Finally completed the Howell install. Lots of pix.

[jbolty]

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

[Joe Dillard]

Outstanding, excellent write-up.

[jbolty]

Update. I was able to get my hands on a couple of GM air cleaner spacer rings. Together they give about 3 1/2" of rise and I needed both of them. I now have about 1" of clearance from the brake booster. One thing left to do: get a giant hose clamp so I can hook up the cold air tube.

The top of the air cleaner only clears the hood by about a half inch (I measured it but squeezing a few hunks of pie dough in there to test the height)

This works for me because I have a 1" body lift. Otherwise it would be a simple fab job to get this worked out. There are some other gm cars and vans that use a remote airbox so there are lots of options.

[Michael_94YJ]

I don't have a carb on my jeep, but cool write-up
Great job, i wish i could do something similar on my 82' Ford

[rustywrangler]

EXCELLENT write up my friend. That wireing harness made me cring but it definatly looks worth it in the end.

[jbolty]

Originally Posted by rustywrangler

EXCELLENT write up my friend. That wireing harness made me cring but it definatly looks worth it in the end.

The first snip was the hardest, but after being fully commited I cut like crazy. It is kind of nice now knowing what each and every wire in the harness goes to.

[PWGUNNY]

HaHa.... I love the pie dough tester. Clever. Nice write up.

[hogzilla]

Wow. Nice job.

It motivates me to get cracking on some of the minor (compared to that) things that have been nagging me lately. Way to make a guy feel lazy !

[goatboy]

I didn't go the Howell way, I went the Mopar way, but in essence, the philosophy of the projects are similar...you are right, the first snip is the hardest...I Sunday on the previous weekend gettin' rid of JUNK... and what I found that out of all those wires, there was only about a half a dozen that meant a dern...most especially the yellow ignition wire and the field wire from the alternator... after it was all said and done, I took the time to bundle and cover all the wiring in convaluted plastic, and installed terminal and fuse blocks, and the whole deal is clean and makes sense...it was a GREAT cancer project for me...took my mind off my other problems...and after my operation, I was on it within a week and a half of my operation...much to the chagrin of family and friends...they cursed me, BUT... I had to do it...

[jbolty]

UPDATE: I was having some trouble with high idle, so after speaking with Troy at Howell I found a scanner on ebay and was able to discover that I had a bad MAP sensor. Called back and Troy shipped it out same day. Runs perfect in every way now.

FWIW. The scanner I got is an Old OTC Scanner 2000. I don't think it will work for anything newer than about 1992 but perfect for this project. Paid about $40, shipped.

[goatboy]

GOOD job! I ran the same kinda schedule when I installed the Mopar kit... but it didn't rain on me!

[88wrangyj]

I have a question about the wiring in the kit. What all does it plug into on the factory harness? The reason I ask is because the factory harness on mine was fried when the previous owner put on a Weber carb and left most of the wiring harness hanging a little to cose to the exhaust. I am going to go with the MSD Offroad 6 with rev-control and a MSD distributer to take care of ignition duties and wire the rest with a Painless 12 circuit universal harness. I'm trying to figure out how much wire splicing it could possibly take if i want to add the fuel injection kit.

[jbolty]

Originally Posted by 88wrangyj

I have a question about the wiring in the kit. What all does it plug into on the factory harness? The reason I ask is because the factory harness on mine was fried when the previous owner put on a Weber carb and left most of the wiring harness hanging a little to cose to the exhaust. I am going to go with the MSD Offroad 6 with rev-control and a MSD distributer to take care of ignition duties and wire the rest with a Painless 12 circuit universal harness. I'm trying to figure out how much wire splicing it could possibly take if i want to add the fuel injection kit.

pretty much replaces the whole harness, under the hood. The only thing left is the power to the fuse box, alternator, power to the ignition and the guage wires