Tuning 87 C4 Corvette

American Delco GM ECUs and PCMs, ALDL, OBD 1.5.
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Tuning 87 C4 Corvette

Postby Oversteer » Tue Apr 02, 2019 7:52 pm


I have a 87 C4 callaway corvette i have just purchased, and i wish to set-up/une car better that the ugly extra injectors and microfuler hack callaway did to car....

Car runs 808 ecm with a AFM, from what i have read i can use 12P code and install a map sensor and tune with Tuner Pro...(with bigger injectors etc)

Does 12p code work well with boost ? does it have a boost control PWM output ?

Any advice welcome, is there a better way of doing this with-out to much modification to car/wiring ?


PS: I sent a PM to antus about purchasing USB interface and NVRAM thing, but i don't know if it sent, its sitting in outbox not sent... is there a minimum of posts or something before i can pm etc ?

*edit sorry i see this is EURO GM ECU area....where should of a USA Delco question go ? can a admin move this please ?*

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Re: Tuning 87 C4 Corvette

Postby vlad01 » Tue Apr 02, 2019 8:18 pm

12P does work well with boost. Not sure about boost control but there is a programmable flexible output that might be able to be used for that?

Is your ECU 165? the 808 as far as I know was only in the Australian and New zealand market but the US counterpart is known as the 165. Anyway the 165 works with 12P

The PMs sit in the outbox until they are read, so it means Antus hasn't looked at the PM yet.

Hope that helps.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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Re: Tuning 87 C4 Corvette

Postby delcowizzid » Tue Apr 02, 2019 8:24 pm

I don't know how to move a thread but someone will file it into one of the appropriate sections .
12p is great for boost and there's a base tpi 350 bin on here that i did on a 4x4 that may be a good starting point instead of the v8 Holden tunes in the 12p zip folder was just a stock old 350 with rams horns and a tpi inlet fitted to it with egr blocked off.
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Re: Tuning 87 C4 Corvette

Postby Holden202T » Wed Apr 03, 2019 11:58 am


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Re: Tuning 87 C4 Corvette

Postby Oversteer » Thu Apr 04, 2019 2:30 am

Thanks for the responses and thread move ;)

OK yes its a 165 i believe.....now onto injectors, i need about 650cc, is there a problem using modern high impedance injectors ? or do i need to stick to low like originals ?

Apparently 165 has ALDL built in(unlike 808) so i just need a cable ?? where to get ?

Can a 165 control boost with a solenoid ?

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Re: Tuning 87 C4 Corvette

Postby delcowizzid » Thu Apr 04, 2019 7:44 am

Injectors will be high impedance stock.i use 60lb seimens dekas a lot but the markets flooded with Chinese copies now and you have to buy from reputable sources to get genuine.
Aldl cable for tuning can be found in the for sale section on here .
Should be able to control a boost solenoid with the flex outputs .
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem

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Re: Tuning 87 C4 Corvette

Postby K1ng0011 » Thu May 02, 2019 3:52 am

Oversteer wrote:Hello

I have a 87 Callaway Corvette with the 165 ecu, i have just got nvram from
pcm hacking so i can tune car and see that you have 12p running on a 165
ecu, can i ask what bin/tune you started with ? Anything else i should know
to get 12p running on the 165 ?



Hello Oversteer,

I am from the US. Here in the US we just have the 165 ECU but it is basically the same thing as the 808 found in australia. It looks to me like you are from australia possibly? So the first thing I think you should verify is that your wiring to the 165 ecu is correct. In the US although we used the same ECU our cars used a MAF sensor not a MAP and our wiring harness needs to be repinned to function properly with OSE12P. I put links to the wiring diagrams for the US ECU and for OSE12P so you can see the difference if you need that. You are using an nvram in your ECU. I did not however. I took the factory memcal and removed the EPROM chip and soldered in a new EEPROM 27SF512 chip directly on the memcal. So I have to rewrite my chip everytime I want to make changes and I do not have real time tuning like you will have with the nvram. In the OSE12P zip file you get from the main OSE12P main thread page you will want to start with the stacked.bin file since that is made for the NVRAM. I am not using the stacked bin since I do not have the nvram and I am burning chips with my '165' ecu. So I can give you my .bin that I currently use but you cannot just copy and used it on your nvram. You will have to open my bin and copy the settings/tables and move those over to your bin if you wanted to use anything from mine. I dont think you will have this issue but be aware that if your car is from the US and setup for MPH you will have to make adjustments to your speedometer since your speedometer sensor is in probably outputting pulses per mile vs pules per kilometer like OSE12P expects. I have not experience with boost. I just have a generic chevy 350 with some headers on it nothing special. I had a LOT of issues getting my car tuned right due to a blown out header gasket so make sure you dont have that same issue. OSE12P has a lot of settings get familiar with the the parameter finder in tuner pro it will make your life way easier. Learn how to smooth tables in tuner pro it will help you a lot. Also learn how to pull up and look at log files. OSE12P has calc VE built into the ADX file you use for logging with tuner pro. What this does is as your are logging it will actually calculate what it thinks the VE should be for a particular VE cell. Using that with the history average is pretty helpful. If you want your ECU to activate any external relays then OSE12P has programmable flex outputs you can wire into the ECU if you want. The OSE Enhanced Flash Tool is what you will use to program these into the bin. You open the program> set up the parameters for the flex outputs> save the bin and the xdf> then you go into tuner pro and enter data into the flex tables. I use two flex outputs to control a single large electric radiator fan that has two speeds. This was my first car tuning with EFI so I am not an expert. I know just enough to be dangerous.

OSE12P: viewtopic.php?f=27&t=356
OSE12P Wiring Diagram: download/file.php?id=23730
US ECU Wiring Diagram: http://www.chevythunder.com/fuel%20inje ... %20(ecm%20#1227165)
Memcal EPROM Replacement: https://www.thirdgen.org/forums/diy-pro ... stion.html
Pulses Per Mile to Pulses Per Kilometer Equation: viewtopic.php?f=8&t=5591#p83334
Basic Tuning OSE12P: download/file.php?id=5966
Advance Tuning OSE12P: viewtopic.php?f=28&t=3051
Fuel Injector Size Calculator: download/file.php?id=3289

Spark Reference Angle: You set your base timing on your distributor with a timing light then go into the .bin and set the spark reference angle to the degrees that you set your initial timing with the timing light. If this is not correct the rest of your timing table will not be correct. The ecu assumes you set the base timing correctly and references that so it knows how much to actually advance the timing based on what you have set in your timing table.

Road Speed Params - speed sensor constant pulses/kilometer: If your car uses mph you will need to find your ppm of your speed sensor and plug it into the equation above.

VE Learn Params Wideband 0v & 5v AFR: If using a wideband O2 Sensor you need to determine what the AFR for your wideband is at 0 volts and 5 volts (lean and rich)

MAP A: Set = Force Open Loop: Very useful in my opinion when tuning. This makes it so the computer will not make any adjustments to the fuel table when up to temp. So you can drive around and look at a wideband to determine how lean/rich you are when the computer is not using int/blm to make adjustments to the ve in the fuel table. Shows you how close your tune actually is. Dont forget to shut this off when you get your tune close.

Injector - injector bias vs battery voltage: you may or may not have this information with your injectors but it has something to do with adjusting your fuel calculations based on battery voltage.

KPA: Higher the KPA the lower the vacuum in the engine. 100KPA wide open throttle. 30KPA probably at idle or cruising down the highway.

VE Table: Fuel table higher the number more fuel. Also there is not perfect VE number. As you drive to different elevations, temps, humidity, ect the VE will change this is only a ball park figure and you can only get close.

INT (STFT): This is the short term fuel table. If your ecu sees that you are not hitting that target AFR you have set it will add/remove fuel to a point to get you there.

BLM(LTFT): This is the long term fuel table. If you are consistently not meeting your target AFR because of poor tune, permanent elevation change, vacuum leak, ect. Then it will make the change to add/remove fuel permanent or until you unhook the battery then the INT/BLM will be relearned or if there is an issue that you fix.

Starting Process My Understanding: Basically if the ECU has power during crank it is looking for an RPM signal from the pickup in the distributor. If it sees and RPM then it will move to the two stages for adding fuel to the engine for starting. All it does is based on the engine temp it sprays the injectors for a defined amount of time to get the engine started.

Spark Advance vs AFR: Basically leaner mixtures should have more spark advance richer mixtures do not need to have as much.

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Re: Tuning 87 C4 Corvette

Postby j_ds_au » Sat May 04, 2019 1:00 am

What a great and informative post!


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Re: Tuning 87 C4 Corvette

Postby antus » Tue May 07, 2019 9:29 am

Agree! Ive linked it from the FAQ area, as well as a link to the post where K1ng0011 submitted his bin as "Q. I have a MAF based '165 PCM and wish to run 12P. How do I do this?" viewtopic.php?f=7&t=1396
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: Tuning 87 C4 Corvette

Postby Oversteer » Tue May 07, 2019 3:25 pm

Yes absolutely great post, couldn't have asked for more, thanks K1ng0011.

Haven't had time to play with it yet, have got Siemens 650cc injectors and fuel pump.....still deciding if i'll do cam and manifold(have a stealth ram off another car already) etc at same time.....and clutch is toast so needs replacing also....which may mean ditching the Doug Nash 4+3 for a T56 !



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