What does your 3bar map read
11-01-2008, 09:15 AM
#1
What does your 3bar map read What does your 3 bar map read while cranking and with the key to the on posistion. I am trying to figure out if this why my car is not starting.
Right now it reads 10.6in hg with key on, and 10.3 in hg while cranking. My stock one reads 31 while key on and 30.9 while cranking.
Right now it reads 10.6in hg with key on, and 10.3 in hg while cranking. My stock one reads 31 while key on and 30.9 while cranking.
11-01-2008, 09:28 AM
#2
I dont know yet because I havent installed mine but your problem explains why when I last cranked my car that it was hard to start and didnt want to idle well. I installed 55# low imedance injectors & rescaled them, I also flashed the OS to a 3 bar SD and still had the stock 1 bar map hooked up. I thought it may have been the injector voltage offset but now I'm pretty sure it was the 1 bar map screwing everything up.
11-01-2008, 12:06 PM
#3
What does your 3 bar map read while cranking and with the key to the on posistion. I am trying to figure out if this why my car is not starting.
Right now it reads 10.6in hg with key on, and 10.3 in hg while cranking. My stock one reads 31 while key on and 30.9 while cranking.
Right now it reads 10.6in hg with key on, and 10.3 in hg while cranking. My stock one reads 31 while key on and 30.9 while cranking.
11-01-2008, 12:41 PM
#4
then can you explain why it will not run well with the 1 bar sensor then. I also have confirmed that it is a 3 bar tune. I am not sure if you read my other thread zombie, but I had a 2 bar sensor with this same tune and in order to make it work I had to drop the fuel pressure from 60psi to 28psi. Otherwise it would create a sever misfire.
But now I can not get the car to run on a 3 bar at all and then when I plug in a 1 bar, it has a very difficult time running and the pressure has to be dropped all the way to 9psi. Anything that you can think of that would come about on all of this.
But now I can not get the car to run on a 3 bar at all and then when I plug in a 1 bar, it has a very difficult time running and the pressure has to be dropped all the way to 9psi. Anything that you can think of that would come about on all of this.
11-01-2008, 03:11 PM
#5
So you have a 3 bar tune that ran fine on a 2 bar sensor? How does that work, the voltages they output for a given pressure are completely different unless someone whipped up a voltage scaler to use the 2 bar on the 3 bar tune. If it was tuned with 3 bar settings and only a 2 bar sensor the tune will be completely off.
2 bar sensor = 2 bar at ~5 volts
3 bar sensor = 3 bar at ~5 volts
2 bar sensor on a 3 bar tune = 2 bar at ~5V, but the ECU thinks it's seeing 3 bar of boost even though it's not since the sensor is outputting 5V at 2 bar and the ECU is thinks 5V = 3 bar. 2 bar on a 3 bar sensor should be about 3.33 volts (two thirds ov 5V). These are rough estimates as most sensors don't read vaccuum all the way to 0 bar so there is some offset.
Any more details? The whole setup sounds confusing. Why would you have a 2 bar sensor on a 3 bar tune? That's really going to throw the things off if it was tuned like that due to the voltage scale. Why don't you just put the 3 bar sensor on and retune the car? Won't take very long if you have someone drive for you while you log / tune it.
How was the car originally tuned and on what sensor?
Cliffs:
The tune has to match the type of sensor being used.
2 bar sensor = 2 bar at ~5 volts
3 bar sensor = 3 bar at ~5 volts
2 bar sensor on a 3 bar tune = 2 bar at ~5V, but the ECU thinks it's seeing 3 bar of boost even though it's not since the sensor is outputting 5V at 2 bar and the ECU is thinks 5V = 3 bar. 2 bar on a 3 bar sensor should be about 3.33 volts (two thirds ov 5V). These are rough estimates as most sensors don't read vaccuum all the way to 0 bar so there is some offset.
Any more details? The whole setup sounds confusing. Why would you have a 2 bar sensor on a 3 bar tune? That's really going to throw the things off if it was tuned like that due to the voltage scale. Why don't you just put the 3 bar sensor on and retune the car? Won't take very long if you have someone drive for you while you log / tune it.
How was the car originally tuned and on what sensor?
Cliffs:
The tune has to match the type of sensor being used.
Last edited by Zombie; 11-01-2008 at 03:21 PM.
11-03-2008, 09:26 AM
#8
Ok some new info if anyone can help. I am still not able to get the car to start. Here is what i tried.
I adjusted the fuel pressure from 20 to 80psi with the 3 bar map, then I changed the spark plugs and adjusted from 20 to 80psi again. Still with no luck. I am going to try and get a video of what it is doing so everyone can see what I am talking about.
I adjusted the fuel pressure from 20 to 80psi with the 3 bar map, then I changed the spark plugs and adjusted from 20 to 80psi again. Still with no luck. I am going to try and get a video of what it is doing so everyone can see what I am talking about.
11-03-2008, 09:36 AM
#9
It might have been tuned with a 2 or 3 bar map with the 1 bar o/s. I have done this a lot on the older vortec trucks, 4.3l, 5.0, and 5.7l. If this is the case try cutting your ifr in half to start it then you will know. Don't leave it like this just try to start it, you are more then likely not getting enough fuel.
11-03-2008, 06:57 PM
#11
He doesnt have EFILIVE yet or any tuning software. It was tuned by a shop out of state. He just happened to have the 2bar and wanted to hear the new combo run. He traded the 2 bar map for my 3bar map that came off my running car and now his car wont start with the 3 bar. The reading he gets when trying to crank it do make it SEEM like it has a one bar tune but it wont run with the 1bar in unless he cuts FP down to like 9psi. Runs on 2bar with FP at 28psi. Hopefully we can get him going as we all know how frustrating this can be
