Hey guys,

Some of you may or may not know, but the 1985 ECM supposedly has provisions for controlling a knock sensor. Supposedly (from what I understand), the only thing you need to do is connect a knock sensor and wiring to that part of the harness that plugs into the ECM. In addition to that, you need to have a chip burned that enables that bit of software on the board.

So, I scored an ECM from a 1985 Fiero GT 4-Speed that I plan on using in my 1987 Fiero SE / V6 with the 5-Speed swap.


Most people will tell me that it won't make much difference at all, and that the only people who really benefit from this mod are people who turbo their car or use a supercharger. In this particular case, I plan to boost the compression of my motor to something like 9.2-9.3. I usually like to advance my timing some anyway, so I really think that I CAN benefit from this.

Can anyone tell me where I need to go, or who I need to e-mail to have a special prom burned for me that will make use of this knock sensor?


Thanks!!

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Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convertible (Wife's Car)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6 5-Speed
1987 Pontiac Fiero SE / V6 (3.2L) Auto
1984 Pontiac Fiero 2m4 SE
1981 Pontiac TransAm (Olds 455BB)
1973 Volkswagen Type-2 Transporter

You want the knock sensor as a fail safe, not a normal operating function. The value I would see is being able to use it to set the spark advance to max *before* knock kicks in. You don't want it kicking unless something is out of whack. The attack and decay times pull fast and return slow. That's annoying in normal driving.

There are many people on here that can supply you a chip with the sensor and codes enabled.

You could try the vendors list page...... btw very sound advise from above....

Thanks, I appreciate the advice. I don't want to be misunderstood, I want to make use of the knock sensor so that I CAN go to a higher advance without running the risk of damaging my motor. Plus I plan on having a much higher compression.

What I've heard tells me that I "CAN" gain about 5-6 horsepower by going with an ECM that has knock sensor capabilities because it allows me to tune my engine more aggressively.

Would you guys agree with this? I have the ECM, and I NEED a reburned chip with everything I plan to do. If I can make my car more reliable, or I can improve it's performance even slightly... I'll go for it.


By the way, I saw a huge list of vendors, but I didn't see any specific one that burns chips. Any idea?
Thanks!!!

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Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convertible (Wife's Car)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6 5-Speed
1987 Pontiac Fiero SE / V6 (3.2L) Auto
1984 Pontiac Fiero 2m4 SE
1981 Pontiac TransAm (Olds 455BB)
1973 Volkswagen Type-2 Transporter

I think it's all semantics but you can run as agressive as you want without the knock sensor but it will afford you *some protection* when knock occurs. It's not 100% effective and you can suck out a piston before the sensor triggers some retard (mainly a worry under boost. NA is not as much of an issue if the compression isn't raised).

Yes, you might gain 5-6HP if you tune the spark and fuel (lean it out some) within an inch of it's life and the knock sensor will help you tell where that point is for spark and you need a WB O2 for the fuel.

There is nothing wrong with adding it in and putting it to work for you. Just don't "depend" on it to save you.

TK

well, the knock sensor only works once its knocking. so, it may be good for tuning to the point where the knock sensor doesnt go off anymore. but, you dont want the ECM to keep killing your timing - you will end up with less overall power that way. you'll have the pre-ignition slowing you down, then the timing slowing you down.

no one has answered your question yet so here ya go http://www.gmtuners.com/

quote Originally posted by markviiisvt4: no one has answered your question yet so here ya go http://www.gmtuners.com/

Thanks Mark 8, I appreciate it.

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Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convertible (Wife's Car)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6 5-Speed
1987 Pontiac Fiero SE / V6 (3.2L) Auto
1984 Pontiac Fiero 2m4 SE
1981 Pontiac TransAm (Olds 455BB)
1973 Volkswagen Type-2 Transporter

I went through all the archives and pulled all this information together when I added a knock sensor to my engine.
The 85 ECM has the capability to handle inputs from the GM ESC module with a knock sensor input. The PROMs from the 6869 ('85) and 7170 ('86-'88) ECMs aren't compatible. In addition to adding the hardware and wiring it in, you will need a new chip programmed to have the knock sensor feature flag enabled. Without a new chip, this setup won't work.

PARTS

'85 GT ECM - GM part # 1226869
Knock sensor is GM part # 10456287
Knock sensor harness connector is GM part # 12102621
ESC module is GM part # 16126761 brodcast code ANRZ
ESC harness connector is GM Part # 12101871

PIc of ESC Module and harness
https://www.fiero.nl/forum/Archives/Archive-000001/HTML/20040223-2-039168.html

WIRING

On the module you have 5 pins. These pins are labeled A, B, C, D, and E.
ESC signal is fed into terminal B7 of ECM harness.
Wire them into the computer as follows:

A = Not used on Fiero application
B = ECM B1 (power)
C = ECM B7 (knock input)
D = ECM A12 (ground)
E = Connect to Knock Sensor

If you are running boost, you may as well add a 2-Bar MAP sensor at the same time.
2 BAR Map sensor is GM part # 12569241 (AC Delco 213-361)
Map sensor pigtail and lead GM part # 15305891 (AC Delco PT-1035)

Links to forums...

85 ECM & knock sensor
https://www.fiero.nl/forum/Archives/Archive-000001/HTML/20030531-2-030008.html
https://www.fiero.nl/forum/Archives/Archive-000001/HTML/20031110-2-036541.html
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Another way is to use an ESC Controller and knock sensor from a 1978-80 non-ECM turbo Buick.
This is a "stand-alone" that can be added into existing wiring to directly control the signal to the distributor.
See here http://home.flash.net/~rjgeorge/knock.htm

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3.4L S/C 87 GT www.fierosound.com
2002/2003/2004 World of Wheels Winner &
Multiple IASCA Stereo Award Winner

quote Originally posted by fierosound: I went through all the archives and pulled all this information together when I added a knock sensor to my engine. The 85 ECM has the capability to handle inputs from the GM ESC module with a knock sensor input. The PROMs from the 6869 ('85) and 7170 ('86-'88) ECMs aren't compatible. In addition to adding the hardware and wiring it in, you will need a new chip programmed to have the knock sensor feature flag enabled. Without a new chip, this setup won't work. If you are running boost, you may as well add a 2-Bar MAP sensor at the same time. 2 BAR Map sensor is GM part # 12569241 (AC Delco 213-361) Map sensor pigtail and lead GM part # 15305891 (AC Delco PT-1035)

Thanks Fiero Sound, I really appreciate all the information and advice. Where did you mount the module by the way? And where exactly does the knock sensor screw into? I assume I have to drill and tap a hole.

By the way, would there be any benefit to me swapping in a 2-Bar MAP sensor on my NA engine? I have no plans of adding boost, but if the 2-bar MAP sensor will improve the drivability / idle then I think it's worth it. Will it do anything like that? I do plan to increase compression to about 9.1 or 9.2
Thanks!!!

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Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convertible (Wife's Car)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6 5-Speed
1987 Pontiac Fiero SE / V6 (3.2L) Auto
1984 Pontiac Fiero 2m4 SE
1981 Pontiac TransAm (Olds 455BB)
1973 Volkswagen Type-2 Transporter

quote Originally posted by 82-T/A [At Work]: Where did you mount the module by the way? And where exactly does the knock sensor screw into? I assume I have to drill and tap a hole. By the way, would there be any benefit to me swapping in a 2-Bar MAP sensor on my NA engine? I have no plans of adding boost, but if the 2-bar MAP sensor will improve the drivability / idle then I think it's worth it.

The module can go anywhere under the hood (well - except for like the manifold! hehe). I stuck mine on the "trunk wall". No drilling required for the knock sensor - you pull the block drain plug and replace it with the sensor. Look up the correct torque value - IT MATTERS!

If you don't have boost - do NOT install a 2bar MAP. All you'll be doing is loosing 1/2 your tables.

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87/88 V6 5spd "FormulaGT" Turbo, 88 Formula
My page:
http://www.fierohut.com