85 IROC TPI 1227730 conversion from 1226870

I converted my 85 to speed density from a MAF system. So far I feel I have made good progress. The car started, but is running badly. I have two codes set, code 41 Cylinder select and code 43 ESC errors. I am using a memcal from a 3.1l V6. I jumped pin 13 to pin 10 on the 16 pin chip. This is the HAC from Thirdgen to convert the chip to 8 cylindars. I assume there is something to do with that memcal as to why I am getting the cylinder select error. The 85 ECM 1226870 has a grounded input for selecting the ECM mode. Does the 1227730 ECM have a input like that, or is the HAC identified on Third Gen correct. I am a little worried about the ESC Code 43. I was under the impression the ECM/MEMCAL controlled the spark advance by direct input from the knock sensor. The 85 system had a separate ESC module that the knock sensor plugs into. The ESC module would signal the ECM to retard timing or not. By the wiring diagram for the 1227730 ECM, the ESC module is eliminated. So I have the knock sensor connecting directly to the EMC. Is this correct? I started my project (engine rebuild from a 305 to a 383) with an engine from the junk yard. It was a 1990 TBI 5.7L truck engine. That engine had a separate ESC module like my 85. This is why I wonder if I wired the knock sensor correctly or not.

I can only help with the ESC, yes it is removed and knock is wired to ECM where new knock module is on Memcal.

you cylinder select jumper should be on pin 56 cylinder select to pin 62 ground is the closest ground to set the fire rate. The knock sensor is wired in series to pin F9 of the 730 ecm. I would also reprogram out the knock error. The knock sensor will only do a retard but since the frequency does not match the sensor with the filter you will never have a knock retard. Not sure what you did about the vss signal but the 730 can except the 2kppm and control lockup just reprogram to optical vss from magnetic pin c6 of the 730, on the 870 it was A10.

Thanks Tunedperformance. I haven't been able to drive it yet so I wasn't sure if the VSS was correct. I guessed at connecting it to B10. All the documentation I have shows C6 unused. If you are certain about C6, I will give it a try.
Is the jumper you are referring to for cylindar select on the memcal or is it internal to the ECM? Is the filter for the knock sensor is on the memcal also? By saying I have the wrong filter, you are referring to me using a V6 memcal? I am looking for the correct one for my application. Do you know a part number?

I can send you a modified .bin to get the vss working if you like. I would start with a aujp gm acdelco 16151348. I have a few new ones that I will be selling. There are 2 ways to get the vss signal to work to help shut off the coolant fans at 35 and to control lockup. The above mentioned or wire in a wire in a 4k magnetic directly from the cable drive on your transmission tail housing and use pin b9 vss ground and pin b10 vss 4k input. the 730 has a built in buffer so if needed you have a output for cruise and newer style 87 up f-body speedometer non cable driven. The jumper I was referring to is on the memcal itself. The knock filter is on the memcal. A v6 memcal has a high resistance value on the knock filter and can be changed to a v8 but the resisters are very tiny to be replacing. I will be unable to reply to any response until this evening.


http://www.tpiparts.net/inc/sdetail/7587

Mark and Tunedperforamce,
I have to thank you for all your help today. The VSS works fine in C6. The programming was straight forward. Also, your help with the memcal jumper worked. The info I got from thirdgen said to cut the leg off the chip. That was at pin 56. I soldered that pin back to the connector and car runs like a champ. I owe you a few beers for the help.
I see in the programming that you can turn on EGR diagnostics. When I was changing over, I had nowhere to plug the EGR diagnostic switch. It was not on the diagram I had. Do you know what cavity that lead should plug to?
I eliminated the ESC error by shutting off code 43 and have know retard attack rate set to zero in temp vs attack rate table. I don't hear any knock, but would like to turn that feature back on. I am interested in buying a AUJP memcal. How much do you want for it?
All in all I am very happy with how the car runs and how much more you can tune with the 730 ECM. Mark, I remember you talked me into it. Thanks for the good advice. Now I get to learn how the VE tables affect engine performance. If someone has a $8d bin for a 383 TPI engine that would be great to see what they changed.

If the egr you have has a temp switch its the 85-89 maf one. This is not used on the sd 730 ecm. Time to data log and even run a wb o2 sensor and jump into the super aujp.:thumbsup:

Tunedperformance, he has a very modified engine and a stock AUJP chip won't help but I think you could help/sell him proper Memcal so he can tune a chip for the engine.

Zaut, Tunedperformance is out of town on dialup sometimes so he is the guy to get correct info from and buy correct Memcal from. Please don't blame me for talking you into this, I only try to help pass on information! :happy: You were heading the wrong direction. If we missed anything regroup and we will try to help.

Even if you could get a modified bin it wouldn't be tuned for your car, most tuners know this and won't offer you one and don't want to be part of hurting your motor if what they have works for them and is wrong for yours. You've come so far and now the real enjoyment of tuning your motor begins, beware is is addicting!

VE is just an exercise in math, speadsheets actually even simplify the math. You need to record data and use your BLM readings to adjust cells in VE table. I did a writeup on how to make a BLM History table and it is linked to in this thread where a guy did the same thing and also has shared his BLM spreadsheet which I believe is proper for your car.

http://www.thirdgen.org/techboard/di...xcel-tool.html

Eaglemark, I was offering to start with he aujp and yes tuning will need to be done with data logging to help dial in the lower and upper ve. The ostrich maybe of real help or look into dynamic efi.com ebl p4. The aujp is just the safest to start off with not a real aggressive timing table unlike the 727 vette's. Im back in to no more dial up. lol

Mark, I am very grateful for the advice of changing to the 730. I need to give credit where is deserved. In my initial run, the BLM and INT bounced around a lot dependent upon RPM. Some of the mid RPM’s were dead on 128. Since the change is not consistent across the RPM range, I will start working on the VE tables. In general, the BLM was low, so I am running rich. I assume that means my VE % is low in the table. I can easily see how data logging and comparing the INT/BLM to VE% will lead me to the correct values. Am I going in the correct direction?

Quote:

---

Originally Posted by Tunedperformance

Eaglemark, I was offering to start with he aujp and yes tuning will need to be done with data logging to help dial in the lower and upper ve. The ostrich maybe of real help or look into dynamic efi.com ebl p4. The aujp is just the safest to start off with not a real aggressive timing table unlike the 727 vette's. Im back in to no more dial up. lol

---

Haven't worked much with $8D, will have to compare spark. Strange when they got to LT1 spark was not nuch differant from car to car or even aluminum head to iron head IIRC...

Quote:

---

Originally Posted by zaut

Mark, I am very grateful for the advice of changing to the 730. I need to give credit where is deserved. In my initial run, the BLM and INT bounced around a lot dependent upon RPM. Some of the mid RPM’s were dead on 128. Since the change is not consistent across the RPM range, I will start working on the VE tables. In general, the BLM was low, so I am running rich. I assume that means my VE % is low in the table. I can easily see how data logging and comparing the INT/BLM to VE% will lead me to the correct values. Am I going in the correct direction?

---

Yup! :thumbsup:

What happens with cams is usually just that. OK mid, rich idle and low, lean high. If you look at your fueling VE table and find the spot where VE is good/128 BLM and use the 3D graph you can help tuning by leaning down from the good VE cell and raising up from VE cell, make a smoother sloped VE table, then data log again. You'll never hit all the cells and see ones you've adjusted, then go around the ones you've adjusted and leave them alone and get the ones just beyond that and use the smooth tool, I like a setting of .50. Use preferences to keep graph on top and can watch it smooth out. Rinse and repeat.

been using S_AUJP since i converted my car and despite all the problems ive been having(all of which is my own faults) im sticking with it. last week i tried to find a more complete 8D and S_ is far better than anything else. if you are worried about too much spark just download AXXD bin and copy the spark tables over. HTH

I analyzed my first data log. Did a lot of excel work, pivot tables averaging ETC. I came up with a nice table VE% tables. I did the smoothing as you suggest. What a nice feature. Then I took the car out for another run and nothing changed. The BLM stayed around 108. So after scratching my head for awhile, I started looking into other data besides MAP, RPM and BLM. It turns out my MAT is stuck on 61.4F. It never changed. I figure MAT plays a huge role in the fuel delivery considering Boyles law. So I trouble shoot the MAT circuit. All is fine. In fact I can unplug it and the temp is still 61.4F. Is my ECM bad, or is there a glitch in TunerPro? I am guessing on the ECM. Fortunately my junkyard EMC came with a warranty of some sort. Weather they have another one or not is a good question!
Thanks 34blazer. I'll look into the AXXD after I get the MAT issue worked out.

check the wiring, make sure the +5V for the IAT is isolated by itself on pin F16, the ground can be redundant with the rest. read the link and you will see i was having the same exact problem. well i hope its as simple as that, because it took me almost a year to figure it out lol


http://www.gearhead-efi.com/Fuel-Inj...-options/page3

Well the MAT will through it off but 108 is a normal rock bottom rich BLM setting so unless you made big change it's still rich.

MAT should have 2 wires, one 5 volt reference and other to ECM. Check for 5 volt and see if data pin is in correct location on ECM.

Here's how to OHM check the sensor. CTS, IAT and MAT are all the same test.
http://www.gearhead-efi.com/Fuel-Inj...ostic-Test-CTS