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AEM cas problems

Old 06-26-11, 10:15 AM
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cas problems

I have a trigger issue of some kind. 1500-2000 rpm it acts like the timing is all mixed up, backfiring, missing,etc. Below 1500 or above 2000 there is no issue. The tuner changed some of the trigger settings and it seemed to clear it up on the dyno, but it is doing it again. Anyone ran into this?
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Old 06-26-11, 01:29 PM
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Did you put a timing light on it to verify the timing is correct at idle? (lined up with mark) ? See the "Pickup Confirmation" section in the AEMPro User Guide. You will use Configure --> ECU Setup --> Set ignition option. I'm assuming this is an FD so you only have one timing mark on the pulley, at -20. You will need to set the leading ignition (in the main timing map) to -5 and trailing (ignition difference map) to -15. This will tell the AEM to have an idle ignition timing of -5L -20T which is what the service manual recommends for checking timing.

So, if idle timing is set to a fixed -5L and -20T in the AEM, the timing light should show that you are on the mark.

I have read recommendations that adjusting the "pickup delay comp" setting for ignition phasing can help with the actual timing drift. This is under Ignition --> Advanced Ignition --> Ignition phasing --> Options
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Old 06-26-11, 03:32 PM
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Yes an fd, timing was set and verified before tuning. It acts like it is firing very late, but only in the 1500-2000 window. I put the pfc back in and it runs fine, so it is related to something with the aem. I'm going to check the air gap on each tooth, I've been told .030-.050 is this correct?
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Old 06-26-11, 05:44 PM
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In the advanced pickups template you can change the sensetivity of the cam, crank and spare speed. The numbers for can and crank need to be changed. I don't have the values I use off hand but I will post then if you need.

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Old 06-26-11, 06:06 PM
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the air gap spec is in the workshop manual... don't know it off the top of my head. First, are you sure all your grounds are clean, in case this is an electrical noise issue? The PFC is one of the most forgiving ECU's for that but maybe the AEM is being more sensitive.

By the way, I don't mess with AEM on Rx-7 applications often but I think AEM did some updates for the FD EMS over the life of the product... is it up-to-date? I wonder if AEM tech support would be helpful for telling you about that.
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Old 06-26-11, 07:16 PM
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Originally Posted by EB Turbo View Post
In the advanced pickups template you can change the sensetivity of the cam, crank and spare speed. The numbers for can and crank need to be changed. I don't have the values I use off hand but I will post then if you need.

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If you would post them it would be much appreciated, will changing any of those values effect the timing map?
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Old 06-26-11, 07:23 PM
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Originally Posted by arghx View Post
the air gap spec is in the workshop manual... don't know it off the top of my head. First, are you sure all your grounds are clean, in case this is an electrical noise issue? The PFC is one of the most forgiving ECU's for that but maybe the AEM is being more sensitive.

By the way, I don't mess with AEM on Rx-7 applications often but I think AEM did some updates for the FD EMS over the life of the product... is it up-to-date? I wonder if AEM tech support would be helpful for telling you about that.
All grounds have been cleaned. I moved the battery to the hatch, ran a 4ga. ground up to the grounding point on the side of the block under the plugs. Ran 2 more to points in the hatch area, maybe I need to run another up to the motor.

The aem has been updated, just came back from aem. I was going to call tech support, just wondered if anyone had already worked through this issue and knew how to fix it. Thx for all the suggestions.
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Old 06-27-11, 09:41 AM
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Originally Posted by ryan1 View Post
If you would post them it would be much appreciated, will changing any of those values effect the timing map?
No, they will not. All these do is effect the sensitivity the ecu has on the sensors. This is by no means the 100% correct setup but this is what I have found to work for me without having any types of issues.

Crank H sens Below "1600"
Crank L Sens Above "1500"
Cam H Sens Above "0"
Cam L Sens Below "0"

I use sync early "On" and Cam and Crank "Rising" edges are "on". AEM comes default with falling edges. if you change to Rising edges your Ignition Sync values almost goes to zero depending on your trigger wheel variance. I dont really think that it makes a difference. but the rising or falling edges will effect your timing marks.

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Old 06-27-11, 07:48 PM
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Thanks, I'll give it try.
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Old 09-16-11, 06:17 PM
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Thought I would update this. I finally got back to fixing the car and it ended up being a bad alternator. On an graphing dvom the alt. had .75v ripple the got worse as engine temp climbed. Changed alternators and 200 miles trouble free miles so far.
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