Ok guys I need help. I have a 1995 A4 Z28 LT1. 355ci, ported stock heads, 52MM Edelbrock tb, descreened, ported/polished MAF(removed the aluminum in the center), 218/224 .570/.565 cam, 30lb Siemens injectors, new O2s(new when the motor was rebuilt, so 10,000 miles ago) mid length headers. I bought a PCM for less tune when I rebuilt it. It worked ok, but for as long as I can remember the car has smelled rich at idle and low rpm. Also, it makes a whistle sound from the intake or tb/MAF area(like the IAC is wide open and it is sucking air through the IAC hole or around the throttle blades). I run premium gas, 93 here in NC. The whistle sounds like a blower, in fact I've been asked many times if it is s'charged. Its agrevating to have it stink like it does. Its really bad at idle. Does anyone know if there is a table that can be changed in the tune to lean it out at idle, or could this be a problem with the TPS sensor? Could the whistling be that the throttle blade set srcew isn't set in the right place? Does anyone know if Edelbrock TBs are know for any problems like this? I'm worried about hurting the rings/walls if they hanv't already been. Any ideas? Thanks guys.

 

You need to scan the car to see just how rich it is. Also, make sure there are no mechanical problems Then you can change the MAF tables to lean it out.

Maybe try putting a stock MAF back in.

 

I just had a few other helpful members PM me. Thanks for replying. We talked about the MAF. I'll try a stock one, as long as I can find one in good shape. Anyone out there have one? Does anyone really know if porting them really helps? It seems like if this is the cause of my problem all along, I'd reccomnend sticking with stock. Anyone know if there actually are any real gains using a ported/descreened over an unmolested one?

 

You shouldn't be hearing a whistling/sucking sound there. Almost sounds like you have a leak before or at the throttle body. Have you checked around there to make sure all the intake piping clamps are tight, no tears in the elbow if you sill have the rubber one, TB bolts tight, no splits in the vac lines around there etc? Any leaks around there and your A/F mixture will change.

Ken R.

 

Well I can hear the sound coming through the intake, like at the MAF or up further maybe at the throttle body. It sounds like the air going around the blades or maybe the IAC is wide open and sucking the air through the idle hole in the TB. It goes away under acceleration but come back at idle. Sometimes when the car is warm and gets turned off and turned back on(if I park it and then get back in and drive again) the sucking sound seems to go away. It seems to go away in park when its warm but as soon as I put it in drive it comes back, like the blades have changed position or IAC has moved.

 

I think I might try to take a video and post it on here so you guys can hear it.

 

I'll take a vid and put it on here tomorrow night

 

I think this link will work:http://s214.photobucket.com/albums/c...ished_0001.flv

 

Good grief I wouldnt deal with that for 5 min. Try wigging the intake ducting around just a little bit while its running see if it changes any when you do that. Feel around the couplings and see if it changes. Wiggle the vacuum lines on the intake just a little also. Then you can try kicking open the throttle blades a little more, a datalog will tell the story there most likely.

Seems to me like the car takes several cranks to start, hard to guess the reason without seeing some data or the tune. Mine always starts at just a touch of the key.

Another thing I notice is it seems to idle rather fast and still pretty lumpy at the same time for the cam that is in it.

On another note does the noise go away when you touch the gas just a little? Almost sounds like a bad bearing in the idler pulley or something. Whistles usually are not nearly that pronounced.

 

I know that it has low fuel psi at crank up. It has a new regulator, but I think it needs a new fuel pump. That is why I usually cycle the key twice to start it. I just did not do that in my video.

 

It does kind of go away. It also seems to go away after its warm and has been turned on and off a few times, but only in park. When its warm and I start it up, its kinda quiet almost gone. Then I put it in gear and it just comes right back like in the video.

 

Well the fuel pressure thing is troublesome. You have got to be absolutely sure the fuel pressure is where it is supposed to be before you start tuning anything. Otherwise you're tuning to a problem not to propper operationg conditions. Before you start doing any tuning at all everything else must be 100% mechanical and electrical or you are just wasting time.

The whistle sounds like the idle air controller whistling. It would be open more when cold to keep the idle up and get the engine running until it warms up.

 

Well I flashed what is in the car and I tested the DataMaster software. I'll get a good reading in the morning on my way to work. I only drove about 2 miles and for about 5-6 mins. I also had the program set on corvette w/ auto trans. I'll change it to f car w/auto. Anything else i should do to ease this along? Can we tell what my fuel psi is in this DataMaster program?

 

Recommendations on what to do about the IAC?

 

The only way to tell squat about the fuel pressure is to just put a gauge on the port at the back.

Look at your log you made see if it shows what the iac counts are if they are 160 or close you can stand to open the tb blades up. Usually anywhere between 40-100 warmed up in gear is pretty good. Closer to 100 with a cammed car is usually not a bad idea.