So what do you do when you have a pretty decently running and driving car....you make it not run in the spirit of potential improvement.
While the last tuning done by EFX on the 0411 LS based PCM was the best its been from prior outfits, there were still some drivability quirks that detracted from it being the street car I want it to be. Also any changes prompted the need for a retune which required the $700+ fees to be paid for the dyno session which has been hit or miss over the years. Lastly, having some safety mechanisms beyond some tuning workarounds was appealing as I'm not looking to purchase a new engine just yet.
So with that, I chatted with Mike at EFI Connection who supplied my original 24x system with goals of a plug and play harness using a Holley platform and retaining my factory gauges. I selected the Dominator unit because this is how I am as a person and his harness coupled with a dakota digital box to handle the gauges. I was able to procure a design file to have the PCM mounted in the factory location since the Dominator can live in the elements so to speak.
I enlisted Mr. Holley (LTs1ow) to help with the install as the other benefit of the new computer is getting rid of a lot of control systems on the car since it can handle it all. Over a couple of days and trip to Hobby Town for a connector or two, the new system was installed, global repository tune loaded and the car fired up. Wild....
3D mount via KirkEvil
Click for noise
PXL_20260427_160034974
The following systems are now controlled by the Holley
- Meth Injection
- Transmission Pump
- 2nd Fuel Pump
The system is wired for an E85 Flex sensor so if I upgrade the fuel system that will be in play.
Other fun stuff
- Tachometer setup went smoothly but had some challenges trying to sort out the MPH on the factory dash plus also holley given some needs for reverse lockout and fan control logic. After trying a few configurations, ultimately I ended up running the VSS from the trans to the Holley, Holley to the Dakota box and then to factory gauges. I learned more than I care to admit regarding frequency and rotations per mile. Works great now so that's all that matters.
- During first remote tuning session, seems I was having a fuel issue which I thought was due to perhaps old pumps finally getting tired. Turned out to be a basic wiring whoopsie where trigger for the second pump needed to be a ground trigger vs a positive one. Before finding this out, I decided to rip out the fuel pump sending unit with Chris and proactively replace the fuel pumps. After a bunch of snafus from Summit, new pumps went in and all was working.
Thanks Summit....wrong pumps
Since I no longer needed a vacuum/boost block, I removed this and cleaned up the engine bay a little bit. Def a nice change and gives access where little (still little) existed prior.
Also saw this while under the car....can't believe this failed after being babied all these years...
Might as well go billet/delrin - oh but no they won't work with where the rear mounts are so more money needed to be spent. Super cool.
So on to the tuning. I used Kohler's tuner and very happy with the experience. Very slick to have someone remote into your system and make changes on the fly. You could instantly feel and hear the engine get happier. The drivability is honestly where it should have always been. At any throttle position the engine accelerates smoothly. As mentioned the first tuning was cut short as after the first power pull I was told "don't do that again" as my fuel pressure took a total nose dive - glad I had Chris there for laptop duty and morale support....and jumping around the jungle gym. After sorting the issue and finally getting weather/schedules to cooperate, I got the car back out and everything is working exactly as it should. This was all done within 3 hrs of remote tuning and its never driven better. Tough to beat that.
Now on to swapping spark plugs and hoping to enjoy the car much more this season.