my s2k is having problem starting sometime with the AEM EMS? it would take 2-3 crank to get it started. sometime it won't start up at all and just cranking. I had to pop in the stock ecu for it to start up, let it warm up and then put back AEM EMS ecu to get it start again(after 2-3 crank).

is this a AEM EMS issue or a tuning issue? anyone else have this problem and what did you do to fix this?


BTW, my s2k is turboed.

 

The problem is the tune for your cold start. Two or three cranks isnt bad really but I would have to say not starting is! Nothing to do with the AEM EMS.

 

Early AEM EMS needs more cranking time before starting. Low voltage will also make it not want to start. Battery fully charged?

 

im pretty sure it's fully charged because with the stock ecu it fire right up.

 

The problem is in your tune. I think this is also the reason why you had it not start again after reving it up a little bit in your other thread. From now on it would help you and the information you get when asking for help if you specify that your car is not stock and what it has had done to it.

 

thanks, i will go get it retune at church automotive next week and let u guys know

 

Shawn at church automotive tune it already. but it's not the tuning problem. he said there was an interesting starting setting, he adjusted that but it still doing it sometime.

it will start right up if i use a booster pack or a jump cable.

i thought it would be the battery since im using the p680 and i thought it was going bad. so i bought a brand new p680. it start up fine now but once in a while it doesn't want to start. it will crank all day. like today i started it up left it there for 20 min, came back and turn it off, a minute later i try to start it up again and it will just crank. again i have to use a booster pack and it will fire up again.

I have the AEM EMS series 2 so those shouldn't have any problem. could it be my ECU? or maybe the AEM ems doesn't work well with the p680 battery and so it not sending enough power to the AEM Ems to start?

 

Sorry for the late bump, I just wanted to see if there's any follow up on your part.

I'm running the original EMS on my 3.5L Sentra, and I have the same issue. For a few years now, start-up has been sketchy, long cranks, sometimes never starting up. I needed help starting last night, at a car meet and another person said his Integra did the same thing on the EMS.

What I've pretty much confirmed is the EMS needs 12-14Volts to start. When you crank the car, the starter (even a healthy starter/battery) draws too much current and the voltage drops too low for the EMS to sync up. Even though the ECU will post information to my laptop, the "Stat Synced" light will not go on, and I have all of the start up settings correct.

The car will start EVERY TIME, when I push-start the car, or when I jump or have a booster box handy. It is definitely a voltage issue. I was considering buying a portable jump starter at walmart to keep in the car, at all times, but I'm also considering replacing my single optima battery with 2 motorcycle batteries. During start-up, the motorcycle batteries would be isolated, one would go to the starter, one would go to everything else, when the car is running, they would be in parallel, so they charge.

 

i know its a necro-post but i figured i could shed some light for anyone following this thread


there are a few reasons for hard starting on the EMS, in my experience, it is typically he tune, but there are also legitimate hardware & software limitations that cause the EMS to be difficult to start

if the crank or cam sensor is a hall type sensor the the car can have difficulty starting if the battery voltage is too low. this is because the signal output strength/voltage is proportional to input voltage.

the EMS is designed or hard coded if you will, to run with a 12 tooth crank trigger, if your car does not have this setup (most cars don't) it uses workarounds in the software to "show the hardware what it wants to see" the ecu wants to see a certain number of events or "signals" to "sync" the sensors and if you only have 1 or 2 teeth on the crank trigger its going to take a few revolutions to satisfy those requirements (this will be more noticeable with low battery as well since the engine will crank slower