C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

85 chip tuning

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Old Aug 22, 2013 | 08:16 PM
  #1  
Jakez89's Avatar
Jakez89
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Default 85 chip tuning

Hello I have an 85 vette with quite a few mods on it (cam,half dome pistons, race chip and racing exhost).

Im sure this question has been asked to death and I apologize if it has already been answered but I did search and found not a lot of info. At any rate from the mods that are currently on it it has a horrible lope at idle (sometimes will die).

I have some spare time a soldering iron and a spare laptop. Is there any way I can hook up to my ecu and tune it while driving or is this completely out of the question. Im extremely new to car computer tuning. I am a pc tech at a local shop so I can handle the learning curve. Just a nudge in the right direction.

Thanks in advance for all the help
Jake
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Old Aug 23, 2013 | 02:20 AM
  #2  
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Cliff Harris
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Your year has a couple of issues. One is that the data rate is limited to 160 baud. That is a big problem when trying to tune because you're only seeing snaphots of what is happening.

If you're serious about tuning I advise swapping in a 1227165 ECM, which was used from '86 through '89. It has a 8192 baud data stream. The swap is relatively simple and mostly involves swapping some of the pins in the ECM connectors. There are several sites online that spell out what is required.
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Old Aug 23, 2013 | 04:12 AM
  #3  
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vetteoz
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Originally Posted by Jakez89
Is there any way I can hook up to my ecu and tune it while driving or is this completely out of the question.
As noted there is no support for the slow , one year only '870 ECM in your car.

Once you have upgraded to the later '165 ECM
http://www.eecis.udel.edu/~davis/z28/ecm_swap/

then you can buy this device
http://www.moates.net/ostrich-20-the....html?cPath=95

" a emulator" that takes the place of the memory chip (memcal ) in your ECM and allows real time ,as you drive adjustments and tuning from a laptop
using cheap ($30 ) software

You also need this adapter
http://www.moates.net/g1-memory-adap....html?cPath=31

which replaces the stock memcal in the ECM and allows the ribbon cable supplied with the Ostrich unit above to connect the ECM.

FWIW,
The '165 MAF ECM (# 1227165) was used on many GM vehicles

http://home.earthlink.net/~cliff_har...age/usage.html

Only the tune on the installed memcal determines what it is setup for ; do not pay extra for a "Vette" '165 ECM
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Old Aug 23, 2013 | 10:04 AM
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Jakez89
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Hey Thanks a lot Cliff Harris and Vetteos I've at got a plan of action that I can move forward on and maybe finally get my idle a little smoother.
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