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6 minute(s) of a 128 minute read
7-21-2010
Both AMS boost controllers come with MAP sensors. The AMS500 has one built into it with a 1/8 threaded port on the side of the box. The AMS1000 has a remote mounted MAP sensor that just get's wired into the box. If you do some research, you will find that NLR (the company that makes the AMS) recommends that you drill and tap a second 1/8" port on the top of the gate and screw the MAP sensor directly into the gate for best boost control. The MAP sensor in this application does not measure manifold pressure but instead is used to measure the actual amount of boost or CO2 pressure that is being applied to the top of the wastegate. It uses this measurement to control the solonoids and maintain a fixed (whatever you are commanding with the controller) amount of pressure on the top of the gate. This is why it offers better boost control than everyone else. So back to the MAP sensorlocation. If they ideally want the MAP sensor in the gate, then logic dictates that they want to MAP sensor as close to the gate as possible. I did not drill my gate. Instead I have a T screwed into my top port. One side goes to the boost/CO2 port (which is coming from the T that is between the 2 noids) and the other side goes to the boost controller.
I requested a change to the 9sec club about 2yrs ago thru the drag racing section. I guess that whomever is responsible for doing that hasn't processed my request yet. Since then, I have been to the 8 sec club. I stopped caring about that a long time ago.
I'm also crew chief and tuner for a 7 second street car. That and quarter will get you a piece of bubble gum in most states.
I swapped out the TPS and it made no difference.Timing and fueling trims (over/under idle corrections) still didn't work. I called AEM and explained the issue. They told me that my tps should never read zero. It should swing from 0.00-1.00% at idle. Know, keep in mind that I used the ECU SETUP/TPS CALIBRATION to set it up which is how the manual tells you to do it. Anyway, he told me to go into SENSORS/TPS/OPTIONS and lower the low side voltage a little until I saw some movement above 0.00. VIOLA!!! Corrections started working.
Unfortunately, that didn't completely fix my hot startup or transition from park/nuetral to reverse/drive stalling issues. I decided to tackle the gear issue first. The solution to this problem came via the IAC. It turns out that I had my throttleblade completely closed and not enough of a hole in my throttle blade. In order for the car to idle correctly in drive and reverse, I had something like 85% open IAC position. This was too close to 100% and didn't leave enough headroom for the transition as it seems to want more than that on the initial shift. I ended up turning the throttle screw in to about 3% and then reconfiguring the TPS again. This put my in gear IAC requirement at 30% which allows the IAC to do it's thing better in either direction. Problem fixed.
Last but not least was the hot start stalling issues. I found that the car would run for about 10 seconds relatively well before it would get itself into trouble and stall out. What was happening was that the start up corrections would kick in immediately after turning the car on and most of these tables were set to ramp down within 25 seconds but the O2 correction was setup to come on within 10 sec across the board. So the O2 correction was fighting the startup corrections. I shortened up the startup stuff and pushed the closed loop O2 correction out to 25 sec. Problem solved.
I'm feeling pretty good about it now. I'm going to try to get the 2 step setup, throw in the 3 bar MAP, 160# injectors, and retune.
Made a huge discovery today. Killed 2 birds with one stone.
Ever since putting in the AEM EMS computer, I've been chasing ghosts that all point back to my TPS. We tried running new wires from the TPS all the way to the computer and replacing the TPS all together. The problem is that it is so intermittent that it was impossible to pin down. I somehow managed to work around it and get the car running good.
So now I'm driving the car and notice that all the sudden I'm having a cooling problem. It would cool fine and then all the sudden, the temp would start to run away. I thought that the fans were running on low speed or that a setting was wrong in the EMS. I had Steve rewire them to eliminate the slow speed function all together. That seemed to help alittle but it was still driving me crazy. The 99* temps that we have been having haven't helped either. This morning I pulled the thermostat out to see if that would help. Took it to the gas station about 10 minutes away. On the way back it got REALLY hot. Like 250*. LoudmouthLS1 sent his pump down with one of our friends for me to eliminate that as a cullprit. I swapped the pump and started the car to fill it with coolant. It got hot fast. That's when we noticed that the fans weren't running. Turned the key off and as soon as the enginestopped running the fans were on. So that explains why I never noticed. I put the key in the on position and watched the voltage with the computer. Sure as ****, it was oscillating full range (.5-4.7v). It had never done this before. Atleast not slow enough to where I could see it happening. The fans were setup to shut off at WOT which is what the sensor reads without signal. Turns out that it was one of the female pins in the connector wallowed out and the vibration of the motor was causing intermittent contact with the male pin in the sensor.
We took the pigtail apart and tightened it up and now, finally, the TPS signal seems to be solid. Took the car for a ride and the temp was still creeping slowly but the fans were good. Got home, put the thermostat back in and now, the temps seem to be under control. I'm feeling pretty good about it right now.
Now I just need to get the Speedo working and the fuel gage.