Misfire

[gotswap]

X,

I need some of your wisdom to help me figure out what is going on. Been posting on the other board for a couple weeks now with no success. This is a copy paste in reverse chronological order.

TIA,

Mike


4/11/08

So I decided to do a bit more troubleshooting on my own before dropping $ on new injectors. I was able to recreate the issue; get the car warm shut it off for ~15 minutes and start it back up. Wala, misfire

I swapped the injectors 1 and 2 pulled the plug and it does not matter what injector is in cyl # 1. Pull the #1 coil while running and no spark pull the # 2 and has spark so swap them out let it get warm again and still get misfire. Pull out the #1 which was the #2 and put in a spare sitting in the garage. No misfire but I guarantee as soon as it gets hot it will start misfiring.

What is going on????? I am back to my original diagnosis is the heat screwing up the resistance on the coils so that they will not fire? What am I missing here?





UPDATE......4/5/08

I called my tuner and he made some adjustment to the temp map but it turned out that was not the issue at all.

Looks like I have a bum fuel injector that just randomly stops working after awhile, it seems that it is alway related to temp but not so much any more. GRRRR

Currently I have RC 750 saturated and I remember seeing it somewhere on the board that these injectors may have issues but can't find it anymore.

Is this true? I'm deciding on just getting a new one or ordering the peak and hold type but don't want to spend the extra cash if I don't have to. Please chime in if you are running saturated 750's or have advice.

Thanks!


I need a bit of help here in diagnosing an issue.

Background

Custom turbo kit with AEM EMS tubular bottom mount log manifold

It seems that I am having a hard time keeping ignition coils in my car. After driving for a while and the underhood temps rise I develop a nasty misfire under load. It usually happens if I drive it, shut down for a bit to go shopping or whatnot and then drive off. I have been through 2 sets of coils in about 5000 miles so I am having a hard time believing this is the only issue.

I know for sure that it is heat related because it goes away if I let it cool 30-40 minutes or if I pop my hood to the safety latch while driving to get air under the hood.

HELP



Thanks,
Mike

[repiv]

I'm afraid turbos and injectors, etc, are beyond my realm of understanding. Perhaps someone else will see this who can help you.

If heat is the issue, then it seems to me that you need to find a way to insulate against it. You're probably boiling the fuel.

[gotswap]

It is definately not related to fuel. It seems as though the resistance of the coils change as the temp goes up and the AEM will not fire them.

[blownS]

Which EMS do u have: 1012 or 1052?

[gotswap]

1052

[kwando]

you might want to see if the EMS is causing the coils to go bad... i don't have a 1052, mine is the older 1012.

[gotswap]

I was hoping you would chime in but alas you have the 1012, the other guy(s2guru) is in the desert. I made a call to AEM today to see what resistance at the coils it will still fire but nothing yet.

[dc_35]

I'm probaly not too much help but I have read about high failure rates on RC saturated injectors over 450cc, as that is the largest saturated they sell, other's (higher then 450) just have larger pintle/valves to accommodate the extra fuel in essence they are just modified 450cc's. this is only true for the saturated line of injectors.
Might not be your problem but this is what I've read.



I found this on a quick google search

I've had over 45 sets of 750cc saturated injectors sent back to me after failure. This was all from a Mustang 5.0 Club as well as several import shops. I stay away from them w/ conviction.
http://www.honda-tech.com/zerothread?id=2235262&page=1

[kwando]

timg hasn't been on here in a while, but i have his number if you want me to get in touch with him. He is a god send when it comes to AEM stuff and our cars.


BTW - If you are looking to sell that extra set of 750, LMK.

[gotswap]

I would appreciate it, Thanks

I sent s2guru a pm to see what ver ems he is running but I don't think he comes back on leave for quite awhile.

[gotswap]

I just got off the phone with AEM and they think the coil drivers in the ECU are going bad. Oddly enough they offered to send me pictures and instructions on how to fix it or send it back for repair, who would have thought. Keeping my fingers crossed.......

[gotswap]

I did the mod latst night, had to desolder several item and now cyl 1 is not firing at all. Looks like the ECU is bad, waiting for an email from them to see what to do now.