I dont know too much about these cars yet, and i just got this one pretty recently to fix up and keep it..
So anyways story goes like this. I was pulling out the spark plugs today to check them to see if they need replaced or not, I dropped one of the rubbler grommets from the coil pack right onto the header which was still kind of hot, so there went that piece of rubber. So an hour or so later i drove the car to the carwash to pressure wash this rubber off my header. And when I started the car to leave the carwash, the fuel pump was very loud. Like a really lound high pitched hum. Kind of like a quiet vacuum cleaner was running. Drove all the way home and its still doing it.
I shut the car off let it sit for about an hour and I came back outside and notices that the small motor right behind the bumper on driver side was going. with key out and everything. And i know this because that little motor is damaged and its has a weird rattly noise when its going, And i started the car again and the fuel pump is still whining very loud and annoying.

Maybe this is related to the fuel pump but a day or 2 after i got this car, it started acting weird where sometimes it would be very sluggish, and eeven it would shut off sometimes when coming to a stpo due to rpms going so low. Then sometimes it would run perfect. And once or twice it jerked while i was driveing like a cylinder completely missfired. And Im thinking the fuel pump may have been going out.
By teh way its supercharged, and supposed to have the walbro 255 fuel pump.. Im a decent mechanic, this just kinda gets me how this is happening!

 

Walbro fuel pump usually has a very audible whine to it. I know mine sure does.

I'm assuming the small motor you are talking about is for the aftercooler? Might be a bad relay for that to allow it to keep running its the car off. That or it is wired incorrectly.

The pumps can go bad. One of mine did. Did you let it run very low or basically empty of gas? I know those pumps do not like to be run dry or they will fail.

Is it making a pulsating noise with the hum or a steady hum?

My old one that went bad starting to pulsate with noise.

Is your car tuned? Stock MAP sensor? Need more info on setup to have any clues about the stumbling issue. If n stock ecu and stock map sensor that can be very normal for it to stumble a little low rpm coming to a stop or similar circumstances.
The oem ecu is a learning ecu so usually can correct the issue itself.

 

I believe its the stock ecu, no tune. It has the comptech supercharger kit.
Im not too sure what this little motor does that just behind the bumper under driver headlight. I dont think it flows water. I thought maybe that it has something to do with that secondary air injection system, as I only hear it come on when i first start it, and I also have a cel for incorrect flow on that system. Also sometimes i here a bigger fan come on when its cold, which i think is for that system, also.
Im pretty sure its the oem map sensor, the PO also said he replaced it not very long ago. The stumbling can also be noticed at higher rpm's sometimes, it feels like it has noticeably less power. Ill try to follow these lines and figure out what this little electric motor is for later today. But as for the fuel pump, This thing is louder than youd think. I underdtand it may be louder than stock, but this is a very annoying hum its doing. And why just randomly after i start the car after rinsing off engine area.. really weird!
Ill see what happens whaen I drive the caar today

 

So i went and started the car today, and the fuel pump in definitily quiter, like how it should be. Also i was looking at that little motor and I think it is for the water in the aftercooler. It says circulation pump on it and the hose coming out of it goes to the front of the aftercooler. This little pump is broken and definitily not working properly. SO a few more questions..
This pump only has one outlet on it and the hose is going to the aftercooler. if this pump circulates water, how does it circulate it with only hose coming off of it? Wouldnt it need a return to keep the flow going, Also since this pump is broken and the hose coming off of it has a rip in it, does this mean that I dont ahve any water in my aftercooler right now? And if theres no water in it would it get too hot? or is it ok to drive with no water in it?

 

Sounds like you might have purchased a neglected setup there.

Is the rip in the hose definitely completely through it?
Pop open the aftercooler and see if there is liquid in there.

Do you have the heat exchanger mounted on the car still?

Pump should definitely have 2 lines connected to it and be routed to the heat exchanger.

 

So upon further investigation lol i noticed that the broken part of the pump is actually where the return water line goes. So looks like the past week of driving has been with no water in the cooler. Still need to find out why the fuel pump was so loud yesterday. I think im goin to order a new one and put it in, make sure tank is clean and also a new fuel filter while im at it. Also ordered new spark plugs at the same time, Take car of basic tune up stuff then see if this hesitaion keeps up. Seems like its lacking fuel when it happens, I guess i really need to just get an a/f gauge hooked up lol

 

Could be running lean. What pulley is on the car?

 

Im not sure which pulley is on it. P O said it was a slightly smaller pulley to get an extra 1 or 1.5 extra psi to maybe be around 7 psi
I ordered a new fuel pump today due to it being very lound yesterday, Also ordered a new water circulator and a new set of ngk laser iridium spark plugs.
Could is possibly be that since there was no water in the aftercooler that stuff was getting too hot and making it run bad for a bit til it cooled down? the cars temp never goes above 3 lines. But also the car never stutters or bogs down unless ive been driving and its heated up. I dont think its done it cold yet.

 

Your coolant temp of the engine won't be affected by the aftercooler not having water. Now if it has been hot out where you are and the aftercooler is obviously not functional the iat's could be very high causing detonation.

You need to buy a wideband and boost gauge and get those setup. How long ago did you buy this? Definitely should not by a boosted S Wioul knowing anything about what's going on.

I'd do a full tune up on it with all fluids plugs etc.

Get a new coolant line for the aftercooler and make sure that is wired up correctly to the aftercooler and make sure it is wired into the right power source.

I wouldn't go into boost much before you know what psi you are running and what your afr's look like.

I'm guessing you are using the comptech rising rate fuel pressure regulator?

 

I just got it a few days ago. It has that red fuel pressure regulator in the corner of the hood area which im guessing is the fuel pressure regulator. But it also has the regular fuel pressure regulator on the fuel rail. Is it supposed to be like this? This car looks to be put together well, but without knowing the af ratio i guess i could be in for a surprise, according to previous owner, he bought it with about 23k miles on it exactly how it sits, it now has 64k miles, After i give it a full tune up ill see what happens with the hesitation