1995 silverado having issues with timing

[drslayer7mm@gmail.com]

I have a 1995 silverado I'm new to tunerpro and am having a difficult time understanding and figuring out what to set my timing tables at... I copied my original chip for a bin.. set the base timing at 0 with timing advance disconnected.. hooked timing advance back up drove the truck and had a lot of popping under load or at wot... disconnect timing advance set base timing at 25 drove the truck with it disconnected and the popping stumbling went away.... the engine is a 355 with a 4x4 comp cam edelbrock performance rpm heads edelbrock performance rpm intake bored out tbi I'm running an 18-20 psi fuel regulator spring with the ep 381 fuel pump... any advice on how I can fig out what to do with my timing table would be great

[sbdblyss]

I have a 1995 silverado I'm new to tunerpro and am having a difficult time understanding and figuring out what to set my timing tables at... I copied my original chip for a bin.. set the base timing at 0 with timing advance disconnected.. hooked timing advance back up drove the truck and had a lot of popping under load or at wot... disconnect timing advance set base timing at 25 drove the truck with it disconnected and the popping stumbling went away.... the engine is a 355 with a 4x4 comp cam edelbrock performance rpm heads edelbrock performance rpm intake bored out tbi I'm running an 18-20 psi fuel regulator spring with the ep 381 fuel pump... any advice on how I can fig out what to do with my timing table would be great

Hello.

I have almost the same setup and I am having a lot of trouble. I have the edelbrock performance package, which includes the heads, cam and intake manifold. I am running lean and thinking about getting a different regulator spring, but I am also getting a ton of knock at higher RPM. I already put in the 381 fuel pump. I am currently running the edelbrock chip that is supposed to make the truck run richer after installing the heads, cam and intake. I think that I need to tune the truck on my own. Have you had any luck tuning? I am using Tunerpro to log, but I haven't done much beyond this. 1995 Silverado, 5.7l 2wd.

Jake

[drslayer7mm@gmail.com]

I haven't had any luck with the tuning but I can tell you the fuel pressure regulator spring makes a big difference mine is running rich I'm about to give up on the fuel injection personally and just drop an hei distributor and a carb on mine.....

[Kitch]

Sorry I'm not an expert here like some but some, so I won't comment on your timing problem.
Changing your fuel pump was a good move, the stock fuel pump seems to struggle with even a mild combo.
Things like knowing what your fuel pressure really is and the air fuel ratios shown by a wide band O2 sensor can help a lot with fault finding and while they can be a bit fiddly to get set up it's worth it once it's done.
Have you checked your fuel pressure with an actual fuel pressure gauge?
Have you altered "Injector Flow rate (TBI lb/hr)" in TunerPro to compensate for the potential increase in fuel pressure?
Are you using a wide band O2 sensor to see whats going on outside the factory narrow band O2 sensors range?

[drslayer7mm@gmail.com]

Yes I have the stuff to check the actual fuel pressure I checked it before the new pump I haven't checked it since the new pump and I tried playing with the flow rate found somewhere online how to re scale them but it seemed to run worse I may try to fool with it some more

[Kitch]

My van ran worse after I increased the full pressure but once I "altered the injector flow rate" and used Dave's spreadsheet to bring the BLM's back into line it went better.
I guess the next step would be see what a wide band O2 sensor is telling... is your new combo going lean.
Just out of interest what's your idle vacuum (or the MAP value) with your combo?

[drslayer7mm@gmail.com]

Truck is definitely running rich.... what spread sheet are you referring to?

[Kitch]

Have you read this Adjusting VE Fueling tables with BLM data Tutorial! (http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1895-Adjusting-VE-Fueling-tables-with-BLM-data-Tutorial!)
Maybe do a search for the most recent spread sheet from Dave W.