There are already plenty of step by step write ups for doing this install so instead here are my general impressions. First, the installation of the tbi, harness and related parts and sensors is the easy part. I don't think that took more than an hour. By far the biggest chunk of time was spent stripping out the old junk and gutting the original wiring harness. I hate to do anything by half so I probably spent longer on this than I needed to but I feel good about the results.
Steps. You have to follow them all, but you do not have to do them in the listed order.
I started friday night after work, to get a jump on it. The very first thing I did was remove the old carb and install the tbi adapter plate. You have to cover the mounting bolts in the plate with rtv to prevent vacuum leaks and I wanted to let that have plenty of time to dry. I then spent a couple of hours doing what prep I could before it got dark. Took out the battery and tray, the glove box, all the vacuum hoses, fuel pump and unwrapped the wiring harness.
Bright and early saturday I got up to rain, not expecting that. So, spent some time rigging a cover to work under. Then got to work on the wires. The directions tell you which ones you will be keeping but I felt better tracking them all down to make sure. I cut the whole bundle of wires right at the old computer and then followed each one to the other end and cut it there too. By the end I had a small handful of wires left. Really just the power from the starter relay to the main fuse box and the wires for the oil pressure sender, alternator field, distributor, neutral safety switch, 4wd indicator and tach on the right side and the sender for the water temp on the left side.
I did away with the relay for the manifold heater, for now at least. Removing it allowed me to completely remove the relay mount and diagnostic connector mount from the battery try. I had planned to just move the relay over closer to the heater but I don't see any need to even have it hooked up in San Diego's climate. It would be a 1/2 hour job to move it and re-connect it though so I'll do it eventually.
Some of the wires that remained I replaced or put new connectors or just shortened to get them out of the way. Dilectric grease on everything and re-connected.
The instructions have you mounting the fuel pump early in the process but since I did not want to lay in a puddle I left that till the end. When I finally got to it I followed the advice to mount the pump to the skid plate. Now that it's there I don't like it and I plan to move it. It is well protected there but the hose comes out just over the lip of the plate and it is too low to suit me. I plan to look for some rubber mounts and screw it to the frame rail or the botton of the tub. They also say that you do not need to mount the filter to anything but it is fairly large and I don't like it flopping around so I will address that later too.
Putting in the new harness is a snap. The only hard part is fishing the wires behind the defroster duct to the computer, behind the glove box. There are no details mentioned about how to actually mount the new ecm but it is pretty obvious how to do it.
The vacuum hoses could not be more simple and are well diagramed but there was one outlet on the tbi (port J) that was not mentioned at all in the instructions. Nothing was meant to go there, so I capped it. That was the only loose end in the documentation.
Getting rid of the pulse air tubes was not hard, with a sawzall. I cut both tubes down low so I could get at the ends to weld them shut. I would have preferred to cut the lower one closer to the cat outlet, but it was not that important to make me drop the skid plate. The other tube, them one attached to the header pipe just below the manifold gave a little trouble. After cutting it I realized that it was loose at the upper connection and the clamp was too rusted to tighten. I was able to get it closed off but I think I will replace the header pipe soon, just to avoid any possible exhust leak.
One odd thing about the kit is that it requires a check engine light, but does not come with one. They send you to Radio Shack for that. I had the drill ready to make a hole for the light but then had a brainstorm. There is a light already in the dash that says "Emission Service" right next to the high beam indicator. (at least there is in mine) There was no way to hook directly up to that light because it is mounted in a board similar to the guage panel. What I did was get a wired bulb about the same size as the others, soldered leads to it and glued it into the old bulb socket, after drilling a hole in the base of the socket to run the wires through. Simple and it looks like it is oem.
** edit, forgot to mention this before
I found the wire powering that emmissions light (It came from the emissions maintence timer, grey) and hooked the light circuit up to that. The problem though is that after start the light stays on. Apparently the computer controls that light by controlling the ground. That's why I had to run a new wire.
For an air cleaner I went to the junkyard and got one from a 1992 S-10 blazer, 4.3. Fits on perfect but it is a little too close to the brake booster, maybe 1/8 inch. I think I can lift it up a couple of inches with a spacer ring to solve that problem. Had to drill a hole in the side of the air cleaner to mount the crankcase vent filter.
That's it. Took just about the whole weekend, doing it by myself. I had a friend come over to help but it was hard for two people to work and still follow the steps without missing anything. If you have someone willing to do the grunt work of taking the dash apart and putting it back together and mounting the fuel pump underneath that would still only save a couple of hours.
Was it worth it? You bet. I have only driven it around the block a few times but I can say without reservation that it runs and drives better than new. It idles like a dream and I can redline the tach easily where before it would run out of rpm's at about 3500. The throttle response is instant and it has way more giddy up from a stop.
A few weeks ago I did an install of a GM HEI distributor from CRT Performance, which made a big difference as well, so I think I am in pretty darn good shape.
First nights work
The result
Saturday morning. We only have about 300 sunny days a year in San Diego. This was not one of them.
Adapter plate
All that remains of the harness
ECM Mount
Ready to button it up
The finished product
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Finally completed the Howell install. Lots of pix.
