Question & Answer section on all things related to PRK wiring harnesses!!
1. IS it cheaper to modify my harness or buy a new harness?
IN most cases it is less expensive and much better to purchase a new harness. With a factory harness that has been modified there are a few issues that arise- length of harness will be much shorter, they don't look as nice, we can't guarantee there won't be any issues due to GM harnesses having problems with cheap overseas wiring with a tendency to break inside the insulation. New harnesses are aesthetically pleasing to the eye and can be made with either show car loom or new split loom, and are custom made to your specifications.
2. Do I have to run the fuel pump through the PCM or can I make it ignition hot?
You have your choice in this situation, its all about how you wire it up. We recommend wiring it separate of the PCM and through your ignition in race and off-road applications. In street driven vehicles we suggest through your PCM.
3. Can I use my drive by wire PCM for a drive by cable application?
NO! This is due to the fact that the PCM does not have the necessary drivers for this function and cannot be flashed to accommodate them.
4. Do I need O2 sensors and an MAF (mass airflow sensor)???
For racing applications you can run a speed density tune that will eliminate the MAF but you will still need your 2 primary O2 sensors. This is only recommended in racing applications where the owner has the ability to tune the vehicle and make the appropriate adjustments due to altitude, temperature, etc.
5. Can I run my electric fans through my PCM?
Yes! It is supported in the PCM to run 2 fans (primary and a/c request) but it has to be turned on in the program. With the execption of factory equipped vehicles. In off road or race application vehicles it is recommend to run the cooling fans separate of the PCM and on their own switch/temperature control.
6. Can my PCM be flashed for another transmission?
Yes- with a simple switch in the program we can change the transmission from or to a 4L60e, 4L80e, non-electronic transmission or manual.
7. Can I use my drive by wire PCM and throttle body?
Yes you can, but PCM's from 2002-2006 must have the matched tac module with the proper operating software to make it function correctly. On PCM's 2006-up E-series, this is not an issue because there is no separate tac module.
8. Do I need to have you make the relays or can I do it?
Any circuit that is going to be an on/off control carrying more than 15 amps needs to have a relay. We suggest that all relays be fused to protect all components.
9. Will all of my gauges work with the PCM?
NO, gauge functionality is not controlled by the PCM. The PCM only monitors temperatures and pressures for tuning. ALL gauges will be hooked up according to your manufacturers specifications using their sending units. This includes speedometers!!
10. Will the harness control my starter or offer a neutral/safety switch?
These functions are not included in the harnesses unless specified and can only be added in automatic transmission applications. The starter wire is not included in your engine harness.
11. How long is the harness?
They are a standard 3 feet from the rear of the engine. This should put your PCM either under the dash or tucked up nicely on the firewall. You can request your harness be made longer (up to 10feet) for $20.00 per foot requested.
12. Is it better to run a 3 or 5 wire MAF?
2000-06 MAF's are 5 wire which incorporates your intake air temperature senor (IAT) and are a larger diameter, easier and cleaner for air intake system and will make more power. 3 wire MAF's will require a separate IAT sensor located in the air intake 6 inches from the inlet side of the MAF.