i have a 94 383 lt4 heads ect. i use tunercat and need help with my hot starts. cold start ups are great. but once hot .my pw goes to 3. to 5. i can spray some carb cleaner into the blower inlet and it fires right up. how can i lengthen the pw at startup in tuner cat

 

Can you explain your situation a bit better? You say you are using TC, but you are reading with what? Carb cleaner into the "blower" inlet. are you SC?

I have pretty (some would say) radical thing I did with my start sequence, but I need to know more about what you are talking about before I give you an idea to go with.

Give us more info on the type of car you have.


Ben

 

i have a94 383 with lt4 heads, intake, 1:6rr, carrol 10 psi sc, 36 lb injectors, full length headers, lt4hot cam, crane hi 6 ign with boost retard, and a nos 300 wet kit. i am trying to get the tuning straight before i run it. it runs good but it wont start after it gets warm. i let it sit for 30 minutes and starts up fine. have good fuel pressure good spark , just not enough fuel to fire once warmed up. if you need any more info,,just let me know..thanks

i use tunercat to program and , datamaster and pcmcomm for looking at data.

 

Let me just say that you may have other problems. In addition, you have not indicated if this just started with a rebuild or if this has been going on since...whenever.

Noting that, here is my suggestion:

Start DataMaster before starting your engine. Next do a start of your car and measure the voltage - specifically during cranking of the starter. Now you will notice a drop in voltage during this time. Note the voltage. I will be in the area of 7 - 10 volts.

Go to TC and under the tables are the "injector offset vs battery voltage" settings. under the area of your cranking voltage only, add a few hundred usec's to the table. Reprogram and test. If still nothing, add a few more hundred and try again.

Your max value in this table is 7782, so you have a range to try. I DO NOT SUGGEST YOU GO UP TO THE MAXIMUM. I know nothing about your engine and have no idea where your voltage lies while running.

I have done exactly this to my PCM and get sharp lightoffs. Just a twist of the wrist is all I need get my car to fire. However, I also know my car will never run in these lower voltages, so I am aware. You need to be also.

GL

Ben

 

my car was a stock lt1. i just decided to do some upgrades the car ran perfect before. upon installing the new engine . i replaced everything i could. all sensors, opti, iac , o2s, batery, starter ,pcm, ign module, waterpump, anything that was stock that could cause trouble. i have a tunercat copy of my current progarm if you would like to take a look, maybe you can see somthing i dont,.. i willl try the voltage test with datamaster.

 

Go ahead and send it to me and I will look at it.

Ben