I have to let my car warm up before I can drive it. Once it switched to closed loop it will perform normally. Would a physical delete of the airbox and egr cause this?

I do have lt1edit and have a file saved if anyone wants to take a peek

Lt4 conversion, hotcam, 5lb supercharger, 3600 stall. 1994 A4

 

Ummm, why did you delete the airbox? Did this start when you did that?

 

Is this the same problem you asked about 7 years ago?

https://www.camaroz28.com/forums/lt1...videos-873341/

By LT1_Edit file, are you talking about the tune file, or a data log produced with pcmcomm, that came bundled with LT1_Edit?

By “delete of the airbox”, are you referencing the changes to the inlet ducting you had to make to install the S/C? What does the new configuration look like? Where is the MAF sensor? How do you add the extra fuel for boost - FMU, in the tune, etc.?

What exactly does it do in open loop - run rough, misfire, surge, run rich, stall?

 

didn't. It came that way. Since I have got it, it has done that.

 

Haha. Omg never realized I asked the same question. Yeah same issue. My tranny fried and it sat for 5 years. Just getting her back out and want to nip this issue in the bud.

The lt1edit file in question is the actual pcm download of the computers data.. all the shift points, and thing like that

Here is what it counts like warmed up:

And what it sounds like when it is cold started:

Once it is warmed up and starts using the O2's, all the issues go away

The supercharger has a 4" pipe that goes to just in front of the drivers wheen. The MAF is located near the end of the tube. I know the fuel rails are not stock. Not sure what size they are, but the superxharger is only 5 or 6lbs of boost and there is no knocking or pinging while under boost

 

Is there a good LT1 tuner in your area?

 

If the engine hasn’t run in 5 years, what have you done to clean the entire fuel system - tank, sending unit/pump, filter, lines, rails an injectors? I assume you meant to say the injectors are not stock, because it would be very unusual for anyone to replace the fuel rails.

Appears you bought the car in it’s current modified configuration. Did it ever run well? Or is this problem something that developed after you drove it or a while? If it never ran right, the tune could be the problem. But if it deteriorated with time, it's possible some component is damaged or faulty.. That’s why I asked about pcmcomm. That can run a data log that may show what has come undone.

I’ve seen cases where the A/F ratio is so screwed up the the PCM can't correct it in open loop, because only the the stored long term fuel corrections (limited to a range of -15% to +25+) are used in open loop - engine runs poorly. But the PCM can also use the virtually unlimited short term fuel corrections in closed loop - engine runs better(but not correctly). Could be the result of the tune, or it could be faulty O2 sensor(s), leaking injectors, fuel pressure, etc. A log may reveal the problem, and it would also help the tuner,

. While you have the tune file available, I'm not a tuner at least not on the stock PCM. I ditched mine 20 years ago for an aftermarket unit.

It has to be 20 years since I've looked at a pcmcomm data log. Over the years superior software like DataMaster and Scan9495 have appeared. If you want to try Scan9495 I'll take a look to see if I can find the problem.

https://www.camaroz28.com/forums/com...95-lt1-874306/

 

The car has always done this since i purchased it. Ed Wright had tuned it per the previous owner. Not sure wtf he did, but one of the big oopsies was there was no 2nd gear kick down if i had the shifter in second or third gear... the line pressure was also set to run at 255 at all times. normal is around 30. Im not sure if it was requested to be tunes this way or not. i have since corrected all transmission settings with LT1Edit.

I did drain the gas tank before starting it. I also plugged in one of the fuel pressure guages and manually bled the fuel out if the line before the clean 93 octane hit it. For good measure I put in one of those boosters to get it around 95/96 octane. So the fuel should be pretty well clean. I have not checked the injectors though. But i really can't see them as being the issue, because the car comes to life when in closed loop. Unless you believe those could still be a smoking bullet.

I'll look into the Scan9495. BTW I really appreciate your time and efforts. Thank you so much.

 

Cam sounds a bit bigger than the LT4 HOT cam. Do you see any boost at idle?

 

no boost until i'm into the throttle. I have a gauge and it reads vacuum at idle. I cant remember the numbers off the top of my head but i would say low teens negative pressure

 

sorry for the long reply but i found out what the issue was. I accidentally forgot to plug the MAF in when replacing the air filter. I noticed the SES light, but also that the car started cold and ran.... not too healthy... but WAY better than before. Replaced the MAF and car runs as it should now.//

Question though. Anyone know what RPM and MPH I should set the shift points with 3.73's on 255/50R16