Big Blue's Transformation

[Gary Lewis]

Shaun - You can start a thread about this if you want. Pics as well and we can collaborate there - and know where it is rather than in email.

David - I hope mine is a bit quieter than that. (But you ought to hear that in the shop with this sound system. )

Now for the bad news. I got the replacement FDM installed and have roughly the same symptoms. On the front tank, where the new FDM is, the pressure goes right on up on the gauge. But on the rear tank it goes up to the set point on the regulator and stays there.

I've not pulled the return to make sure that's the problem, again, but I'm loathe to do that. Instead I think I'm going to call Spectra. Perhaps they had a bad batch of those FDMs?

Thoughts?

On second thought, there's about 12" of hose from the wye to connector that hasn't been proven. I know from the wye to the rear tank is open, but it is possible that something is wrong from the wye to the front tank.

I think I have a piece of that stainless fuel tubing that his the 5/16" fitting on one end, so if I disconnect the return from the FDM and connect it to that line I can run that line into the empty gas can and test to see if the return is completely open.

If so, then I'll call Spectra.

[ArdWrknTrk]

On second thought, there's about 12" of hose from the wye to connector that hasn't been proven. I know from the wye to the rear tank is open, but it is possible that something is wrong from the wye to the front tank.

I think I have a piece of that stainless fuel tubing that his the 5/16" fitting on one end, so if I disconnect the return from the FDM and connect it to that line I can run that line into the empty gas can and test to see if the return is completely open.

If so, then I'll call Spectra.

I don't think there's any way the FDM is faulty (twice) but it may be possible.

Good catch Dant!

Thank you for sharing your personal experience.

With my old T-19 I had turned a knob of Padouk.

I loved the deep maroon color it took on and the polish it acquired from years of use.

I epoxies it on and didnt worry about changing the boot because I could release the stick down at the bottom.

[ArdWrknTrk]

I don't think there's any way the FDM is faulty (twice) but it may be possible.

Good catch Dant!

Thank you for sharing your personal experience.

With my old T-19 I had turned a knob of Padouk.

I loved the deep maroon color it took on and the polish it acquired from years of use.

I epoxies it on and didnt worry about changing the boot because I could release the stick down at the bottom.

I'm so excited for Big Blue!

And, of course Gary & Janey's big adventure.

Hope this all gets sorted today, and the Wye proves to be the problem.

[Gary Lewis]

I'm so excited for Big Blue! :nabble_anim_jump:And, of course Gary & Janey's big adventure.Hope this all gets sorted today, and the Wye proves to be the problem.

I pulled the return line off the front FDM and put it in a gas can. Powered up the pump and the regulator's gauge settled at 5 psi - right on target. Switched over to the rear pump and it worked perfectly as well. Put the return hose back on the front FDM and the rear still worked fine. But switch it over to Front and the pressure wraps the gauge around like it'll twist it off.

 

So I called Spectra and spoke with their tech. He can't believe that I got two bad ones, but fully agrees that my testing proves I did. He also had me check the labels on these two and they are from the same batch, V161, and were both produced the 37th week of 2017. So he told me to call the supplier and get a third one.

 

I called Herko Automotive, who sold it to me, and they will send me a third one once they get one of these two back. So one gets shipped out in the morning. And they agreed to check and make sure the new one is from a different batch - although I didn't get a good warm, fuzzy feeling they actually will.

 

To summarize, it appears to me that there are two possibilities:

 

1. Bad FDMs: Yes, maybe it can happen to get two bad FDMs since they are from the same batch. But the tech said they test every one of them, so it doesn't seem likely.

 

Opening Pressure: What if the front FDM just requires a different pressure to open the check valve? I don't think the valve ever opens, but what if it is set to open at something like 40 psi and the rear one opens at a much smaller pressure? Whatever pressure the rear is opening at is not causing the regulator any problems, but the excess pressure on the front sure is.

 

This won't really stall the initial firing of Big Blue as I can run off the rear tank just fine as long as there's an FDM in the front. I can certainly drive the truck on the rear tank alone as I've gotten along fine for however long I've had the truck on the slightly smaller front tank.

 

But, if the third FDM doesn't fix it then it seems like I'll need to go EFI sooner than I thought as I'll want the extra gas capacity for trips.

 

So, do any of y'all see another possible problem in this? Something else that could cause the rear to work and the front not to?

[ArdWrknTrk]

I pulled the return line off the front FDM and put it in a gas can. Powered up the pump and the regulator's gauge settled at 5 psi - right on target. Switched over to the rear pump and it worked perfectly as well. Put the return hose back on the front FDM and the rear still worked fine. But switch it over to Front and the pressure wraps the gauge around like it'll twist it off.

 

So I called Spectra and spoke with their tech. He can't believe that I got two bad ones, but fully agrees that my testing proves I did. He also had me check the labels on these two and they are from the same batch, V161, and were both produced the 37th week of 2017. So he told me to call the supplier and get a third one.

 

I called Herko Automotive, who sold it to me, and they will send me a third one once they get one of these two back. So one gets shipped out in the morning. And they agreed to check and make sure the new one is from a different batch - although I didn't get a good warm, fuzzy feeling they actually will.

 

To summarize, it appears to me that there are two possibilities:

 

1. Bad FDMs: Yes, maybe it can happen to get two bad FDMs since they are from the same batch. But the tech said they test every one of them, so it doesn't seem likely.

 

Opening Pressure: What if the front FDM just requires a different pressure to open the check valve? I don't think the valve ever opens, but what if it is set to open at something like 40 psi and the rear one opens at a much smaller pressure? Whatever pressure the rear is opening at is not causing the regulator any problems, but the excess pressure on the front sure is.

 

This won't really stall the initial firing of Big Blue as I can run off the rear tank just fine as long as there's an FDM in the front. I can certainly drive the truck on the rear tank alone as I've gotten along fine for however long I've had the truck on the slightly smaller front tank.

 

But, if the third FDM doesn't fix it then it seems like I'll need to go EFI sooner than I thought as I'll want the extra gas capacity for trips.

 

So, do any of y'all see another possible problem in this? Something else that could cause the rear to work and the front not to?

I'd really like to see how pump pressure unseats the return port.I don't have it in front of me, but being who/what I am I would probably open it up or stick and endoscope in the valve to satisfy my curiosity.

[Gary Lewis]

I'd really like to see how pump pressure unseats the return port.

I don't have it in front of me, but being who/what I am I would probably open it up or stick and endoscope in the valve to satisfy my curiosity.

I'm curious re that as well, Jim. I'm just not sure I'm curious enough to set up the test.

In theory there's a valve that opens when the pump is powered, but not otherwise. So you could set the FDM in some liquid, like water, and apply power. With the output plumbed to the return the pump would run and the valve should open. But to test the pressure at which it opens you'd have to raise the voltage on the pump and record the pressure, or let the pump's output go back into the container and apply regulated air pressure to the return.

But it really doesn't matter. If the third FDM doesn't work with the regulator than I'll just run on the rear tank while sporting the carb, and move to EFI sooner than planned.

[ArdWrknTrk]

I'm curious re that as well, Jim. I'm just not sure I'm curious enough to set up the test.

In theory there's a valve that opens when the pump is powered, but not otherwise. So you could set the FDM in some liquid, like water, and apply power. With the output plumbed to the return the pump would run and the valve should open. But to test the pressure at which it opens you'd have to raise the voltage on the pump and record the pressure, or let the pump's output go back into the container and apply regulated air pressure to the return.

But it really doesn't matter. If the third FDM doesn't work with the regulator than I'll just run on the rear tank while sporting the carb, and move to EFI sooner than planned.

These are the questions that I wake up to.

If you only knew someone with a bad FDM that you could dissect with impunity.. 🤔

[85lebaront2]

I pulled the return line off the front FDM and put it in a gas can. Powered up the pump and the regulator's gauge settled at 5 psi - right on target. Switched over to the rear pump and it worked perfectly as well. Put the return hose back on the front FDM and the rear still worked fine. But switch it over to Front and the pressure wraps the gauge around like it'll twist it off.

 

So I called Spectra and spoke with their tech. He can't believe that I got two bad ones, but fully agrees that my testing proves I did. He also had me check the labels on these two and they are from the same batch, V161, and were both produced the 37th week of 2017. So he told me to call the supplier and get a third one.

 

I called Herko Automotive, who sold it to me, and they will send me a third one once they get one of these two back. So one gets shipped out in the morning. And they agreed to check and make sure the new one is from a different batch - although I didn't get a good warm, fuzzy feeling they actually will.

 

To summarize, it appears to me that there are two possibilities:

 

1. Bad FDMs: Yes, maybe it can happen to get two bad FDMs since they are from the same batch. But the tech said they test every one of them, so it doesn't seem likely.

 

Opening Pressure: What if the front FDM just requires a different pressure to open the check valve? I don't think the valve ever opens, but what if it is set to open at something like 40 psi and the rear one opens at a much smaller pressure? Whatever pressure the rear is opening at is not causing the regulator any problems, but the excess pressure on the front sure is.

 

This won't really stall the initial firing of Big Blue as I can run off the rear tank just fine as long as there's an FDM in the front. I can certainly drive the truck on the rear tank alone as I've gotten along fine for however long I've had the truck on the slightly smaller front tank.

 

But, if the third FDM doesn't fix it then it seems like I'll need to go EFI sooner than I thought as I'll want the extra gas capacity for trips.

 

So, do any of y'all see another possible problem in this? Something else that could cause the rear to work and the front not to?

Question is, do they test the return for opening? Before you go to all the issue of dropping and reinstalling the tank to switch, how much slack do you have in the lines, enough to say put a new FDM in a 5 gal pail so you can observe things.I don't know who Amazon's source is as far as having dealt with them, I ordered my front FDM directly from SPI and still had a bad one (FWIW, most are made in China). What does NAPA want for one or any other local parts store?

[Gary Lewis]

These are the questions that I wake up to.

If you only knew someone with a bad FDM that you could dissect with impunity.. 🤔

I have two of them from Huck, one front and one rear. Want me to send them to you?

Seriously though, are you ready for the rag joint? I'm headed to the shipping place in the morning.

[Gary Lewis]

Question is, do they test the return for opening? Before you go to all the issue of dropping and reinstalling the tank to switch, how much slack do you have in the lines, enough to say put a new FDM in a 5 gal pail so you can observe things.

I don't know who Amazon's source is as far as having dealt with them, I ordered my front FDM directly from SPI and still had a bad one (FWIW, most are made in China). What does NAPA want for one or any other local parts store?

Bill - I have the tank half installed, or half uninstalled depending on how you look at it. So getting the FDM out isn't a huge deal at this point. But I don't want to go to someone else as Herko owes me a new FDM at no extra cost.

As for the slack, no there's not nearly enough to allow getting the lines to an FDM off the truck.