I have a 87 Z28 with a 2.73 rear end. I recently put an l98 in her and could only find a 350 chip ( ABWN) that is set up for 3.27 rears. I hope my problem is obvious. My shift points are gone to poop and Im not sure what else this chip is doing that I dont want it to. GM never made a 350 chip with 2.73 rears incorperated into it.
I do plan on getting programming equipment soon but money is a little too tight to buy all that stuff.
Does anyone know of someone or a company or anyway of getting a stock programmed chip with my rears in it.

Really, Im not begging for a prom just the info where I can purchase one. Im desperate.

Dennis

 

The ECM doesn't control the shift points. Either the TV cable is mis-adjusted or the govenor isn't correct for the added torque of the L98.

Suggest the tranny board for more info.

RBob.

 

Throttle valve cable is maladjusted.

Governor shouldn't be too far off, given going from a 5.0 to 5.7, assuming you didn't go from way mild to way wild.

 

The ECM gets only the input of speed.
That’s the point where your 2.73 rear end should be correct.
VSS should give the correct speed to the ECM.
If you Speedo give an incorrect value you can help that, selecting the correct Speedo drive and driven gear at the transmission.
Do a search on the net "Speedo gears" and you will find information about.
You should take in account the diameter of the rear tires to.
I have posted a picture showing my driven gear Purple one. See last picture of this link.
https://www.thirdgen.org/techbb2/sho...hreadid=234883
Regards,
Cobra289

 

The torque of the engine has nothing to do with the govener. Only the output shaft speed influences the govener so your probably installed the tv cable improperly.

 

This is only a question so please don't bite my head off, I prefer to keep it where it is presently located. The Torque Converter Clutch (TCC) solenoid is the only part of the transmission controlled by the ECM, correct? External components that affect or influence the TCC's operation are the Brake Release switch, ECM, TPS, Vacuum Sensor, VSS, and CTS. Now if someone changes their gear (example 2.77 to 3.27), they would also have to change their speedo gear and get a new chip burned to reflect the changes for proper operation. Each stock chip is burned to reflect the parameters of the engine and gear in that particular car. One of the steps in the TCC troubleshooting chart is "INSURE PROPER MEM-CAL/EPROM IS INSTALLED" . I don't have any experience in burning chips, so I might be wrong here. But wouldn't the parameters in the chips for the systems mentioned be based on what is supposed to be there, rather than what is there. Just curious!!!!

 

Hi Trickster,
Like I say the only thing that you need to do is change the Speedo gear when you change the rear ratio. (2.77 to 3.27)
You don't need to burn a new EPROM.
The EPROM doesn’t have any parameters with the rear ratio.
So every chip is burned to reflect only the engine and the corresponding emissions.

A MEM-CAL is the combination of EPROM plus the Limp-Home chips.

The important thing is that you use an EPROM for Automatic Transmission to get a correct TCC control.
Manual EPROMS don’t have these settings activated, but if you burn an EPROM you can activate these items.
Be aware that the rear tires diameter got his influence in the Speed (VSS) but you can adjust it in the same way as the rear ratio changes. Just put the correct Speedo driven gear.
I hope that this will help you.
Regards,
Cobra289