Bad Regulator?

[DrededSS]

Rob, There are no kinks in the return line, it is flowing full blast back into the filler neck.

Mitch, It is a FASS for the duramax. The feed line comes from the FASS directly to the PPE CP3 and T's off, then goes over to the FICM. The return line leaves there and goes back to the filler neck. The return line off the FASS actually routes back into the stock metal lines back by the tank.

I have my stock CP3 in storage, so I could swap regulators to see if that changes anything. I'm out of time to play with it for at least a week now. I'll be out of town until Dec. 13th. Mark Broviak routed everything, and he should be back from vacation on Wednesday. Larry at Danville said Jon had this problem before too. Hopefully Mark will have the fix since he has had this problem before.

McRat, I'll try that when I'm back in town. Now I have to do maintenance on the old faithful LLY since it gets neglected but still manages to always be reliable

 

[LarryJewell]

both my Fass 150/95 and Fass 150/150 push 9psi at idle, the 150/95 would pull down quite a bit more at WOT than the 150/150, but both pushed the same 9psi at idle.

 

[DrededSS]

When I originally picked up the truck at Danville, Mark told me the gauge was going to peg out due to the way something was setup. Looks like I'll need to talk to him. It's a good thing I have to go out of town. It would drive me crazy if I was home but not working on it. I found my new fuel pressure gauge that goes to 60 psi, but I can't find the wire harness for it!

 

[GMC_2002_Dmax]

Are both CP3's the same, LB7, LLY or LBZ, or are the mismatched ??

Do they have the same regulators or is one modded and one stock ???

If you have a modded pump and a stock pump and or one modded regulator and one stock or different regulators on each pump you will need to do a lot of work on the regulator amps table to fix it.

Since the Valley pump is modded and you cannot take that one out of the equation easily you need to pull the belt off for the second CP3 and with the FASS pump off increase the regulator amps at idle to restrict flow to the rail until the psi is in line with actual vs commanded.

Once you have it fixed bring the second pump back on line by attaching the belt to the second CP3 pulley and see if the changes stay or go bad again, if they do not maintain the desired psi you can try to retune the amps table again, if that does not work then you have to change parts or live with it.

Then bring the FASS back on and see what it does and try again, most likely the FASS is pushing thru the regulators.

You need to log the Actual and desired rail psi, regulator ma to see what it's doing.

If you see the amps going to ZERO and then up to 1200-1500 and then ZERO you have a problem with the regulators trying to maintain PSI due to either the mods or the mismatch.

If I can help you I will.

 

[sweetdiesel]

Are both CP3's the same, LB7, LLY or LBZ, or are the mismatched ??

Do they have the same regulators or is one modded and one stock ???

If you have a modded pump and a stock pump and or one modded regulator and one stock or different regulators on each pump you will need to do a lot of work on the regulator amps table to fix it.

Since the Valley pump is modded and you cannot take that one out of the equation easily you need to pull the belt off for the second CP3 and with the FASS pump off increase the regulator amps at idle to restrict flow to the rail until the psi is in line with actual vs commanded.

Once you have it fixed bring the second pump back on line by attaching the belt to the second CP3 pulley and see if the changes stay or go bad again, if they do not maintain the desired psi you can try to retune the amps table again, if that does not work then you have to change parts or live with it.

Then bring the FASS back on and see what it does and try again, most likely the FASS is pushing thru the regulators.

You need to log the Actual and desired rail psi, regulator ma to see what it's doing.

If you see the amps going to ZERO and then up to 1200-1500 and then ZERO you have a problem with the regulators trying to maintain PSI due to either the mods or the mismatch.

If I can help you I will.

That is a really good way to do it But correct me I am wrong I think he would also have to unhook the controller and not just the belt?

As Tony said logging milliamps is good too.IMO its a little better than rail pressure in this situation.And ajusting these milliamps make big changes so it can be time consuming but worth it in the end

at 15 psi you are pushing the regulators open...They where never made for pressure,Even at 3-4psi your milliamps will change from the regulator trying to compensate it is just less noticable unless you are actually looking for it

Good info Tony

 

[05smoker]

Lee, make sure the return fuel line from the fass is not kinked or blocked in anyway.

This was our exact problem with the Airdog. Our return line was moved out of the way to weld and we didn't unkink it and move it back when done welding.

Not sure but I have a feeling this contributed to our injector issues later.

Can you regulate the flow of the FASS?

 

[LarryJewell]

This was our exact problem with the Airdog. Our return line was moved out of the way to weld and we didn't unkink it and move it back when done welding.

Not sure but I have a feeling this contributed to our injector issues later.

Can you regulate the flow of the FASS?

I've heard you can shim it

 

[DrededSS]

Are both CP3's the same, LB7, LLY or LBZ, or are the mismatched ??

Do they have the same regulators or is one modded and one stock ???

If you have a modded pump and a stock pump and or one modded regulator and one stock or different regulators on each pump you will need to do a lot of work on the regulator amps table to fix it.

Since the Valley pump is modded and you cannot take that one out of the equation easily you need to pull the belt off for the second CP3 and with the FASS pump off increase the regulator amps at idle to restrict flow to the rail until the psi is in line with actual vs commanded.

Once you have it fixed bring the second pump back on line by attaching the belt to the second CP3 pulley and see if the changes stay or go bad again, if they do not maintain the desired psi you can try to retune the amps table again, if that does not work then you have to change parts or live with it.

Then bring the FASS back on and see what it does and try again, most likely the FASS is pushing thru the regulators.

You need to log the Actual and desired rail psi, regulator ma to see what it's doing.

If you see the amps going to ZERO and then up to 1200-1500 and then ZERO you have a problem with the regulators trying to maintain PSI due to either the mods or the mismatch.

If I can help you I will.

See my post #35. I took off the belt to take the PPE CP3 out of the equation. Plugged in or not with the belt off, same 11,500 psi out of the Industrial Injection unit in the stock location. It is a modded CP3. Not sure what PPE does to theirs. The PPE unit is wired into the factory harness, which means they are not regulated independently.

With the FASS off in any combination of CP3, the desired psi does equal the actual. With the FASS off and the belt off the PPE CP3, desired psi does equal the actual. Pretty much if the FASS is off, the desired does equal the actual. I'm trying to find my harness to hook up a higher psi gauge on the FASS to see if it has spazzed out.

If I can get a friend over here, I'm going to unplug the return line at the engine and run it to a jug. There are no kinks though.

And please don't take this the wrong way, but I think a couple of you are treating this problem as if I installed something new on the truck and found this problem. I have 1,000 miles on break-in and another 5,000 trouble free miles. All of that on pretty much the same tunes. And the stock tune acts the same as my daily driver as my race tune.

 

[DrededSS]

I would NEVER get this kind of help on other sites.

THANKS!!!

 

[DrededSS]

Found my gauge wiring harness. It's a 100 psi electronic fuel pressure gauge. My FASS just pegged it. We double checked the wiring on the gauge to make sure something wasn't messed up. Tried it 4 times with truck on and off. Somehow my FASS is pumping at over 100 psi

Fuel is pumping from the return line back into the tank.

I don't think I explained my fuel line routing correctly in that earlier post. Here is a little diagram. Factory lines are still in place. The factory hard lines under the hood are all still in place. I have a small leak in the factory hard line on the frame that is being fed by that return port of the FASS (red in the picture).

None of the lines are crimped. My water separator has some residue on it, but I can't tell if it's leaking from the seal or if the hard line leaked has got on it.

 

[SmokeShow]

looks like it's time to let FASS take a look at it or bypass that FICM and tune out the lope from the pressure on the inlet side of the FPRV.

That's why I asked if you were sure the FASS was for a DMax because the ones they make for a 12Valve apparently run at like 60 psi or so. Apparently a person can have either made into the other by sending it in to FASS. Sounds like yours did it itself though somehow.

Wonder if your voltage problem screwed up the electronics of the FASS and is making the pump over spin or something making far greater pressure???



when the rail pressure is right, does the truck run alright as far as the smoking, loping/surging and voltage fluctuation are concerned or is the voltage still surging, even if the rail is high or low at idle?


C-ya

 

[DrededSS]

looks like it's time to let FASS take a look at it or bypass that FICM and tune out the lope from the pressure on the inlet side of the FPRV.

That's why I asked if you were sure the FASS was for a DMax because the ones they make for a 12Valve apparently run at like 60 psi or so. Apparently a person can have either made into the other by sending it in to FASS. Sounds like yours did it itself though somehow.

Wonder if your voltage problem screwed up the electronics of the FASS and is making the pump over spin or something making far greater pressure???



when the rail pressure is right, does the truck run alright as far as the smoking, loping/surging and voltage fluctuation are concerned or is the voltage still surging, even if the rail is high or low at idle?


C-ya

I noticed the FASS sounded different the past few days. It's usually more noisy and changes tones. With this problem it has had a constant sound. With the FASS off, the truck idles normal and sounds normal and has normal rail pressure.

I'll have to trace the wires to make sure they aren't rubbing somewhere. Something has gone wrong in the FASS' wiring or in the stock fuel lines backing up the FASS. Larry said they have had problems with the check ball inside moving, but that usually causes low pressure, not the opposite. I'll talk to him tomorrow to see if we can figure it out or if they just need to send a new pump.

FASS' website boasts my particular model of being able to run upwards of 165 psi. It seems that a spring change in the regulator backs that back down. Kindof strange that I didn't have a problem until now. Perhaps something broke in the area of the pump that pressurizes? Maybe my fuel leak on the frame got to some of the FASS wires?

I should look at the bright side, my CP3's aren't starving.

 

[sweetdiesel]

I noticed the FASS sounded different the past few days. It's usually more noisy and changes tones. With this problem it has had a constant sound. With the FASS off, the truck idles normal and sounds normal and has normal rail pressure.

I'll have to trace the wires to make sure they aren't rubbing somewhere. Something has gone wrong in the FASS' wiring or in the stock fuel lines backing up the FASS. Larry said they have had problems with the check ball inside moving, but that usually causes low pressure, not the opposite. I'll talk to him tomorrow to see if we can figure it out or if they just need to send a new pump.

FASS' website boasts my particular model of being able to run upwards of 165 psi. It seems that a spring change in the regulator backs that back down. Kindof strange that I didn't have a problem until now. Perhaps something broke in the area of the pump that pressurizes? Maybe my fuel leak on the frame got to some of the FASS wires?

I should look at the bright side, my CP3's aren't starving.

If it is OK at idle with the fass off...you could use a hobbs switch and bring on the fuel pump vs boost...Just another option

I didnt think Fass pumps would allow flow though them with out power?

 

[DrededSS]

If it is OK at idle with the fass off...you could use a hobbs switch and bring on the fuel pump vs boost...Just another option

I didnt think Fass pumps would allow flow though them with out power?

I thought that too, but I did some reading on other sites and it looks like FASS changed that a year or two ago. That's why I was able to let my truck idle today without any issues with the FASS turned off.

I'm fine with using a switch or regulator if needed. But something has still gone wrong that I need to find. It wasn't doing this until this week. Gotta be a wire or something inside the unit itself.

Diesel-Dan isn't on this site yet, so I had to make a post at that other place.

 

[GMC_2002_Dmax]

See my post #35. I took off the belt to take the PPE CP3 out of the equation. Plugged in or not with the belt off, same 11,500 psi out of the Industrial Injection unit in the stock location. It is a modded CP3. Not sure what PPE does to theirs. The PPE unit is wired into the factory harness, which means they are not regulated independently.

With the FASS off in any combination of CP3, the desired psi does equal the actual. With the FASS off and the belt off the PPE CP3, desired psi does equal the actual. Pretty much if the FASS is off, the desired does equal the actual. I'm trying to find my harness to hook up a higher psi gauge on the FASS to see if it has spazzed out.

If I can get a friend over here, I'm going to unplug the return line at the engine and run it to a jug. There are no kinks though.

And please don't take this the wrong way, but I think a couple of you are treating this problem as if I installed something new on the truck and found this problem. I have 1,000 miles on break-in and another 5,000 trouble free miles. All of that on pretty much the same tunes. And the stock tune acts the same as my daily driver as my race tune.

Are they matched CP3' ?? Both LB7 just one modded and one stock ???

The reason I asked is because the amp scaling differs from LB7-LLY-LBZ and once you mod the regulator and or CP3 the whole way of looking at tuning it changes.

here is your post:

Tests:

FASS on, PPE on, Industrial on: Idle PSI 18,000

FASS on, PPE off, Industrial on: Idle PSI to 26,000

FASS off, PPE on, Industrial on: Idle PSI to 6000 (desired)

FASS on, PPE on, Industrial off: Idle PSI to 26,000

FASS off, PPE on, Industrial on: Idle PSI to 6000 (desired)

The common denominator is the FASS being on, both CP3's running the desired psi is in line with actual.

Now I am confused, you stated above this:

Plugged in or not with the belt off, same 11,500 psi out of the Industrial Injection unit in the stock location.

So which is it ???

Does it maintain 6000 psi or 11,500 ???

Tony

 

[GMC_2002_Dmax]

That is a really good way to do it But correct me I am wrong I think he would also have to unhook the controller and not just the belt?

As Tony said logging milliamps is good too.IMO its a little better than rail pressure in this situation.And ajusting these milliamps make big changes so it can be time consuming but worth it in the end

at 15 psi you are pushing the regulators open...They where never made for pressure,Even at 3-4psi your milliamps will change from the regulator trying to compensate it is just less noticable unless you are actually looking for it

Good info Tony

The controller just splits the control and amplifies it so it has enough power to run both regulators, I never tried to diagnose it with it disconnected and removing the 2nd CP3 belt disables the CP3 completely.

I learned a long time ago that when troubleshooting you need to figure out a plan, execute a series of tests and then analyze the results, then use a process of elimination until you achieve the desired results.

I have had the opportunity to tune many modded trucks and have learned a few things along the way.............I think that the fix it doable but there is still some missing info regarding what the pumps are and what regulator mods are.

 

[IdahoRob]

Remember the truck ran trouble free for many miles with good idle rail pressure and no lope. I did work on his idle pressure way back when.

Nothing changed in tuning or hard parts and the problem popped up.

I don't see that the problem is in the tune, but I've been wrong many times before. FASS is off and it runs like it should, FASS is on and that brings on the problem, my guess now is the FASS pushing through the regulator. Lee, I agree that something changed in the pressures on the lift pump.

 

[DrededSS]

Now I am confused, you stated above this:

[/COLOR][/COLOR]Plugged in or not with the belt off, same 11,500 psi out of the Industrial Injection unit in the stock location.

So which is it ???

Should have written as this: "With the belt off and PPE electrical plugged in or not, same 11,500 psi out of the Industrial Injection unit in the stock location with FASS on."

The Industrial unit is modified. I do not know what the PPE unit is setup for. However, Mark assured me the difference in the two would not matter due to the way he set things up. And as Rob said, there have been no problems until now. Dallas at Industrial also was sure the FASS was pushing through.

I can definitely say that I have learned a lot through all of y'all's ideas.

 

[DrededSS]

And I just got off the phone with Larry at Danville. I hadn't told him about the 100 psi until this morning. He's 99% sure he knows what is wrong with my FASS unit and is mailing the fix out to me.

I'll let y'all know how it goes. Thanks again for all of the ideas and help.

 

[McRat]

Running "mismatched" CP3's won't hurt anything that I've experienced. Until recently, I always was running mismatched CP3 of various combinations. Now I have two Wicked Diesel strokers.