Anybody here tune their own AEM EMS? Have a problem with jerky throttle

[Kyle_J]

I've had this issue for over a year and its driving me crazy to the point where I want to drive the car off a cliff. Basically it seems as if my throttle does not engage until after I have already pressed on the gas pedal. Then the throttle engages and results in a very rough transition from idle to cruising rpms. Also if I watch throttle % it does not register right away when I push on the gas pedal. I've checked/fixed everything I thought would have an impact on this with no success. Just wondering if anybody here tunes their own ems and if they have had this issue or knows what could be possibly going on with mine.

Also the car is an 04 STi with a built motor/heads and was previously tuned at AMS. Now this issue started after I blew a head gasket about a year ago. That would make me think it is something that is simply out of calibration since I had everything apart. Yes the throttle is calibrated.

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[Scooby6152]

Have u reset ur tps?

[WRX-17]

My two first thoughts on this are:
1. Was the TPS sensor ever removed and reinstalled without correctly clocking it?
2. The TPS needs to be setup properly in AEM... try following this guide, I had great success with it. There is the part talking about the TPS and how it should read in the AEM.

I hope one of these will help you out!

[Kyle_J]

The throttle body is DBW so there isnt really a tps to remove. I just disabled decel fuel cut off for now until I can get the car on a dyno for a tune.

[reid-o]

I've found that there are a combination of factors
1) the MAP sensor is on the throttle body and so it's not isolated
2) the native TPS filter setting is low

I've found that what happens at vacuum during cruise areas is that the MAP signal is jumpy, so the load point skips to different cell despite you holding the throttle super still. It's basically reading the different cylinders firing.

Second the TPS reads with too much sampling, so despite you having your foot still, it tracks the minute changes thus moving the throttle plate. You can log this to verify. Hold the throttle as still as you can and watch the value move a tad.

You need to enable TPS filter option and increase it to around 18-25. That should help a lot.
Next is go into sensors and increase by very small amounts the MAP filter. Don't get nuts or it won't sample enough and you'll get some backfiring on throttle lift off as there will be some lag.

I've found both to make a huge difference. The other option that I haven't tried is to remote mount the map sensor on a hose to prevent the oscillations. It normally only happens at part throttle between 2k and 3k when the avcs starts to kick in. You can also just connect the ecu and in the fuel table watch as the map sensor bounces around despite having a rock solid idle.

[05_wRex]

Any update on this? My car was tuned at ams also...I am experiencing the same issues and cant get an answer out of the seller. (current ams employee)

aem v1 ems. hesitation between 2500-2900 rpm and the car is really jumpy when im trying to be really smooth...its really really annoying. Where is the tps filter option?

[TheBoz]

Setup -> Sensors -> Manifold Pressure Sensor -> Options - MAP Sensor

Add to the Map Filter Slowly until you get the desired result. If you pull an ECU log fo the boost, you should see lots of spikes, with a low number, and with the filter higher it should start to smooth out. Teeth is in relation to crank teeth.

On my 06 STI AEM EMS V2, with an AEM 3.5bar I have my filter set at 7.

I dont have any hesitation at all. Keep a close eye on the AFR's during that hesitation, there are a lot of things that can help it to run better. If you have AVCS kicking in, that can cause some strange stuff also.

[TheBoz]

I just realized you askied about throttle filtering

Fuel -> Acceleration Fuel -> Throttle Accel -> Throttle Accel Pump -> Options(Adjust those)

[05_wRex]

Originally Posted by TheBoz

Setup -> Sensors -> Manifold Pressure Sensor -> Options - MAP Sensor

Add to the Map Filter Slowly until you get the desired result. If you pull an ECU log fo the boost, you should see lots of spikes, with a low number, and with the filter higher it should start to smooth out. Teeth is in relation to crank teeth.

On my 06 STI AEM EMS V2, with an AEM 3.5bar I have my filter set at 7.

I dont have any hesitation at all. Keep a close eye on the AFR's during that hesitation, there are a lot of things that can help it to run better. If you have AVCS kicking in, that can cause some strange stuff also.

It was set to 11 when I got the car. Its at 15 now and is much better. Are there any adverse effects of running it at its max of 15? It is a aem v1 ems.

I also have a couple logs with a question about knock.

I dont know how to add an attachment on this particular forum, but I have it exported to text.

If anyone would care to take a look and let me know if its ok or if its something to be concerned with that would be great.

Thanks,
Sean

[Kyle_J]

I decided to mess with mine a bit more yesterday. Increased the map filter and it got a little better. Another odd thing I noticed is that my car is setup for full boost comp according to the boost fuel correct table, but my fuel map looks to be setup for hybrid boost comp. Its hard to believe the car was tuned at AMS for how rough the fuel map looks. I wish we had a dedicated section for the aem ems here on nasioc.

[aftabulis]

Have you had any other major specific issues with the ECU or are you happy other than the throttle issue?

[reid-o]

I mirrored the stock coil dwell settings and its working great. I have no idea if my packs will die a horrible death though, but the base aem cal dwell settings uses 2.9 for all rpm ranges. There's an rpm multiplier that's 100% for all ranges. I made it 135% at the lowest rpm and 70 ish % at 8k. No hesitation and idle smoothed out too. Use at your own discretion.

Stock dwell is roughly 4.5 at idle to 2.4 at redline.

Car want getting enough dwell at low rpms.

[05_wRex]

Originally Posted by Kyle_J

I decided to mess with mine a bit more yesterday. Increased the map filter and it got a little better. Another odd thing I noticed is that my car is setup for full boost comp according to the boost fuel correct table, but my fuel map looks to be setup for hybrid boost comp. Its hard to believe the car was tuned at AMS for how rough the fuel map looks. I wish we had a dedicated section for the aem ems here on nasioc.

Mine was tuned at ams and I'm having loads of issues. Stupid stuff that a tuner should know. Took me all of 30 minutes to fix the driveability out on some back roads. Maybe they got lazy?

[05_wRex]

Originally Posted by reid-o

I mirrored the stock coil dwell settings and its working great. I have no idea if my packs will die a horrible death though, but the base aem cal dwell settings uses 2.9 for all rpm ranges. There's an rpm multiplier that's 100% for all ranges. I made it 135% at the lowest rpm and 70 ish % at 8k. No hesitation and idle smoothed out too. Use at your own discretion.

Stock dwell is roughly 4.5 at idle to 2.4 at redline.

Car want getting enough dwell at low rpms.

I'll give this a shot. Thanks for posting!

Is your v1? or v2? All I'm seeing is a dwell vs voltage and rpm table. Should I be looking somewhere else? options list teeth max and min and a coil dwell factor of 60.

[reid-o]

Originally Posted by 05_wRex

I'll give this a shot. Thanks for posting!

Is your v1? or v2? All I'm seeing is a dwell vs voltage and rpm table. Should I be looking somewhere else? options list teeth max and min and a coil dwell factor of 60.

Version 2. The rpm table is a multiplier and applied to the dwell vs voltage. You have to do the math to reverse it.
You can also log coil dwell so if you don't like algebra you can just step on the gas and increase or decrease the rpm values till it matches the stock table at 14v.

If you're having cam sync issues at low loads that's a version 1 issue. I've never had such issues. All low load issues were my due to my not understanding how compensations come into play. If you're having Avcs issues at low loads that is not something that can be tuned out afaik

[05_wRex]

Originally Posted by reid-o

Version 2. The rpm table is a multiplier and applied to the dwell vs voltage. You have to do the math to reverse it.
You can also log coil dwell so if you don't like algebra you can just step on the gas and increase or decrease the rpm values till it matches the stock table at 14v.

If you're having cam sync issues at low loads that's a version 1 issue. I've never had such issues. All low load issues were my due to my not understanding how compensations come into play. If you're having Avcs issues at low loads that is not something that can be tuned out afaik

My rpm table was straight 85% all the way across. I used 114(135% of 85) at 800 rpm and 85 at 8000 and calculated the in between. I did take it out for a little bit. It felt a little crisper, but could just be in my head. I got it cruising much better than when I got it before I made the change. I was hoping this might help even more. Lol.

Ams told me they had problems with the stock ecu and access port. They would not explain what the issue was, so I can only make assumptions and try to fix it myself. I pretty much got kicked out the door with no answers. Answering a technical question with "looks fine to me." Is not an answer. Lol. I just want what I paid for. Lol.

But anyways. That was the best I could figure since the tables are a little different between v1 and v2. Let me know if you think I made the correct change. Lol.

[reid-o]

Originally Posted by 05_wRex

My rpm table was straight 85% all the way across. I used 114(135% of 85) at 800 rpm and 85 at 8000 and calculated the in between. I did take it out for a little bit. It felt a little crisper, but could just be in my head. I got it cruising much better than when I got it before I made the change. I was hoping this might help even more. Lol.

Ams told me they had problems with the stock ecu and access port. They would not explain what the issue was, so I can only make assumptions and try to fix it myself. I pretty much got kicked out the door with no answers. Answering a technical question with "looks fine to me." Is not an answer. Lol. I just want what I paid for. Lol.

But anyways. That was the best I could figure since the tables are a little different between v1 and v2. Let me know if you think I made the correct change. Lol.

Just know that I'm not sure if this will burn up the packs but the stock ecu alters coil dwell to have more at low rpm and less at high which makes sense, it sounds right. I just followed the stock settings and logged to verify.

[05_wRex]

Originally Posted by reid-o

Just know that I'm not sure if this will burn up the packs but the stock ecu alters coil dwell to have more at low rpm and less at high which makes sense, it sounds right. I just followed the stock settings and logged to verify.

I experienced some sputtering today in the cruise range that I've never felt before. Returning the dwell setting back to the way they were fixed the issue. Just FYI.

[ShardAerithes]

Originally Posted by Kyle_J

it seems as if my throttle does not engage until after I have already pressed on the gas pedal. Then the throttle engages and results in a very rough transition from idle to cruising rpms. Also if I watch throttle % it does not register right away when I push on the gas pedal.

Kyle I was having the same issue. My 05 STi would not register any throttle input when I first touched the accelerator pedal. It would then surge to slightly above 10% tps as I continued to push the throttle. This would result in that rough transition from idle to cruising RPM.

I re-calibrated the Electronic Throttle Control system. You don't even have to plug your laptop into the AEM EMS.

Check out page 8 in the AEM EMS install guide and follow the instructions CAREFULLY:
http://www.jegs.com/InstallationInst...17-30-6821.pdf

If you have the AEM datastream gauge you can confirm that the throttle calibration is successful just by switching to TPS.

I originally diagnosed this problem by watching as I depressed the pedal and the TPS signal on the datastream gauge did not change until it jumped to over 10%.

Now I can press the pedal gently and watch as it goes 2,5,7,8,10+% (and values in between).

The car feels INCREDIBLY smoother now - almost like I just got it retuned. It feels like a whole new car, the driveability is unreal as compared to before.

I hope this proves useful to you Kyle and anyone else having this issue.