Hey guys,

After swapping my stock ECU for PFC, before cranking the car up I did the sensor check as per Dale Clark's FAQ & everything looked OK to me-



However, I noticed a humming/clicking/buzzing sound coming from the engine bay, around the UIM area. Here is a video of the noise- . Sorry for the poor quality :/. This is with the key set to 'on'. Note- the video makes it sound louder than it is, but it's definitely an audible high frequency type clicking noise.

When I swap the stock ECU back in, the noise goes away.

At first I thought something funky was going on with the IAC/ISC valve, maybe it was getting switched on/off by the pfc at a high rate. However, after unplugging it, the noise still occurs.

Someone on FB suggested that it may be a coil, and to check grounds, but as far as I can tell the grounds seem ok. Also, I'd be curious to know why the noise is not also occurring with the stock ECU if it was a coil.

I want to fire her up with the PFC, but I wanted to see if anyone had any input before regretting my decision. It sounds to me like some solenoid is getting cycled, but I'm not sure why it's happening with the PFC and not with the stock ECU. Anyone have any insight?

Thanks in advance!!

 

Could it be an injector?

 

Personally I would turn the car over and then start the process of pin pointing what it could be.

 

You clip the proper wires when you installed the pfc?

 

I agree with IR, it sounds like either the wrong wires were cut or pinned out or not cut at all.

 

Yep, cut the four wires (Aws, egr sw/sol, split air). I double checked that the wire location & colors that were cut were correct. I guess I'll triple check just to be safe.

 

I think I may have figured out what was going on. While looking thru the settings menu, I went to PIM Voltages and noticed it was set to Option 2. Immediately after setting it to normal, the clicking went away. I started it up and it seems to run ok so far. Previously on the other option it ran horribly.

I got this PFC from a friend with similar mods, I was just going to run with his settings and then have the tune tweaked (if need-be) on a dyno. From what I've researched thus far, it looks like the options other than normal are for other map sensors, i.e. gm 3 bar, apexi etc. Since I'm using an OEM map sensor that would explain why it ran crappy (as it was miscalibrated)- it also seems that maybe the map voltages were triggering a solenoid or two, maybe the turbo precontrol? Anyways, glad to at least have made some progress.

Question for those with more PFC knowledge- from my reading it looks like the settings on the PIM menu from the commander are very basic, i.e. add/subtract fueling %. For finer detail you must use a datalogit to edit the basic fueling maps. Now, my question is, would there be any fueling settings related to the tune in this area? Or is the PIM purely for MAP sensor calibration? I know the tune raises boost to about 12lbs, so I want to make sure the fueling settings are ok to support that- and I am not sure if changing the PIM option would affect that. In any case I will probably dyno and check out the AFRs to be safe, but I was just curious in the meantime :P

 

You were probably hearing the WG solenoid switching. If you had a PIM calibration issue, the PFC was probably "seeing boost" pressure and engaging in boost control. Same thing happens if you pressure test your vacuum system while the ECU is powered on.

Unless you know what map is loaded in the unit, you probably want to reload the base map if you're running light mods and were using the factory ECU previously. That should be a safe starting point for a stock or very mildly modded car.

BTW: you *can* run stock boost levels with the PFC by lowering the duty cycle of the WG. Lowering the "boost" setting doesn't really do what you think but it will change when fuel cut kicks in which is an important safety function.

 

Try touching your IAC valve when the sound is happening and see if that's where the noise is coming from.

 

I wanted to chime in here as this was my old power FC that I sold to damunky.

When I purchased my car it was running on the tune that currently is still on this power fc. It was tuned by pettit racing for my car with the following setup:

Stock Port Engine
Pettit K&N Intake
Blitz FMIC
Downpipe
Apexi N1 Catback
Airpump & emissions still in place
Stock 550/850 Fuel System
Walbro 255 Fuel Pump

With the target boost level at .85 kg/cm^2 (12 PSI) and the wastegate duty cycles set near the stock values at primary=56 and secondary=64 I had a perfect 12-10-12 boost pattern and solid AFR progression to 11.3 when under full boost. The car idled between 950 and 1000 rpms.

Given that his mods are nearly the exact same (except for the intercooler...which is soon to be the same as he has my blitz FIMC in his garage) I didn't see the need to lose the fuel and timing map that was stored on the power fc.

It was my understanding that while the tune may not be absolutely perfect for his car the fuel map would be closer to what is needed than the base tune found on the power fc and that the non-fuel map parameters could be modified to suit his idle.

That also being said, I found that it was GM 3 bar map sensor in my car when it was running on the power FC. The 3 bar and all my extra solenoids and UIM related systems I have since removed are currently on their way to damuky.