STIFFLER

Hey guys I have code 51 (Faulty or Improperly Installed Ecm). I have taken my spare 730 Ecm and Memcal and adapter and switched it in the car. I am still getting the same code. Is there something I am missing?

RBob

iTrader: (1)

The MEMCAL or adaptor is bad (the adaptor is for the MEMCAL?). Code 51 is basically a checksum error on the EPROM. The SES light is probably flashing rapidly. Try it w/o the adaptor, then with a new MEMCAL.

RBob.

STIFFLER

Tryed it without the adapter and got the same thing. As for a new memcal I am still trying to find one and it might be awhile.

STIFFLER

well I got a new memcal today and swapped it in.. and I am still getting the same code 51. I am at loss here I have tried everything. I have tried a new memcal, proms even the original GM prom,adapters,ZIF's and ECM's and this code still pops up.

I just did an engine swap so maybe there is a loose wire somewhere. Switched from TPI to a miniram so maybe it has something to do with the code?

Would the order of the fuel injector connectors have anything to do with it? I labelled them but by the time the swap was done some of the labels were worn off or I couldn't read them right.

Bad Injectors? I bought them used but they all ohmed in spec.

RBob

iTrader: (1)

Have the codes been cleared? IOW, this isn't an old code is it? If not the only other item I can think of is bad grounds on theECM harness. These would be the grounds that attach to the engine block, rear of cylinder heads.

RBob.

STIFFLER

Yes I cleared the codes and they just came back.. I will check the grounds on the back of the cylinder heads. But what about the injector connectors are they suppose to go on a specific cylinder?

JP86SS

iTrader: (1)

The injectors have two sets, one set on odd cylinders, the other on the evens but I don't think that would give you the error.
Maybe a power or ground lead is loose at the ecm connectors. May want to wiggle each to check that.
Is the memcal from a V8 application? A V6 would give cylinder select error.
Burn a chip putting "$AA" in the bin for the mask ID and see if the 51 goes away.

junkcltr

iTrader: (1)

It does not matter how you connect the injector wires. The ECM doesn't care about that. You could have the odd side wire connected to the even side of the engine and the ECM would never know. I once pulled a harness from a thirdgen that had a broken wire and someone was running all 8 injectors from only one wire. The car ran fine with no codes.

I would do what JP86SS said and disable the checksum. If that doesn't fix it, then I would closer inspect the blue socket connector in the ECM to make sure you didn't bend a pin over by accident.

Last, ANYTHING other than the right MEMCAL for the ECM will set the SES and have the symptoms you are seeing. That is, putting a 730 memcal in a 165 ECM will cause that. Putting a 730 V8 memcal in a 730 V6 will work fine in terms of setting codes (for a while) but the engine won't run properly because the hardware timers will be set incorrectly.

J

vernw

iTrader: (2)

Good point! Might want to pull the little cover on the ECM and see what broadcast code is on your memcal.

junkcltr

iTrader: (1)

If the reference ground for the A/D converter has a bad connection (i.e., bad ground) then a code 51 will be set. As Rbob said, check your ground wires. Check them with an ohmmeter and visually. Again, check them with both tools.

STIFFLER

The memcal is the stock one from my 305 5 speed. Is the mask ID the prom ID if not where do I find it using tunercat?

The broadcast code is AXYC.
I ohmed the ground wires from the back of the heads and they all had a connection to the front of the ecm connectors.

Refrence ground for the A/D converter I do not know where or what that is..

Thanks

vernw

iTrader: (2)

That's the latest/last 305 TPI with a T-5 prom made. Should be a good one, it's also the base I used to do the tuning on my 383.

JP86SS

iTrader: (1)

Should be address L8008 if its an $8D mask. (or just address 08)
Your current value there should be "8D", change it to "AA" and the code will not set an error due to the checksum being bad.
That will rule out the chip as the problem.

After checking into it, If you are getting the actual code from the ECM then your problem IS the checksum.
Nothing else can set that bit from what I'm seeing.

Junkcltr, Rbob..
Can you explain why the A/D ground would cause that as well.
I'm curious.

junkcltr

iTrader: (1)

I have to double check but I swear that the the 6E and 8D code does a check of the A/D test channel to see if it makes after it calculates the checksum. Then it decides on setting error 51. If the A/D ref is floating then the 'test' channel could report out of spec.
I could be wrong.....it has been a while since I looked at the "init" code. Maybe RBob can verify.

STIFFLER

I got the checksum utility off of tunercat and it says my checksum matches... So does that rule out the checksum error for code 51?

I am not familiar with tunerpro but I did download it and put the $AA in the mask ID and then L8008 in the offset.. burnt the chip and got the same results..

JP86SS

iTrader: (1)

I dunno what else to tell you except connect up TP or another logging program and see if all the sensors are reading and responding. Did you do any rewiring or fixing connectors while the swap was done? (Use a meter if you aren't getting data or able to log) Maybe a mixed up wire is putting 5V where it shouldn't or the grounds are not connecting good enough.
Or it is the Memcal itself is not connecting good or something with the adapter like we thought before.
It's bound to be something small so you'll have to just work back though everything and confirm what is correct, then see what is left to find the problem.

STIFFLER

Hey guys, I was doing a search on knock sensors and I remember that when you do a 305 to 350 swap you need a 350 knock sensor. So i left the 1987 knock sensor on the motor now my car is a 92 SD car could that MAF sensor be the cause of the problem somehow? Since my ESC is in the memcal correct and the 89 and earlier have a separate ESC by the brake booster. Can I just swap the 305 knock sensor on there? or do I need to buy a 350 SD sensor?

STIFFLER

Well I swapped my 305 knock sensor on and Iam still getting the code... I don't even have to start the vehicle to get the code.. just turn the keys foward and link up.. Oh well on to the next..

Grim Reaper

Have you tried A KNOWN GOOD 7730 ECM with the new memcal/eprom? Also exactly how did you clear your codes? Just checking the basics.

The only other possibility is the wiring harness/connector has a short in it. And I'm not entirely sure about that either. Usually code 51 comes with either a bad memcal or ECM.

STIFFLER

I have tried a known good ECM but not a known good memcal AXYC memcal.. I got a AXXB from a friend and tried it and it gave me the same code.. I clear the codes with my diacom.