Tuning an 86

Steven Smith

Steven Smith

CCCUK Member
Before I purchase parts from the US is anyone selling a ALDL to laptop cable or a reader / writer for the EPROM ?
If not I am looking for recommendations for the above that you have used and actually work please.
 
teamzr1

teamzr1

Supporting vendor
You need to expand on what you're wanting to do ?
Are you looking to have the ECM calibration tuned ?
A tuning product that does both the reading and burning Eproms and software to make tuning changes to the calibration
is around $260
Or if you're not doing the tuning than just need the Eprom burner can be bought for around $130
Also, if wanting to reburn a used Eprom than you also need a Eprom eraser product
I do custom tuning and the Eprom for 1986 is a 27C128 and would be best to use a new one to burn new tune into
Are you looking for a E-prom reader/burner ?

When I tune OBD1 C4s I can touch
ECM Switch Parameters

VATS Select
Base PW Calibration Method (X = Calc.)
Normally Open Fan Request Input
Manual/Auto Transmission, X = Manual
Overdrive Default Off/On (X = On)
Use TCC Output for Shift Light
No Ref. Pulse Diagnostic (Err 12)
O2 Sensor Diagnostic (Err 13)
CTS Sensor High Diagnostic (Err 14)
CTS Sensor Low Diagnostic (Err 15)
TPS Sensor High Diagnostic (Err 21)
TPS Sensor Low Diagnostic (Err 22)
MAT Sensor Low Diagnostic (Err 23)
Vehicle Speed Diagnostics (Err 24)
MAT Sensor High Diagnostic (Err 25)
EGR Diagnostics (Err 32)
MAF High Diagnostics (Err 33)
MAF Low Diagnostic (Err 34)
Burn Off Diagnostic (Err 36)
Cyl. Select Diagnostic (Err 41)
EST Monitor Diagnostic (Err 42)
Knock Diagnostics (Err 43)
O2 Sensor Lean Diagnostic (Err 44)
O2 Sensor Rich Diagnostic (Err 45)
VATS Diagnostics (Err 46)
Missing Cal Pack (Err 52)
Over Voltage Diagnostic (Err 53)
Fuel Pump Voltage (Err 54)
ECM Constants
Initial Spark Advance
Max Spark Advance
Cool. Comp. Spark Spark Bias

Highway Mode Spark Enable Coolant Temp.
Highway Mode Spark Max Load Threshold
Highway Mode Spark Enable RPM Treshold
Highway Mode Spark Enable Delay Time
Knock Retard Enable RPM Threhold
Knock Retard Enable MPH Threhold
Knock Retard Enable Cool. Temp. Thresh.
Max Knock Retard (Not in P.E.)
Default Knock Retard if MALF 43
Fuel Cut Off Vehicle Speed
Fuel Resume Vehicle Speed
Fuel Cut Off RPM
Fuel Resume RPM
Fan On Coolant Temp Threshold (A/C On)
Fan Off Coolant Temp Threshold (A/C On)
Fan On Coolant Temp Threshold (A/C Off)
Fan Off Coolant Temp Threshold (A/C Off)
Injector Flow Rate - Single Fire
Injector Flow Rate - Double Fire
Max Accel. Enrich. Async Pulse Width
Minimum Delta TPS For Accel. Enrich.
Minimum Delta LV8 For Accel. Enrich.
Closed Loop Fuel Enable Cool. Temp.
Hot O2 Timer
Warm O2 Timer
Cold O2 Timer
Maximum BLM Value
Minimum BLM Value
Min. Coolant Temp for BLM Update
Max. Coolant Temp for BLM Update

Fast O2 R/L Hysteresis
Fast O2 R/L Hysteresis - Air Diverted
Decel Enlean Enable Delta TPS Thresh.
Decel Enlean Enable Delta LV8 Thresh.
Decel Enlean BPW Multiplier
MAF Hgh Diagnostic (Error 33) Threshold
EGR Off (%TPS)
EGR On (%TPS)
Min. MAT to Enable EGR
TCC Unlock Speed (Low Gears)
TCC Lock Speed (Low Gears)
TCC Unlock Speed (High Gears)
TCC Lock Speed (High Gears)
TCC Unlock Prevent/Auto O/D Engage Speed
TCC Enable Coolant Temp. Threshold
Min. Load Limit for TCC Lock, Low Speed
Min. Load Limit for TCC Lock, High Speed
TCC Min Load Limit Hysteresis
TCC Min Load Limit High/Low Speed Thresh
Shifter Kickdown Prevent RPM Threshold
TPS Kickdown/TCC Unlock Prevent -1st Gr.
TPS Kickdown/TCC Unlock Prevent-Not 1st
Idle Speed Adder in Park/Neutral
Idle Speed Adder for A/C On
IAC Startup Park Position
IAC Startup Delay Time
IAC Control Deadband RPM Error (in P/N)
IAC Control Deadband RPM Error (Drive)
IAC Steps added to Warm Park, A/C On
IAC Steps added for Cold Engine
IAC Gain Scalar for Prop & Deriv (P/N)
IAC RPM Rate Deadband, Idle Stability
DFCO Enable RPM Threshold
DFCO Disable RPM Threshold
DFCO Enable LV8 Threshold
DFCO Disable LV8 Threshold
DFCO Disable TPS Threshold
DFCO Disable MPH Threshold
DFCO Enable Cool Temp Threshold
DFCO Throttle Follower Default %TPS
DFCO Stall Saver T/F %TPS Correction
DFCO Stall Saver T/F %TPS Corr. Duration
DFCO Stall Saver Async Inj. Pulse Width
DFCO Stall Saver Async Inj. Pulses
Stall Saver Spark Correction Enable RPM
Stall Saver Spark Correction Disable RPM
Throttle Follower Step Period - in P/N
Throttle Follower Step Period - in Drive
T/F Step Period Correction Vs. Speed
T/F Step Period Correction in O/L Idle
Throttle Follower Slope Gain
Max. Throttle Follower Steps - in Drive
P/N Throttle Follower Multiplier
Closed Loop Idle Enable Vehicle Speed
Throttle Follower Adder - Vehicle Moving
AIR Control Enable Coolant Temp.
Shift Light Enable Coolant Temp. Thresh.
Shift Light Enable Vehicle Speed Thresh.
Shift Light Enable %TPS Threshold
Shift Light Enable LV8 Threshold
Shift Light Enable RPM Threshold
Shift Light Disable RPM Threshold
Shift Light Force On RPM Threshold
Shift Light Force On Disable RPM Thresh
Number of Cylinders
Display Injector Flow Rate
Tables
ECM Switch Table
ECM Constant Table
Main Spark Advance Vs. RPM Vs. Load
Cool. Comp. Spark Adv. Vs. RPM Vs. Cool. Temp.
Highway Mode Spark Advance Vs. Load
Startup Spark Advance Vs. Startup Cool. Temp.
Startup Spark Advance Decay Delay Vs Startup Cool.
Startup Spark Adv. Decay Period Vs. Startup Cool.
Startup Spark Adv. Decay Step Vs. Startup Cool.
Knock Retard Attack Rate Vs. RPM
Knock Retard Recovery Rate Vs. RPM
Max Knock Retard in WOT
WOT %Change To Fuel/Air Ratio Vs. Coolant Temp.
WOT %Change To Fuel/Air Ratio Vs. RPM
%TPS To Enable WOT Vs RPM
Open Loop Fuel/Air Ratio %Change Vs. Coolant Temp.
Open Loop Fuel/Air Ratio %Change Vs. Load
Startup Fuel/Air Ratio %Change Vs. Coolant Temp.
Warm IAC Park (Steps) Vs. Coolant Temp.
Desired Idle Speed vs Coolant Temp.
Mass Air Flow Table #1
Mass Air Flow Table #2
Mass Air Flow Table #3
Mass Air Flow Table #4
Mass Air Flow Table #5
Mass Air Flow Table #6
Max. Air Flow Vs. RPM
BPW Fuel Table Vs Load Vs RPM
Injector PW Correction Vs. Battery Voltage
Accel. Enrich %BPW Factor Vs Async Pulse
No. of Accel Enrich Async Pulses Vs. Coolant Temp.
Accel. Enrich. Async Factor Vs. Coolant Temp.
LV8 Accel. Enrich. Factor Vs. Delta LV8
LV8 Accel Enrich Coolant Factor Vs. Coolant Temp.
LV8 Accel. Enrich. Decay Rate Vs. Coolant Temp.
Crank Fuel Pulse Width Vs. Coolant Temp.
Crank Fuel Multiplier Vs. Reference Pulses
Crank Fuel Pulse Width Multiplier Vs. TPS
BLM Cell RPM Boundaries
BLM Cell MAF Boundaries
Fast O2 Rich/Lean Threshold Vs. MAF
Rich/Lean O2 Count Offset Vs. Coolant Temp.
Upper Zero Error Reference for Slow O2 R/L Vs. MAF
Lower Zero Error Reference for Slow O2 R/L Vs. MAF
Fan PWM Duty Cycle Vs. Coolant Temp.
EGR % Duty Cycle Vs. LV8 Vs. RPM
TCC Unlock %TPS (Not In 4th) Vs. MPH
TCC Lock %TPS (Not In 4th) Vs MPH
TCC Unlock %TPS (In 4th) Vs MPH
TCC Lock %TPS (In 4th) Vs MPH
Shift Light On %TPS Threshold Vs. RPM
Shift Light Off %TPS Threshold Vs. RPM
Shift Light On Delay Time Vs. %TPS
 
Steven Smith

Steven Smith

CCCUK Member
teamzr1 said:
You need to expand on what you're wanting to do ?
Are you looking to have the ECM calibration tuned ?
A tuning product that does both the reading and burning Eproms and software to make tuning changes to the calibration
is around $260
Or if you're not doing the tuning than just need the Eprom burner can be bought for around $130
Also, if wanting to reburn a used Eprom than you also need a Eprom eraser product
I do custom tuning and the Eprom for 1986 is a 27C128 and would be best to use a new one to burn new tune into
Are you looking for a E-prom reader/burner ?

When I tune OBD1 C4s I can touch
ECM Switch Parameters

VATS Select
Base PW Calibration Method (X = Calc.)
Normally Open Fan Request Input
Manual/Auto Transmission, X = Manual
Overdrive Default Off/On (X = On)
Use TCC Output for Shift Light
No Ref. Pulse Diagnostic (Err 12)
O2 Sensor Diagnostic (Err 13)
CTS Sensor High Diagnostic (Err 14)
CTS Sensor Low Diagnostic (Err 15)
TPS Sensor High Diagnostic (Err 21)
TPS Sensor Low Diagnostic (Err 22)
MAT Sensor Low Diagnostic (Err 23)
Vehicle Speed Diagnostics (Err 24)
MAT Sensor High Diagnostic (Err 25)
EGR Diagnostics (Err 32)
MAF High Diagnostics (Err 33)
MAF Low Diagnostic (Err 34)
Burn Off Diagnostic (Err 36)
Cyl. Select Diagnostic (Err 41)
EST Monitor Diagnostic (Err 42)
Knock Diagnostics (Err 43)
O2 Sensor Lean Diagnostic (Err 44)
O2 Sensor Rich Diagnostic (Err 45)
VATS Diagnostics (Err 46)
Missing Cal Pack (Err 52)
Over Voltage Diagnostic (Err 53)
Fuel Pump Voltage (Err 54)
ECM Constants
Initial Spark Advance
Max Spark Advance
Cool. Comp. Spark Spark Bias

Highway Mode Spark Enable Coolant Temp.
Highway Mode Spark Max Load Threshold
Highway Mode Spark Enable RPM Treshold
Highway Mode Spark Enable Delay Time
Knock Retard Enable RPM Threhold
Knock Retard Enable MPH Threhold
Knock Retard Enable Cool. Temp. Thresh.
Max Knock Retard (Not in P.E.)
Default Knock Retard if MALF 43
Fuel Cut Off Vehicle Speed
Fuel Resume Vehicle Speed
Fuel Cut Off RPM
Fuel Resume RPM
Fan On Coolant Temp Threshold (A/C On)
Fan Off Coolant Temp Threshold (A/C On)
Fan On Coolant Temp Threshold (A/C Off)
Fan Off Coolant Temp Threshold (A/C Off)
Injector Flow Rate - Single Fire
Injector Flow Rate - Double Fire
Max Accel. Enrich. Async Pulse Width
Minimum Delta TPS For Accel. Enrich.
Minimum Delta LV8 For Accel. Enrich.
Closed Loop Fuel Enable Cool. Temp.
Hot O2 Timer
Warm O2 Timer
Cold O2 Timer
Maximum BLM Value
Minimum BLM Value
Min. Coolant Temp for BLM Update
Max. Coolant Temp for BLM Update

Fast O2 R/L Hysteresis
Fast O2 R/L Hysteresis - Air Diverted
Decel Enlean Enable Delta TPS Thresh.
Decel Enlean Enable Delta LV8 Thresh.
Decel Enlean BPW Multiplier
MAF Hgh Diagnostic (Error 33) Threshold
EGR Off (%TPS)
EGR On (%TPS)
Min. MAT to Enable EGR
TCC Unlock Speed (Low Gears)
TCC Lock Speed (Low Gears)
TCC Unlock Speed (High Gears)
TCC Lock Speed (High Gears)
TCC Unlock Prevent/Auto O/D Engage Speed
TCC Enable Coolant Temp. Threshold
Min. Load Limit for TCC Lock, Low Speed
Min. Load Limit for TCC Lock, High Speed
TCC Min Load Limit Hysteresis
TCC Min Load Limit High/Low Speed Thresh
Shifter Kickdown Prevent RPM Threshold
TPS Kickdown/TCC Unlock Prevent -1st Gr.
TPS Kickdown/TCC Unlock Prevent-Not 1st
Idle Speed Adder in Park/Neutral
Idle Speed Adder for A/C On
IAC Startup Park Position
IAC Startup Delay Time
IAC Control Deadband RPM Error (in P/N)
IAC Control Deadband RPM Error (Drive)
IAC Steps added to Warm Park, A/C On
IAC Steps added for Cold Engine
IAC Gain Scalar for Prop & Deriv (P/N)
IAC RPM Rate Deadband, Idle Stability
DFCO Enable RPM Threshold
DFCO Disable RPM Threshold
DFCO Enable LV8 Threshold
DFCO Disable LV8 Threshold
DFCO Disable TPS Threshold
DFCO Disable MPH Threshold
DFCO Enable Cool Temp Threshold
DFCO Throttle Follower Default %TPS
DFCO Stall Saver T/F %TPS Correction
DFCO Stall Saver T/F %TPS Corr. Duration
DFCO Stall Saver Async Inj. Pulse Width
DFCO Stall Saver Async Inj. Pulses
Stall Saver Spark Correction Enable RPM
Stall Saver Spark Correction Disable RPM
Throttle Follower Step Period - in P/N
Throttle Follower Step Period - in Drive
T/F Step Period Correction Vs. Speed
T/F Step Period Correction in O/L Idle
Throttle Follower Slope Gain
Max. Throttle Follower Steps - in Drive
P/N Throttle Follower Multiplier
Closed Loop Idle Enable Vehicle Speed
Throttle Follower Adder - Vehicle Moving
AIR Control Enable Coolant Temp.
Shift Light Enable Coolant Temp. Thresh.
Shift Light Enable Vehicle Speed Thresh.
Shift Light Enable %TPS Threshold
Shift Light Enable LV8 Threshold
Shift Light Enable RPM Threshold
Shift Light Disable RPM Threshold
Shift Light Force On RPM Threshold
Shift Light Force On Disable RPM Thresh
Number of Cylinders
Display Injector Flow Rate
Tables
ECM Switch Table
ECM Constant Table
Main Spark Advance Vs. RPM Vs. Load
Cool. Comp. Spark Adv. Vs. RPM Vs. Cool. Temp.
Highway Mode Spark Advance Vs. Load
Startup Spark Advance Vs. Startup Cool. Temp.
Startup Spark Advance Decay Delay Vs Startup Cool.
Startup Spark Adv. Decay Period Vs. Startup Cool.
Startup Spark Adv. Decay Step Vs. Startup Cool.
Knock Retard Attack Rate Vs. RPM
Knock Retard Recovery Rate Vs. RPM
Max Knock Retard in WOT
WOT %Change To Fuel/Air Ratio Vs. Coolant Temp.
WOT %Change To Fuel/Air Ratio Vs. RPM
%TPS To Enable WOT Vs RPM
Open Loop Fuel/Air Ratio %Change Vs. Coolant Temp.
Open Loop Fuel/Air Ratio %Change Vs. Load
Startup Fuel/Air Ratio %Change Vs. Coolant Temp.
Warm IAC Park (Steps) Vs. Coolant Temp.
Desired Idle Speed vs Coolant Temp.
Mass Air Flow Table #1
Mass Air Flow Table #2
Mass Air Flow Table #3
Mass Air Flow Table #4
Mass Air Flow Table #5
Mass Air Flow Table #6
Max. Air Flow Vs. RPM
BPW Fuel Table Vs Load Vs RPM
Injector PW Correction Vs. Battery Voltage
Accel. Enrich %BPW Factor Vs Async Pulse
No. of Accel Enrich Async Pulses Vs. Coolant Temp.
Accel. Enrich. Async Factor Vs. Coolant Temp.
LV8 Accel. Enrich. Factor Vs. Delta LV8
LV8 Accel Enrich Coolant Factor Vs. Coolant Temp.
LV8 Accel. Enrich. Decay Rate Vs. Coolant Temp.
Crank Fuel Pulse Width Vs. Coolant Temp.
Crank Fuel Multiplier Vs. Reference Pulses
Crank Fuel Pulse Width Multiplier Vs. TPS
BLM Cell RPM Boundaries
BLM Cell MAF Boundaries
Fast O2 Rich/Lean Threshold Vs. MAF
Rich/Lean O2 Count Offset Vs. Coolant Temp.
Upper Zero Error Reference for Slow O2 R/L Vs. MAF
Lower Zero Error Reference for Slow O2 R/L Vs. MAF
Fan PWM Duty Cycle Vs. Coolant Temp.
EGR % Duty Cycle Vs. LV8 Vs. RPM
TCC Unlock %TPS (Not In 4th) Vs. MPH
TCC Lock %TPS (Not In 4th) Vs MPH
TCC Unlock %TPS (In 4th) Vs MPH
TCC Lock %TPS (In 4th) Vs MPH
Shift Light On %TPS Threshold Vs. RPM
Shift Light Off %TPS Threshold Vs. RPM
Shift Light On Delay Time Vs. %TPS
Click to expand...
I want a ALDL cable so I can view live data using something like TunerPro or Tunercat.
Planning to install a new cam and lifters (already purchased) and new Bosch 3 injectors this along with the mods already completed (cats removed, Tri Y headers, smog pump removed etc) I think it will need a tune to get the most benefits.
So was looking at what I need to write it to the EPROM.
 
teamzr1

teamzr1

Supporting vendor
Tunercat sells either just a eprom burner that has the unit the eprom plugs into and a cable from ADLC and laptop
You than need the OBD1 tuner software to make the tuning changes and that bin file is saved, and you use than the burner
to burn new tuned into the 27C128 eprom
They sell a package product that is the tuning software and the burner around $260, and they charge like $30 to ship outside the USA

Also, they sell their Datacat product that is an OBD1 scanner that comes with scanner software and the USB cable from laptop to the ADLC
For 1986 C4 that uses the 12 pin ADLC connector
This scanner allows from laptop to scan, record, replay, see DTCs, chart and also can export the testruns recorded data to
Excel to analyze the raw data

I have been using this tuner and scanning products of theirs since 1995

If you do not intend to do the custom tuning than that is what my business is that you read the Eprom, which is saved as a
bin file, email that to me
Also email me the collected OBD1 scanner data and from that I do a custom tune and email that to you
and you burn that into Eprom

obd1.jpg
 
Steven Smith

Steven Smith

CCCUK Member
teamzr1 said:
Tunercat sells either just a eprom burner that has the unit the eprom plugs into and a cable from ADLC and laptop
You than need the OBD1 tuner software to make the tuning changes and that bin file is saved, and you use than the burner
to burn new tuned into the 27C128 eprom
They sell a package product that is the tuning software and the burner around $260, and they charge like $30 to ship outside the USA

Also, they sell their Datacat product that is an OBD1 scanner that comes with scanner software and the USB cable from laptop to the ADLC
For 1986 C4 that uses the 12 pin ADLC connector
This scanner allows from laptop to scan, record, replay, see DTCs, chart and also can export the testruns recorded data to
Excel to analyze the raw data

I have been using this tuner and scanning products of theirs since 1995

If you do not intend to do the custom tuning than that is what my business is that you read the Eprom, which is saved as a
bin file, email that to me
Also email me the collected OBD1 scanner data and from that I do a custom tune and email that to you
and you burn that into Eprom

View attachment 31005
Click to expand...
I have just seen that Moats net is back in business.
That look likes another option.
Their Ostrich 2 looks to be perfect.
 
Steven Smith

Steven Smith

CCCUK Member
teamzr1 said:
Tunercat sells either just a eprom burner that has the unit the eprom plugs into and a cable from ADLC and laptop
You than need the OBD1 tuner software to make the tuning changes and that bin file is saved, and you use than the burner
to burn new tuned into the 27C128 eprom
They sell a package product that is the tuning software and the burner around $260, and they charge like $30 to ship outside the USA

Also, they sell their Datacat product that is an OBD1 scanner that comes with scanner software and the USB cable from laptop to the ADLC
For 1986 C4 that uses the 12 pin ADLC connector
This scanner allows from laptop to scan, record, replay, see DTCs, chart and also can export the testruns recorded data to
Excel to analyze the raw data

I have been using this tuner and scanning products of theirs since 1995

If you do not intend to do the custom tuning than that is what my business is that you read the Eprom, which is saved as a
bin file, email that to me
Also email me the collected OBD1 scanner data and from that I do a custom tune and email that to you
and you burn that into Eprom

View attachment 31005
Click to expand...
Can you burn the new tune into the original EPROM or do you need to buy new ones ?
What is the cost of a custom tune ?
If you want to.message me directly
my email address is:
steven.smith777.j@gmail.com
 
teamzr1

teamzr1

Supporting vendor
GM has the EPROM burned at a low voltage
So You could erase one with an EPROM eraser ( or a UV light) but may not be fully erased
With a EPROM burner could then have the eraser checked to see if EPROM is erased and if not erase again

I just stuck the correct EPROM for your 86, and it is a 27C128
When code is burned in, a label is then placed over the glass eye you see
To Erase take label off and then do the erase process and then when it is blank put another label over the eye before
burning code in

Really if you're going to other tunes in future you could buy some new ones, maybe like $2 US from like here


For best complete custom performance tune and me doing that tuning is you have a OBD-I scanner in record mode and drive the car to collect
all engine and tranny sensors to email to me as now that is like the car being with me and I know exactly how to bias the tune as your C4 is functioning and tuned for best functioning and performance gains

I'd give you a discount price of me analyzing your recorded scanner data testruns ,
doing a custom tune and emailing you the tune for you to burn into an E-prom

For $200 US

Maybe if you do not want to buy a EPROM burner, you have a local shop that could burn the bin file (tune) into E-prom for you ?

M27C128K.jpg
 
Steven Smith

Steven Smith

CCCUK Member
teamzr1 said:
GM has the EPROM burned at a low voltage
So You could erase one with an EPROM eraser ( or a UV light) but may not be fully erased
With a EPROM burner could then have the eraser checked to see if EPROM is erased and if not erase again

I just stuck the correct EPROM for your 86, and it is a 27C128
When code is burned in, a label is then placed over the glass eye you see
To Erase take label off and then do the erase process and then when it is blank put another label over the eye before
burning code in

Really if you're going to other tunes in future you could buy some new ones, maybe like $2 US from like here


For best complete custom performance tune and me doing that tuning is you have a OBD-I scanner in record mode and drive the car to collect
all engine and tranny sensors to email to me as now that is like the car being with me and I know exactly how to bias the tune as your C4 is functioning and tuned for best functioning and performance gains

I'd give you a discount price of me analyzing your recorded scanner data testruns ,
doing a custom tune and emailing you the tune for you to burn into an E-prom

For $200 US

Maybe if you do not want to buy a EPROM burner, you have a local shop that could burn the bin file (tune) into E-prom for you ?

View attachment 31065
Click to expand...
Thanks for your reply.
I very much doubt any tuning shops over in the UK would remember what an EPROM is let alone have a burner.
I have a basic understanding of what I need going forward.
I need to get the new cam fitted and have the injectors refurbished or renewed, then start data logging and send you the information.
I also think a new Eprom is the way to go so I always have the original tune as a backup on the original EPROM.
 
teamzr1

teamzr1

Supporting vendor
Steven Smith said:
Thanks for your reply.
I very much doubt any tuning shops over in the UK would remember what an EPROM is let alone have a burner.
I have a basic understanding of what I need going forward.
I need to get the new cam fitted and have the injectors refurbished or renewed, then start data logging and send you the information.
I also think a new Eprom is the way to go so I always have the original tune as a backup on the original EPROM.
Click to expand...

GM stopped using EPROM's for Corvettes back in 1996 and also all other GM vehicles and electronics went to flash memory
Also, harder as your '86 EPROM is only 128K bytes where by 1990 GM had to go to 512 K bytes
(Think of even C7s GM had to go to 2 meg bytes flash memory)

I agree on saving the OEM EPROM but also if a burner you could read that calibration and have it saved in a tuning directory you make for later use if need be or any tunes I email you

Might want to buy some spare new EPROMs as getting real tough fining these as I normally buy a tube of them which is about 10 EPROMs
 
teamzr1

teamzr1

Supporting vendor
Steven,
if you need new or race type fuel injectors, I have used this shop for many years
Here are ones for 1986 C4

fuelinjectorconnection.com

OEM / New / Rebuilt Injectors

Fuel Injector Connection is the leader in high performance fuel injectors from top manufacturers including Bosch, Siemens, and Lucas.
fuelinjectorconnection.com fuelinjectorconnection.com

You should consider though the stock ones are only like 22 lb/hr flow and with 3rd party CAM and Ethanol gas is going with bit larger
and tune for for those
 
Steven Smith

Steven Smith

CCCUK Member
teamzr1 said:
Steven,
if you need new or race type fuel injectors, I have used this shop for many years
Here are ones for 1986 C4

fuelinjectorconnection.com

OEM / New / Rebuilt Injectors

Fuel Injector Connection is the leader in high performance fuel injectors from top manufacturers including Bosch, Siemens, and Lucas.
fuelinjectorconnection.com fuelinjectorconnection.com

You should consider though the stock ones are only like 22 lb/hr flow and with 3rd party CAM and Ethanol gas is going with bit larger
and tune for for those
Click to expand...
I will source some EPROM's now as they are getting harder to find.
I already have the cam and lifters:
www.compcams.com

Xtreme Energy Computer Controlled 206/212 Hydraulic Flat Cam Chevrolet Small Block

Xtreme Energy Computer Controlled 206/212 Hydraulic Flat Tappet Cam for Chevy Small Block. Great in throttle body, crossfire or carbureted engine and 305 TPI. (Note: for 1987-1998)
www.compcams.com www.compcams.com
Recommended by Comp cams for to mods I have.
I had been looking at the Bosch 3 injectors from FIC but hadn't considered going bigger, not looking to build a race car just trying to make the best out of what I have for a reasonable cost.
 
Steven Smith

Steven Smith

CCCUK Member
Just so I order the correct parts which one of the 3 shown is correct?
 

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teamzr1

teamzr1

Supporting vendor
Steven Smith said:
Just so I order the correct parts which one of the 3 shown is correct?
Click to expand...

As to fuel injectors GM tended to go a bit too small and the C4s were not designed for E10 gas which runs even leaner
so now is the time to go a bit larger and I can control them in the tune so the AFR would be best

I do not know your elevation, but if at sea-level then most density / airmass so would run leaner then if at higher elevation

Also, when having time, what OBD-I scanner you're getting ?
If the Tunercat Datacat OBD-1 scanner, I also have that and would allow you to email your testrun recordings for me to analyze
Be best if you do a scanner testrun before your nods so we can do compares of engine before and after the mods and custom tuning

Just making a guess but think the last 3 numbers are the speed the Eprom functions
If so, I think the bottom one be a bit too fast as the ECM's coprocessor is only like 8 Mhz
So leaves the other 2, and maybe the letter before speed is version # ?
I would go with top one at 150

IF cannot get the 128s try for 27C256 K

27128to256K.jpg
 
Last edited:
Steven Smith

Steven Smith

CCCUK Member
teamzr1 said:
As to fuel injectors GM tended to go a bit too small and the C4s were not designed for E10 gas which runs even leaner
so now is the time to go a bit larger and I can control them in the tune so the AFR would be best

I do not know your elevation, but if at sea-level then most density / airmass so would run leaner then if at higher elevation

Also, when having time, what OBD-I scanner you're getting ?
If the Tunercat Datacat OBD-1 scanner, I also have that and would allow you to email your testrun recordings for me to analyze
Be best if you do a scanner testrun before your nods so we can do compares of engine before and after the mods and custom tuning

Just making a guess but think the last 3 numbers are the speed the Eprom functions
If so, I think the bottom one be a bit too fast as the ECM's coprocessor is only like 8 Mhz
So leaves the other 2, and maybe the letter before speed is version # ?
I would go with top one at 150

IF cannot get the 128s try for 27C256 K

View attachment 31070
Click to expand...
Thank you for your advice.
I am at sea level, I use ethanol free fuel where possible but E5 at worst.
My car has already had the cat removed, Tri-Y headers and better exhaust fitted before I got it.

Looking at either Datacat or Moates for the Hardwear, Moates is fully compatible with Datacat and significantly cheaper.
 
Last edited:
teamzr1

teamzr1

Supporting vendor
IF the stock fuel injectors with the mods end up to be too small than they are max'd out
Add weather, elevation, gas type of driving with the mods the stock injectors could be running at 100% duty cycle
The spray pattern above 80% begins to degrade, so fuel charge is not good

Objective is lower than that 80% at worse case conditions
Putting larger injectors in I can control via the tune say using 28 lb/hr that they act like 22s and up to 28 lb/hr,
control the AFR for part throttle and at WOT
.InjFlow.jpg
So doing some math
Using stock at 22 lb/hr, to using 28 lb/hr or 32 lb/hr
Notice for each how much flywheel HP the injectors can handle either at 80 or 100% duty cycle

22lbhr.jpg
 
teamzr1

teamzr1

Supporting vendor
Steven Smith said:
Thank you for your advice.
I am at sea level, I use ethanol free fuel where possible but E5 at worst.
My car has already had the cat removed, Tri-Y headers and better exhaust fitted before I got it.

Looking at either Datacat or Moates for the Hardwear, Moates is fully compatible with Datacat and significantly cheaper.
Click to expand...

OK fine, then as long as it does Datacat so I can replay your recording and also export that scanner recording data to
Excel and analyze and make report on what all engine sensors were reporting
 
Steven Smith

Steven Smith

CCCUK Member

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Last edited:
teamzr1

teamzr1

Supporting vendor
As I mentioned in other post,
if not finding the 128K you can use a M27C256 K and when burning the code in to set the memory offset address I showed below
27128to256K.jpg
 
Steven Smith

Steven Smith

CCCUK Member
That's brilliant thank you, I will order the EPROM's now so I have them ready.
I will also look on AliExpress for the burner.
I have had some really good quality parts for the C4 from there.
 
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