SD2 quirks

[TurboBuRick]

Paul, do you have the braided ground strap from the back of engine to firewall? Tight?

 

[Paul69camaro]

Dave and Rick,

Thanks again for the help, I had to fly out on a last minute business trip but when I get back I hope to continue digging in. I'll check for the braided ground strap on the back of the engine Rick but I do know that I have a 4 awg ground from the front of the motor straight to the battery.

Paul

 

[TurboBuRick]

The 4 awg from the battery grounds the motor and makes it the main ground for the entire car. The ground strap from the firewall to the engine grounds the body of the car. We want to make sure the body has a solid link to the engine.

Rick

 

[Paul69camaro]

Ground strap is there and is secured tightly. I'm going to add an addition ground back there just to be sure. Since I got back in town, weather has sucked so no progress has been made.

Paul

 

[Paul69camaro]

Finally got a chance to spend some time on the car, unfortunately not much progress was made. I added a ground off the back of the engine to the firewall and double check all the other ones off the main harness. Using a voltmeter I verified continuity between the engine and firewall and also to the battery. Readings showed .2 ohms so I'm fairly confident an engine ground isn't the issue. I also checked the ground on the MAP sensor and that was solid as well. I pulled the computer out and inspected the pins for corrosion and ensured the powerlogger was full seated, everything checked out. Car still does the same thing as before, where the correction will pull max fuel when the lights are on, it even changes by simply hitting the brakes... One good thing was that I changed the acceleration enrichment (cell 12) to 240 and it helped with the lean spike but it is still there. It improved by almost an entire point (if before it was around 12.5:1 now its 11.7:1). The car still shows a bit of knock during that time and the injectors still max out for a split second. I think my next step is going to be to replace the pump and lines with racetronix units in anticipation for using the flex fuel feature of this chip and see if the current walbro in there is just tired (probably 10 years old but only around 5K miles on it). Hoping that'll fix the lean spot. I'm not sure what else to do regarding the lights on issue, any of yall think it could be caused by HID lights?

Paul

 

[TurboTdr3.8]

I'm not sure what else to do regarding the lights on issue, any of yall think it could be caused by HID lights?

The HID lights have a transformer to run the voltage way up to the make the HID light to work , it could be interfering with the PL with the RF noise , same as the non resistor spark plug that someone else had problems with making the car act up also , This is just a SWAG at this point . might try standard headlights and see what happens .

 

[huntsg]

You said you checked the ground on the MAP sensor. An easy check is to run a wire from MAP sensor ground to the battery ground and then turn on the lights. This will be definitive.

 

[Eric Stage I]

We need to see how much the voltage changes from lights on to lights off. Maybe we can tune this out with the injector offset table. Also see if the MAP signal is changing lights on/off.

On the lean spike, this looks to me like the VE table needs tweaking. It doesn't look like a fuel supply problem. The VE probably needs to be increased about .1-.2 seconds before the lean spike.

 

[Paul69camaro]

Guys, Thanks again for the quick replies. Eric, If I'm not mistaken, the MAP signal does change with the lights... I'll take a quick log tonight of the car idling and switch the lights on and off and post it up. The impedance from the ground on the MAP and the battery is around .1-.2 ohms. I'll also disconnect the HIDs and see if that is causing the issue. I kind of doubt it because like I mentioned earlier, when the brake lights come on, it also messes with the correction factor but no where near as much as the headlights.

Paul

 

[Paul69camaro]

Just an update, messing with the HID's did nothing, it acted the same way with regular headlights plugged in... I also replaced the battery since the old one looked a little low but that didnt do anything either. I'm attaching two logs below, one is with the car running at idle switching the headlights on and off every 10 seconds, the second is with the car off doing the same thing but every 5 seconds. The MAP reading definetley changes with the lights... Thanks agin for y'alls help.

Paul

 

[Paul69camaro]

I ran the ground from the map sensor and the headlights directly to the battery. Same issue... I don't know what else to do at this point beside replace the map sensor. Any ideas? Eric, do you think the injector offset table can help this?

Paul

 

[TurboBob]

grounding to the battery has helped a couple guys, but its not the best solution. If you look at your engine off log, where you are switching the headlights on and off. The MAP reading changes, but the TPS does not.... so, we want to power the MAP sensor like the TPS.

1, have you done anything with the 5v to the MAP sensor
2, is your car a digital dash car or analog.
3, remove the MAP ground wire to the battery, you can try connecting it to the engine, thats where it needs to go anyway.


Bob

 

[Paul69camaro]

Bob,

Thanks for chiming in!
1. The 5 volt for the map sensor was fed off the 5 volt TPS supply from the TCI transmission computer (EZ-TCU)
2. My car is a digital dash car
3. Where on the engine do you recommend? Should I connect the MAP power and ground to the factoryTPS power and ground?

Thanks for your help.

Paul

 

[TurboBob]

Bob,

......Should I connect the MAP power and ground to the factoryTPS power and ground?

Thanks for your help.

Paul

yes

 

[Paul69camaro]

Bob,

I'm sure it's been said a million times but you sir are a badass! I finally got a chance to work on the car today since I've been out of the country and after changing the ground over to the TPS my problem was fixed. The MAP signal no longer jumps. I haven't logged a run yet but I think the lean spot is gone because I don't get a hint of knock anymore at WOT. If we ever cross paths I'm buying you a beer!