OBDII conversion - troubleshooting time
12-08-2007, 11:25 AM
#21
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Originally Posted by jr's3800
I think from a tuneability standpoint we stand to learn a lot here.. We will have to get the base programming close to right and that will be done with a lot of the data that we have from the stock chip, then he will be able to have the changes done as he learns more or for what he plans to do with the system..
I think this will be a step in the right direction and we will have learned a lot from this in terms of what can be done, what can't be done and tuneability... So this does spark my interest.. This will also provide Brad with what he would need if he ever decided to do a series II swap in the future..
All in the learning process.. And Brad is aware of all of the possibilities that may or may not happen.. So we will learn from this process
I think this will be a step in the right direction and we will have learned a lot from this in terms of what can be done, what can't be done and tuneability... So this does spark my interest.. This will also provide Brad with what he would need if he ever decided to do a series II swap in the future..
All in the learning process.. And Brad is aware of all of the possibilities that may or may not happen.. So we will learn from this process
12-09-2007, 10:30 AM
#22
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Gonna have to put this on hold for a few weeks.
A major component of a certain vehicles resurrection has been delivered
A major component of a certain vehicles resurrection has been delivered
12-09-2007, 03:27 PM
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Originally Posted by sandrock
Gonna have to put this on hold for a few weeks.
A major component of a certain vehicles resurrection has been delivered
A major component of a certain vehicles resurrection has been delivered
12-21-2007, 01:16 PM
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Alright, a little update. (I actually posted this, then deleted it because I was not sure, but now I am sure, so it'* time to rewrite it again).
I swiped two ICM harnesses from Don yesterday. One is specific to a 1993 L27/67, the other is specific to any Series 2 96-up. There is only one small difference between the two, and that would be an addition of the ICM ground on the S2 harness. After looking at the 93 FSM schematics for the ICM, it looks like there are only these grounds: pin L (ref low(ground)), and pin M (sensor grounds). On the S2 harness, pin K is populated, and goes to the ground rung on that harness.
Now, on the ICMs I have seen, pin K is not even there. This is probably of no importance, but I thought I would share that info with anyone who is interested.
I swiped two ICM harnesses from Don yesterday. One is specific to a 1993 L27/67, the other is specific to any Series 2 96-up. There is only one small difference between the two, and that would be an addition of the ICM ground on the S2 harness. After looking at the 93 FSM schematics for the ICM, it looks like there are only these grounds: pin L (ref low(ground)), and pin M (sensor grounds). On the S2 harness, pin K is populated, and goes to the ground rung on that harness.
Now, on the ICMs I have seen, pin K is not even there. This is probably of no importance, but I thought I would share that info with anyone who is interested.
12-21-2007, 02:59 PM
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Kind of an off note.... But we were looking at Boozes car and Brads 93 SSEi... The One thing I forgot was that the 96+ uses the V5 Compressor, and not the HR6 Compressor...
So do we try to use the HR6 which is designed to cycle on and off or the V5 Variable unit... I would think we should be able to make the V5 Variable unit work, but will thew Bracket I have Fit on the series 1 engine...? I think I still have that Bracket... I'll have to bring it with me the next time for a quick line up fit on the new Booze motor...
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So do we try to use the HR6 which is designed to cycle on and off or the V5 Variable unit... I would think we should be able to make the V5 Variable unit work, but will thew Bracket I have Fit on the series 1 engine...? I think I still have that Bracket... I'll have to bring it with me the next time for a quick line up fit on the new Booze motor...
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12-23-2007, 10:22 AM
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Don, I compared the wiring diagrams for both AC systems. Both of them use the same setup as far as power to the clutch is concerned. In other words, there is no variable output to the new style compressor...it is a solid 12 volts, just as the older compressor.
The difference is that the OBD2 uses a pressure sensor, whereas the older system uses pressure cycling and high pressure cutoff switches , inline with the AC request input. The AC refrigerant head pressure fan switch found in the older system is eliminated in the OBD2 setup. So, in other words, the newer system uses one sensor to do the work that 3 switches used to do in the older system.
To mimic the older system, it appears all I will have to do is find out what resistance the OBD2 pcm expects to see in order to turn on the high-speed fan relay, and leave in the pressure and cycling switches. Or if I want to go to the variable, fit that compressor in and add the pressor sensor. No other mods will be necessary.
Going back to the ICM, it appears the 1995 vin 1 uses pin K, and I will have to look later to see if the 94 L27 uses it. This, however, is NOT pcm dependent, as the ICMs interchange between even the 92/93 (which do not use pin K) models and all S2 models. It would be interesting to see how many ICM-related issues the 92-93s have as opposed to the rest of the line, and the solution was a bad ground.
The difference is that the OBD2 uses a pressure sensor, whereas the older system uses pressure cycling and high pressure cutoff switches , inline with the AC request input. The AC refrigerant head pressure fan switch found in the older system is eliminated in the OBD2 setup. So, in other words, the newer system uses one sensor to do the work that 3 switches used to do in the older system.
To mimic the older system, it appears all I will have to do is find out what resistance the OBD2 pcm expects to see in order to turn on the high-speed fan relay, and leave in the pressure and cycling switches. Or if I want to go to the variable, fit that compressor in and add the pressor sensor. No other mods will be necessary.
Going back to the ICM, it appears the 1995 vin 1 uses pin K, and I will have to look later to see if the 94 L27 uses it. This, however, is NOT pcm dependent, as the ICMs interchange between even the 92/93 (which do not use pin K) models and all S2 models. It would be interesting to see how many ICM-related issues the 92-93s have as opposed to the rest of the line, and the solution was a bad ground.
12-23-2007, 06:27 PM
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I was saying the the HR6 is a Compressor that cycles... It has to as it isn't variable in any manner, this is the reason the system was designed to cycle...
The V5 is a Variable unit that does not cycle while on... Its a Variable unit and the system pressure is ramped up or down for the varying cooling ability and I believe thats controlled with the Pressure sensor...
I believe that you will be able to go to the V5 unit if you so desire.. Take a look at the Malibu, tou have a V5 compressor on it but with a Smaller clutch
And I think I still have the V5 Compressor Bracket from the 99 Motor, but we'd have to see if it will fit your car
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The V5 is a Variable unit that does not cycle while on... Its a Variable unit and the system pressure is ramped up or down for the varying cooling ability and I believe thats controlled with the Pressure sensor...
I believe that you will be able to go to the V5 unit if you so desire.. Take a look at the Malibu, tou have a V5 compressor on it but with a Smaller clutch
And I think I still have the V5 Compressor Bracket from the 99 Motor, but we'd have to see if it will fit your car
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12-23-2007, 06:44 PM
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Very interesting work you have going on. Nothing really pertains to my car but I will keep an eye on your progress because it amazes me what you are capable of doing. So many people on here have gone way beyond normal repairs or mods. I love being surrounded by 3800 gods 
12-23-2007, 07:29 PM
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Well, I wouldn't consider myself a god...not until this engine runs with this mod that is
The A/C system, though I have figured it out, is NOT important to getting this mod to work. In fact, if I were to run this engine alone on the OBD2, modifications would be minimal. It'* getting all the existing peripherals to coexist with the new computer that'* the trick.
Speaking of peripherals, I am still hashing out the harness for the OBD2 computer. The sector I am working on now is the transmission connector. For those that kept up with my progress on this car, they know about my transmission buildup. For the uninitiated, here is the Cliff Notes version: a '95 HD trans with a modified channel plate so I could use the '93 electronics setup. This means having a temp switch instead of a sender. It also means that I have one of two options: 1) Modify the trans connector to interface with '93 spec electronics, or 2) Change out the trans internal harness and go back to a 1995 setup.
Since I am doing this in such a way as to go back to a '93 PCM as a backup, I elect to modify the PCM harness. Only pins "D" and "E" (TCC apply and 12v in) stay the same. The rest either get shuffled around, deleted, or in the case of the trans temp sender, get their own harness. One item of note is that for the '93 trans to be electrically identical to the 95, pin "A", which normally goes to "TCC brake input" on the 93 pcm, will now double-up with pin "E", which supplies the transaxle solenoids a positive 12 volts. The OBD2 pcm takes its brake switch input directly from the brake pedal and does not share with the transaxle like the '93 does.
The A/C system, though I have figured it out, is NOT important to getting this mod to work. In fact, if I were to run this engine alone on the OBD2, modifications would be minimal. It'* getting all the existing peripherals to coexist with the new computer that'* the trick.
Speaking of peripherals, I am still hashing out the harness for the OBD2 computer. The sector I am working on now is the transmission connector. For those that kept up with my progress on this car, they know about my transmission buildup. For the uninitiated, here is the Cliff Notes version: a '95 HD trans with a modified channel plate so I could use the '93 electronics setup. This means having a temp switch instead of a sender. It also means that I have one of two options: 1) Modify the trans connector to interface with '93 spec electronics, or 2) Change out the trans internal harness and go back to a 1995 setup.
Since I am doing this in such a way as to go back to a '93 PCM as a backup, I elect to modify the PCM harness. Only pins "D" and "E" (TCC apply and 12v in) stay the same. The rest either get shuffled around, deleted, or in the case of the trans temp sender, get their own harness. One item of note is that for the '93 trans to be electrically identical to the 95, pin "A", which normally goes to "TCC brake input" on the 93 pcm, will now double-up with pin "E", which supplies the transaxle solenoids a positive 12 volts. The OBD2 pcm takes its brake switch input directly from the brake pedal and does not share with the transaxle like the '93 does.