AEM V2 Stumbling in low RPM/medium load

[arknotts]

I got my AEM V2 up and running pretty well and am starting to do some light road tuning. It idles, run and drives pretty well but medium load (~ -6 psig to 0 psig) at low rpms (1500-3000) it stumbles and actually kicks back just a little bit. Higher RPMs are a lot better but it also feels like it doesn't want to build boost. I had this setup running on the stock ECU/Maft Pro pretty well (IS300 coils, 660cc injectors).

My tach is also reading different than Tuner Pro. It is a couple hundred RPM off at idle (reads faster) and progressively gets worse with RPM to about 500 RPM difference at 4000 RPM. It also is a little erratic at idle, "bouncing" just a little bit like the signal is off. Here is what I have verified:

Cliff notes:

Symptoms:
* Stumbles at medium load (~ -6 psig to 0 psig) at low rpms (1500-3000)
* Tach is a little erratic at idle and differs than what Tuner Pro sees, with the difference increasing as the RPMs rise
* I rack up a few timing errors during driving (about 13 on my last 1/2 hour drive with the laptop hooked up...not much but I need to check my wiring)

What I've checked:
* Base timing is set to 10 degrees via the ignition timing sync wizard
* AFRs are within 5% of my target AFRs during these load conditions
* Logs look fine...timing matches what's on the ignition map and all injectors are firing at the same pulsewidth that corresponds to the fuel map

Any ideas? I wanted to give it a light road tune before spending $$$ on a dyno tune so they don't have to troubleshoot this.

 

[Enraged]

still using stock multiplex ignitor? Not sure about the v2, but the v1 isn't a fan of the stock setup, switching to a DH10 or similar seems to fix it.

 

[oldsking]

Hell and I thought I was the only one with these problems! Mine acts the say way, like if im cruising and try to let the motor build boost say in a lower RPM range like you mentioned it bucks but if I down shift and let the motor build up it pulls fine. Do you notice if you are spooling hard that your tach is not at all reading properly in the 4k range?? Mine doesnt read properly

 

[arknotts]

Yes, I'm still using the stock igniter. I would like the AEM to directly control a set of COP coils, but thought I'd try to get it working on the stock setup first. Who at Toyota thought a multiplexed ignition system is a good thing?!

oldsking, I haven't got into much boost at all yet but my tach is off by about 500 rpms at 4000 rpm regardless. Are you still on the stock igniter too?

 

[oldsking]

Yep I am still on the stock ignitor but running is300 coils which isn't not much different than the stock coils. I wonder if something in the settings is off ??

 

[scubajtw]

I am having a similar issue. V2 AEM DH61 ignitor stock coils. At 4k tac drops off and sound like a 2 step. Any luck on the CPS set up in the AEM?

 

[Enraged]

Did any of you try contacting Aaron at Driftmotion? He's pretty knowledgeable with this stuff, maybe he can help.

 

[scubajtw]

I have not I have been working with ToyotaNOS ie Steve

 

[oldsking]

I think we need to hit up Aaron for sure, I'm going to shoot him a text.

Scubajtw, how all did you go about setting up the dh61 in the AEM tables? I'm wanting to do this just scared on the teeth settings and such

 

[arknotts]

Sounds like people have had this issue for a while (even with the v1):

http://forum.aempower.com/forum/index.php/topic,8345.0.html

I have a DH61 igniter coming in a few days and I'm going to see if it helps.

 

[oldsking]

Okay guess talked with my boy Aaron

Now let's make sure we all are on the same page and realize that these boxes have a BASE TUNE... That being said they still have to be professionally tuned or do it yourself at your own cost Me insight is that the load hesitation appears to be a heavy fuel map so I have leaned it out a bit and it helped but keep in mind that your timing map may need work too.

Now the tach issue needs to be addressed... With the new kits available the harness should be labeled tach output (its a single wire that should not be going to a pin on one end) which needs to be placed with the tach source wire from your harness. To help out the wire should be on the AEM plug (A19) and on the M1 plug of your harnes be pin 10 (refer to the TSRM to confirm) so basically you need to cut it and attach the AEM tach wire output to the tach side of the wire.
The reason for this is the box is for a Honda application and for Driftmotion to make this work, they took the time and research to place the right settings and resistors which allows for the multiplex system to work correctly and accurately. I hope to fix my wiring of the tach tmrw weather permitting and as for my tune I still have work to do

 

[arknotts]

Thanks for heading that up! Understandably these boxes just have a base tune. No other way around it and I'd never expect it to run perfect out of the box. I'm definitely having mine professionally tuned, I'm just trying to figure out this ignition miss before paying someone big bucks to troubleshoot it during dyno time.

I'll give that tach fix a try. This is likely an Aaron question, but it sounds like the internals of the box have been modified slightly. Is it still able to handle sequential ignition/injection when the multiplex system is removed?

 

[arknotts]

OK, so I have some good news and a few updates. Called Aaron, talked to him for a little bit, and learned a little more how his kit is set up to handle the multiplexing correctly. I tried another stock igniter, and unfortunately had the same symptoms. I already had a DH61 igniter on hand so I thought I would give it a try anyway. Wired it up (only thing that changed was the igniter), synced the timing again, and my symptoms are 99% gone! The tach seems to be completely fixed (no more jumping around) and overall it feels much smoother. Every now and then I will still get some very slight hesitation/misfire but THIS I can attribute to it simply needing a professional tune, not what I was experiencing before.

I'd like to add a disclaimer to this as well. I never started this thread with intentions to imply that driftmotion's product was flawed/inferior because I don't believe it is (you'll notice I didn't even mention them in my post). I have had nothing but good experiences dealing with Aaron. I started this thread to make sure this wasn't a hardware issue on my end, to ensure I didn't have to pay twice for dyno time.

So what does this mean? In short, we all know our cars are old and the wiring is starting to suffer on them. Multiplexing, in theory, will work just fine but will start to break down with any sort of signal noise/loss in the line. The DH61 simply seems to be the best solution for me right now, without completely re-wiring the ignition system. If it works--it works, and the simpler the better. While I'm sure Aaron could have helped me get my car running right on the stock igniter, this is the simplest solution for me right now.

 

[Sinistr]

I'm glad to hear that you are getting all your issues ironed out. I am currently in the market for a stand alone EMS and have been kinda on the fence about the DM AEM box.

 

[oldsking]

Sounds awesome man! Did you have to use the pin for the tach to work correctly? I have a spare Dh61 sitting here and would like to try it also. Can ya give me some insight on how you wired it and set it up in the AEM map?

 

[arknotts]

Nope, didn't have to use the tach pin...it's running off the igniter. I only temporarily hooked it up to see if it actually solved the issue, but here is what I did:

• Make the adapter harness so the DH61 will plug into the engine harness.
• Plug the 6 pin connector from the igniter to the engine harness to let the DH61 power the coils
• Unpin coils 1,2,3 from the AEM side of the ECU harness
• Get some spare pins (got mine from summit) and wire three new wires into these three pins
• Run these three new wires to the 4-pin igniter plug and connect them to the proper pin on each (you can ignore igf)
• Start 'er up and sync your timing again (mine was pretty far off)

This essentially bypasses the multiplex circuit in the ECU harness. I need to work on a more permanent solution to this, but that's how I verified it would actually fix the issue.

 

[scubajtw]

I am still having the same issues bucking and kicking at 2000-3000 rpm. I have had this all of the way through the process. Stock ignition, DH61, COP 1zz coils waste spark, and now COP wired sequential. I am wondering if I have a setting off in the CPS or in the dwell timing.

Do any of you happen to have the numbers for a baseline for the CPS? I know that I was having a heck of a time picking up any signal. But I finally got it and the sync tooth count is steady at 22.

 

[Funkycheeze]

You can just use the engine harness wires to go from the ECU plugs to the igniter plug if you want it wired in permanently.

 

[arknotts]

I wired mine in permanently through the engine harness once I verified it helped the issue. I still have a very slight "vibration" (the best I can describe it) right at ~2200-2300 rpms but it doesn't buck and hiccup like before. I still need mine dyno tuned so it may just need tuned out. I would like to take a look at my CPS signal as seen by the AEM, or worst case hook up a scope to it to see what's going on at that rpm.

 

[Funkycheeze]

If you look at my guide, it describes how to look for sync errors on the CPS signal to determine if you have a bad CPS. probably a tuning issue at this point. Also check to make sure everything is grounded properly.