1991 Isuzu Impulse RS (Delco Management)

**90base** · 01-07-2016

Hello,

I make a thread a while back (long while) http://www.pcmhacking.net/forums/viewto ... 590#p32569 about my Geo Storm running Isuzu Impulse RS Management with a Boosted Impulse engine and was interested in doing some tinkering with TunerPro.

Can anyone help me out? I found an ADX file for the LOTUS ELAN M100 which has the same engine and ecm confiugraion along with most of the sensors. Someone over there said they could help me disassemble the BIN file. But I havent seen a response.

Some Information

ACDELCO Part # 88999205 {#16142013}

PROM # AUFM 0669

PROM ID in Datamaster : 9969

1991 Isuzu Impulse RS
1.6L Turbocharged AWD
Delco Engine Management with Waste Spark setup

**1project2many** · 01-07-2016

I'm not sure I can help much. A freely available checksum utility identified it as a valid .bin based on the checksum and gave it a mask ID of B4. It looks like your scan software identified the correct promid of 9969.

Disassembling a file can take time. Lots of it. I'm sure a few folks here who have some experience could help with tips and tidbits but just like delcohacking, it will likely come down to you doing most of the work. Sorry... it would be a cool project but it's a huge amount of time. :(

I did find this neat little manual online: http://www.lotusm100.com/manuals/Ela...-Manual-v6.pdf
Does your vehicle use the same ALDL plug as what's on the ninth page?

The program in the .bin looks fairly simple. There is a lot of unused "space" in the code which you can see with a hex editor. I'm guessing the ecm doesn't interface with the gauges or control the transmission? If so you may be able to use a more common ecm to run the engine. The 36th page has an illustration of a cam driven crank/cam sensor which is very cool. It looks like it may have been designed to work with a "seven notch" DIS system similar to what was used in many GM four and six cylinder engines in the late '80s and '90s. The next page shows the same style ignition coils used with the seven notch systems. P.62 shows the same signals are used as with the other GM ignitions of the era and P.64 shows a module that looks like one from an '87 to '93 Cavalier 2.0 / 2.2.

If you decide to persue this route there are some significant questions to answer:
1) Is the crank signal compatible with the seven pin GM module, or can the Isuzu module be used with a different ecm?
2) Is the intake manifold valve in the Lotus manual present on the Isuzu engine? Can it be controlled by an alternate GM ECM with stock programming?
3) What is the CO potentiometer (P.132)? Is it present on the Isuzu engine? How does this part work in conjunction with the emissions system? Is it compatible with another stock GM ECM?
4) How much more do we not know about the Isuzu system that might impede success?

Good luck, and please keep this thread updated.

**90base** · 01-07-2016

Originally Posted by 1project2many

I'm not sure I can help much. A freely available checksum utility identified it as a valid .bin based on the checksum and gave it a mask ID of B4. It looks like your scan software identified the correct promid of 9969.

Disassembling a file can take time. Lots of it. I'm sure a few folks here who have some experience could help with tips and tidbits but just like delcohacking, it will likely come down to you doing most of the work. Sorry... it would be a cool project but it's a huge amount of time. :(

I did find this neat little manual online: http://www.lotusm100.com/manuals/Ela...-Manual-v6.pdf
Does your vehicle use the same ALDL plug as what's on the ninth page?

The program in the .bin looks fairly simple. There is a lot of unused "space" in the code which you can see with a hex editor. I'm guessing the ecm doesn't interface with the gauges or control the transmission? If so you may be able to use a more common ecm to run the engine. The 36th page has an illustration of a cam driven crank/cam sensor which is very cool. It looks like it may have been designed to work with a "seven notch" DIS system similar to what was used in many GM four and six cylinder engines in the late '80s and '90s. The next page shows the same style ignition coils used with the seven notch systems. P.62 shows the same signals are used as with the other GM ignitions of the era and P.64 shows a module that looks like one from an '87 to '93 Cavalier 2.0 / 2.2.

If you decide to persue this route there are some significant questions to answer:
1) Is the crank signal compatible with the seven pin GM module, or can the Isuzu module be used with a different ecm?
2) Is the intake manifold valve in the Lotus manual present on the Isuzu engine? Can it be controlled by an alternate GM ECM with stock programming?
3) What is the CO potentiometer (P.132)? Is it present on the Isuzu engine? How does this part work in conjunction with the emissions system? Is it compatible with another stock GM ECM?
4) How much more do we not know about the Isuzu system that might impede success?

Good luck, and please keep this thread updated.

I took a look through that manual the other day. I do have an IAC on the Intake manifold but it is just after the throttle body, not on the opposite side. I have no problem doing alot of this myself with just a few pointers along the way. I have never messed with these systems , so Im still a NEWB so to speak. I have howver learned to convert decimal to hex, and hex to decimal to facilitate this project. I look forward to working with you and really appreciate you taking the time to answer. Im at work now, when I get home I will update this thread with all of the information that you have asked!

Thanks

Brandon

**90base** · 01-16-2016

Sorry its been so long but here is a little update to answer some information from your post.

http://www.ebay.com/itm/Ignition-Con...dVzMDO&vxp=mtr

That is the exact Ignition Module for my car. Although the ignition modules from the 2.0 Cavaliers worked as well. They had a different part number but multiple users have tried them with success.

The IAC valve on my car is on the throttle body its self and not on the opposite side of the manifold like on the elan. I have no clue as I am the first person to try anything like this with my car. Although it is the same IAC used on many other GM models, therefore I wouldnt imagine we would have any issues there. https://www.google.com/url?sa=i&rct=...53059435619759

Not exactly sure what a CO Potentiometer is but from a simple google search it appears to be some sort of Intake Air Temp Sensor, which my car does have and is the same as many other GM models. This car was built by Isuzu when GM was Majority Stock holder. While it is of Isuzu design GM did get to put their hands on some of it, Mainly the Engine Management System.

I have the standard Pluger type IAC valve found on Most GM vehicles of the era. http://www.ebay.com/itm/Fuel-Injecti...tVpL-g&vxp=mtr

I have a Standard GM 2-Bar MAP Sensor http://www.ebay.com/itm/GM-2BAR-MAP-...NWUyFc&vxp=mtr

I have a Standard 2pin Coolant Temp Sensor http://www.ebay.com/itm/Ac-Delco-213...ZSpkqe&vxp=mtr

I have a standard GM Throttle Position Sensor http://www.ebay.com/itm/NEW-PREMIUM-...ZUigaz&vxp=mtr

I have what appears to be a standard GM ecm that has the removable MEM-CAL chip in it along with the ESC board.
WHILE THIS ISNT MY ECM IT IS VIRTUALLY IDENTICAL, EXCEPT THIS ONE DOES NOT HAVE A MEM-CAL
https://www.google.com/url?sa=i&rct=...53059671111380

I am able to get Datamaster TTS to datalog the ECM just fine using a small Ebay board to do the negotiating. I have been provided with a few tables which are still unknown at this point and an adx to get tunerpro to atleast communicate. I am willing to do any learing I need to just need a little guidance along the way.

If you can be of further help I would really appreciate it!

Thanks

Brandon

**1project2many** · 01-17-2016

The air valve I am referring to is a vacuum actuated valve which selects long or short runners in the manifold. It is controlled by an electric solenoid. (Pp. 57-59) You are correct that it's at the opposite side of the manifold from the throttle body (p. 74) but it is definitely not the IAC (Pp. 59-60).

The CO potentiometer is not an air intake sensor. Please see p. 49. "The CO potentiometer is a variable resistor, the adjustment of which controls the base setting of the air/fuel ratio." It sounds like a way to change what we often call the "desired AFR." Neat idea. There is no equivalent device that I'm aware of in US emisisons compliant GM cars.

Does tunerpro appear to relay correct data for the engine?

I think you should spend time studying the Lotus manual. Like GM service manuals, it has very good information which will be key to finding success if you wish to change to a different ecm. If you choose to use the 1227749 then you'll want a copy of the wiring diagrams and service manual for a Pontiac Sunbird, roughly 1991 vintage. Diagrams are available on this site but I don't know of a source for the complete FSM online.