ComputerNerd

I've been trying to get my car running right since I bought it.
It had a rough idle, bad stumble, and gas fumes would burn your eyes.
I have since found out the bottom throttle body gasket was trashed. I pulled the throttle body cleaned it and replaced all three gaskets. Car ran 100% better after.
I then decided to do a little tune-up. So I put on new plugs, wires, and oxygen sensors.
Car still seems to have a few issues. Idle drops from 800 to 600 (approx rpms) at a red light and lights dim slightly. Makes me think it's going to kill, but hasn't so far.
Also #1 cylinder header tube doesn't seem to heat up as fast as the rest. Could this be a bad injector? I have had a problem with starting the car after it sat 15min. I have to press the accelerator down half way for it to crank. On the other hand if it sits over night it fires right up... I have some accel 30# injectors that I am planning to install, after I get a new tune.

Could someone look at my new data file and just tell me what they see.

Right click and save as:
121403.cvs
121403.uni

Any help would be greatly appreciated....

Fastbird93

Well, I downloaded it and took a look, and everything was just wacky. Way outta there.

Then I realized that you have a different year car, and thus a different set of definitions than the 93 cars do.

Sorry, but I tried to help.

GetaZforgetGT

I would check your IAC motor and passage. Your IAC numbers are pretty high at Idle...they should be in the 20-40 range at 800 rpm idle. Is it an aftermarket TB? Do you have a Airfoil?

Check for carbon build up in the IAC passage.

ComputerNerd

I have a stock tb with an airfoil installed. I just did clean the iac when I disassembled the tb last week. Could it be bad?

GetaZforgetGT

The IAC can go bad.

Check the ohm rating.

Here's how

ComputerNerd

Thanks I'll definitely check that this afternoon...

Anything else from my data look out of wack?

Injuneer

Normally an A4 will idle at 550rpm in gear and 650rpm in neutral. Appears because your coolant temp is a little on the low side (often in the 165degF range) it is setting an idle temp a little higher, e.g. - 750rpm. The IAC counts are a little high at idle... e.g. 65, but the PCM seems to respond normally by raising and lowering the counts to control the idle, and the idle does respond. Perhaps your airfoil is blocking the idle air inlet.

Your MAP at idle looks way too high.... 17-20"Hg. Should be more like 9-10"Hg with a stock cam. And in the data on lines 3661-3725 the MAP seems to jump around way too much (jumps from 10 to 22, 11 to 27 in one line??).... almost like a cylinder or two was firing with the intake valve open.

Left side of the engine is adding a lot of fuel in upper load ranges, right side is cutting a little fuel most places. Definitely some sort of imbalance. Misfires?

ComputerNerd

I have noticed a random misfire from time to time. I am thinking #1 is not firing properly. I did the spray water on the headers test and #1 was cold at first then after the car warmed up it seem to get up to temperature.

I do have a hotcam and I'm not sure how good my tune is. I believe the idle is set at 750. As far as I know the injectors are stock and probably have around 140k on them.

Would a bad or leaky injector on #1 cause some of my problem?
"unstable idle at red light"
"random misfire"
"hard restart when car sits 15-20 min"

This car as had many hands trying to get it running right before I purchased it. SlimZR28, Teal94Z, and CrazyJoe are all previous owners...

After fixing the throttle body gasket leak the car runs 100% better, but still not perfect. I plan to get a new tune and swap the injectors with some 30#, so I can rule out injectors and or tune as the problem.

quicksilver97ta

That air foil can really restrict air into the iac passage. I got a dremel and enlarged that passage on the air foil (bottom leading to the back) and it dropped about 30+ counts and even reduced some cam surge.

Injuneer

When you post a tech question like this, it would be very helpful if you included info like the fact that the PCM had been reprogrammed. It really frustrating to find out you spent a lot of time puzzling over something that would have been obvious with the proper info up front. Who did the reprogram? The HOT cam will not account for the odd MAP numbers.... not 20"Hg at idle.

ComputerNerd

Sorry about that...
In the past posts a usually give a brief history of the car. I guess this time I forgot that.
I was told Madwolf did the tune, but like I said before several people have played around before me. I'm not sure that they didn't try to adjust the tune to fix the previous stumble which I believe was caused by the throttle body leak...
I could post a novel on things that they tried from previous posts I read.
Once again I greatly appreciate your time and patience in helping me fix this problem.

ComputerNerd

Just removed my airfoil and replaced the iac with another one I had. I did test both of them and got around 50 ohm on my meter.
While I was at it I made another run for new data...

Right click and save as:
121603.cvs
121603.uni

If anything is seemed to be more sluggish without the airfoil...

crazyjoe

Glad to hear that you're making some sort of progress with the car, sounds like you're really close to figuring out what's up. I sure hope that you do get it running right, should be a quick little ride when it's all said and done. Good luck.

Joe.

ComputerNerd

What's up Joe...
Just PMed you not realizing you were posting here.
Yes the car is running much better.
Just trying to work the last of the bugs out.