Hello,

I'm new to these forums so please be kind to me while I try and sort a few things out in my mind in regards to a 1227165 MAF conversion to a 1227730 SD conversion.

I'm located in the land down under and I recently purchased (second hand) a TPI setup. I intend to get this in to my 350 powered 1971 HQ GTS Monaro 2-door.

I have been doing a LOT of googling and trawling of the net for some information on the MAF to SD conversion. I did come across Mike Davis' Z28 page in which he details this conversion. I have also some references to it here on these forums.

I know people talk about when using the knock sensor from the 165 to wire it directly the 730 ecu (via a resistor) and the setup then uses the knock filter that is located in the memcal. Now as you some of you would know, these memcals (AUJP for example) are getting expensive and most on-line auto places I have searched won't post to australia.

My question is, has anyone succesfully been able to use the 165 knock sensor and ESC setup with the 730 ecu?

I have read through the schematics (from ludis' site) for the 165 and 730 and I have noticed that both ecu's have the ability to pass the KS signal from a ESC module into the ECU or via a knock filter if it's located on the memcal. Here is australia, the knock filters for the 808 ECU's are located in the memcal.

My theory is that you can feed the output of the 165 ESC module signal into the 730's pin, B8 (ESCIO#) which electronically, is the same setup as the 165. That is to say, that it is feed into a 10K resistor, into a CMOS (or TTL) logic inverting gate and then into micro's port (memory IO port?) extender IC.

Is anyone else able to confirm my theory or has actually been able to do this? I am at the stage of where I'm buying new sensors and I don't want to waste my money on parts that I may never use.

I know this is a long post and I apologise.

Many many thanks!

Col.

 

All this is to try to get around using an AUJP memcal? Won't you need the '730 Memcal anyway, just to run the 730 ECU? It might be a lot easier to just buy a chip burner and make your own. $100 to get burning

 

It's not so much to get around not having using a AUJP memcal but more on still being able to use a knock sensor. The knock filter with the 730 is located on the memcal. I think that I have found a way to use (recycle?) the 165 knock filter and ESC setup with the 730 so the reliance on having to find a 730 memcal for the knock filter is no longer an issue.

I do intended to burn my own roms. My programmer supports flash roms, ram chips, eproms, eeproms, microcontrollers and heaps of other devices. Currently supports about 21,000+ different devices.

 

Yes that should work. Although I think you'll still have issue with the NETRES that are on the memcal under the ESC filter and memcal specific.

What's your timeframe for your project? I should be able to test the theory, but not for a few weeks.

mike

 

I have a long time frame as I'm currently rebuilding the car from the ground up. Once I have the chassis redone, I intend to get the car into a running state so that I can get the car up and down my driveway under its own power. I have a rather steep driveway and this is the safest way it can be done. The time frame for this is the next 3-6 months.

If you could test this theory out Mike, I would be very grateful thank you.

As for the NETRES, I'm still working on that one. If fact it does raise another question I have. Will the ECU run without a NETRES but throw an error code or does the ECU require a NETRES in place before it will start. I know the NETREST is involved with the limp-home mode but does it play any part when the processor is executing its code normally?

Thanks again,
Col.

 

Couple of things, the NETRES sets the injector firing rate. It should be in place for at least that. I'd wager that the MEMCAL from a '165 uses the same setup as the '730 MEMCAL regarding cylinder selection.

Your idea of tying the '165 knock filter into the '730 ECM should work. I've never done it, but have looked at it before. Note that the $8D code ('730) uses the ADC to read the voltage on the knock sensor. This is where the 3.9K resistor comes into play.

The malfunction testing for the knock sensor via the ADC will need to be bypassed. This can be accomplished with the diagnostic parameters in the calibration.

RBob.

 

Thank you for the answer on the NETRES. I agree with you that the MEMCAL and cylinder selection would be the same for the 165 and 730 ECU's. With the schematics, all the hardware pins marked CAL are the same for both processors. Of course, you could manipulate it differently in software and if things work on the previous version of ECU, why change it? But having said that, design engineers think differently to the people who do the maintenance so you never know what they think or change!

I don't know if it will. Both signals, once processed by the knock filter, end up on the same ADC input.

It will be interesting to see the result when Mike tries it out.

Cheers,
Col.

 

The schematics in the ESC area can be confusing. The input to the ADC is basically directly from the sensor. Then on to the knock filter on the MEMCAL (stock '7730). How the knock sensor diagnostic works: there is a 4K ohm resistor to 5 volts in the ECM on the sensor input line. The sensor has a nominal resistance of 4K ohm (3.9K being a common value). This has the 5V divided in half to about 2.5 volts. This is what the ADC looks for.

The voltage from the knock sensor into the ADC is tested for voltage. The upper & lower limits typically being 3.6 and 1.4 volts. If the voltage is within this window then the ECM believes the sensor and wiring is intact.

The stock '165 MAF knock sensor has a resistence of about 100K ohm. This is why folks tie a 3.9K resister in parallel with it when swapping to a '7730 and a '7730 MEMCAL.

Using the MAF knock sensor and filter and bypassing the common knock filter input will have the ADC looking at 5 volts. The malf 43 parameters can be changed, or just tie a 3.9K resister from pin F9 to ground.

RBob.

 

Thanks RBob,

I see what you getting at there. I wasn't paying attention to the ESC pin going to the processor that is also in parallel with CAL29 to the knock filter on the MEMCAL.

Col.