Re: Crusty Rusty Leaky Squeaky 67 Step
 

Thanks, guys!

Well, I've encountered somewhat of a setback. Woke up about 3AM to the faint smell of 91 octane. Went downstairs to the shop and the fumes were stronger there. After a little detective work, I found a couple of small drips off the front edge of the tank. No puddles or anything, but still a problem. Went back to bed thinking I probably had a pinhole in one of the welds on the Boyd tank. My reasoning was that I had only put 12 gallons into a 19 gallon tank so it couldn't be from anything on top. Plus, I hadn't run the pump to purge and test the line integrity yet.

This morning I jacked the rear of the truck up for a closer look and found that, in fact, the leak is coming from around the submersible pump gasket. How that is possible I don't really know but the miserable truth is that I have to pull the bed back off the truck to fix the leak. Barely room to position the camera up there as it is. Tried looking with a light and inspection mirror, but was unable to get any decent access. Certainly no way to fit hands and tools up there to attempt to tighten the screws around the perimeter of the cover. Stay tuned....

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Hmm I wonder if it will require some sort of special tightening sequence and torque wrench to get the right amount of pressure on each screw.
It also probably wouldn't hurt to replace those screws with Allen bolts and get a flat washer and spring washer for each screw to resist vibrational loosening.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

:cuss: - :m6: - :censored: - :m7:

Leak is definitely the gasket around the pump. Still not sure how 12 gallons in a 19 gallon tank can create this problem...

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Had the same issue when installing my tank also and it only had 5 gallons in it...

Re: Crusty Rusty Leaky Squeaky 67 Step
 

That's really odd isn't it? Kinda counter intuitive if you ask me. I can see this happening if the tank is completely full and the fluid is up against the gasket. Wonder if it would be worth calling Boyd's to see what they have to say.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

I had a chat with them and didn't get any solid answers beyond barometric pressures and some other stuff that was above my head... LOL

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Humm, temperature change overnight creating pressure and the vapor created from filling? Bummer but at least it’s a short bed!

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Is the tank vented properly? Just a thought.

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Must be something in the Midwestern air Victor, because I'm chasing a mind bender problem on my '72...Good luck!!! Btw...when did you paint your box lime green? Lol...did a real double take in the pic where the box was coming off...

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Vic,
Would you like to try a different type of gasket material? I have a type here at work called “Gylon” it’s a blend of Garlock and nylon, has some crush to it, I also have a product called “Gore” sealing tape: it has a self adhesive backing and you wouldn’t have to fully remove the sending unit/pump to install it.

Here’s a picture of the material....
Let me know, I have other kinds as well.
Ben

Re: Crusty Rusty Leaky Squeaky 67 Step
 

At least you got to talk with them, Dan. Their website doesn't list a phone number and requests that you email them with questions... which I did. Still waiting to hear from them but it hasn't been very long. What did you do to get yours to stop leaking?
I don't think that was the case, Mike. I put 7 gallons in with no problem. The other 5 gallons I put in later was room temperature and the heater runs down there all the time so no big temperature fluctuations. Short bed or not, I'd much rather have had no reason to pull it. ;)
Well, not in the traditional sense. BW sells a rollover vent, but I didn't want one. Prefer the sealed system with the valve in the gas cap. It has a fill neck that came out of a Blazer which has a vent tube for filling purposes, but that's it. When I pulled the lines going to the EFI, there was no fuel in the lines or fittings. So if there was any pressurization, it wan't enough to force the fuel thru the pump and up into the line. Leak was just around the EFI cover gasket.
:lol: It's sitting right below a fluorescent light which makes it look lime green. Used to be a guy on the radio called Mr. Leonard that drove a lime green Pinto and wore lime green leisure suits. I ain't that guy. ;)
Something like that might help if re-torquing the fasteners doesn't do the trick. I'd really rather not have to pull the pump and put on a new gasket. BW sells them but I think they're rubber. I did what Brian had suggested and replaced the Phillips screws with socket cap screws so I could actually torque the fasteners. I started at 25 in-lbs, but waiting to hear from the company to see what (if anything) they recommend.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

We made a thicker gasket and tightened more... fixed my problem...

Let me see if I can find that phone number... it has been about a year and half

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Vic,
Did that gore tape fix the leak? Sure hope it did.
Ben
:metal:

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Got a nice reply from the owner today. Basically said you need a vent. I'll have to see what I can come up with. The only unused 1/2" NPT bung is right under one of the cross sills. I may be able to run a piece of aluminum tubing to a remote vent setup. Will have to see what works best.
Decided to go another direction, Ben. Thanks a million, though. I ended up using a product called Seal-All. It looks similar to model car glue but stays somewhat flexible when it dries. I ran a bead around the outside of the gasket and then covered it with aluminum tape. It's BUGLY, but it should work just fine. Also used it to seal around the fittings and each of the nylon washers.

After all that, I tested the pump and lines. That was a bit of a learning curve. The pump would come on for a second or two and quit. According to the all knowing Google, that's normal. It primes the injectors and then waits for the crank signal before re-energizing the fuel pump relay. So to test the system, I had to disconnect the weather pack connector at the pump and jumper 12VDC to it. But during my research, I also read that low fuel level can cause the pump relay to deactivate. I ended up calling Radley Chevrolet out in VA (who sold me the LS and trans) and talked to a guy named Mike. He said the fuel level signal was not used in the GMPP computer and harness. But the best bit of info he gave me was the phone number for the GMPP help center. WooHoo!! If I have any issues when I fire this puppy up in a day or two, hopefully I'll have someone to steer me in the right direction.

The fuel lines are leak free, the pressure reads 60 psi and holds 50 psi back pressure when you shut off the pump. No injector leaks either. I believe I'm about ready to make some noise. I got the bed back down on the frame and started all the bolts. Need to sort out the vent and get it back down on all fours. Painted the intake tube and installed it and the MAF sensor today also.
Getting closer...

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Awesome!!! I’m super excited for you to get it fired up. I had a issue with my fuel tank leaking from my gas lines on the red truck , I switched to a “vented” gas cap and the issue never appeared again. I apparently had bought the wrong year gas cap. Some tanks have the vent lines and some have the cap that is vented.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

To answer your question on the fuel level sender the ecm doesn't look at that for fuel pump relay control. With key on it primes system and then shuts off until it is cranked over. Looks like your ready to fire that baby up !

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Here I go away for a few days and all this happens! Great progress! God luck on the fire-up!

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Turns out, mine had neither... but it does now. :lol:
Installing a newfangled LS engine has been quite the education for me, Jason, with more schooling on the way I reckon.
Thanks Chip... video below.

Crusty fired up for the first time today. Everything went pretty well all things considered. I have some issues to address but that's to be expected. The temp probe that triggers the electric cooling fans is bad, but Derale is sending out a new one. Neither the tachometer nor the speedometer work, will have to get some tips from Classic Instruments tomorrow. And for some reason the check engine light on the dash is flickering when the engine is running. The MIL light in the relay box doesn't seem to doing that, but it's hard to tell because it's a lot smaller light. HF has a sale on a couple of their Zurich scan tools. May be time to invest in one.

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What a GREAT feeling for you!... and all of us who have been watching and waiting for this! Congratulations sir!!!:chevy:

Re: Crusty Rusty Leaky Squeaky 67 Step
 

It's Alive!
I bet you are just itching to go for your first drive.
For your next video can we go with you on a drive?

Re: Crusty Rusty Leaky Squeaky 67 Step
 

WOOOOO HOOOOO! Go Vic Go! Congratulations!

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Awesome Job Vic!!

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Good work Vic!

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Cool!!! Sounds great!!!

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Sounds great! Hopefully your issues are minor and easy to fix.

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Sounds great Vic.....

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What a milestone!!!

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I can't be the only one thinking this, when do we get to see the hood?
I've been dying to see it in paint.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Thanks, guys, for hanging in there with me. It's been a lot longer slog than I imagined. I know you understand how relieved I was that the engine actually fired up on the first try. It's a big step forward for a LS newbie. Certainly not as ambitious as some of you who've transplanted donor engines and had to jump thru even more hoops to make it all work, but still a big moment.

I spent a half hour on the phone yesterday with a GMPP tech and he was very helpful, although at the end of the call I still didn't really understand the difference between the VSS +/- and speedout wires. My BIL, Rick, and I had a long conversation about pull up - pull down resistors and after the call, I stumbled across a line in the Classic Instruments manual that stated the tachometer signal needs at least an 8V reference level and to use a 1K ohm resistor if the input wire is coming from a PCM/ECU. I only had about a dozen loose resistors in my electronics box, but luck was with me and I had one that was exactly 1K. After connecting it between switched 12DC and the signal post, I have a working tach.

Now it's on to the speedo. The GM tech seemed to think that having the NAV system and the cruise control piggybacked off the same wire going to the digital interface box for the speedo might be attenuating the signal. So today I'll patch a wire directly from the GMPP harness to the speedo box to delete the other two sinks temporarily. If that doesn't work, I'll be on the phone to Classic Instruments on Monday. ;)

I still have some work to do in the engine compartment, so it will be a little bit before I get the hood on. It's been leaning up against the back of the shop gathering dust since I brought it home from paint.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Cobbling together a patchwork of components from several different manufactures can be tricky and time consuming even if you have experience and for the guys that don't do this kind of stuff all the time it is a daunting challenge but you are smart and determined and you will get through it, hell you already solved one tricky problem and you just started working on it, you will have it working properly before you know it.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

That's always a great feeling to get past a major bump in the road...so sweetens the finished product!

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Had to use the pull up resistor with my classic instruments as well. Have you calibrated speedo and put it in learn mode yet?

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What you are experiencing is exactly why I stay old school... I would have burnt the truck to the ground long ago... LOL

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Thanks, Brian.
So true, and this was a biggie.
I'm still not getting the speedo signal to the SN74Z box for some reason, Jason. It has power and the green LED is on, but the manual says if it doesn't blink, there's a problem with the signal. I used a patch cable to bypass the other devices and directly connect the SPEEDOUT cable to the SPEEDO IN terminal on the box, but no luck. I have a handheld oscilloscope ordered off eBay, since that's the only way (I know of) to verify the signal. Tomorrow I'm going to hook the laptop to the diagnostic cable for the transmission, fire up the software that came with the C&C package and see if it will talk to the TCU. Maybe something will stick out. The guys at Classic said it would be best to use the ECU signal (speedout) versus the VSS +/- input. Best I can tell, the single wire is a square wave and the two wire input is a sine wave. Only difference on the SN74Z (aside from the terminals used) is the filter switch. Off for square wave, on for sine wave. If I'm unable to sort it out with the software, I'll make another run at CI's customer service.
Ain't that the truth, Dan. If I'd left the Gen1 SBC in it, I'd be out doing donuts right now. :lol:

I did get a few things done today. Re-bled the brakes, topped off rear end lube and trans fluid plus I got the Kamikaze charcoal filter mounted and hooked to the newly installed vent tube. I think I'm safe from any tank pressurization issues now. As you can see from the photo below, it looks like a bomb went off in my recently completed interior.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

I used the single vss output from the ecm to the sn74 box. I will look at my setup again and see if I can help in anyway.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Far as I can tell I have a single computer speed signal going to the sn74z speedo in terminal. Switches 1-5 off on the sn74z on the back of speedo switches 5,6,7,8 open. I used the marked mile method and according to GPS it's right on the money. According to my notes I called Classic instruments and that's what they told me to do. Gm uses 16,000 ppm for speedo.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

Thanks, Jason. From what I can find online, I think several things are going on.
1. There's an orange wire coming out of the GMPP harness marked SPEEDOUT that's coming from the TCU. It is what I currently have connected to the SPEEDO IN terminal on the SN74Z with switch settings as you described.
2. There's a brown wire (circuit 818) that passes thru the 12 pin bulkhead connector that is supposed to be Vehicle Speed - Out. The I-sheet states it is a non-scaled output for use with auto-scaling speedometers and will not function unless a vehicle speed sensor is connected to the ECM thru the VSS wire in the harness. This is the wire the GMPP help desk tech referenced in our conversation Friday when discussing the inoperative speedo. However, as far as I can tell, there's no non-terminated wire in the harness that ties back to it.
3. Again, as best I can tell, the plug marked VEH SPD is meant to accept a sine wave that varies between 0-5V. The I-sheet states it's optional and not needed for engine operation... which is true to a point. But, apparently, without it there may be idle and stalling problems per this article. While it may ultimately be a driveability, fuel mileage issue, I don't think it's relevant to the speedo not working.

So with all that, do you recall the wire color coming out of your harness that goes to the speedo in on the SN74Z? If your setup is like mine, the harness wire is too short to make the trip and had to be spliced.

Re: Crusty Rusty Leaky Squeaky 67 Step
 

I modified a stock factory wire harness myself. The wire color was white. What year computer ecm does your kit have I can look at pin out ok gm site. I am a tech at gm dealer so I have access to schematics pin out etc.

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I would think the wire that was labeled speed out on your harness would be the one to go to sn74

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This is above my head. Probably what's kept me from doing this swap. I'm not only old but old school......good luck Vic