Fuel injection issue

[odd boy]

Hi everyone,

A friend of mine has replaced the stock injectors on his 98 Camaro with (FAST 36#) ones, he has done that after the duty cycle reached 130% with the stock ones. Of course, he’s done that because of 610 cam installation.

I followed the injector calculation that is posted in Calculating Injector Flow rate thread to correct {B4001} injector Flow rate, but I think there should more work on these injectors’ tables, like

{B4006} Small Pulse Threshold
{B3701} injector pulse widths
{B3702} injector timing
{B3703} injector timing trim
{B4001} injector voltage correction
{B4003} minimum injector pulse width
{B4006} Small Pulse adjust

Please help us the car runs too rich all the time, the car doesn’t go lean even if we reduce the VE values extremely, so we point finger at the injectors’ configuration.

For sure we followed VE tutorial step by step, also we put all PE values leaner than the VE to make sure that all values will be supplied from backup VE only

[405HP_Z06]

Hi everyone,

A friend of mine has replaced the stock injectors on his 98 Camaro with (FAST 36#) ones, he has done that after the duty cycle reached 130% with the stock ones. Of course, he’s done that because of 610 cam installation.

I followed the injector calculation that is posted in Calculating Injector Flow rate thread to correct {B4001} injector Flow rate, but I think there should more work on these injectors’ tables, like

{B4006} Small Pulse Threshold
{B3701} injector pulse widths
{B3702} injector timing
{B3703} injector timing trim
{B4001} injector voltage correction
{B4003} minimum injector pulse width
{B4006} Small Pulse adjust

Please help us the car runs too rich all the time, the car doesn’t go lean even if we reduce the VE values extremely, so we point finger at the injectors’ configuration.

For sure we followed VE tutorial step by step, also we put all PE values leaner than the VE to make sure that all values will be supplied from backup VE only

Take a look at this script. The values came from the GM ASA PCM which used these injectors.

For this to work, your {B4001} data units need to be set on imperial (lbs/hr) and {B3702} and {B3703} data units set on imperial (*F).

This also assumes you are using an unreferenced fuel pressure regulator.

*****
To execute a script
1. Load the tune
2. On the menu bar: Edit >> Run Script
3. Navigate to script location and select
4. Select 'Run' on the script file processing window
5. Select the ""Results"" tab and confirm no errors occurred
6. Close the script processing window
7. Confirm the tables were modified correctly
8. Save new .tun file with a new name

[joecar]

Measure your friend's rail pressure and post it here, along with his tune file.

[joecar]

Also post your friend's logs.

[odd boy]

405HP_Z06,

Thanks for your help, but my flow rate should be different because the fuel pump delivers 60 psig. I don't know if I can use the rest of the tables rather than the flow rate?????


Joe,

The rail pressure is 60 psig, and the tuning file is attached. Unfortunately, the log file wasn’t saved. by the way I kept all changes I did in the history

[joecar]

If rail pressure is 60 psi instead of 58 psi, I calculate 5.326 g/s instead of 5.238 g/s or the 5.234 g/s in the tune file... but thats only a 1.7% difference.

{B4006} Small Pulse Threshold
{B3701} injector pulse widths
{B3702} injector timing
{B3703} injector timing trim
{B4002} injector voltage correction
{B4003} minimum injector pulse width
{B4005} Small Pulse adjust

To find values that suit your non-stock injectors for those tables you need injector flow testing equipment to run the various flow measurement experiments... and to spend time doing research on a few live vehicles... it's not that simple, if it were then the answers would already be posted.

Cheers
Joe

[405HP_Z06]

If rail pressure is 60 psi instead of 58 psi, I calculate 5.326 g/s instead of 5.238 g/s or the 5.234 g/s in the tune file... but thats only a 1.7% difference.
To find values that suit your non-stock injectors for those tables you need injector flow testing equipment to run the various flow measurement experiments... and to spend time doing research on a few live vehicles... it's not that simple, if it were then the answers would already be posted.

Cheers
Joe

No doubt, measuring is the most accurate method but why not start from the tables GM used for these injectors?

[odd boy]

So, what shall I do in this case? any advice.

[joecar]

No doubt, measuring is the most accurate method but why not start from the tables GM used for these injectors?

That's exactly what would be done... start with the GM values and adjust/observe/edit from there.