Identify this chip??

[PaulRV6]

Can you please help me identify this chip? It could be a stock chip. Thanks

 

[626gn]

I've seen factory 86 chips with those markings..

 

[JayC]

Looks like a stock chip to me

 

[dynoman]

Back in the late 80's early 90"s guys in the Electronics Lab at Rochester Products ( home of the QuadraJet carb ) were cloning HyperTech chips and selling them for half the price of HyperTech's . I had one in my GN and this could be one of them . The label looks like it is from a Brady label maker which we used at Delco Products & Rochester Products .
I came across the cloning equipment when my wife took over the Electronics Lab in 2014 .

 

[PaulRV6]

My stock 87 chip has markings on the back with JT8(G)AA29/P. And the questionable chip also has similar sequence. What do these digits mean?

 

[Anthony P]

CMW is the broadcast code for the eeprom used for the factory LC2 engine in '86 models.

Attached is a spreadsheet that lists the GM broadcast codes from about 1985 to 1996 with their respective applications, prom id's, ecms, etc.

 

[PaulRV6]

That is interesting. I am amazed at how much information some of you guys have about these cars. It boggles my mind. Thanks again

 

[Pronto]

Probably not a good idea to run it either way.

 

[626gn]

That is interesting. I am amazed at how much information some of you guys have about these cars. It boggles my mind. Thanks again

Anthony P is next level Encyclopedia Brown with Buick info

 

[PaulRV6]

Well this is just for my test hot air engine, I tried and 87 stock chip and I found this one but didn't know where it came from until now.

Could I ask another question on this thread about the stock 86/87 chip?
What are the parameters for going closed loop

 

[PaulRV6]

That's for sure. Thanks guys. Any insight on my closed loop parameters?

 

[Red Sector 7]

Could I ask another question on this thread about the stock 86/87 chip?
What are the parameters for going closed loop

When the car is cold and first started, it will go into open loop. ECM ignores the 02 sensor and uses a look-up table until coolant temp is up, then goes into closed loop and references the 02 sensor to maintain 14.7:1 A/F ratio.

 

[PaulRV6]

Ok so the only parameter is the coolant temperature that is set in the chip? Do you know what that temp would be? Thank you

 

[Red Sector 7]

Ok so the only parameter is the coolant temperature that is set in the chip? Do you know what that temp would be? Thank you

There is a little more to it than that. I don't recall what that temp would be, but the stock thermostat is 180* so perhaps around 160*F or so as a guess. Unless I'm mistaken there is also a time element involved, ie the ECM will only stay in open loop for say 3-5 minutes at cold start, then go into closed loop. So there is more than one parameter involved with respect to the stock chip due to cold start emissions more than anything else. The stock chip uses air intake temp in conjunction with the MAF reading to determine fueling once into closed loop.