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Old 08-10-2020, 10:51 PM   #51
ls1nova71
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Re: First time swap started

I'm not sure why the speedo wouldn't work if the needle was returning to zero when powered up, unless you aren't getting a speed signal to it for some reason. However, I would be more concerned with how accurate it is going to be. The sweep of the two are different enough it may cause it to be inaccurate. If you take the S10 speedometer and draw an imaginary line from zero through the center of where the needle mounts, you will see that the other side will land at roughly the 83ish MPH mark, where as if you do the same thing on your original speedo you are going to be somewhere around the 65MPH mark. That's a pretty big difference.
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Old 08-11-2020, 06:31 AM   #52
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Re: First time swap started

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Originally Posted by ls1nova71 View Post
I'm not sure why the speedo wouldn't work if the needle was returning to zero when powered up, unless you aren't getting a speed signal to it for some reason. However, I would be more concerned with how accurate it is going to be. The sweep of the two are different enough it may cause it to be inaccurate. If you take the S10 speedometer and draw an imaginary line from zero through the center of where the needle mounts, you will see that the other side will land at roughly the 83ish MPH mark, where as if you do the same thing on your original speedo you are going to be somewhere around the 65MPH mark. That's a pretty big difference.
I had already figured that it would be off, but hoped that some pcm adjustments could address it. First I have to get the needle to move at all.
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Old 08-11-2020, 09:06 AM   #53
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Re: First time swap started

You will be able to adjust the tune to compensate for the needle being off, but then the odometer won't be right.

But anyway, did you have the speedo powered up when you put the needle on? If you didn't then the needle may be way off and not able to re-enter it self. If you did, then its probably not the issue. Did you notice if the odometer worked while you drove it? If it didn't, then you most likely aren't getting a speed signal to it since you say the needle moved once when you powered it up.
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Old 08-11-2020, 09:34 AM   #54
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Re: First time swap started

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You will be able to adjust the tune to compensate for the needle being off, but then the odometer won't be right.

But anyway, did you have the speedo powered up when you put the needle on? If you didn't then the needle may be way off and not able to re-enter it self. If you did, then its probably not the issue. Did you notice if the odometer worked while you drove it? If it didn't, then you most likely aren't getting a speed signal to it since you say the needle moved once when you powered it up.
When I first tested the cluster, it appeared that the needle would reset to 0 when power was applied... or at least I reset the needle to 0 - but yes, it would move. I did not notice it yesterday, so I'll need to check it.

The odometer was not moving at all either, so something's totally off.

So first, I need to verify that the board is getting power. Then from what I understand I can hook up a multimeter to the signal wire & ground, and should be able to get some kind of measured voltage to at least verify that some kind of signal is coming from the PCM.
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Old 08-14-2020, 09:06 AM   #55
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Re: First time swap started

Ah, the joys of projects.

Radiator cap leaking slightly at full temp. Go to store and get replacement ('safety release' style was all they had). Doesn't even get up to temp before it starts leaking through the 'safety valve'.

New AC Delco cap coming today.

Voltage low - 11.xx at battery, 11.xx at alternator. PCM wire to alternator showing ~5+ volts, so on my year motor I believe that's correct (some years it's 10-12?). So have to pick up an alternator.

I can get a new AC delco from amazon (105 amp) for $125, or a new 130 amp carquest from Advance for the same price, plus a 25% coupon. But I'd need a new belt, to replace my... new belt. Don't know if the extra amps are justified.

Still haven't gotten around to looking at my gauges issue. Maybe this weekend.
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Old 08-14-2020, 11:55 AM   #56
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Re: First time swap started

Hang in there. It's all the little stuff that makes it worth it. I always have my alt. tested before installation.
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Old 08-14-2020, 12:03 PM   #57
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Re: First time swap started

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Hang in there. It's all the little stuff that makes it worth it. I always have my alt. tested before installation.
I'm just trying to figure out if I actually need one, or if the PCM isn't giving the right signal, or if I need something else.

I see folks talking about adding a light/resistor but that seems to be only carb swaps.. I think.
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Old 08-14-2020, 12:28 PM   #58
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Re: First time swap started

I think you are right on that light stuff. I had to put a resistor on my older serpentine system swap to make the alt work. I would still have it tested. Heck, I have the new ones tested before I leave with it. Better than chasing wires and PCM issues.
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Old 08-15-2020, 10:48 AM   #59
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Re: First time swap started

New AC Delco radiator cap and new alternator and we're back in business.

Still not sure what's up with my gauges. Temp sender wire is sending positive voltage that slowly drops as the engine warms up, so that seems normal.

Speedo is getting +10v at idle at the sender wire. I can jump a ground and sort of 'scrape' the sender connector on the board and get the needle to jump - the faster I scrape, the more the needle moves up. So it appears that with some kind of signal the needle will move. But it doesn't move when I'm driving. I'll need to jack up the wheels and put it in gear and see if/how the signal changes.

Could it be that the PCM isn't putting out the right kind of signal for this board?
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Old 08-17-2020, 08:18 AM   #60
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Re: First time swap started

Took some time yesterday to try and figure out the speedo. Pulled the cluster, looked things over, tried to read a signal from the PCM with the wheels off the ground. Yes, it's getting something, no, I can't see the details with a simple multimeter. Apparently if you have an older-style needle sweep meter, you can see the pulses, but not with my digital one.

With a bluetooth dongle in the OBD port, and an app on my iPad, the PCM is registering speed, so the sender from the transmission seems fine.

I throw my hands up and figure bad board or I screwed something up and walk away from the cluster.

Took the rest of the day to replace the front brake hoses since my truck has been pulling slightly to one side since the beginning of the year. Should have done that while the motor was out... lord.

So I put the cluster back together, put it in so at least I can see my fuel level, and take the truck for a spin to test the brakes out.

Speedometer works. What. The. Heck.

Drove it around the block, came back and pulled into my driveway, there's a slight bump there - thump - needle drops to 0. Doh. Ok, gotta figure out a loose connection now.

But hey! It works. Worked. For a little. I count that as a win.

Then I parked and the lower radiator hose clamp which apparently wasn't quite tight enough decided to barf all over the driveway. Of course it did. One of these days I'm going to get this thing housebroken.
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Old 08-17-2020, 08:30 AM   #61
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Re: First time swap started

Well that is better news about the speedo. I have to admit, I giggled just a little over the radiator hose. I will let you know about my bad karma for that when it happens.
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Old 08-17-2020, 09:13 AM   #62
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Re: First time swap started

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Well that is better news about the speedo. I have to admit, I giggled just a little over the radiator hose. I will let you know about my bad karma for that when it happens.
I get it, I just had to roll my eyes over it. Of COURSE you sprayed coolant again.

I think with the old (bad) radiator cap the system wasn't building to full pressure, and with the new one it finally got high enough to blow coolant past the clamp/neck and all over.

It's especially annoying since I've had leaking coolant issues from the get go.

Thermostat housing to pump - check.
Replaced thermostat that has new seal - still leaked.
Added coolant safe sealant to housing - ghetto fixed. (apparently there's a newer design to the pump/housing but we'll do that someday)

Reducer fitting for the steam line to radiator - leaked.

Cap - leaked.

Now bottom hose - leak.
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Old 08-17-2020, 10:56 AM   #63
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Re: First time swap started

Definitely sounds like you have a bad connection in the speedometer somewhere. How did you attach the power, ground and speed signal wires to the circuit board of the speedometer?
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Old 08-17-2020, 11:11 AM   #64
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Re: First time swap started

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Definitely sounds like you have a bad connection in the speedometer somewhere. How did you attach the power, ground and speed signal wires to the circuit board of the speedometer?
The original flexible circuit board had little square metal tangs in it, I popped them out and soldered the wires to those tangs, then pressed them on to the pins on the back of the board. Works for every other gauge, maybe they're just not a solid enough connection for the speedo signal.

I was thinking of just soldering them right to the pins to secure them.
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Old 08-19-2020, 02:02 PM   #65
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Re: First time swap started

Alright - update.

Took the silverado for a spin yesterday and she didn't pee all over the driveway when we got home (yay!)

The speedo was NOT working at first, but I've narrowed down the issue to a molex connector I added at the firewall to make the engine harness detachable from the passenger compartment. Either I didn't crimp it right or something cause if I sort of kick at the wires the speedo comes back on. So just need to add a better connection there.

On another note, love the power this thing has. Totally different truck. I think the shift points could use some tuning for harder acceleration, but at cruise speeds it's wonderful.
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Old 08-19-2020, 05:14 PM   #66
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Re: First time swap started

Getting there! Woohoo!
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Old 08-21-2020, 09:45 AM   #67
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Re: First time swap started

Consider that there is torque management in the system. It really dampens the shifts. It's also why the transmissions last way longer than the non computer controlled versions did. There's no free lunch. If you take out torque management you will give up trans life. If you do a performance rebuild then torque management can be pulled without loss of reliability. You also need to consider that when torque management is removed you may need to tune the spark curve for knock. When it shifts harder it could knock and pull a bunch of timing back causing it to fall flat on its face.

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Originally Posted by TrybalRage View Post
Alright - update.

Took the silverado for a spin yesterday and she didn't pee all over the driveway when we got home (yay!)

The speedo was NOT working at first, but I've narrowed down the issue to a molex connector I added at the firewall to make the engine harness detachable from the passenger compartment. Either I didn't crimp it right or something cause if I sort of kick at the wires the speedo comes back on. So just need to add a better connection there.

On another note, love the power this thing has. Totally different truck. I think the shift points could use some tuning for harder acceleration, but at cruise speeds it's wonderful.
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Old 08-21-2020, 11:52 AM   #68
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Re: First time swap started

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Consider that there is torque management in the system. It really dampens the shifts. It's also why the transmissions last way longer than the non computer controlled versions did. There's no free lunch. If you take out torque management you will give up trans life. If you do a performance rebuild then torque management can be pulled without loss of reliability. You also need to consider that when torque management is removed you may need to tune the spark curve for knock. When it shifts harder it could knock and pull a bunch of timing back causing it to fall flat on its face.
I've read about the torque management, I think I'd like to leave it in place. While I couldn't help some harder pulls for the grins of it, the real-world purpose of this truck is to do truck stuff. Towing my boat, hauling stuff, etc.

Since 99% of the time will be low-intensity driving, I'd like that protection for the trans.
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Old 08-22-2020, 04:33 PM   #69
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Re: First time swap started

As I understand you don't need to take out all of the torque management out. Per the tune it can be adjusted to leave certain percentage in.
If you still have the stock tune in the ecm the trans will up shift sooner because GM wants the vehicle to go up into a higher gear as soon as possible for better gas mileage. A tuner can adjust the shift points to what ever makes you happy. Because there are bunch of 40 mph streets I use quite often I have the tuner delay the lock up of the torque converter until 45 mph. Helps prevent lugging the engine. All the tuner needs is your tire diameter, trans type and gear ratio to do the calculation.
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Old 08-27-2020, 08:46 AM   #70
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Re: First time swap started

So I made a dorky little overview video talking about my swap. Skip ahead to about 4:20 or so to hear the exhaust.

https://youtu.be/sdrgC7R4Tds
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