plowboy77

My understanding is that the ECM ('7730) needs input from the VSS to function properly. I may have stalling problems and such otherwise.
My questions is: Where does it go on a retrofitted 4X4?
Would it go on the Transfer case ouput shaft to read even in low range, or on the transfer-case input shaft so the ECM doesn't see a funny signal?? My thought is that on the output shaft is fine since I have a 4-speed manual and shifting and converter lockup is not a concern. Cruise control would be a nice luxury though! (see sig. for vehicle this goes on)

Thanks for anyone's help! I know I'll have loads of other questions.

Apeiron

Transfer case output shaft. What's so funny about that?

plowboy77

Well, I was mostly curious because I got on JTR's page and they said the VSS would need to go on the input shaft. .......But come to think of it, that was on an automatic.....

I guess, now I need t o figure out what it will take to get Cruise control to work.

Thanks!

Apeiron

Shouldn't make any difference whether it's an automatic or a standard.

plowboy77

When I went back to look. They were using it on an electronically controlled 4L60E auto. literature says:
"The reluctor ring must be installed in the governor area because the ECM would get an erroneous speed signal if the
reluctor ring was located on the output shaft of the transfer case when the transfer case is in low-range."

for a manual it would probably be fine on the output.

thanks for the input!

I'm sure I'll want to know alot of other things!
Russ

dyeager535

I don't know the ECM your using...is it 2 pulse VSS or other? If 2 pulse...

Your best bet IMO is to get a cluster out of an '81+ truck.

'82 up could have had a 700R4, so if the truck had a 700R4, it will have VSS, which bolts to the back of the speedometer housing. (edit: 700 wasn't determining factor for VSS, it was electronic cruise control. Of course all trucks with ECM have VSS, that includes CA CCC trucks)

Of course you'd likely want to swap all of the gauges, since the speedometer alone won't match the other faces. (color and "font" if you will) Nothing wrong with that though, I *personally* don't like the hard line oil pressure, un-numbered temp gauge, nor the ammeter. (I think your 76 has all of those)

I just TPI'd my '74-86 K5, so I may be able to help you somewhat if you need more info.

plowboy77

thanks for the input dyeager 535!
I have a '7730 ECM, which I believe is 4 pulse. I think I'm running the same transmission you are??? (SM-465?) and was considering the VSS that Stealth Conversions has that is made to install on the differential. (Though I think I'd try to place it on the tranfer case output yoke.) Unless the different speedometer route would work better. (BTW I agree on the the un-numbered gauges)

How did you do your TPI'd Blazer?

dyeager535

OK the '90-91 R-V trucks (old bodystyle) used an electric speedometer, and a "DRAC". I believe for some years the camaro did as well. I still can't recall if it's a 2 or 4 pulse system though.

If you check out www.jagsthatrun.com they have a section on VSS, as well as pictures.

Only two transfercases I know, used in our bodystyle trucks, are setup to use the DRAC...the NP241 and the 205. Obviously that is only two years of trucks, and unless you want to swap the t-case, kind of out of the question. The NP208 can apparently be converted, but as old as yours is, unless you have upgraded the drivetrain, not an option.

jagsthatrun sell pieces that bolt to the speedo output on the tranny/t-case, so I suspect you could go that route as well, probably easiest/cheapest.

Personally I'd like to go with the digital speedometer...the cable drive ones seem to be showing their age, at least mine is, it bounces a bit, and although I'm sure I could fix that, the electric speedo out of a '90-91 would just be nice to have. Plus the DRAC is "programmable" so bigger tires can be run and it can be changed to show correct MPH, instead of changing speedo gears.

My TPI is from an '88 Camaro, except the '165 ECM which is 1987. (for a manual trans 305 car)

My TPI "install" pics

I ran the wiring into the engine bay through the grommet in the firewall...I hate drilling holes in the truck, there are already plenty stock! So I just de-pinned the ECM connector, cut the center out of the heater wire grommet, and passed the wires to the ECM through there. Nice and clean.

I used an auxillary fuse panel to power everything...I made sure to keep all the stock fused items on their own fuses, with power at the proper time. Unless you have a newer fuse panel, this will be a bit more of a challenge for you, as the later fuse panels (plastic fused ones) have ports you can tap into easily to get power.

I bought a new 31 gallon fuel tank for the '87-91 K5's (internal baffles for EFI) and managed to find a sending unit for the same rigs. IMO that is about the easiest way to do this, BUT the Saginaw fittings GM used are one of a kind, and impossible to find. You'll end up using adapters from someone like Earls, at about $8 a piece IIRC. I was able to get my hands on the fuel lines from an '87-91 K5, and I just bent them to work on the drivers side. Not real pretty, but it works.

Other than that, I think my swap was considerably easier than yours will b, solely because of the fuse panel bing setup for so many accessories that aren't being used.

My swap would have been much "easier" had I gone with speed density. MAF is hard to plumb on these trucks for cold air intake (as the later ones were stock) but as you can see from the pics, I managed to do it.

I really think I need to go down to 3.08 gears though now. I've got a lot of low-end torque, and even with 3.42's and 33" tires, I'm turning 2500RPM on the freeway, and it doesn't need to be. That 465 low gear will hide any rear axle ratio, and I'd rather be able to hold the gears longer, since there are only 3 useable. It definitely seems to stop making power around 4500RPM, and that was what I expected.

If there is anything more specific you want info on, please let me know, I'll help you to the best of my abilities.

jwfirebird

iTrader: (2)

after market CC from audiovox, i think it was, for a man trans car runs off the tach output. i bought mine from pepboys for about 100 bucks. put it on my little peon.(02 Neon ES)

plowboy77

Thanks for the infomation all!
Yeah, the more I looked into the cruise control, the more I realized I'd be better off with an aftermarket stand-alone unit.

So dyeager535, kinda sounds like my best bet may be to find an early 90's Blazer or Suburban to donate some parts (speedo, tach? various gauges, fittings, etc.)
yeah 4500 RPM was about what I had in mind. I run about 2500 at 70 mph right now (fast enough for me) and I built the engine figuring it wouldn't see much more than 5000 in the first place.
One other question. Did you end up running a heated O2 sensor? I noticed you are running headers on your K5.

Thanks!
Russ

dyeager535

As long as the 90-91 trucks used the same VSS setup as your injection setup, I'd say yes, that is a better idea. Amazingly, the electronic gauges aren't that difficult to find.

Supposedly no tachs in the trucks after 1981. There have been reports there were, but nothing concrete...they aren't in my '86-88 GM parts manual. So as you can guess, a stock tach in the '81+ style is RARE.

No heated O2 sensor, and it does closed loop no problem, and seems to stay there. I suspect running these engines at the factory designed 195* (with the cooling fans coming on so much later) that the heat going into the exhuast is plenty...idle is where people seem to have problems with going open loop, so if the engine temp increases at idle, it probably helps the O2 sensor as well.

I'm curious to know how the 90-91 trucks did cruise. '83-ish up until ?? used a completely standalone electronic system for cruise...used VSS, and a "computer" just above the gas pedal. If they stayed standalone in 90-91, that might be an option as well, if you are thinking of grabbig the gauges from one of these trucks. A little work rewiring the column (I'm sure ignition switches, wires, and the column wires changed) but then again, they had moved wipers and headlight dimmer to the column, so that would introduce more issues to your swap.

plowboy77

Howdy, been a away for a while....
Ok, dyeager535,
Makes sense to get ahold of an 87-91 fuel tank and sending unit since a custom TPI tank with pump cost around $820!!!! (not cool)....but what pump do you put in the stock 87-91 tank for TPI? The TBI pump for the Blazer won't produce enough pressure. Is there a specific part number?

Thanks for your help!
Russ

TheGreatJ

A Vortec 350 pump should mount into the older style hanger just fine, and it'll produce up to around 60psi. Just go into the parts store and ask them to pull one for a '90 C1500 TBI and one for a '96 Vortec and compare the two. If they mount the same, buy the Vortec piece.

For that matter, a regular 3rd gen TPI pump might fit the hanger as well. If nothing else, drop a pickup tube to the bottom of the hanger and use an inline pump outside the tank (plus it's easier to change that way if it ever goes out.)

dyeager535

The box the pump I'm running now says it's an AC EP375.

I crossed that on AC Delco way back before I bought it, I think the seller had it listed for a late 80's or early 90's Cadillac. It's not a "perfect" fit, but it is also not something you need to modify a bunch. Just something with the bottom rubber insulator IIRC. Going to have to pull the tank again (used sender is bad) but the pump works great.

Slightly noisy compared to what a 2004 vehicles fuel pump sounds like, but in an older truck, that's the least of your noise worries. I can't hear it when my truck is idling and I'm inside it, let's put it that way.

Dave Y

just FYI, the pump for a TBI third gen and a TBI 90 blazer is the same PN, and the TBI and TPI third gens used the same fuel tank sender, so, anf pump that fits a efi third gen(walbro 190/255) will fit in the tank off a 86-91 EFI R/V type truck