code read.

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Old 01-25-2006, 07:58 PM
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Had my code read.

It was PO100. The guys at autozone read it. Their book gave a list of things to check. First was a vacuum leak. I don't think I have any of those. Next was intake looe or cracked. I don't think that's the case either. Next was the MAF. Mine appears to have been replaced. Then came the VAF. What the heck is that? Any ideas on how to track this down? Thanks.
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Old 01-25-2006, 08:32 PM
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Re: Had my code read.

"P0100 Mass or Volume Air Flow Circuit Malfunction"

Check your MAF wiring / connector.
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Old 01-25-2006, 10:48 PM
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Re: Had my code read.

Also check your engine sensor fuse under the hood.
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Old 01-26-2006, 05:55 AM
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Re: Had my code read.

As long as that code is active, you are running in speed density mode. The most likely cause is a torn/folded or otherwise goofed up intake elbow. Take it completely out of the vehicle and look it over real well. Specially up near the TB. I see them folded under there all the time. Other unlikely causes are loose oil fill cap, dip stick not seated or a bad PCV valve.

Also, another common cause of the problem is using a cotton filter that gets over oiled.

If you want to test the performance of the MAF, you need a multimeter that will read frequency. Check from the yellow wire to ground and you want to measure over 7KHz when you snap the throttle with the engine running. If the response is low, try cleaning with an electrical contact cleaner when the MAF is completely cool. Brake cleaner is not recommended since it will leave a residue behind that over time will darken the sensor wires.

Last edited by Guest47904; 01-26-2006 at 06:00 AM.
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Old 01-26-2006, 06:30 PM
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Re: Had my code read.

I took the cover off of the fuse block on the passenger side near the firewall. I looked at the lid to see which one it was, but some of it was faded out. Which one is it? If it is bad, would every sensor throw a code? I only got the maf sensor code.
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Old 01-26-2006, 06:43 PM
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Re: Had my code read.

Originally Posted by speedygonzales
As long as that code is active, you are running in speed density mode. The most likely cause is a torn/folded or otherwise goofed up intake elbow. Take it completely out of the vehicle and look it over real well. Specially up near the TB. I see them folded under there all the time. Other unlikely causes are loose oil fill cap, dip stick not seated or a bad PCV valve.

Also, another common cause of the problem is using a cotton filter that gets over oiled.

If you want to test the performance of the MAF, you need a multimeter that will read frequency. Check from the yellow wire to ground and you want to measure over 7KHz when you snap the throttle with the engine running. If the response is low, try cleaning with an electrical contact cleaner when the MAF is completely cool. Brake cleaner is not recommended since it will leave a residue behind that over time will darken the sensor wires.
Will speed density mode hurt my mileage? Jut a curiousity thing. How do I clear the code? I see that the maf was replaced at some point. Maybe the guy just didn't know how to clear the code. Wishful thinking, I know. Even if that's not the case, I can start eliminating things by checking them and resetting the computer. My dipstick is seated, but maybe it wasn't at some point before I got the car. Same with the oil cap. I've replaced the pcv valve. The old one still rattled freely, but what the heck, $2, do it on principle. It's still got the paper filter. If the inlet elbow is damaged, though, that is subject to change. How do those things set off a maf code? I'd like to learn as much about this engine as I can. I understand a decent amount about carbed engines, but haven't learned about computerized ones. Yet.
I'll go check the inlet elbow shortly. Could a vacuum leak somewhere else cause the same problem?
Unfortunately, I don't have a multimeter that measures frequency. On second thought, there is a possibility that the one at work does. I'll have to check on that.

Last edited by gasnmyveins; 01-26-2006 at 06:50 PM.
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Old 01-26-2006, 08:45 PM
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Re: Had my code read.

Originally Posted by gasnmyveins
I took the cover off of the fuse block on the passenger side near the firewall. I looked at the lid to see which one it was, but some of it was faded out. Which one is it? If it is bad, would every sensor throw a code? I only got the maf sensor code.

Nope, if comes up as MAF circuit malfunction or something similar to that. It's a yellow 15a fuse if that can narrow it down, just pull and check them.
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Old 01-26-2006, 10:20 PM
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Re: Had my code read.

There are only a couple of yellow ones. I'll try to check them tomorrow. Thanks.
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Old 01-26-2006, 10:20 PM
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Re: Had my code read.

There are only a couple of yellow ones. I'll try to check them tomorrow. Thanks.
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Old 01-28-2006, 12:02 AM
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Re: Had my code read.

P0100 only sets for a static MAF reading. One common cause is loss of the 12V power supply from the pink wire on the harness connector. That seems to happen a lot on the 97 models, but you don't have a signature or any info at all about your car, so we're just guessing.
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Old 02-02-2006, 01:07 PM
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Re: Had my code read.

Sorry, I guess that would help. It's a 96 roadmaster. No mods yet. The maf appears to have been replaced at some point in the not too distant past.
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Old 06-03-2006, 09:42 AM
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Re: Had my code read.

did u fix the problem?
i am having the same issues here. po100, and checked voltage to all the wires and they came up within reason. so i tried to switch out the MAF and it did nothing ( yes i did reset the codes b4 and after i installed the new one). i dont know where to go from here, but now the car is dying in traffic on me, gettin annoying.
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