View Full Version : engine runs for about 5 seconds and dies

02-24-2013, 06:03 AM
engine: gen III 3sgte powered by autronic SM4 ecu, walbro fuel pump and stock injectors

This is my first time starting this engine since I bought all of the parts for it (formerly parted out), rebuilt it, and wired in the Autronic ecu. My engine starts and runs for about 5 seconds at a time and then it dies from a lack of fuel from the sound of it (not the fuel pump shutting off). I have a feeling it has something to do with the fuel pressure regulator. According to the vacuum diagram that I found in a google image search it doesn't need a vsv and it connects directly to the intake manifold, but I'm thinking that I need a vsv between it and the manifold. I am tempted to put on my AEM fuel pressure regulator that I have lying around but I would rather get the stock one running first and then work on getting the aftermarket one going.

02-24-2013, 07:39 AM
Does not need a VSV. Might want to check your startup/idle maps and see if you are giving enough fuel to keep it running.

02-25-2013, 08:29 AM
This definitely sounds like a tuning issue.

02-25-2013, 08:32 AM
Yeah, now I believe it is a tuning issue. I was adjusting the fuel maps today and getting the same problem. I'll keep toying with it tomorrow after my battery has a full charge again.

02-26-2013, 05:37 AM
u check for codes.

02-26-2013, 06:06 AM
u check for codes.

It is an aftermarket computer, there won't be codes but it tells me what the errors are. But there are errors flashing on the computer screen that say low cyl sync % only and misfire when I adjust the timing to where it won't start. It should be around 20% to 80%. When it runs for the 5 seconds there are no errors on the laptop display.