mortes2000

What's up guys, sorry in advance for such a long post but I have an in depth question about my AP1 having starting issues with the AEM. First off, when we installed my custom turbo kit on my bone stock 01 S2K, it had no issues firing right up. It was tuned for up to 10 psi on 100 octane on an AEM 1052 and ran problem free for almost a year.

Then I decided to have a 3mm headgasket installed so I could throw some more boost at it. Since that time, I've had trouble starting it. It was retuned to around 20 psi again on 100 octane and has no trouble running once it's fired up. It's not a daily driver so it sits in the garage most of the time. For awhile it would start up if it was on a small battery tender overnight, so I suspected low voltage from the battery not enabling the AEM to get a strong enough signal from the cam and crank sensors to start.

As time went on, it would get harder to start on the battery tender so I had to use a full size battery charger to start it. At that point I changed out the battery since it was under warranty but still had the same issue. Now, the car won't fire even when the battery charger is set to full strength.

Just yesterday the guy who tuned the car came over and checked all the parameters on the AEM and said everything was how it was supposed to be. The start sync was on but still it wouldn't fire. He suspected something wrong in the fuel delivery, but I recently checked the flow of fuel from the Walbro 255 with an LPH gauge and both volume and pressure are within spec. The RC 750 injectors were purchased new so I highly doubt that they would go bad after a year and a half of limited use.
I talked to the guys at AEM about the update for the 1052 with the different resistors for the cam and crank sensors but the tech at AEM couldn't guarantee me that the update would take care of the issue. Before I take out the AEM and possibly waste $100 or more on the update I was hoping to get some feedback on what else it might be.
The guy who tuned my car isn't a Honda specialist but is very familiar with the AEM EMS since he tunes all kinds of Vettes and domestics with it. Anyways, I'm stuck at this point and getting quite frustrated. Sorry again for the long question but any help would be appreciated. Thanks.

EngineerX

Post won't read w/o paragraphs, write start

Kirpich

I had a similar issue. Without changing the tune map, it would run worse and worse. I still don't know what caused it.

Now that it's been retuned, it runs good, but cold start is terrible. Hot is fine, but if it sits overnight, it takes 2 fuel pump primes, and 2 good long cranks.

I think it might have something to do with timing and engine temp table. this is only my opinion, but if you play around with timing tables for cold start, you'll improve it.

MugenRioS2k

check your

Initial crank pulse and crank injector time
Screen cap from AEM V2 Their stock and 750cc injector

joes sled 2000

Do youre self a favor and find a good tuner with aem/s2k experience . There is no reason for hard cold startups with the ems system . I run a ems 1052 box with id 725cc injectors . I had the unit tuned by a well known/experienced tuner and with all honesty can say that my cold starts (even below freezing) are as good as stock .

dsddcd

Trader, you jumped ship to AEM?

dibi

glad to hear someones are.

Kirpich

Thanks, MugenRio! I, however, don't have the V2 1052, just the original 1052. I assume the numbers will be similar, just gonna have to dig through the menus to find the right table.

Ian300D

I have a aem tune for a AP1 and those injectors. Want to give it a whirl just to see if it affects your start up. I wouldn't drive around in it, but can't hurt for just starting up.

mortes2000

I have a new tuner looking to hopefully help me out sometime this week..if we cant figure out starting issues i would appreciate that map