This is a great site and I have researched some good info here lately. Now its time I think I ask a question. I think I have a fuel problem? Maybe someone can help. My 95 GMC C2500 Sierra now has a 383 stroker Which has the following: comp cam 224/230 duration 510/520 lift with 1.6 roller rockers, 10:1 compression, high tin block, pro comp aluminum heads, holley 670 CFM TBI, MSD ignition and distributor. My fuel pressure is 12psi. I have to stand on the throttle to get her to start and she'll run rough for 10 secs or so then dies out like its starving for fuel. Im not sure where to go from here. Do I need a bigger fuel pump? I am confused on the fuel issue. I have been told it goes by the size of the motor. Or does it require more fuel per upgrades within the motor? Any thoughts would be helpful and appreciated.

 

You need much, much more fuel. Simple as that. Better fuel pump, I suggest Walbro 190, bigger injectors and/or higher fuel pressure. Then chip tuning. Read the stickies about tuning the chip, it is absolutely necessary.

 

I dont know if this changes things, but I forgot to add in my engine info that this is a 85 and earlier high tin block and heads. Also I have a 4L60E thats been beefed up. Will this holley throttle body perform right with this engine? Some say yes others say no.
BronYrAur, thanks for the reply!

 

way more fuel. im not sure the injector size in the holley tbi but you will need a bigger pump to feed that thing and tons of tuning. thats a tough combo to tune if you dont have any chip burning experience.

 

Yeah, it'll be difficult to dial it in but you should be able to do it. Just read around the boards about prom tuning now and see what it's all about. You need to dive in and start burning chips for that engine.

I'm also not sure what injector size those Holley TBIs have, I had one but had a GM injector pod on it. I'd say just turn up the fuel pressure as much as you can right now and go from there with the tuning. You've got some researching to do.

 

I have been researching the many tuning options out there. Many there are! I was wondering if there was a set up where I could start with something tuned for me to my motors specs and still have the ability to make changes from there. Not having any experience in this area I dont want to mess up my motor. Id like to learn as I go but feel more comfortable having something to start with. Is this possible? Theres a lot of great info here Ive been reading and printing to read and reread again and Its slowly sinking in. Thanks!

 

In a nutshell.....no. There are companies that sell mail order chips but it is not humanly possible to guess what is needed for a particular combo of parts. The only other option is to have a shop tune it with the vehicle in hand, which usually cost about 3 times as much as the tuning equipment.

Just so you know you are putting your engine in danger just running it on the stock tuning. Read through my "free tune" sticky at the top of the page, i'ts helped a lot of beginners.

 

Im looking at the APU1 AutoProm Package USB version. Looks like it has a little of everything I need except the ziff and chip adapter. Will this work for my engine setup? Thanks for all the help guiding me in the right direction.

 

I have no idea what the Holley injectors are rated but I've got a cam similar to yours on an aluminum headed roller 383 and I'm using 68lb. injectors at 21psi. I'm probably going to need to turn it up more because with that cam the engine likes the A/F ratio at just a tad under 14.0. When the ratio is at 13.8 or 13.9 the engine idles real smoothe but if it dips to 14.0 or higher it begins to vibrate a bit and the smootheness goes away. In short, you're going to have to turn up your fuel pressure. I'm also running the EBL.

 

I am just now getting it to run for the first time. The valves needed adjusting. My tuning is way out, Ive already changed the oil and filter because there was so much fuel in it. Shes just not burning all shes getting, I guess. But Im leaving it alone till Thursday when all my goodies come from Moates! Then maybe I can get her feeling better. Till then I have a note book full of information Ive printed. Trying to read and keep notes so I dont feel so in the dark or intimidated when everything gets here. Thanks for the response, Im sure Ill be back this weekend with smoke coming out of my ears from info overload!