vbb

The History
The guy before me had my 05 S2K supercharged, and returned it to almost stock before selling it to me. I bought it with the K&N intake and Megan header installed. I have the stock cat and exhaust system. For some reason, the guy didn't remove the FMU from the supercharger, so that's still on the car, and I believe he left the Walbro fuel pump in there too. He also left the AEM EMS in the car running everything. I (thought) I did my duty and gave the car a lengthy test drive and once-over before I bought it. It had no problems, other than the fact that the car cranked a few times at start up because of the AEM EMS. Other than that, it drove perfectly fine.

The Problem
Well, on Saturday, I decided to go back to the stock 05 ECU. As soon as the ECU was installed, all of a sudden my car developed some idling problem where the rpms would dip down to around 500-600 before the car would catch itself then rise back up to 1000rpms. The CEL light was immediately on as well. I drove the car home and parked it. I then reset the ECU and let the car idle for awhile. The CEL went away, and the idle seemed to smooth out. I took the car on a test drive, and all seemed to be good, until I tried a WOT run. When the car hit VTEC, my CEL came on and blinked. I know that's bad, so I backed off immediately. CEL went away and I drove the car lightly back home and left it parked. The car drove perfectly fine on the way home.
The above was a quick summary, the full Part I thread is here: https://www.s2ki.com/forums/index.php?showtopic=748445

The diagnostic check
Today, I started the car again and the CEL was back on (steady, not blinking thank goodness). I drove it 2mi up the road to Autozone and got the codes pulled. This is what it came back with:
-P0301-P0304 misfire detected in all 4 cyl
-P0172 too rich?
-P0453 Evaporative Emission Control System Pressure Sensor High Input
-P0411 something to do with the air system/vaccum hose

So now, I'm not going to drive it, unless it's straight to the shop. The ironic thing is, aside from the idle and an obviously rich-running exhaust, the car seems to run perfectly fine. But with the misfire codes popping up like that, even though it was that brief moment at WOT on the test drive, I know better than to drive it around.

Does anyone have any idea what could be causing these issues? I want to at least have an idea before I blindly take the car up to the dealership b/c frankly I don't trust them.

Druz

Didn't see this thread before I responded in the other. I sent you a PM as well. I'd make sure you have to stock injectors, the correct spark plugs, and the stock fuel pump in.

I haven't worked with a FPR that come on some s/c setups but if you are running off the stock ECU and the FPR is still connected, I would definitely ditch that.

AMS MIKE

remove the FMU and put the return fuel lines back to stock. That is a rising fuel pressure unit. Boost ONLY!

replace spark plugs with factory plugs (plugs on S/C car are probably fouled)

make sure stock injectors

make sure vacuum lines are installed correctly

Is there anything tapped into the ecu plugs? perhaps something wasn't put back correctly

sounds like O2 sensor is fouled and thats why you are getting CEL at higher RPMS, especially at WOT.

vbb

Let's say the previous owner didn't remove the larger fuel pump and injectors. I don't know this for sure, but since he left the FMU from the Vortech on the car, it wouldn't surprise me if he was too lazy to take the other things off too. Do you think leaving these parts on the car would be causing the problems I'm having? It definitely sounds plausible.

Kind of makes me wonder... would I be better off putting the AEM EMS back on the car instead of trying to run the stock ECU? It seems that the stock ECU doesn't like whatever mods are on my fuel system, but with the EMS, all was good. Then again, I don't want to be doing damage to my car and not know it because the EMS is "hiding" a problem. If I'm not mistaken, my CEL won't come on when I have the EMS in there, unless it's programmed to... so I could be running a fouled up O2 sensor, misfiring, or any host of problems and never know it if the EMS is on there, right?

vbb

All good suggestions. See the post above... for all I know, I have a larger fuel pump and injectors in the car, and that's causing an issue with my stock ECU in there.

Just like I asked Druz... would you recommend pulling out the stock ECU and running the AEM EMS like I was until the fuel system on the car can be completely returned to stock?

AMS MIKE

do you have the AEM EMS calibration file?

if not, download AEM PRO to your lap top
connect EMS to car
connect EMS to lap top (serial cable)
key to ON position (don't start)
open AEM PRO
ECU>Connect
let EMS do its thing opeing the current file on the ecu
File>Save As

email me the file BuyAMS@aol.com

AMS MIKE

not to state the obvious....but have you called the guy you got the car from and asked him questions? That sounds like the simpliest idea and a good start!

AMS MIKE

You need to get the car running on the stock ecu. AEM EMS is a fantastic set up, but when your car has issues and its "stock", the best way to figure out the issue i a known good ecu.

If you can get me the EMS cal file off the ecu then I can look at it and see whats going on.

Druz

If you have to drive the car, put back on the EMS and run that map until you can figure out what all is still on the car. My suggestion, when you take it to get looked at about the other things, put the EMS on just for that short drive. It may be a pain, but you said it drove fine with it on. Better safe than sorry.

If the guy basically gave you the EMS and FPR, then it is good possibility he may have gave you higher injectors or a larger fuel pump as well.

Like the guy above mentioned, if you have the previous owner's contact info, dropping him a line and he might help clue you in.

vbb

[QUOTE=AMS MIKE,Nov 29 2009, 08:57 PM] not to state the obvious....but have you called the guy you got the car from and asked him questions?