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

870 to 165 Conversion Instructions

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Old Feb 6, 2003 | 08:28 PM
  #1  
Bluevette85's Avatar
Bluevette85
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From: Latham NY
Default 870 to 165 Conversion Instructions

This seems to be a popular topic recently. I have sent several members my instructions for this so I figured I would post it here.

DISCLAIMER: This worked for me on the stock TPI and on my Superram conversion. You should double check all wiring yourself because it is easy to misconnect something and fry the ECM. Do this at your own risk.

These two sites have information you can use. The davis site has some
errors and I have noted the corrections below.

www.chevythunder.com/fuel%20injectioon%20ecm%20pinouts.htm

www.eecis.udel.edu/~davis/z28/ecm_swap/

The pin changes below are one way only. i.e. A11 gets moved to C12 but C12
does not go to A11.

There are a few connection changes from what davis posted on his site.

870_________165
-------------------------
A11----------------C12
D2-----------------C1
D8-----------------C15
B4------------------D4
+D12---------------D2
C9------------------D11
B11-----------------B12
+D13---------------A11
+D14---------------D16
+D15---------------D15

*Combine the old C15 into the old D14 (which is now the new D16)
*Combine the old D16 into the old D15 (which is the new D15, it doesn't
change)

+ indicates differences in what davis says to do.

The original C12 is a redundent wire and is not connected to anything in the
165.

You can use your 85 MAF without a problem. From what I have read, the 85
MAF can be used in 86-89 but 86-89 cannot be used in 85.

Buy the MAF relay connectors at Napa #EC85, $4.49 each. The two relays are slightly different. The power relay uses all 5 pins but the burn-off uses
only 4 pins. You can use the power relay for both but I used one of each
type. I use the relays for an 86.

There is a six connector plug coming off the 870 ecm wires which goes to the
burnoff module behind the breadbox. You must disconnect this or your
conversion won't work. This plug is lettered and this is what davis calls
the "MAS connector". The relay connectors you buy from NAPA are labeled
ABCDE and you connect everything as follows: (some changes from what davis posted) I put the relay connectors under the dash with the ecm wires so I didn't have to run a bunch of wires into the engine bay.

MAF Burnoff Connector pin A----------MAS pin D
MAF Burnoff Connector pin B----------must run a new line to D12 on ecm connector. You must buy ecm connector pins.
MAF Burnoff Connector pin C----------MAS pin A
MAF Burnoff Connector pin D----------not connected to anything
MAF Burnoff Connector pin E-----------MAS pin A

MAF Power Connector pin A---------MAS pin F
MAF Power Connector pin B---------MAS pin E
MAF Power Connector pin C---------splice into ecm pin B2
MAF Power Connector pin D---------MAS pin D
MAF Power Connector pin E--------- MAS pin A

I tried to use the 870 burnoff module instead of the relays but it wouldn't
work so adding the relays was the only solution.

I used the ARAP bin and made some adjustment so it would work on my 85
(changed the injector constant, fan switch, MAF filter switch). I also
disconnected my cold start injector and with a slight adjustment in the
start-up fueling table, it starts right away (this is ARAP85 below). I'm using the Craig Moates adapter and scanning software www.moates.net , flash chips, Winbin, and Pocket Programmer www.transtronics.com

I used Winbin to view and change the bin file. Don't forget to calculate the checksum before saving any changes.
www.passtimeracing.com/eric/Cars/EFI/index.htm

Use the 6e ecu file (change 'txt' to 'ecu')
http://temp.corvetteforum.net/c4/vettewn//6ev009.txt

I started with the ARAP bin (change 'txt' to 'bin')
http://temp.corvetteforum.net/c4/vettewn//arap.txt

This will not work without changes specific to the 85 (change 'txt' to 'bin')
http://temp.corvetteforum.net/c4/vettewn//arap85.txt

I programmed out the EGR in this bin (change 'txt' to 'bin')
http://temp.corvetteforum.net/c4/vet...rap85noegr.txt

These bins provide a starting point for tuning and are not meant to be ideal for all setups.

Hope this helps.



[Modified by Bluevette85, 8:45 PM 2/6/2003]
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Old Feb 7, 2003 | 10:32 AM
  #2  
NHVett's Avatar
NHVett
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From: Eagle IDAHO
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Default Re: 870 to 165 Conversion Instructions (Bluevette85)

Hey Walter, Maybe this could be posted in the "Tech Tips". Thanks again. :steering:
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Old May 5, 2003 | 10:02 AM
  #3  
SBNova's Avatar
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Joined: Dec 2002
Posts: 1,088
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From: Lakeland fl
Default Re: 870 to 165 Conversion Instructions (Bluevette85)

So let me get this straight.... The only wires that need to be connected are the ones you listed as repinned or spliced? OR, is everything else (not listed) go to the same designation on the new (165) ECM ? When complete, does everything still work in the car- like the cluster and instrument center?

BTW- sorry to keep bringing up an old topic.
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Old May 5, 2003 | 01:47 PM
  #4  
Bluevette85's Avatar
Bluevette85
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Drifting
 
Joined: Nov 2001
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From: Latham NY
Default Re: 870 to 165 Conversion Instructions (SBNova)

Yes, any wire not mentioned stays in the same place. Your dash cluster works the same; you don't lose any features.
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