So I did a cam swap about a month ago got truck tuned. Problem is sometimes the truck starts, sometimes it doesn't. It turns over but doesn't fire. I do it again n it goes to start but backfires. So I have to do this randomly until it starts. Sometimes it does it on the cold start sometimes on the warm start. I will take video today n post it up later on. It's an 08 silvy 4.8 with a 215/222 on a 113+4 advance. .602/.604. Any ideas? I am running to get a fuel psi gauge to see if pump is going bad

 

What was the fuel pressure, just out of curiosity? And has the truck done that since you put the cam in or recently ? Are your springs rated for over .600 lift

Did u ever get a video ?

 

maybe the tuner gotta work on his tunning...

 

springs are rated for that lift had to pay extra with the cam package, and i couldnt find a gauge to read it have to check tomorrow. anyways here is the vid, this is actually a good start, she would do this about three more tries before she fires up

Rough Start - YouTube

putting it on the dyno so justin from blackbear can tune it some more.
performance is not affected and once she starts she wont die or act funny, its just the initial start thats being a PITA. its already tuned for the cam but its not perfect so he wants me to get her tuned again

 

Never heard of that on newer body style engines?

 

If you hit the throttle while cranking it does it do the same thing?

 

Backfiring is probably fuel in the cylinders from it turning over. U positive u were dot to dot on thd cam?

 

mine does the same thing, just no backfiring. Doesnt do it when cold but after its been running and almost cooled off is when i seem to have to crank it a few seconds to start it. Really annoying especially when you know people are walking by going, look at that piece of ****

 

LMAO....I know the feeling. You know, when that SOB won't crank for **** and people are looking and you just slide down in the seat...fumbling around for your sunglasses and a hat so no one will see who drives that shitbag.

Yep, been there, but the tune was fixed. Truck always fired up fine cold....just when at operating temp there was a problem. If I shut it off and then tried to start it up again I would have to give it some gas as I remember. Also if it idled for a little while it would start running rough and then shutdown. I don't want to even state it, because I can't remember correctly, but I will just say it didn't restart correctly because the computer is using the same temp that it did for initial startup. This either gives the engine too much or not enough fuel.....therefore the engine can sometimes act as though it is flooding.

The tuner can change the temp that the computer uses and this will help with startup issues.....as I remember. Anyway, as I said I can't really remember the whole issue but I'm sure Justin can work it out...some things just take time so it won't end up worse than before.

 

Guess i need to break down and set up a time to go dyno tune. When i had mine tuned i took the computer to him and he did whatever then took it back to him when i got it running so he could check a couple things and that was it. So i know im not near dialed in as i should be.