2003 Srt-4 tune

[lilkdude87]

I put the 93perf tune on my 03 Srt-4 earlier and when i ran it down the road boost jumped to 15 at wot and it ran like dog shit it sputtered like it had a miss fire so i put the original tune on it and it only went to 12psi and ran like a champ can anyone explain this please

[gizmodo]

Are you stock? You need to provide more information about the vehicle before anyone can offer suggestions.

[lilkdude87]

oh yea sorry i forgot that yea im stock except for a bov and hardpipe kit

[gizmodo]

If you are only spiking to 15 psi on the 93 tune and 12 psi on the stock tune I would suggest a boost leak test. Did you happen to see what your AFR was when it was running poorly? Were there any codes?

[lilkdude87]

it was tested for a boost leak when the bov and hardpipes were put and it had no leak also my buddy was telling me it could be a lack of fuel i dont have a wideband but i do have a pyrometer that will have to do till i get a wideband when i dynoed it EGTs went to 1400

[gizmodo]

1400? That's pretty low. Is the probe before the turbo? I've seen 1700+. Something isn't right with your car. It sounds like a boost leak. Are you sure all vacuum lines are hooked up as they were from the factory?

[lilkdude87]

no the probe is right before the cat and lines are hooked up except for the line on the stock surge valve and on the stock intercooler pipe but i got those capped so they shouldnt be leaking but like i said earlier i tested it for a boost leak shortly after i put the bov and hardpipes on

[gizmodo]

no the probe is right before the cat and lines are hooked up except for the line on the stock surge valve and on the stock intercooler pipe but i got those capped so they shouldnt be leaking but like i said earlier i tested it for a boost leak shortly after i put the bov and hardpipes on

That red line goes to the TIP sensor and is very important. Hook that back up before Duster comes into this thread.

That's why your temps are so low. In my opinion that is a nearly worthless location for an EGT probe. It should be pre-turbo to get more accurate results.

[Quick]

If it was leak tested when the bov and hardpipes were installed it doesn't mean it isn't leaking now right? how long ago was that?

[lilkdude87]

well where do i hook that wire back up to then? and it wasnt that long ago but a boost leak is not gonna cause the to stumble

[gizmodo]

There is a set of three solenoids in the engine bay. You want the red one. It will have a white line going from it to the TIP sensor, which is mounted to the driver's side fender. See the attached image for more info. While you are at it, make sure ALL your vacuum lines are hooked up properly.

[lilkdude87]

no the line i unhooked came of the stock intercooler pipe theres no where to hook it back up to it was a vacuum line i got it capped now im tryin to figure out y the car stumbles every once in a while and it stumbles hardcore with the 93 tune

[gizmodo]

Please re-read what I have said, and look at the diagram again. The red "vacuum" line you unhooked is indeed your problem. Capping it is not a solution. Look at the diagram above. It clearly shows the line connecting between the intercooler and the throttle body. You need to get your cold side pipe tapped for that line. The problem you have is without the TIP (Throttle Inlet Pressure) sensor getting a signal, the car is guessing as to what is happening, which can cause all kinds of fuel and timing problems.

This is a post from Dr. Who on the big forums. He is a member of the SRT Engineering team:

The red line from the stock soft pipe _IS_ the TIP (Throttle Inlet Pressure) sensor pressure tap. The TIP sensor does double duty which is why it is plumbed to the solenoid.

On startup and long deceleration events, it checks ambient atmospheric pressure. The rest of the time it is sampling the throttle inlet pressure which is read right from the red line you removed. Lord knows what your engine controller is thinking when it sees atmospheric pressure on the TIP sendor and then boost on the MAP (Manifold Air Pressure). I'm surprised you haven't thrown more TIP/MAP sensor performance faults or the mainfold pressure/throttle position correlation - high flow/vacuum leak fault.

The engine controller uses both the TPS and the TIP/MAP relationship in concert to determine boost/fuel/spark/.

The engine controller tries to run "pre-boost" such that the TIP is a good bit higher than MAP which keeps the turbo spooled anticipating acceleration and therefore reducing turbo lag.

The TPS and TIP/MAP relationship is also used in determining engine idle airflow demands which commands the IAC (Idle Air Control) actuator.

That'll be $50 consulting fee.

-Doc

EDIT: Oh, and all of you guys with aftermarket TB's... Did you know that the stock TB idle air stop screw is very carefully calibrated at the TB supplier for a specific airflow ? The aftermarket TB's could have widely varying idle airflows which are outside the acceptable range and more than the amount that the IAC can adjust for....

[lilkdude87]

ok so where can i get it tapped to hook that line up

[gizmodo]

Take it to a machine shop and have them add a nipple. You can go to Home Depot and get a nipple from their air compressor section and have that added to the pipe. Be sure to zip tie the hose to the nipple. Or, just put the stock pipe back on.