SD2 quirks

[Paul69camaro]

I really hope someone can help me cause I'm stumped. I switched over to the SD2 chip over the weekend and got the car running decently smooth. I followed the directions and set the fuel pressure, IAC and TPS as specified. I have not touched the VE tables but in the 16 parameters I've set it to closed loop (097) for parameters 2-4. I set my injector size to 50 but had to turn the offset down to around 5 to get the corection down. Here is were it gets weird, sometimes the car idles around were its set, but more often the correction maxes out (removing 10% fuel) and the car runs rich. Tonight I decided to mess with it some more and at times thAFR correction would stay around 0 even thought the AFR was off over 1 point (rich). To add to the story line the car will sometimes drive around and hit the AFR from the tables but then most the time it won't (runs rich). I tried bumping the injector size up to 55 and that seemed to fix it for like 10 minutes but then all of it sudden it pegged out the correction (adding 33% fuel). What am I doing wrong?

Paul

I'm adding a couple of logs. I'm not sure why the parameters didn't show up on the Idle log (wonder if that has anything to do with it?)

 

[huntsg]

So did you set parameters 1, 5, and 6? These will get the tune close at idle and cruise around speed while keeping the tune smooth between squares in the table. These are the first place to start.

 

[huntsg]

Also, post a log for us to look at.

 

[Paul69camaro]

Huntsg,

Thanks for the help! I uploaded a couple of logs in the first post. I did mess with parameters 1,5 and 6. It seems to get the AFR correct for a bit then it'll go way lean. It's like the setting don't stay programmed or something. I'll then adjust them back and it'll go way rich again. I'll try to get more logs tomorrow but earlier today just ad idle I changed the injector size and offset to 55lbs and 25, it idled perfect with little correction for like 2 minutes and then it went way lean...

Paul

 

[Paul69camaro]

Also, I'm assuming I can make changes with the car running by entering the value and simply pressing enter right?

 

[huntsg]

I'll take a look when I get home. One thing that is paramount is that the powerlogger is seated securely on the ECM. Otis now running the car so it has to be right and can't move.

 

[huntsg]

You can but be careful. It has to be in monitor or record mode.

 

[huntsg]

Also make sure you're running the latest version of plc and your chip is flashed with the most current version. I think there is a sticky in this section with them.

 

[Eric Stage I]

Your TPS signal is way too jumpy. This is causing it to jump in and out of idle mode fueling, and causing other problems. At idle, the voltage should not jump around. There may be a wiring/ground problem or bad sensor.

 

[Paul69camaro]

Thanks Eric! I'll order a new one tomorrow and see what it does but I think your right. I noticed every now and then the TPS would stay steady and the car would idle nice but didn,t think it would be that big of a deal. Thanks again!

Paul

 

[Paul69camaro]

So I received a new ac delco TPS sensor today. Before I installed it I started the car with the old sensor and it was perfectly steady for the first 5 minutes the car ran. After that it started jumping around again so I swapped in the new one and still had the same issue. I checked voltage at the sensor and my meter read 4.98 volts. I checked continuity between the negative battery terminal and the negative terminal on the tps plug and that seemed good. Im starting to run out of ideas but tomorrow I plan to check the ECM and wiggle stuff around to see if anything changes. I did notice that with the car off the TOS reads way lower than when it's running (around .32-.34 volts), is this normal? Anyone have any other advice or suggestions?

Paul

 

[TurboTdr3.8]

I did notice that with the car off the TOS reads way lower than when it's running (around .32-.34 volts), is this normal? Anyone have any other advice or suggestions?

It should stay close to what it set at like mine is .42 running at idle and when the engine is off it may be at.40 .

 

[TTA308]

I say 42 key-on and 44 at idle... seems to work for most.

 

[Paul69camaro]

I must be having electrical gremlins cause I swore I had the tps set but this morning I went out and had to mess with the car again. Engine off the TPS was now at .32 volts. I started the car and it was .34 so I adjusted it again to .42. I wiggled the ecm connectors trying to get it to act up but stayed steady. I drove it all day today and no issues... I was able to tune some more today and the car is running better than ever. Spool up and throttle response is day and night better than before. I've got the car back up to 20 lbs on alky and it feels strong, it's time to start adding more boost but I'm hesitant to do that until I know the tps issue is resolved 100%.

 

[toomanymodz]

I do believe one of the modifications when switching to SD2 is to ensure a 5 volt reference is used so that the powerlogger has a correct boost reading. This requires a cut/splice behind the glovebox and tapping into wire C14 at the ECM. That wire is the 5v to the TPS. I would check that connection or re-do it with solder and heat-shrink tubing. I bet that is where your gremlin is.

 

[TurboTdr3.8]

I do believe one of the modifications when switching to SD2 is to ensure a 5 volt reference is used so that the powerlogger has a correct boost reading. This requires a cut/splice behind the glovebox and tapping into wire C14 at the ECM. That wire is the 5v to the TPS. I would check that connection or re-do it with solder and heat-shrink tubing. I bet that is where your gremlin is.

I used the harness jumper from Alky control to get the 5 v from the tps and run from map sensor straight to pl analog connector so you do not have to cut the wire at the ECM for C14 , less splicing the better off you are . I do not know if this will cure your problem but I see where you are coming from

 

[TTA308]

I must be having electrical gremlins cause I swore I had the tps set but this morning I went out and had to mess with the car again. Engine off the TPS was now at .32 volts. I started the car and it was .34 so I adjusted it again to .42. I wiggled the ecm connectors trying to get it to act up but stayed steady. I drove it all day today and no issues... I was able to tune some more today and the car is running better than ever. Spool up and throttle response is day and night better than before. I've got the car back up to 20 lbs on alky and it feels strong, it's time to start adding more boost but I'm hesitant to do that until I know the tps issue is resolved 100%.

Put the TPS at 42 with the key OFF, any lower than this and it tends to move around from my experience.

 

[Paul69camaro]

I finally got some time to mess with the car again today. Driving around even with the parameter 1 and 5 at 105 it still pegs out the correction (-10% fuel) anytime I'm into parameters 6-8 (set at 120, 118, 118 respectively) the correction is within 5%. I tried putting the TPS at .42 with the car off and it still moved around between .44 and .46 so I took it back down to .42-.44 with the car on. I check grounds, and connections (all soldered joints) and even added grounds directly to the engine and TPS of the battery and nothing changed. While looking at the parameter table with the car idling it doesn't seem to move off parameter 1 like it used to with the old TPS sensor. I'm confused because I can get the car to drive great but Idles rich. If I change the injector size (make it 60lbs) corrections for parameters 1 and 5 are more reasonable but the rest are way lean. Any ideas? Should I just start digging into the VE tables and say screw the global parameters? Thanks in advance for y'alls help.

Paul

 

[Eric Stage I]

Yes, go into the VE table at the MAP and RPM where it's rich and start reducing VE until the correction is close to zero.

 

[Paul69camaro]

Eric,
Thanks for the quick reply! Is this something that you have run across before? Also, the chip has been updated to the flex fuel version but I'm not running a flex fuel sensor (the maf connector is just unplugged), is there a setting somewhere that I need to adjust? Thanks again.

Paul