I have a 92 RS oringinally a 305tbi now changed over to a 350 gmpp vortech crate motor. Im running a 350 tb from cfm technologies and along with 75lb injectors that they have recommended me. I had a custom chip burned for this combination as well from a company called Wester's Garage. When the motor was first tested with the 75lb injectors it was running very rich and souned like it was missing when it was cold. Once it warmed up the car seemed to idle better but still ran rich. The mechanic I was working with decided to try a set of stock (55lb injectors I think) 350 injectors from a tbi truck he had lying around and the car idled perfect. The problem tho was it didnt have much more power than the 305 I just had taken out and now was running on the lean side. My mechanic said that even tho the car was programmed for the 75lb injectors, they are still to big and that was the reason it was running very rich. After driving the car for a while once I had gotten it back, I felt flat spots with the stock 350 injectors and an unsteady rpm when minimal gas was applied. I decided to put the 75lb injectors back in ( since never road tested with them) and the car ran really well once warmed up. It had twice the power and overall ran better. There still is a problem with the rpm fluctuating up and down when the gas is held at a minimum in neutral. The car is running really bad when its cold and reaks with gas smell. Its also started to put out black smoke now. Once it warms up it and driven for a while all the problems seem to go away but the idle still, every different time I stop is at a different rpm, some times way too high or too low. i have been told by ppl in the proffession among others that the injectors are two big and others are saying its the programming or other things and the injector size is fine. The motor was installed at a gm dealership that sells gmpp. I was given this car to take running like **** and with no suggestion or clue from the mechanic on what to do with it. Are these injectors too big or should there be other things/ adjustment in the tb, vacuum leaks, that I should be looking at? Any help or advice is greatly appreciated since I am lost now with this car and am batting my brains trying to figure out what is wrong with it.

 

Sounds like your car is running like crap. The reason it's running like crap is it isn't tuned. Your only option is to tune it. I'm guessing wester's garage is a mail order type of chip. They didn't get it on the first try. Your going to be playing tag with them to get it right. You'll need to data log your car and send them the info if they are going to have a fighting chance of ever getting the car to run. If they don't know what data logging is your screwed. Your best bet would to learn how to tune your car your self. That way you know it's right. The injectors aren't too big. You tune is just way off. Having 75 lb injectors is like saying you have a holley jet kit that goes up to 75 lb's it's up to the tuner to decide what "jet" to use. In my opinion mail order chips are a hit and miss afair, mostly miss. Some guys on here have had luck with brian at TBICHIPS.com. You might give him a yell and see if he can help. Also do a search for WINALDL it's free scanning software that will let you see whats going on inside your ecm. Thats where the data log come from. Your chip tuner should have pointed you in that direction.

 

I couldn't have said it better. Tuning is your problem. It will take more than a rough stab to get your chip right. You will need to data log and have an expericned burner look at the data. It will take many burns to get ytour set-up dialed in. Don't fret though. It can be done and many of us have great sucess when burning our own chips. There are a couple of great links at the top of the page in the "new to TBI" thread. You should also read the stuff at the top of the page in the DIY PROM board. That will help put things into perspective.

 

if you take the time and invest the $$ to tune you will find this forum extremely helpfull. besides it is fun. but requires some $$ and a lot of time studying how to tune and then more time tuning. you are in exactly the position many of us were in when we decided to modify our cars.

 

Thanks for the advice. I went ahead and found a web site where some one offered a free down load of winaldl so as soon as I get a cable adapter Im going to dowload the program. I'll get all the information I need off of this and fax it to the programmer (located in Canada, yes mail order) since he agreed to alter it for nothing so Ill give him another shot. Thank *** my recently retired transmission isnt going to be this complicated when I replace it!!! With probably only have half the power it should be making it blew the trans. Once its fixed Im sure the rear is a gonner as well. Oh well, better start savin and working some hard hours!!