Prom and Ecm tuning

**chevytruckz** · 07-31-2013

Hi everyone, pretty clueless on what you can do to upgrade your prom and ecm looking for some insight. Have a 1994 chevy k1500 i put vortec heads on it, a pretty large hydraulic cam (lift 488, dur 234), and gm performance intake and it has flat tops in it. It is a complete dog right now and runs a little sparatic, I can tell its starving for fuel and air big time. Is there something I can do to send in the computer to get it programmed for these mods, or other things anyone knows of to do. I have the stock throttle body on it right now with a spacer. Thanks

**EagleMark** · 07-31-2013

That PCM just needs a chip with adapter you can install. Chip set up for the engine of course.

Do you have a link to cam specs or all of them?

What injectors and fuel pressure?

I just did one similar to this and the bigger problem then idle and running is supplying enough fuel to feed the new beast first!. We calculated the BB 74 lb/hr at 15 PSI and worked well. Pressure was very high to use SB 61 lb/hr injectors. So start with fuel to supply HP of... is there any HP estimates for that engine? Somewhere between 300-350.

**chevytruckz** · 07-31-2013

Thanks, and I am running the stock 350 injectors its a bone stock TB with like 13 or 14 psi fuel pressure. I have BB injectors that I can throw in just didn't know if I should. I cannot find the link to the cam and I ordered only two months ago. It is the summit special Lift 488/488 duration 234/234 that's what I remember. Its supposed to be around 350 hp. Also do you know where I can get this chip and adapter?

**EagleMark** · 07-31-2013

I can do the chip and include a Moates adapter. But...

Calculating fuel needed with the BBC 80 lb/hr injectors would need 15-16 PSI to support that HP. With the stock 61 lb/hr injectors around 26 PSI which is a PIA to tune and would need a Vacuum Reference pressure regulator. Either way this is not an easy tune...

Is this the cam?
http://www.summitracing.com/parts/sum-1106

What kind of compresion ratio does your engine have? This cam recommends 9.5 to 1...

That cam sucks for good idle and even tuned is kind of gutless until it revs up. It's not a very good choice for a DD street truck! If this is an auto trans? Well you should have a 2500 to 2800 RPM stall converter and probably 3:73-4:10 gears. The cam revs to 6300 RPM and is rated to work from 2800 up... the way a stock chevy truck runs on street it never even sees 2800 RPM...

Now with those gears and stall converter it would drive way better, but expect fuel mileage to be around 5 MPG... but you will go FAST!

**chevytruckz** · 07-31-2013

I do believe that is the cam, I will check the spec sheet when I get home from work to be sure. I have 3:73 gears in it, It has the auto trans and I put a b & M lockup 2500 converter in it. Fuel mileage isn't to important it's not my daily driver... It has between 10to1-10.5-1 let me know what else you think, thanks alot much appreciated.

**EagleMark** · 08-01-2013

Sounds like you have a plan!

Many people make big cam mistakes by going to big without all accompanying changes and well the drive ability is not good. Yeah it goes like hell at WOT but not much fun to drive around town etc...

For now you can start run and drive the rig... but NO WOT high RPM!!! You don't have enough fuel! Luckily the stock chip does not have enough spark either so if you did some WOT runs you were lean... but not enough spark to hurt...

You need a set of 80 lb/hr BBC injectors, adjustable regulator and a good gauge to set fuel pressure. Stock pump in tank will not do, need a TPI pump from 90 Camaro or 96-97 Vortec truck pump. They look identical and will bolt in, just way more volume and capable of more pressure.

Even though we need more fuel to supply engine at WOT high RPM, right now your probably pig rich because the cam lowers vacuum/raises MAP kpa, this dumps fuel at idle on stock chips. So still not good to drive, it will wash oil out of rings. Sniff your dipstick, if you smell any gas? Change oil! Your plugs are probably black if not wet from idle and low RPM cruisng... just a thought...

At minimum you are going to need a cable to hook up to ALDL port and data log with a lap top after a starter chip. (Should also have a Wide Band O2 Sensor.) I'm guessing 2-3 shots minimum to get your monster dialed in. With the converter you have we should have no issues running a higher idle RPM which makes tuning idle a lot easier. If your trying to hear the lope? Well that may take a morning of remote desktop control of your laptop and an emulator so I can do it live. The entire transmission calibration also needs to be tuned with all these changes, there's nothing right about a stock chip tranny tune for what you have. But if you have made other mods to trans? We will have to see data to make shift point changes. WIth like a shift kit... chip still says "A" but transmission is now doing "B".

You have quite a few bucks in this build and don't know what's left in your budget? But a wide Band O2 sensor is something that would go well with this engine/type vehicle to keep an eye on things as well as a good tool for tuning. A Ostrich Emulator or AutoProm for future tuning if you want to get into that?

**Fast355** · 08-01-2013

Originally Posted by EagleMark

That PCM just needs a chip with adapter you can install. Chip set up for the engine of course.

Do you have a link to cam specs or all of them?

What injectors and fuel pressure?

I just did one similar to this and the bigger problem then idle and running is supplying enough fuel to feed the new beast first!. We calculated the BB 74 lb/hr at 15 PSI and worked well. Pressure was very high to use SB 61 lb/hr injectors. So start with fuel to supply HP of... is there any HP estimates for that engine? Somewhere between 300-350.

I was running 61# injectors at 30 PSI to fuel my beast at one point in time and ran them over 50 PSI with boost reference.

**chevytruckz** · 08-01-2013

Your are right on about running rich the plugs are looking pretty dark and I have been checking the oil after every drive. The tranny has nothing done to it (yet anyways) no shift kit. I still have some money left to spend because It needs to run right so the injectors/adjustable regulator and fuel pump I can do no problem. The computer stuff I should be able to do you will just have to walk me through it (where things are, chords to plug in, etc.). Let me know what you think the first steps to take should be thanks.

**chevytruckz** · 08-02-2013

Also you said you are able to do all of this custom programming to the computer yourself??

**EagleMark** · 08-03-2013

I can walk you through everything needed on your end and do the chip tuning.

**chevytruckz** · 08-05-2013

That's great, what's the first step I should take?

**EagleMark** · 08-05-2013

Originally Posted by EagleMark

You need a set of 80 lb/hr BBC injectors, adjustable regulator and a good gauge to set fuel pressure. Stock pump in tank will not do, need a TPI pump from 90 Camaro or 96-97 Vortec truck pump. They look identical and will bolt in, just way more volume and capable of more pressure.

At minimum you are going to need a cable to hook up to ALDL port and data log with a lap top after a starter chip. (Should also have a Wide Band O2 Sensor.)
You have quite a few bucks in this build and don't know what's left in your budget? But a wide Band O2 sensor is something that would go well with this engine/type vehicle to keep an eye on things as well as a good tool for tuning. A Ostrich Emulator or AutoProm for future tuning if you want to get into that?

Give Robert a PM to get on list for a cable.
http://www.gearhead-efi.com/Fuel-Inj...uy-ALDL-Cables!

I'll send a PM...