98 Cobra On3 Turbo street car build
- Thread starter 5.0calypso93lx
- Start date
I literally just received it yesterday lol. I was actually able to track down a pal that has access to All Data and that is super helpful also. It's also much easier to read. It's almost like they've translated what's in the FSM.
Did my first re-pinning of a connector on the Holley harness. The Holley came with some cheapo looking GM map sensor that I didn't love so went with a Low Doller Motorsports 3 bar map. Turned out really nice and clean
This was the old connector that was replaced
Also went with the low doller left hand vacuum tree. The far two left ports are connected and the 3 on the right are all isolated. Should give me a clean, undisturbed vacuum / boost source directly from the intake manifold lid. I am planning on mounting the block behind the intake mani to try and get the shortest possible source to the map sensor
This was the old connector that was replaced
Also went with the low doller left hand vacuum tree. The far two left ports are connected and the 3 on the right are all isolated. Should give me a clean, undisturbed vacuum / boost source directly from the intake manifold lid. I am planning on mounting the block behind the intake mani to try and get the shortest possible source to the map sensor
i bought a vacuum block on clearance somewhere a while back with intentions of mounting it behind the intake off the mouts for the plastic egr connector but ordered the wrong size vacuum fittings it and never did anything with it. I should revisit that and clean up some of my mess.
Yea, I have a smaller 3 port one that I used to run that I got off ebay, but I wanted one with a dedicated port for the MAP. It's arguably the most important sensor out of them all
Found a fair price on some black powder coated coil covers so made the change to them. Really liking these over the silver ones that were on it before
Was that green connector the one that came on the Holley harness?
I'm using a Low Dollar sensor for my fuel pressure. The first one I had failed in 20 minutes, but the guy swapped it out quickly. This one has been going strong since.
I bought the Holley off of Andrew Sheridan who is the Mustang Lifestyle YouTube channel guy. That is the connector that came on the Holley harness when I got it from him so I can't say for sure if that's how it came from Holley. The kit came with some cheapo 3 bar GM MAP sensor which I didn't use. I bought a LD 3 bar map sensor and repinned the harness to use the LD connector.
The Holley install has definitely been a challenge. I really wish Holley would make the mod motor harness longer so you could install under the seat similar to the fox body kits. Most of the challenge has been finding a good spot to mount the ecu and leash electronics boards while retaining the factory ecu and passenger airbag. Most people just cut that out and mount everything there, which would be perfect, but my wife and kids ride in this car often and it's not something I'm willing to remove. The actual connections are the easy part, but finding ways to cleanly route everything has been difficult as there is just so little room to work on these cars.
One issue I did run into was the coolant temp sensor for the Holley. The 96-98 cars use two coolant temp sensors in the coolant crossover. One is for the gauge cluster and one is for the actual ecu. The problem for me is that I really need to keep both as I want the cluster to be functional, but the ecu also needs the other CTS as it uses that information from that sensor for the A/C.
I ended up ordering an additional CTS from Low doller and I mounted it into the coolant crossover on the passenger side. I need this sensor to be accurate as this is what the Holley will use. I then moved the factory CTS that was in that port to an additional port on the On3 coolant crossover delete thermostat housing. This location isn't as accurate, but I really don't care about the accuracy of that sensor while the engine is cold.
One issue I did run into was the coolant temp sensor for the Holley. The 96-98 cars use two coolant temp sensors in the coolant crossover. One is for the gauge cluster and one is for the actual ecu. The problem for me is that I really need to keep both as I want the cluster to be functional, but the ecu also needs the other CTS as it uses that information from that sensor for the A/C.
I ended up ordering an additional CTS from Low doller and I mounted it into the coolant crossover on the passenger side. I need this sensor to be accurate as this is what the Holley will use. I then moved the factory CTS that was in that port to an additional port on the On3 coolant crossover delete thermostat housing. This location isn't as accurate, but I really don't care about the accuracy of that sensor while the engine is cold.
I ended up mounting the Holley ECU on the upper passenger side of the trans tunnel. With the carpet laid flat you really can't tell it's even there and it allowed access for all the plugs from the harnesses to plug in easily. It's also on the inside of the car and easily accessible so turned out to be a nice spot for it.
I ended up ordering a Sharpe performance firewall pass through and that is where all the Holley wiring is routed. There are just too many additional wires that need to go through the firewall to be able to pass through the stock harness pass through. It's still a mess right now as I'm working on the tune, but once I get the car up and running better i'll start tidying everything up more. You can also see in the second pic where I mounted the power supply bus bar
The only way, imo, to get a truly clean Holley install on these cars is to build the harness yourself. Their harness sucks, I bailed on it and built my own when I initially installed everything, and I'm in the process of rewiring my Holley right now because I moved a bunch of cocomponents to add A/C back in the car.
Have you test fit the fender liner and wheel in place to check clearance? It's really tight in that area.
It's not the prettiest spot, but it's definitely functional. I mounted the Leash Electronics relay board and power supply board behind the glove box. These aren't very heavy boards so was able to use some heavy duty velcro to mount them. I'll be keeping an eye on these to make sure these aren't coming loose.
The intent for these are to have a clean, central power supply to my smaller, add-on electronics like the wideband, boost gauge, dakota digital speedo corrector device and Holley ecu power. The board is triggered via the red wire with green tracer in the passenger kick panel
The intent for these are to have a clean, central power supply to my smaller, add-on electronics like the wideband, boost gauge, dakota digital speedo corrector device and Holley ecu power. The board is triggered via the red wire with green tracer in the passenger kick panel
Lastly this is essentially where I currently am. I have all the connections made and am working on updating the ecu firmware and starting on the startup tune. I hope to hear this thing make noise very soon
I agree completely now that I've gone through this process. At some point I would love the car to just be rewired entirely, but on the other hand that's just not a project I want to tackle right now. I've removed so much of the factory wiring and added other wiring that it really could use that clean up. Having said that, that probably also requires either a Holley Dominator ECU or at least one Holley I/O module. Just not sure I want to go down that road with this car.
I have. It's definitely tight, but everything is going to be routed up above the power bus bar which is above where the fender liner mounts. Should be good there.
That makes more sense now. I would have been more than a little upset if my new set up had a connector that looked like someone had chewed on it.
I watched a video not too long ago where someone installed a Holley system on a 99+ and they had a harness that allowed the stock gauges to work with the Holley and had enough slack to mount the ECU under the passenger seat. I think it was a 2000 though. So it needed coil drivers as well. There was a lot of wiring to tuck and hide.
Have a link to that video? Unless they extended it or drilled a hole through trans tunnel it's not even close to reaching. I have seen where some drilled through trans tunnel which I just wasn't willing to do.
All of my factory gauges will be functional also. I had Lethal Nate modify my OEM engine, trans and starting harness.
It's for the 99-04. I don't know if it will work for your generation. I forgot to add, I like the pull through you found. I need to do something like that on mine.
Users who are viewing this thread
