Code 41 help

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Sep 20, 2015 | 01:23 PM

FrankCastle

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Code 41 help

Long time reader, first time poster. I have an 86 iron head that I recently put a new cam in. I also bought a new prom chip to go with the new cam. When I put the new prom chip in I get a code 41. When I put the stock old chip back in I get no code 41. I was thinking it was the prom chip and had pcm of nc burn me a new one. Still code 41 with the new new prom chip. I know it's not the cam shaft sensor because the cam didn't have one. I don't belive the tpi came with a cam sensor. I have also replace the ignition module. I'm starting to think maybe a bad ecm computer? Has anybody encounter a code 41 memcal error? Any help would be greatly appreciated.

Sep 20, 2015 | 11:52 PM

Cliff Harris

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Did you swap just the EPROM chip or the whole MEMCAL?

There are internal grounds in the MEMCAL that must be in place or you get the error code.

I'd suspect that the new EPROM has a problem. It's apparently seeing something that isn't there.

Sep 21, 2015 | 10:03 AM

FrankCastle

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Code 41 help

I only changed out the eprom chip. My old chip does not give me a code 41. Old chip will give a 32 code after driving a little but I'm sure it's because I have the egr removed and blocked off. I had the chip burner remove the egr system from the new chip so new chip does not throw a code 32 but will throw a code 41 3 seconds after start up. I had pcm of nc burn me a second aftermarket chip and I still get the same 41 code. My only other ideas are getting another chip from a different company or get a new pcm. Any thoughts?

Sep 21, 2015 | 10:39 AM

WVZR-1

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Quote:

Originally Posted by FrankCastle

I'd suspect that the PROMs you've been buying have been done on "less than equivalent" PROM cores/blanks. Your original doesn't so I'd think there's likely no other explanation. I'd be having discussions with BOTH of the vendors who sold you their product.

Are you using any sort of an adapter and a chip or are these meant to be "DIRECT REPLACEMENT" PROM?

Sep 21, 2015 | 11:56 AM

FrankCastle

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Code 41 help

There is no adaptor for the new prom. It plugs right in whare the old one did. I think I need to get another prom burned from a different company and see if throws the same 41 code.

Sep 21, 2015 | 12:07 PM

WVZR-1

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Quote:

Originally Posted by FrankCastle

There is no adaptor for the new prom. It plugs right in whare the old one did. I think I need to get another prom burned from a different company and see if throws the same 41 code.

Unless it's done on a correct core you'll likely have the same issues.

Contact user ID "MrWillys" and ask for advice. Maybe some snapshots and information off of yours that DON'T work would be helpful.

Sep 21, 2015 | 12:44 PM

FrankCastle

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Code 41

What exactly do you mean "on a correct core"? Does that mean that even if the new prom chip "fits right in" the new prom chip and old pcm are incompatible? Or do you think it's simply the type of chip they are using for the burn? New chip and old chip do look different.

Sep 21, 2015 | 11:37 PM

Cliff Harris

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From: Anaheim CA

Quote:

Originally Posted by FrankCastle

EPROMs are erased as a whole. When you erase the chip there is NOTHING left. You have to erase and program the whole thing to change one byte.

The usual process is to read the old chip and store that info as a file on the computer. Then you erase the EPROM. Then make your changes to the file. Then you program the file back into the EPROM.