gm vortec engine and orion t-case: VSS setup from downey

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orangefj45

orangefj45

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hey guys. i just installed one of the downey VSS units on the back of an orion HD and thought i'd share the info:

i'm working on a customers' fj60. we're doing a 1999 vortec 5.7-NV4500-Orion HD swap. since it has to get smogged ( and pass the referee's test ) as well as run properly, we've decided on running the VSS setup from downey.
initially i wanted to be able to use the VSS on the orion but it's a jeep setup that uses a 20 pulse signal and we did'nt want to mess with any converters so we're going to utilize it for an electronic speedo.

i talked to jim @ downey and vic @ AA; none of us could come up with a reason why this unit should'nt work on an orion or orion HD other than some possible spacing issues so we decided to roll with it.

here's a pic of the downey unit:
IM000356.webp
 
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next, i slipped on the new spacer with the reluctor wheel and held the new cast aluminum downey cover in place to see where the reluctor wheel needed to end up. since the casting on the orion and orion HD is heavier/thicker than the stock case, i had to press the reluctor wheel down 5/16" in order for the speed sensor to read it properly. the spacing is different for the stock case and proper measurements are provided in the instructions from downey for running the stock t-case with or without the AA rear mount.
IM000361.webp
 
next, i installed the spacer and reluctor wheel setup. i had to omit the washer and stake-nut downey supplied in the kit since i'm using an AA shaft with standard threads. so i used another nylock-nut and the AA washer in their place. i always keep a few of these nylocks on hand just in case. it's also not the best idea to re-use nylocks.......
IM000363.webp
 
last but not least was the speed sensor install ( can be seen in the previous pic ). downey supplied me with the proper VSS for this setup. it's crutial that the sensor rides about .0030-.0050" from the reluctor wheel in order to send the proper signal. after doing a quick mock-up i was able to measure the spacing at .0046" which is right within the recommended range. so without any mods, i installed the VSS.
the truck is running right now but still needs some finishing touches. by the end of this week, i should be able to drive it and then we'll see the results. i also need to finish splicing in the VSS pig tail since the VSS i used utilizes a different connector than what came on the howell harness we installed in the cruiser. luckily we had the original harnes from the donor truck so i scavenged a connector/pig tail from it.

here's a pic of the final result. so far, so good! :cool:
IM000365.webp
 
that is the vss supplied by AA. the problem with this unit is that it's from a jeep rubicon. so it utilizes the wrong pulse signal which won't work with the vortec engine/ecm. there are aftermarket companies that sell "adapters" to convert the signal to other pulse widths.
in this case, we decided to go with the downey unit to send the proper signal to the ecm. we will be using the jeep vss for a digital speedo since there's no place to attach the original fj60 speedo cable.
 
. i also need to finish splicing in the VSS pig tail since the VSS i used utilizes a different connector than what came on the howell harness we installed in the cruiser. luckily we had the original harnes from the donor truck so i scavenged a connector/pig tail from it.

here's a pic of the final result. so far, so good! :cool:[/quote]

The AC Delco part number for the electrical plug-in connector for our VSS is #PT-1798. It actually cost more then the VSS, we're actually too embarrased to sell it.
 
i just got back from the shop and got the wiring portion done. i called howell engineering ( i used their harness for the engine as well as a re-programmed ecu, fuel pump, fuel filter,.... ) and the tech told me that the "a" terminal should always be the purple wire on their harness. so i scavenged a matching pigtail ( to plug into the gm vss ) from the original gm harness and made a short wiring adapter by crimpint the matching weatherpack connector ( this was supplied by howell with their engine harness ) onto it. that way i did not have to cut the howell harness. the adapter is only about 4" long. worked out really well.

i also did some more tinkering with the 60 today. the engine starts and runs great, the alternator is charging, the clutch is working properly,....... now i just need to finish welding up the twin-sticks and get a longer throttle cable and we should be able to go for the first test drive.
the gm truck throttle cable is at least 6" too short so i'm going to try to find one out of a van; they're usually longer. i like using the factory gm components as much as possible because they're easy to come by, not very expensive and the dealer stocks a lot of this stuff. if the van cable won't work then i'll have to go to the local speed shop to pick up a lokar cable.


more info about this conversion can be found on this thread:

Algers vortec fj60! - Pirate4x4.Com Bulletin Board
 
lehiguy said:
I know it's common with TBI to just omit the VSS when getting a chip made for the application. Does that not work with a Vortec setup?
Click to expand...


the VSS can be omitted. however, this truck has to go to the referee in order to be able to get it to pass smog here in comy-kalifornia. that means you have to run both cats, all 4 O2 sensors, a smog legal air cleaner, a VSS, proper manifolds, the smog canister, a check engine light, a diagnostic port and other assorted goodies...............
 
orangefj45 said:
the VSS can be omitted. however, this truck has to go to the referee in order to be able to get it to pass smog here in comy-kalifornia. that means you have to run both cats, all 4 O2 sensors, a smog legal air cleaner, a VSS, proper manifolds, the smog canister, a check engine light, a diagnostic port and other assorted goodies...............
Click to expand...

Sorry to hear that... At least it can still be done. I had a revelation when I called an engineer at the county health dept. division of air quality. I only need a cat and an air pump if it came on the donor motor, as long as it's newer technology than the engine I took out. The guy was actually pleased to hear that my 350 burns less gas then the 2F did and thought it was all good. I was was relieved!
 
The engine will run better with the VSS and get better highway economy by entering into lean cruise mode and enabling the EGR valve. The vortec PCM probably has other features that use the VSS signal. I'm fairly certain that if you are a running an electronic transmission you need the VSS.

Cool product & great write-up Georg. How does the Ref confirm that your VSS is sending the correct signal? Do they scan the PCM while under power, or do they just need to see the VSS?
 
with a late model auto like the 4L60E or 4L80e you definetly need a working VSS in order for them to shift properly or you'll have to run a full manual valve body conversion package.

the ref will look for the VSS. then when you go to smog the rig, they run it on an in-ground dyno. they call it "enhanced smog". this has been standard issue in my part of CA for about 10 years now...........

this rig should definetly get better fuel economy and put out less pollutants than the old 2F did. hopefully the ref will not be a major pita altough i'm trying my best to make sure that everything is according to the way they want to see things done. clean install and wiring is definetly a plus when you have to go see the ref.
 
Smog commies defiantely suck! My stock TBI passed as well as my wifes lx470. Fortunately our version of the smog ref's aren't that sharp and didn't notice the missing charcoal canister or the ramshorns manifolds.

when they run it on the dyno do the also scan the computer? Do they check for chipped pcm's?
 
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