smack w/o efie?

[nomadsoflight.co.nr]

bonjour folks! first let me thank everyone for the wealth of information i found on this forum and badly needed in the process of joining the "h2 revolution". i'm currently trying to put a smack into our 88 toyota dolphin motorhome, unfortunately our trip has already started, so i'm kinda patching it together with whatever i have out here. as this rig has EFI i understand i'd need an EFIE if i wanted any serious mpg gains which is not easy to make in the wild. we set off from NY, headed north first to quebec and will continue towards alaska first thing tomorrow. does it make any sense to put the booster (which i'll hopefully finish today) without an efie? any ideas that can help us to save at least a little bit of fuel (which is at $5.40 in canada now)?
one more thing: there seem to be two O2 sensors in there. one is as expected near the "engine exhaust outlet", but the other is further along the exhaust shortly b4 the cat and it's not hooked up to anything (see attached pic) - is this cool?
any help appreciated,
thilo

[TuxAir]

1988... hmmm ODB1 system... I'd try the smack unit without adding the EFIE first and see what your results are over some time. If nothing significantly differs, or your mileage gets worse, then add an EFIE. Check this thread for RedMeanie's EFIE kit.

As for the rear O2 sensor not being hooked up, I'm surprised you're not throwing a CEL . Is there no wiring at all underneath for it? Maybe it was snagged by road debris?

[sharkdive1]

The 88 Toyota only has one O2 by the engine. The one by the cat had to have been put there by mistake by someone, it is in the wrong spot, it should be after the cat to work.

[nomadsoflight.co.nr]

what is a CEL? and regarding what sharkdive said - it does not look aftermarket, but i should not worry about it not being wired as it's not supposed to be there in the first place, right?
thx, thilo

[TuxAir]

CEL = Check Engine Light
The other part could be true... it is not needed and somehow it is there and just not wired up. I just find it a bit strange The picture , to me at least, looked like it was showing a post-cat o2 sensor.

[sharkdive1]

CEL = Check Engine Light
The other part could be true... it is not needed and somehow it is there and just not wired up. I just find it a bit strange The picture , to me at least, looked like it was showing a post-cat o2 sensor.

I agree with Tux that it is strange, but in 17 years of working on cars and trucks, that is not the first time that I have seen an extra O2 that should not be there. I have seen them on a Ford and on a Honda.

Sharkdive

[nomadsoflight.co.nr]

ahhh - CEL! now that's interesting as the CEL does come on about every two minutes. i step off the gas for just a moment and sure enough after another three seconds it's off again. only happens when i'm on the highway=press the gas continuously. figured it's sth with the emmissions and did not mind much - should i?