oilwell1415
Well-known member
I debated which forum to post this in, but figured it would be most beneficial, assuming it's beneficial at all, here. If it should be in the clones or Holley forums I'm sure someone has a button that moves it there.
Last November when I was off work for Thanksgiving I finally installed the Holley HP system on my truck after having it sit on the floor in my office for severa; years. Truck is a 1990 F-150 with straight 6 and 5 speed. Mods are Heddman headers, 19lb injectors, AFPR for a Mustang, and 3.8 V6 rocker arms. Truck and engine have about 540k miles on them and the reason I got away from the stock system was because of phantom driveability issues that no amount of work would fix. The most annoying of these was a commanded high idle of 1500-2200 rpm. I chose the Holley system because it looked like the most straight forward to get up and running for someone who isn't a programmer and doesn't want to be a programmer. I also needed a new wiring harness since mine was falling apart after 35 years and half a million miles. Every time I touched it the insulation flaked off and often fixing one issue created 3 more. If the Pimp with a new wiring harness had been available when I bought this I think I would have given it serious consideration, but it wasn't.
Since I've got the 300 there was no plug and play option for the wiring harness, so I had to get the PCM and harness kit and build it out. I think I spent the better part of the first day going through the wiring diagrams and harness identifying and marking the wires I needed and they verifying that what I had done was correct. The harness that comes with the system has about 4 times as many wires as I actually needed, so the job looks much worse than it really was. The Holley instructions are a joke and so is their customer service, so you're largely going to be figuring things out on your own. They do have an active forum where most questions are answered by one guy who really knows his stuff, but his answer is always the same: read the instructions. That isn't helpful when you've already read them 3 times and they still don't make any sense. I worked on it maybe 3-4 hours per day for 4-5 days, so I didn't really bust my butt getting it done. Looking back I could probably do the actual installation in 2 days if I worked all day and had the wiring identified and marked when I started...but it would be a long and hard 2 days and I don't really enjoy putting in that kind of effort any more.
Once I got the install done I had to mess with the program a little bit to get it running. The main issue is that the 300 is not setup for sequential injection like most if not all other TFI Fords from the era are. That meant I couldn't use the Holley provided TFI ignition parameters and had to build my own ignition profile, which really wasn't a big deal at all. Once I did that the truck miraculously started right up, but would not idle below 1500rpm which was the problem I did all of this to cure. Not happy. After much research and foul language I learned that the crappy Holley instructions had struck again. I chose to convert to the GM style stepper motor IAC when I did the install, which is a decision I'm now not sure was the correct one. For some reason the IAC was running backwards. When the engine idled to slowly the IAC would stall it; when it idled too high it increased it more. The PCM said it was going the right thing, but the IAC was doing the opposite. Turns out that Holley intends for you to use GM sensors and/or sensor strategies for everything except the IAC. For some reason on that they use the Chrysler wiring which is opposite of the GM wiring. This would have been a useful thing to put in the instructions, but they didn't. In order to find this information you have to dig about 4 layers deep in tech support documents to find the problem. Once that was rewired it was doing great.
I went through the initial learning process in the driveway and it went fine. Then I went for a drive and was amazed at how smooth and responsive it was. I've owned this truck for 30 years and I don't think it has every run this well, and at that point I hadn't done any tuning at all. And it was back to laying rubber in 3 gears, which I had assumed it stopped doing because of its age. Turns out the stock computer just wasn't letting it do all it could do. Either that or it would have been a monster if I had done this years ago, but I doubt that's it.
I drove it on the startup tune for 2 days just to see what the initial learning would do. Then on day 3 it wouldn't start. It would barely turn over and kicked back against the starter like it had 60 degrees of timing in it, which it turns out it did. This was when I turned to the Holley forum and was told to read the instructions. Finding no help online I went back to basics. It was obvious that there was too much timing so I retarded the distributor until it would start, but then it wouldn't advance correctly. I ended up having to change the reference angle in the ignition profile I built from 60 degrees to 20 degrees, which really makes no sense but it got the truck running again and I was able to drive it. At this point it was getting about 8mpg, which was a problem. I added back a bunch of timing and it's now running great again and mileage is up to about 13-14mpg. I'm sure part of that is me driving it like a teenager again and part of it is that I still have some tuning to do. Our weather has been so random lately that I haven't messed with it. Plus I'm just enjoying having a truck that runs properly again. I have never figured out why it randomly added 60 degrees of timing while sitting in the garage over night.
Overall I couldn't be happier with the system. I still have some work to do with tuning, but even without the tune fully sorted out it's still running better than it ever has other than getting about 1-2 mpg less than it did before, but that could be my spirited driving. My only consistent sore spot continues to be the IAC. I used an Accufab adapter for the stepper IAC and sometimes it sticks closed until it warms up a little. I haven't really looked into this at all because it isn't a huge problem, but it is annoying when it does happen. But for the most part I highly recommend the upgrade, especially if you are having random issues that can't be resolved. The wiring harnesses in these trucks aren't getting any newer.
Last November when I was off work for Thanksgiving I finally installed the Holley HP system on my truck after having it sit on the floor in my office for severa; years. Truck is a 1990 F-150 with straight 6 and 5 speed. Mods are Heddman headers, 19lb injectors, AFPR for a Mustang, and 3.8 V6 rocker arms. Truck and engine have about 540k miles on them and the reason I got away from the stock system was because of phantom driveability issues that no amount of work would fix. The most annoying of these was a commanded high idle of 1500-2200 rpm. I chose the Holley system because it looked like the most straight forward to get up and running for someone who isn't a programmer and doesn't want to be a programmer. I also needed a new wiring harness since mine was falling apart after 35 years and half a million miles. Every time I touched it the insulation flaked off and often fixing one issue created 3 more. If the Pimp with a new wiring harness had been available when I bought this I think I would have given it serious consideration, but it wasn't.
Since I've got the 300 there was no plug and play option for the wiring harness, so I had to get the PCM and harness kit and build it out. I think I spent the better part of the first day going through the wiring diagrams and harness identifying and marking the wires I needed and they verifying that what I had done was correct. The harness that comes with the system has about 4 times as many wires as I actually needed, so the job looks much worse than it really was. The Holley instructions are a joke and so is their customer service, so you're largely going to be figuring things out on your own. They do have an active forum where most questions are answered by one guy who really knows his stuff, but his answer is always the same: read the instructions. That isn't helpful when you've already read them 3 times and they still don't make any sense. I worked on it maybe 3-4 hours per day for 4-5 days, so I didn't really bust my butt getting it done. Looking back I could probably do the actual installation in 2 days if I worked all day and had the wiring identified and marked when I started...but it would be a long and hard 2 days and I don't really enjoy putting in that kind of effort any more.
Once I got the install done I had to mess with the program a little bit to get it running. The main issue is that the 300 is not setup for sequential injection like most if not all other TFI Fords from the era are. That meant I couldn't use the Holley provided TFI ignition parameters and had to build my own ignition profile, which really wasn't a big deal at all. Once I did that the truck miraculously started right up, but would not idle below 1500rpm which was the problem I did all of this to cure. Not happy. After much research and foul language I learned that the crappy Holley instructions had struck again. I chose to convert to the GM style stepper motor IAC when I did the install, which is a decision I'm now not sure was the correct one. For some reason the IAC was running backwards. When the engine idled to slowly the IAC would stall it; when it idled too high it increased it more. The PCM said it was going the right thing, but the IAC was doing the opposite. Turns out that Holley intends for you to use GM sensors and/or sensor strategies for everything except the IAC. For some reason on that they use the Chrysler wiring which is opposite of the GM wiring. This would have been a useful thing to put in the instructions, but they didn't. In order to find this information you have to dig about 4 layers deep in tech support documents to find the problem. Once that was rewired it was doing great.
I went through the initial learning process in the driveway and it went fine. Then I went for a drive and was amazed at how smooth and responsive it was. I've owned this truck for 30 years and I don't think it has every run this well, and at that point I hadn't done any tuning at all. And it was back to laying rubber in 3 gears, which I had assumed it stopped doing because of its age. Turns out the stock computer just wasn't letting it do all it could do. Either that or it would have been a monster if I had done this years ago, but I doubt that's it.
I drove it on the startup tune for 2 days just to see what the initial learning would do. Then on day 3 it wouldn't start. It would barely turn over and kicked back against the starter like it had 60 degrees of timing in it, which it turns out it did. This was when I turned to the Holley forum and was told to read the instructions. Finding no help online I went back to basics. It was obvious that there was too much timing so I retarded the distributor until it would start, but then it wouldn't advance correctly. I ended up having to change the reference angle in the ignition profile I built from 60 degrees to 20 degrees, which really makes no sense but it got the truck running again and I was able to drive it. At this point it was getting about 8mpg, which was a problem. I added back a bunch of timing and it's now running great again and mileage is up to about 13-14mpg. I'm sure part of that is me driving it like a teenager again and part of it is that I still have some tuning to do. Our weather has been so random lately that I haven't messed with it. Plus I'm just enjoying having a truck that runs properly again. I have never figured out why it randomly added 60 degrees of timing while sitting in the garage over night.
Overall I couldn't be happier with the system. I still have some work to do with tuning, but even without the tune fully sorted out it's still running better than it ever has other than getting about 1-2 mpg less than it did before, but that could be my spirited driving. My only consistent sore spot continues to be the IAC. I used an Accufab adapter for the stepper IAC and sometimes it sticks closed until it warms up a little. I haven't really looked into this at all because it isn't a huge problem, but it is annoying when it does happen. But for the most part I highly recommend the upgrade, especially if you are having random issues that can't be resolved. The wiring harnesses in these trucks aren't getting any newer.
