Aftermarket gauge install in 1st gen S10

[MadMikeZ28]

A local speedometer shop had refered them to me. When I called I new what I needed and I started off telling him what I had, (replacing my speedo with a mechanical Autometer) he stopped me there and before I could tell him what I needed and told ME what I needed.
The guys at the local speedometer shop were some what lost when I tried them but Rodger knew what was going on.

I think all you will need is a speedo and a hall effect. Hopefuly he gets you taken care of in your budget.

[greyhnd]

Yup, Rodger gave me about the same kind of treatment. Was glad I called and talked to him. I know I'll need a new speedo cable, although I wish I could avoid taking the old one out, but I'll learn something new by doing it. He told all about different pulses per mile and all kinds of other stuff. I'll get back with him and find out exactly what info he needs from me then go from there.

[MadMikeZ28]

Taking out the cable is not so bad. ya gotta get under the truck of course so for us older guys that is the challenge. There may also be a couple metal tabs folded over to hold the cable to the firewall down low where it comes out at. Grime and such may make it hard to see.

The pulses you can tell what you have by looking at the OE speedo. The speedo in my pic is two pulse. Off the cable drive it has two blades that go around the cup that drives the needle. The two blades are what send the signal back to the eye for the VSS.

[greyhnd]

I've seen the "blades" you speak of on my factory speedo. I think it might be the same as the one in your pic, but without looking I can't swear to it. What drives me batty is that until I had a problem and asked here, I had no idea I needed a hall effect unit and that what I thought would be take out the old and in with the new turned into a clusterfrack. I took another look at the cable and it doesn't look like it will be that tough to take out.

I suppose it's about an equal process, but when installing the new cable, is it easier to start at the dash and go to the tranny or the other way around. I'm going to duct tape the ends of the 2 cables together so I can pull and follow the same route from firewall to trans. Does that make sense?

[greyhnd]

Okay guys, this will sound like a stupid question. To stay with my mechanical sppedo I'll need a new cable and a Hall Effect unit. The cable will be easy. What I'm wondering is if the Hall Effect units sold by Summit that are for the AutoMeter Electric speedo's are what I need to use, or does a mechanical speedo take an entirely different kind of Hall Effect Sender? The speedo I'm using is an AutoMeter mechanical model #2492. If it's just a regular Hall Effect unit then I can be in business in just a few days.

I've tried looking at the RPO codes to determine what tranny and rear gear ratio I have, but they're so faded I can't make out what they are. The parts manager at the local Chevy dealer told me he can help me get the correct drive gear just by looking at the old one and knowing how far off my speedo is. Figured I might as well get that taken care while I'm working on the tranny.

[MadMikeZ28]

I don't know if one of the hall effects for an electric speedo will work as they are usualy 16 pulse and the factory VSS for the OE cable driven speedo is 2 or 4 pulse.

I have done this before, but the vehicle was not yet 20 years old. A dealer was able to look up the rear gear ratio of the factory rear end by the VIN number. The numbers at the end of the VIN lead to the build sheet data base for the vehicle.

[MadMikeZ28]

I was doing some searching for 2 pulse hall effect unit and www.jagsthatrun.com came up in my search.
Scroll down and on the left you will see a link to where you can download a PDF chapter of their book on speed sensors. Then to the right of that and down just a bit you will see speed sensors and can click on that to see what they sell.
Back in 2004 when I bought mine from Speedometer solutions I paid $93 for a hall effect unit so Jags That Run are not so expensive.

[greyhnd]

Mike - I looked at my OEM speedo and I think it's a 2 pulse. There are 2 "flaps" that spin as the cable turns. The hall effect sensor is about $20 cheaper at the JagsThatRun site and I can get another speedo cable from a place online for about $40. Gets me in at about $100 total or so. I'm not sure exactly the length of cable I need and I don't want to yank the old one out until I get a replacement. I might be able to eyeball it and get close or call the Chevy dealer and see if they have any idea. Only problem with calling them is they sometimes act like an old 1st gen S truck isn't worth messing with. I love my old truck so they can kiss my arse.

[MadMikeZ28]

Well if its any help I have the cable out of a 84 and it is about 70" long from one end of the housing to the other end. Better a little longer than shorter.

[greyhnd]

That will help a lot. I've looked at this place for a replacement cable
http://www.transmissioncenter.org/speedometer_cable.htm. Don't anything about them at all, but I might call and see if they sound legit. I've also thought about one of the Lokar "cut-to-fit cables, but I'm afraid I'll have a problem getting the cable ends to stay fastened to the cable.

[MadMikeZ28]

That Lokar cut to fit sounds cheesy

[greyhnd]

Cheesy....that's a good word for it. I'm going to look a bit further for cables, but if I don't find anything else that I like I'll go with what I've looked at. I still have a hard time believing I can't find a damn speedo cable here locally. Surelly I'm not the only person in the county that's replaced a stock speedo with an aftermarket one. I guess everyone goes electrical when they change.

[MadMikeZ28]

Well I replaced my speedo with a mechanical and there is a speedometer specialty shop right here in California yet they did not have, or as far as I know, make a cable. They are the ones that turned me onto Speedometer solutions in Wisconsin.

[greyhnd]

I'm going to find out how good jagsthatrun.com is in a few days. I would probably have better luck trying to find an axle shaft for the 3rd axle of the power take-off valve for the left side view mirror on a 1931 1/2 International Harvester 3 1/2 ton snow plow.

[MadMikeZ28]

Come on...its not so bad.
Just a small technicality. Usualy when some one asks what they need to install gauges I tell them all I know. Your thread did not start off that way so this coming up right now is just a small set back.

[greyhnd]

Okay Mike, I guess you're right. The past few days it's been one step forward two steps back, so my humor has been hit and miss. I wonder why the gauge manufacturers like AutoMeter don't have the hall effect units? They must know that people who go from an OEM mechanical speedo to one of their mechanical ones are going to need them. I realize now there are many variables, but you'd think they would at the least provide some sources for the parts you might need. Would sure save aggravation for a lot of people. I should quit whining and be thankful there's a place like this forum where I can get answers to my questions.

[MadMikeZ28]

It would be nice if manufactures took into account these variables. Like here in California we started see computer controled vehicles as early as 79. Here all S Trucks starting in 82 had computers and a VSS.
But as with justr about everything custom you are left with figuring some things out yourself.

[greyhnd]

When this project is all over and done maybe I'll be able to answer other peoples questions instead of always being the one asking them.

When I get ready to swap the speedo cable, is it easier to pull the OEM cable out through the firewall toward the tranny, or to go from the outside into the dash? I know I want to "tie" the old and the new together, like pulling wiring in a house. Seems it would be better to pull the new through the firewall and go to the tranny. That way I can follow the route through the engine compartment to the transmission. Maybe I'm making an issue out of nothing.

[MadMikeZ28]

I don't know if you can tie the two together. There is a grommet where it goes through the firewall. Maybe tie some wire to the old as you pull it out from the cab so then you have the wire to pull the new through to get it behind the dash. Outside under the cab to the tranny is easy. You'll see tabs spot welded to the body that need to be pryed open to free the cable.

[greyhnd]

Mike - I'll have to pop that grommet out of the firewall to make the swap won't I? The new AutoMeter speedo has a replacement grommet included in the box. I went out and took a look at the route the cable takes and I was able to see the tabs holding the OEM cable in place.

I've also been trying to reach jagsthatrun.com by phone most all day, but keep getting an answering machine. I finally sent them an email to make sure the part I want to order is the correct one. I also wanted to make sure the place was legit since I'd never used them before.

[MadMikeZ28]

I think you may need you OEM grommet. It might be easier though to pop it out and slip it onto your new cable.

Jags that run is legit. I'm sure lots of people that have done V8 swaps has used them. I got the 4.3 to 2.8 mounts from them and was able to speak on the phone at the time. They are in California so there may be a time difference.

[greyhnd]

I'm not sure how big an operation jags that run is, so it could be they are closed on Mondays or something. I'll try again on Tuesday to reach them and make sure I'm ordering the correct part. I tried to take into account the time difference, about 3 hours from Indiana to California, I'm on Eastern time where I live.

I was wondering if it might be easier to pop out the grommet and put it on the new cable before installing. If the old cable comes through the grommet okay, I'll just leave it alone and work the new cable through.

[phantom_mia]

greyhnd they might have been closed for the holiday, yesterday was smoke me a kipper day "yom kippur", lot of stuff was closed around here including schools

[greyhnd]

phantom, I didn't realize it was a religious holiday. Where I live if you aren't German Catholic (not be confused with German Chocolate) you aren't considered a local. They have a proud German heritage here and I'm Methodist, or otherwise considered the anti-christ...LOL.

[phantom_mia]

german chocolate and german catholic both heavily laden with guilt.

its good to be different, down here we have a mixed bag of everything

[redbaron]

HELLO???
We are watching YOU!!

[MadMikeZ28]

Quote: Originally Posted by redbaron

HELLO???
We are watching YOU!!

[greyhnd]

Talked to JagsThatRun and I think I'll be all set come payday. The unit they sell is called a Reed Pulse Sensor, only has 2 wires, one goes directly to the ECM and the other is ground. No "hot" wire is needed and I was told that if it's connected to a power source it will fry. They quit selling the hall effect sensors because they had a much higher rate than this unit. I need to get my new speedo cable ordered as well.

[greyhnd]

I've been checking under the hood to see what path the speedo cable takes. The only thing coming through the firewall that looks remotely like the cable comes through on the drivers side right up in the corner, behind the washer fluid reseviour. It looks like it's gunked up with silicone or something. From what I can tell it travels down and passes through a hole in the frame rail. Does that sound right? I didn't have the truck up on jack stands so I couldn't tell if it ended at the tranny.

[AL4X4S10]

That sounds more like the E-brake cable, if i remember right the speedo cable is a bit lower more towards the engine.

I've been wanting to do this for a while on my pick up and have learned something new about the hall effect sensor, I always thought that lil box was just for cruise control, never had an S-Series apart that didn't have cruise.

AL

[greyhnd]

I never thought about the emergency brake cable being up that high on the firewall, but now that you say that it is a big cable coming out of the interior. I'll look some more and see if I can find something closer to the engine. Thanks for the tip.

[MadMikeZ28]

The e-brake cable will be in a big metal spiral flex tube. Should be able to some what follow the cable from the tranny on up

[greyhnd]

I'm going to try and get the truck up in the air tomorrow so I can get a better look. One nice thing, with the recent rebuild on the engine there's not a ton of oil and grease all over the place. Hopefully that will make it a bit easier to work on.

[greyhnd]

A short update. After much swearing, pushing and pulling I got the old speedo cable out. The hole in the firewall is right under the brake master cylinder so it was almost impossible to get to it from outside. I lubed the crap out of the grommet and let it sit overnight and this morning it popped right out. Looks like there's one other clip down low on the firewall and so far I haven't been able to get to it. I've tried from up top and also under the truck. The cable is still attached to the tranny and I'm waiting on the new one to get here before I take it out. I ordered the cable and the speed sensor on Friday morning, so hopefully they'll get here in a couple days.

Where is the ECM located on an 88? I think I've reqad here that it's behind the glovebox?

[jtcfanof3]

Ya, under the dash in the pass side footwell.

[greyhnd]

By footwell, you mean just ahead of the passenger side door? That's what I would call the footwell, but hey, I'm from southern Indiana and we see things differently sometimes...LOL.

[greyhnd]

Got the new speedo cable and VSS today. Quick shipping from both companies, one in California and one in Louisiana and I ordered both last Friday.

Here's my question. The wiring directions that came with the VSS are clear, but before I tear into the ECM to hook it up I want to make sure I've got it right. It's a 2 wire unit, one for ground and the other is the output/signal. According to the wiring diagram I have the output wire should go to the VSS pin on the ECM(Pin A10) and there is a ground at Pin12. The ground connection ahouldn't be a problem, but the output connection is what concerns me. If I snip off the connection coming from the OEM VSS and connect to it before it goes into the ECM will that take care of it okay? I have 3 grounds to work with, one at Pin A12 and 2 others at PinD9 & D10. They are labeled "direct ground". Which would be the best for me to tap into?

The other thing is where is the ECM located. jtc says under the dash in the "footwell" and I also read that it's behind the kick panel on the passenger side. If anyone can explain it to me I'd be grateful, because I really don't want to take anything else off the dash if I can help it.

[MadMikeZ28]

Since you found your VSS just unplug it and toss it aside and use those wires.

[greyhnd]

Mike - I didn't go through all the posts in this thread, but if I'm not mistaken you told me just that same thing earlier. I was just out in the truck and unplugged the connector. That will make short work of wiring the new "VSS" unit. I guess I had another one of those "can't see the forest for the trees" moments.

[AL4X4S10]

Any updates/progress/pictures on this project??

AL

[greyhnd]

I've got some pics of this crazy thing....finally. I need to get them on the PC so I can post them. Got everything hookep up and ready to drop the new gauges in the dash. I decided to use Weatherpak connectors, that was a dumb idea. They are too damn big to shove behind the dash. It's been raining and turned cold here so I haven't done much for a week or so. I finally settled on using "bullet" connectors for the wire ends. Not sure how that will work but I'll keep my fingers crossed.

I did get the truck started and drove it around the block to check everything. My fuel gauge still pegs on full and the temp gauge and oil pressure gauges are giving funky reqdings, so I think I'll need to get some matching senders. I'm hoping the fuel gauge is just a ground problem, but I can't locate my ohm meter to check the damn thing.

[greyhnd]

I've been off my feet with a prosthetic problem for a few days. Got back to my truck today to button it up and I've encountered a weird problem.

When I have the headlights off the gauges work okay. When I turn the lights off the gauges quit working. Effects everything except the speedo which is cable driven. I have no gauge lights whether the lights are on or off. I'm using the grey wire that originally took care of the dash illumination to power the gauge lights. I'm running the gauge power from what was the #1 pin on the old dash plug, pink w/black stripe I think.

It seems to me that one has nothing to do with the other and I can't understand why the light switch cuts the power. What the hell am I doing wrong here?

[MadMikeZ28]

Got a ground issue?
I had a clutch cable of mine turn cherry red once and it snapped. I looked and saw the ground from the motor to the body had broken.

[phantom_mia]

i swear this thread has turned into a novel

[MadMikeZ28]

Yes it has!
But I am glad the OP is not starting a new thread each time for the same thing like others have done before.

[phantom_mia]

tru dat

[greyhnd]

I screwed up in my last post....lights off = gauges work, lights on = gauges no work.

Mike, I ran my gauges + side from one gauge to the next and then finally to the power from the wiring harness. I did the same with the gauge grounds except I went to a "scotchlok" connector along with the gauge lighting ground, then on to the wiring harness ground. Should I consider using a different "hot" wire for the gauge lighting instead of the one from the dash dimmer?

I'll have to check my connections again tomorrow. My brain is fried tonight.

[jtcfanof3]

First thing first, throw away that scotchlock!
lol

[MadMikeZ28]

Was there at least two grounds on your harness? One for the lights and one for gauges? Or did you ground the gauges and the lights to one source?

And where are the pics???

[greyhnd]

Mike, there was only one ground on the factory harness, so all the grounds, both gauges and lights, end up at the same place. The grounds for the directional indicators, high beam and check engine LED's also end at the same place. That being the reason I used a "scotchlok" connector.

I'm taking pics as I go, but I've misplaced the connector to get them off the camera into the computer. Once I get the dash problems ironed out I'll figure a way to transfer the pictures.

jtc, I used the scotchlok to bring all my grounds together. Wasn't the way I wanted to do it, but I was running out of ideas.