VCP Stacks Tuning

[cityprocar]

I had the heads changed from the iron heads to Edelbrock aluminum heads on my 5.0 engine. The valves and rockers were also changed. We are now having troubles tuning the car using the laptop connected to the Redline computer that came with Wayne Presely's VCP stacks intake manifold. The problem seems to be getting into the program and doing the tuning. Wayne actually tuned the engine in Ohio with the iron heads and ran very well. Now having big problems as the car starts, but barely runs. Anyone in the Galesburg, Illinois area with VCP experience? I really need the help and the weather is great for a drive! Any help would be appreciated

[Olli]

You should really contact Wayne for help. Here is a thought though, you said that your real problem, other than the tune, is that you can't get your laptop to communicate with the Redline ECU. It might just be that your laptop OS is too new. I had this same problem when I tried to get my laptop to communicate with my Retrotek BOSS EFI a couple of months ago. I had to download new drivers to my laptop from Professional Products' online forum.

You need to find out what OS the Redline is compatable with.

Olli

[Bob Cowan]

Stacks from any vendor with any computer system can be a bit tricky to tune. The learning curve is rather steep. The other thing about stacks is that they are VERY particular about the parts that go with them. A seemingly small mismatch in parts can make a huge difference.

EFI is pretty forgiving. Unless you make huge changes in engine parameters, your previous tune should at least allow the car to run a little bit, and get you in the ball park. Adding air filters generally decreases air flow; especially the old fashioned "tea strainers". If it stalls out with the air cleaners, you could be running too rich to begin with.

You can't do much with the mixture until you gain software access. It sounds like you've never used your own computer for this? Sometime gaining access can be a pain. You need the proper combination of COM ports, adapters, and drivers for them to speak to each other. I would guess that your computer has USB ports, and the EFI has a 9 pin serial port. Usually, the tuning software can search for available ports - but only if all the software matches. I upgraded my laptop this month, and had to go out and buy a new USB/Serial adapter. My other one was 8 years old, and didn't work with WIN 7.

If the engine ran well before, and now doesn't, here's some thoughts:
- what did you change besides the heads?
- do you have an intake gasket leak or an unplugged vacuum port?
- are there any plugs left over? Did everything get plugged in like it's supposed to be?
- are you running on all 8 cylinders? Maybe one injector isn't working?
- If it's sequential, are all the plugs on the right injectors?

So, off the top of my head, here's some thoughts on tuning:
- What are the new intake valve sizes, and what are your TB bore sizes?
- Did you change the cam? What are the specs on the cam now?
- did you balance the throttle bodies so they are all exactly the same.
- Did you go back over every single step of the job to see if you made a mistake?

[cityprocar]

Thank you for the detailed information. I will go through everything once again to see if there are any errors.

Again, thank you

Gary