clearing cel codes via mmcd

[packinkimber45]

hey guys, I was wondering about clearing codes via mmcd on a palm. if you have not done repair to fix cel code, should mmcd clear cel code at all? what I mean by this is should you be able to clear it, and off course if not fixed cel code will come back? reason I ask is tried to clear a cel just to make sure mmcd and palm is working right and it wont let me clear code. or do I need to fix problem first. thanks guys.

 

[steve]

Which ECU?
1990 ECUs are missing the function to clear the codes from the datalogger interface software, so you have to disconnect the power to clear the code.

Steve

 

[packinkimber45]

Which ECU?
1990 ECUs are missing the function to clear the codes from the datalogger interface software, so you have to disconnect the power to clear the code.

Steve

I have a 90 eprom ecu, that answers question 2 then. that is too bad. but I am not lazy I can live with that. is there any other functions via mmcd that will not work with my 90 ecu? thanks steve.

 

[packinkimber45]

reason why I asked is after correcting my safc install I checked my mas unit and previous owner hacked the crap out of the mas. both honeycombs were taken out. so I put a another stock mas from my 91gsx and now my ecu has a stored code 12 mafs. I guess I will try to determine if this mas is defective. is there a way to do that by ohming it out?

 

[steve]

Not really. The MAF has three signals it outputs, IAT. Barometric pressure, and Airflow.
IAT and Baro are variable resistances that wind up changing the voltage on the pins. Airflow is a variable square wave where the frequency changes in relation to the flow.

The easiest thing to do is pull the negative battery terminal for 30 seconds.
If the MAF isn't working you won't get a HZ on the SAFC (assuming the SAFC is set correctly)
Mine reads 3 HZ with the engine stopped. I assume it does that so the ECU can tell if it's broke vs no airflow.

'90 EPROM ECUs can resolve the problem by changing to 91+ software.

Steve

 

[packinkimber45]

Not really. The MAF has three signals it outputs, IAT. Barometric pressure, and Airflow.
IAT and Baro are variable resistances that wind up changing the voltage on the pins. Airflow is a variable square wave where the frequency changes in relation to the flow.

The easiest thing to do is pull the negative battery terminal for 30 seconds.
If the MAF isn't working you won't get a HZ on the SAFC (assuming the SAFC is set correctly)
Mine reads 3 HZ with the engine stopped. I assume it does that so the ECU can tell if it's broke vs no airflow.

'90 EPROM ECUs can resolve the problem by changing to 91+ software.

Steve

I'm getting 3hz on my safc w/ engine off and at idle. changes as it should when I drive. but I am getting code 12 mafs. do you mean changing the programming on the eprom chip? any ideas why I am getting code 12? mas is unhacked. my mods are listed on my profile. so the only function via mmcd that will now work on my 90 ecu is clearing the codes via palm, unless I upgrade the programming on my ecu chip? thanks.

 

[steve]

Did you clear the code by disconnecting the battery?

The 91+ software versions have the programming to clear the CEL codes via the datalogger.
If you have a EPROM ECU you can get a chip using the later software.

Depending on which versions of MMCd you have there are other functions that aren't supported on DSM's. That's not too surprising since the later versions are released by a guy with a 3000GT.

Steve

 

[packinkimber45]

Did you clear the code by disconnecting the battery?

The 91+ software versions have the programming to clear the CEL codes via the datalogger.
If you have a EPROM ECU you can get a chip using the later software.

Depending on which versions of MMCd you have there are other functions that aren't supported on DSM's. That's not too surprising since the later versions are released by a guy with a 3000GT.

Steve

I am going to have to do that. thing is that when I replaced the mas with the stock one, that was when mmcd found the code. my check engine light never came on. before I changed the mas I checked via mmcd and no codes were stored in the ecu. only when I changed to stock mas is when I found the stored code in ecu. I also corrected the wiring on the safc the same time, so I dont know if this contributed to this. before owner had safc hooked but air flow wire was not hooked up along with some wires hooked up to wrong wires on ecu harness. I will clear the code as soon as I get the chance to. so when you say the 91+ software are you talking about the mmcd software version or the actual software in the car ecu? sorry if that sounds like a stupid question. I have the 1.8g version of mmcd. I also have the latest one as well stored on my home pc.

I know this thread is not for this but I would like to ask you since I am already talking to a wiseman.... I dont have an afpr and injectors yet and honestly money is very tight and I cannot afford to spend one yet. however I do have a walbro 255 and a big 16g on the car since previous owner did all mods... should I leave the safc hooked up? should I disconnect it and run without it for a while as well as put back on stock fuel pump and stock turbo? not sure what I can do to car to get it running right and not screw up anything. I want to start logging, but I want this car to start running right. thanks.

 

[92awddsm]

. so when you say the 91+ software are you talking about the mmcd software version or the actual software in the car ecu? sorry if that sounds like a stupid question.

I know this thread is not for this but I would like to ask you since I am already talking to a wiseman.... I dont have an afpr and injectors yet and honestly money is very tight and I cannot afford to spend one yet. however I do have a walbro 255 and a big 16g on the car since previous owner did all mods... should I leave the safc hooked up? should I disconnect it and run without it for a while as well as put back on stock fuel pump and stock turbo? not sure what I can do to car to get it running right and not screw up anything. I want to start logging, but I want this car to start running right. thanks.

Steve was talking about the actual eprom chip itself. If you use an e391 chip in the ecu, you will have all the functions of a 91^ ecu but still use the actual 90 ecu. And the only stupid questions are the ones that are not asked.

You can leave the afc hooked up and tune it to keep fuel trims as close to 100% as possible. The 255 sometimes tends to overrun the stock fpr at idle but for the most part, they usually work fine while cruising and during low boost as long as the fpr is in good shape. Just keep boost low and save for injectors and an afpr. If you are concerned that the 255 will cause problems, reinstall the stock pump and rewire it untill you can get the other parts that are needed.

 

[packinkimber45]

Steve was talking about the actual eprom chip itself. If you use an e391 chip in the ecu, you will have all the functions of a 91^ ecu but still use the actual 90 ecu. And the only stupid questions are the ones that are not asked.

You can leave the afc hooked up and tune it to keep fuel trims as close to 100% as possible. The 255 sometimes tends to overrun the stock fpr at idle but for the most part, they usually work fine while cruising and during low boost as long as the fpr is in good shape. Just keep boost low and save for injectors and an afpr. If you are concerned that the 255 will cause problems, reinstall the stock pump and rewire it untill you can get the other parts that are needed.

ok at first I thought he meant the ecu chip but then I started to think he might have been talking about the mmcd software. should I leave the big 16g hooked up as well? the car is set for 15 psi. I have been wanting to turn it down, just not sure if I should. the car is not being driven so that was not an issue, however I would like to start driving the car . my low fuel trim is at 118%, med trim 100%, and hi trim 100%. can I do some tunning on via safc with the set up I have right now, or do I need to wait until I get the afpr and injectors? on the safc tuning guides it tells you not to use the fuel trim techniques outlined in the article unless you have an afpr. so am I ok to tune to get my fuel trims at the numbers I need? also on the afc I have read it should be set to 2 cylinder due to car only has 2 coils and I have read to set it at 4 cylinder. which one is the right setting? sorry guys, I know I have a lot of questions, but I just want to make sure I am doing things right, and that I do not blow up my car. thanks for the replies guys.

 

[92awddsm]

ok at first I thought he meant the ecu chip but then I started to think he might have been talking about the mmcd software. should I leave the big 16g hooked up as well? the car is set for 15 psi. I have been wanting to turn it down, just not sure if I should. the car is not being driven so that was not an issue, however I would like to start driving the car . my low fuel trim is at 118%, med trim 100%, and hi trim 100%. can I do some tunning on via safc with the set up I have right now, or do I need to wait until I get the afpr and injectors? on the safc tuning guides it tells you not to use the fuel trim techniques outlined in the article unless you have an afpr. so am I ok to tune to get my fuel trims at the numbers I need? also on the afc I have read it should be set to 2 cylinder due to car only has 2 coils and I have read to set it at 4 cylinder. which one is the right setting? sorry guys, I know I have a lot of questions, but I just want to make sure I am doing things right, and that I do not blow up my car. thanks for the replies guys.

Leave the b16g on and turn boost back to about 12-13 psi and tune for that. And yes, you can tune the afc for fuel trims without the regulator. I ran my car for about a year with a 255 pump and stock fpr without any issues other than a rich idle.

As for the afc, set it to 2 cylinders. If you sety it to 4 cyl, you will see that it is wrong because the rpm display will not be correct.

 

[packinkimber45]

Leave the b16g on and turn boost back to about 12-13 psi and tune for that. And yes, you can tune the afc for fuel trims without the regulator. I ran my car for about a year with a 255 pump and stock fpr without any issues other than a rich idle.

As for the afc, set it to 2 cylinders. If you sety it to 4 cyl, you will see that it is wrong because the rpm display will not be correct.

ok, I will do that and make sure it is set at 2 cylinders. turn boost down as well to 12 psi. I will do a boost leak test before I do anything as far as tuning. I will do some tuning to get my trims where they need to be. hooked up a logger to my car and my low trim is at 118%, medium trim 100%, and high trim 100%. took the car for a drive previously which I probably shouldnt have done. hopefully didnt screw anything up. anyways when I was trying to figure out the afc my fuel trims never changed. put everything back to where they were from the last owner. how about the throttle points, are they good at 30% low and 80% high? are my fuel trims where they need to be? will need to read up on tuning so I can do it right. so I can use the techniques they were going over to get the car tuned and baseline settings, thats good. when they say that if you have 450's which I have to leave both table values at zero, are they talking about the ne points hi and low throttle corrections or the throttle points hi or low.

 

[steve]

As for the afc, set it to 2 cylinders. If you sety it to 4 cyl, you will see that it is wrong because the rpm display will not be correct.

Only if you messed up and used one of the wire to the Power Transistor Module for the RPM input rather than the CAS or the Ignition Pulse Detect signals. I thing the VFAQ corrects the mistake of the SAFC install manual and uses the the CAS but I'll have to go look.

Yep it tells you to connect the Green RPM wire to pin 21 which is the CAS input. It will pulse 4 times per rev. So the SAFC should work set to 4 cylinder mode.

Steve

 

[92awddsm]

ok, I will do that and make sure it is set at 2 cylinders. turn boost down as well to 12 psi. I will do a boost leak test before I do anything as far as tuning. I will do some tuning to get my trims where they need to be. hooked up a logger to my car and my low trim is at 118%, medium trim 100%, and high trim 100%. took the car for a drive previously which I probably shouldnt have done. hopefully didnt screw anything up. anyways when I was trying to figure out the afc my fuel trims never changed. put everything back to where they were from the last owner. how about the throttle points, are they good at 30% low and 80% high? are my fuel trims where they need to be? will need to read up on tuning so I can do it right. so I can use the techniques they were going over to get the car tuned and baseline settings, thats good. when they say that if you have 450's which I have to leave both table values at zero, are they talking about the ne points hi and low throttle corrections or the throttle points hi or low.

Your fuel trims should be as close to 100% as possible. Set all corrections to 0 and tune from there with the 450cc injectors. If trims are above 100%, you need to add fuel(set corrections to +) and if they go below 100%, you need to take away fuel (set corrections to -). When you make corrections, generally, 1% on the afc equals roughly 3% in fuel trim. An example would be, 118% ltft would be lean so you would want to go to about +6 on the low throttle correction at 1000 rpm. Once you get the ltft close to 100%, drive the car around after it is fully warmed up in low rpm and try to keep tps reading below 30% and see where the trims go and adjust as needed in the rpm range you are running. This is always easier if you have someone with you that can drive while you tune or vice versa.

As for the mid and high throttle trims being at 100%, that is pretty normal when you first hook up the afc. The mid and high doesnt begin to change until coolant temp gets over 185% and you get into heavier acceleration and wot. As long as you are running low boost and have corrections set at 0, you should be pretty safe to go out and start running the car hard enough to get trims to start cycling. Tuning isnt that hard but there is a learning curve to it. You are doing the right thing by learning to fine tune with the 450's before you jump to larger injectors. This way, it will make your tuning process easier with larger injectors because by then, you will be familiar with the afc and how it works.

 

[packinkimber45]

Your fuel trims should be as close to 100% as possible. Set all corrections to 0 and tune from there with the 450cc injectors. If trims are above 100%, you need to add fuel(set corrections to +) and if they go below 100%, you need to take away fuel (set corrections to -). When you make corrections, generally, 1% on the afc equals roughly 3% in fuel trim. An example would be, 118% ltft would be lean so you would want to go to about +6 on the low throttle correction at 1000 rpm. Once you get the ltft close to 100%, drive the car around after it is fully warmed up in low rpm and try to keep tps reading below 30% and see where the trims go and adjust as needed in the rpm range you are running. This is always easier if you have someone with you that can drive while you tune or vice versa.

As for the mid and high throttle trims being at 100%, that is pretty normal when you first hook up the afc. The mid and high doesnt begin to change until coolant temp gets over 185% and you get into heavier acceleration and wot. As long as you are running low boost and have corrections set at 0, you should be pretty safe to go out and start running the car hard enough to get trims to start cycling. Tuning isnt that hard but there is a learning curve to it. You are doing the right thing by learning to fine tune with the 450's before you jump to larger injectors. This way, it will make your tuning process easier with larger injectors because by then, you will be familiar with the afc and how it works.

so my car is running lean then. how about the throttle points... there is two settings, hi and low... in the tunning guide it says to have at 30% low and 80-85%hi. is that where I should set mine as well? if not what values should I have on mine. I will try that at 1000 rpm... do I set that on both hi and low ne point 1k rpm? how about the rest of the ne points for the rest of the rpm ranges on both low and hi? when I hooked up a logger the other day and went for a drive, I left the setting the last owner had on afc and went for some wot pulls and got lots of knock.... as high as 43! I got really scared and stoped. I tried doing some changes, knock went down a little bit, but still high like in the high twenties or mid thirties. after doing those changes my mid and high trim was still 100%, not that I want to change it, but they never seemed to change. sorry I have a lot of questions but I have never done this before and its hard for me to understand the tutorials in the tech area. I do really want to learn this though. I want to do my own tuning though since it is one of the most crucial things you do on dsms. thanks.

 

[packinkimber45]

....

 

[packinkimber45]

^^^^^steve....92awddsm... still there?. or anyone

I am going to try to adjust the safc this weekend, however what isnt clear to me at this point is what percentages I should have the throttle point set to. as far as hi and lo. thru some research today and yesterday, I am confused if I should have th-point lo at 30% and th-point hi at 80% or do I have it as th-point lo at 69% and th-point hi at 70% or do I need it at different values since I am using my stock 450's injectors. thanks in advance again.

once I have some success I will post logs.

 

[steve]

I was waiting to see if you would read enough to figure out what this was for and why to set it one way or the other. The manual isn't too bad in this regard. The throttle point sets the TPS percentages where the hight and low throttle settings apply, inbetween the SAFC interpolates between them for the correction value. If you high and low setting are identical then the throttle point doesn't matter. If you set them at like 69/70 then no interpolation happens you either on the low setting or the high settings.

I usually use the low settings for closed loop corrections and the high settings for open loop. To start out with your going to have the same values in both. Since you have stock injectors the only thing your trying to do right now is fix some of the FPR overrun problems. Just following Kyles guide to start until you learn more.

http://www.dsmtuners.com/forums/showthread.php?t=58403
http://www.dsmtuners.com/forums/showthread.php?t=111005

Steve

 

[packinkimber45]

I was waiting to see if you would read enough to figure out what this was for and why to set it one way or the other. The manual isn't too bad in this regard. The throttle point sets the TPS percentages where the hight and low throttle settings apply, inbetween the SAFC interpolates between them for the correction value. If you high and low setting are identical then the throttle point doesn't matter. If you set them at like 69/70 then no interpolation happens you either on the low setting or the high settings.

I usually use the low settings for closed loop corrections and the high settings for open loop. To start out with your going to have the same values in both. Since you have stock injectors the only thing your trying to do right now is fix some of the FPR overrun problems. Just following Kyles guide to start until you learn more.

http://www.dsmtuners.com/forums/showthread.php?t=58403
http://www.dsmtuners.com/forums/showthread.php?t=111005

Steve

thanks steve. I actually have been reading the articles on safc tuning and how it works in the tech area for the last two days. not trying to get easy answers here, just trying to understand. this is new for me, and a little bit scary since I know what could happen if I screw something up. as far as the manual I dont have the manual on the safc since it was already on the car when I bought it. I will look for the manual online to reference to. what I dont understand is this statement in the link you provided which is what I have been reading the last two days.....

"In the Th-Point section of the SAFC, set the low trigger at 30%, and the high trigger around 80-85%.

In the NePoint section, set them to: 1k, 2k, 3k, 4k, 4.5k, 5k, 6k, and 7k,.

Now, you want to use baseline corrections for fuel injectors. If you have 450's, leave both tables at zero. If you have 550's, put them around -10%. If you have 660's, usually around -18% would be a fine starting point. If you have a hacked MAS, then you will want to use about 5% MORE than these values. "

"leave both tables at zero"... is the th-point lo and hi that is being referred to or the ne points where you make the corrections? thanks.

 

[steve]

"In the Th-Point section of the SAFC, set the low trigger at 30%, and the high trigger around 80-85%.

In the NePoint section, set them to: 1k, 2k, 3k, 4k, 4.5k, 5k, 6k, and 7k,.

Now, you want to use baseline corrections for fuel injectors. If you have 450's, leave both tables at zero. If you have 550's, put them around -10%. If you have 660's, usually around -18% would be a fine starting point. If you have a hacked MAS, then you will want to use about 5% MORE than these values. "

"leave both tables at zero"... is the th-point lo and hi that is being referred to or the ne points where you make the corrections? thanks.

Kyle is talking about the two correction tables, hi-thrtl and lo-thrtl, not the th-point or the ne points.

Steve

 

[packinkimber45]

Kyle is talking about the two correction tables, hi-thrtl and lo-thrtl, not the th-point or the ne points.

Steve

ok so the hi thrtl and lo thrtl correction table where you set 1k 2k 3k etc... ok I think I understand. ok then what settings do I set the th-point lo and th-point hi then? 30% 80% or 69% 70% or different values due to my mods? sorry, I'm beginning to sound repetitive here. I just want to make sure I am not missing anything.

 

[want_a_gsx]

make sure you have the "sensor type" in the SAFC set on Karman. i had it on a different sensor and the check engine light went on. as soon as i put it on karman, it cleared up