I have an 86 Iroc TPI (maf), and will soon be swapping in my 406. Obviously, I will be burning some proms. I have had my scanner on newer vehicles, and the data refresh rate is much faster than the 1.25 seconds my 86 ECU takes. I know that a "faster" ECU will be able to manage engine operations more efficiently, but my question is this....Can I swap from an 86 ECU to an 89 ECU, and what are the modifications required to do so?

Thanks,


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Mike Metzler (Desert86Roc)
Mike@SpeedworldMotorplex.com
[*] Webmaster: SpeedWorldMotorplex.com[*] Click Here For My Racing Page[*]86 IROC 305 TPI (406 build in progress)
ET's @ 1250 ft[*] 14.28 @ 95.461 mph (uncorrected, NOS, no headers)[*] 15.365 @ 86.785 mph (uncorrected, Headers, no NOS)

 

This is all just my personal opinion but i would just swap over to the 7730 ECM found in speed density cars. That way you can eliminate the maf and the restriction it could impose on your 406. It can be done. There is info on this at diy-efi.org I think. Also try http://www.eecis.udel.edu/~davis/z28/ecm_swap_730/
Good luck!

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1991 5.7L Z28 - gutted air boxes, K&Ns, airfoil, ported plenum, relocated MAT, accel TPI base, accel 300+ ignition, accel cap&rotor, homemade AFPR, derale fan switch, vette servo ,flowmaster exhaust, torque conv. lock-up switch, and fresh 255/50/16 Dunlop sp800s. More to come!

 

I think the conversion to SD would be more wiring than I want to get into right now.
I am purchasing the equipment necessary to burn proms, and wanted to start with tweaking my 305 to learn before dropping the 406 in.

Based on the article at the site you recommended, i guess I already have a faster ECU...I just need an 89 chip for cold start injecter delete, correct? Any other changes necessary other than chip?

The aftermarket MAF that i use should not pose much of a restriction. I guess the SD cars are the ECUs with the "fast" refresh rate then?

Thanks.

 

I don't know a whole lot about the 165 ecms but it seems to me you are correct. Just burn an 89 305 bin file to use in your ecm. What I do know is that scanning my Dad's 87 Vette, I see more info on my 91 Z. The 730 ecm has a faster baud rate.

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1991 5.7L Z28 - gutted air boxes, K&Ns, airfoil, ported plenum, relocated MAT, accel TPI base, accel 300+ ignition, accel cap&rotor, homemade AFPR, derale fan switch, vette servo ,flowmaster exhaust, torque conv. lock-up switch, and fresh 255/50/16 Dunlop sp800s. More to come!

 

What model is your ECM actually . is it a 870 or a 165?? I know the 870 was the slow ecm. not husre of the early 165 was slow as well. Can sombody confirm this. If you are looking to build a decent 406 then I would go straight to the 7730. Its not a bad swap at all. some repinning you connectors and a 90 emcal and 90 knock sensor and map. I converted my 85 870 corvette ecm to the 7730.

I cant confirm the baud rate on your particular 86. but if its a 165 ecm yes you can install a 89 programmed chip but then you will have to use a scan tool for the 89 vin.
If I am off on some info feel free to correct me.
Dennis

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85 vette,383,miniram,ZF6,4.10's..best ET 11.81@117.00 60' 1.65
http://geocities.com/bowtie8

 

I think we got off the subject but here is my .02.
As for the baud rate it is the same for the 89 - 92 ECMs (maybe the 88 model too), 8192 bps. The difference is the PROM that is use for the the 89 & 90 to the 90 - 92 models. The earlier models use one with 128K memory and the latter used one with 256K memory.
As for the difference between the 86 and 89 ECU? Besides the baud rate, I think, you also have a nineth injector for the 86 and none for the 89. I don't know what else may be different.

Good Luck


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89 IROC 350 Auto
TRUE DUAL Exhaust
Edelbrock Performer Aluminum Heads
ZZ9 Cam
TPIS Level 5 Chip
14.01 @ 97.0mph with 2.77's gears

 

I think my original question was answered...I do have a 165 ECM. 89 is a MAF without a 9th injector (which I would rather have)... I dont know if the 89 has more data output to a scanner, over my 86...but I believe it does. On my 86, my scanner does not read anything about TCC lockup, and later ones do (I am not sure what year that started)...

Does anyone know...starting with a base 86 ECM & chip, what data outputs (as seen by an autoxray or other scanner) were added on each subsequent year?

Thanks guys...all this is good info.