pcmhacking.net

barana wrote:So has anyone sliced off the top of the metres chips and documented the difference between 4, 6 &8 lhm's or is all a bit of a blackbox to ppl?

There is a PDF of what they are like on older networks ... http://pcmhacking.net/forums/viewtopic. ... =30#p22659

Not sure if the later ECUs are using the same network, but its very possible nothing changed other than the values.

The resistor mod in this thread just tells the ECU how often to fire the injectors with respect to reference pulses from the dizzy/crank, its is used for normal running as well as LHM.

MrWillys wrote:The ESC (electronic spark control (knock filter)) for the GM TPI 7165 mass air cars was not mounted on the memcal, but was a remote circuit that can be seen here.

http://www.chevythunder.com/198689_f__y ... 227165.htm

In the 1990 model when the switch to speed density occurred the ESC was moved to the memcal. .

This explains why I cannot get knock detection to work. I have a memcal from an 87 F-body 5.0L thinking the knock filter was on it - but knock did not work.
Does an 808 have the knock filter on the memcal and if so would the memcal function in a GM 7165? Limp home mode is not really a concern - I would just like to get knock detection working.
Or would it be best to remove the knock filter from a 7730 5.0L memcal and mount it directly on the NVRAM board?
Or another action?

PS: I am running a Cadillac Northstar in my 88 Fiero GT with excellent results other than this issue.

Daviero wrote:Does an 808 have the knock filter on the memcal and if so would the memcal function in a GM 7165?

Yeah it will work, the '165 is almost identical hardware to a '808. I dont know if the 7730 uses the same type of knock filter though.

The filter needs to match the engine, the bore diameter is what most influences the knock frequency. So try and something that is the same bore and runs a '165 to get the filter from.

Daviero wrote:

MrWillys wrote:The ESC (electronic spark control (knock filter)) for the GM TPI 7165 mass air cars was not mounted on the memcal, but was a remote circuit that can be seen here.

http://www.chevythunder.com/198689_f__y ... 227165.htm

In the 1990 model when the switch to speed density occurred the ESC was moved to the memcal. .

This explains why I cannot get knock detection to work. I have a memcal from an 87 F-body 5.0L thinking the knock filter was on it - but knock did not work.
Does an 808 have the knock filter on the memcal and if so would the memcal function in a GM 7165? Limp home mode is not really a concern - I would just like to get knock detection working.
Or would it be best to remove the knock filter from a 7730 5.0L memcal and mount it directly on the NVRAM board?
Or another action?

PS: I am running a Cadillac Northstar in my 88 Fiero GT with excellent results other than this issue.

Get the esc unit from a 86 thru 89 Camaro, or Corvette along with the appropriate sensor and wire it as originally installed for the 165.

MrWillys wrote: Get the esc unit from a 86 thru 89 Camaro, or Corvette along with the appropriate sensor and wire it as originally installed for the 165.

Right. I also just read about Festy's Universal Knock Filter Module: https://pcmhacking.net/forums/viewto ... 993#p31600
Seems like that might be a better match since my bore is different that the 5L the 7165 came off?

Daviero wrote:
Right. I also just read about Festy's Universal Knock Filter Module: https://pcmhacking.net/forums/viewto ... 993#p31600
Seems like that might be a better match since my bore is different that the 5L the 7165 came off?

The 305 is 3.671, and the Northstar is 3.7? I would think it's close enough.

MrWillys wrote:

Daviero wrote:
Right. I also just read about Festy's Universal Knock Filter Module: https://pcmhacking.net/forums/viewto ... 993#p31600
Seems like that might be a better match since my bore is different that the 5L the 7165 came off?

The 305 is 3.671, and the Northstar is 3.7? I would think it's close enough.

That would make the knock frequencies around 6.14kHz and 6.10kHz - should be close enough to give decent results.

festy wrote:
That would make the knock frequencies around 6.14kHz and 6.10kHz - should be close enough to give decent results.

Picked up a new 305 ESC unit today. I'll see how well it works on the Northstar.....
Thanks guys!

Holden202T wrote:netres resistors. The factory TBI setting is used for 2 cylinder mode in OSE 12P.

magic ! Ta ... looks easy eh ? Ok looks as if I can get a VR, possibly VS computer .... is that any use, I think I remember reading in the prologues that these have a transmission chip, and may not be suitable ?

VR Manual computer, or VN/VP

VR auto is a different computer and controls the auto aswell, and VS is MAF and for ecotec V6 (also controls computer) so I'd avoid that unless you want to tune a MAF based system .... vr and earlier areall MAP based.