I have an 87 z28 with a 2.73 rear end. I had to change the chip when I did an engine swap and the only chip I could find was for a 3.27 rear. Is this a bad thing, will I notice a real difference If I reprgram a new chip to 2.73 rears? Its just that Id have to learn how to program and stuff and it seems like overkill to me.

What should I do?
Dennis

 

It would behoove you to get the proper chip for your 2.73 rear and engine. Otherwise you are going to have some interesting headaches troubleshooting various problems. An example would be shift points.

 

Do you remember sending me a list off proper shiftpoints? HAHAHA.
This is why shifting is gone to @#%$ then eh?
How can I get a chip that has my rear end programmed? the 350 never came out with a 273 rear end if I am right.

Dennis

 

You are correct, they were only in the 5.0L. The 4 letter code on the eprom was ABUN for Federal and ABUT for California. However, I seem to remember you saying you did an engine swap. Did you go from a 5.0L to a 5.7L?

 

Yeah I know. I still have the old ABUN chip but I have a 350 in it now. Is there someone you know that can make me a chip with the 273 end programmed in it?
I am plannig on getting my own programming equipment but money is tight now.

Dennis

 

UH-HUH,

Just checking to see if I knew were'nt you. You might put in a check with grumpy or one of them on the DIY PROM forum to see if they could help you.

 

:lala: :lala: What? Me? does this face look like it would do something like that?

Dennis

 

Would you like an honest answer or should I lie a H*LLUVA LOT

 

Honestly though I never thought to see if you could do it. I really just wanted to know if you knew of someone or a company. Either way , youre still tops in my books :rockon:

dennis

 

Hold on a sec... Does the MAF code even store information about rear axle ratios?? (I'm a SD guy, and the speed density code doesn't have anything about rear axle ratios in it from what I can see).

Also, there's no way for the ECM to affect shift points, seeing as how the 700R4 is controlled exclusively by a throttle valve system (only the lockup converter is ECM controlled)...

 

Oh cool. Is there anythig that I dont want the engine to do beacuse of this chip then?

Dennis

 

I'm taking a peek at some $6E code right now...

 

Thanks a bunch


Dennis

 

Well, I couldn't find anything in the code (ABWT) regarding rear axle ratios (this was using the 6Ev011.ecu that comes with TunerPro).. I've never really heard of rear axle ratios coming into play with the PROM either, seeing as how the ecm doesn't really manage anything that would concern different gear ratios (it gets its speedometer signal from the sender in the trans, everything past that it could care less about).

As far as your shifting problems go, I'd check the TV cable adjustment (and further, verify proper operation of the TV system).

 

 

I guess that save me alittle cash.......maybe......ARGH! I have fiddling with that tv cable all week and I cant get it right!!! It s good at warm temps but cold she shifts harder than Ron Jeremy in his prime!
Could a faulty fuel pump have something to do with the hard shifts? Its worth a shot to ask I guess. I think mine is on its last legs

Dennis

 

This isnt a 4l60/80, ecm has nothing to do with the shift points for a 700R4 the TV cable does. Bad shifts will be caused by low trans fluid, misadjusted TV (detent) cable or the trans is cooked.

 

I apologize for mentioning shift points in an earlier post. I used that example because of a previous thread he had concerning the TV cable and problems shifting. As thirdgen88 mentioned, the ECM controls the Torque Converter Clutch (TCC) solenoid. One of the steps in diagnosing that system is to insure that the proper MEM-CAL or EPROM is installed in the ECM.