Hunting airleaks - considering FTB mod while I´m at it?

[svein]

I´m at what I thought was the end to my big project of converting my 6.5 suburban into running on wvo.

I have re-done all the fuel lines (except the diesel return line, I ran out of hose, haha

), and made an almost identical setup for the diesel and the wvo like the following:

Diesel side:
tank->inline plastic prefilter->T out to diesel heater->acdelco ep1000lift pump->coolant heated 10micron filter->selection valve

WVO side:
tank->inline plastic prefilter->acdelco ep1000 lift pump->coolant heated 10micron filter->plate heat exchanger->selection valve

Common, after the selection valve, the lines run like this:
selection valve->electrical heater (for wvo)->T for temp gauge->T for fuel pressure gauge->original fuel filter manager.

From there onwards it´s stock until I´ve connected onto where the rubber hose from the ip/injector return to the diesel hard line was, where I´ve connected a rubber hose to/from the return fuel selection valve. I have a clear plastic pre filter here as well to monitor the return fuel.

I also have fuel pressure gauges between the lift pumps and the filter in both lines.

The truck runs well, and I can read pressure between 4-7psi on normal driving, lowest I´ve seen is 1,5 at WOT, and the highest is 8ish with lift pump running and engine off. However, it dies after a while (like 5mins of calm driving) when I am running it on WVO, and I can see that it sucks air somewhere even on the diesel side.

I can see some very small air bubbles being sucked into the pre filter on the dieselside - almost invisible. On the filter on the return side, however, a rather large air bubble comes into the plastic inline filter every 5-10s.

I´ve been trough all the connections I´ve made and re-tightened them, without any luck, so I fear that it might be sucking air either from the fuel filter manager, or from the line from the FFM to the IP.

I´ve bought clear tubing for testing purposes, and I am taking the sub to a shop on Monday to try to hunt down the air leak(s) again in temperatures above freezing, but all this doing my regular job and not being able to play with my car has led me to thinking (a bit to much), so I have some questions I´d like to ask:

1. The plastic inline filters do not fill up with fuel. On the feed side, it´s a small air bubble, and on the return line a much bigger one. When I´ve been driving the truck, and I stop and idle for a while, it fills a bit, but still with a large air bubble. Google has told me that air bubbles in inline filters are completely normal and not dangerous. Any opinions here?

2. The diesel return line is the original line, so it can definitively have some leaks I haven´t seen. I´ve been reading up about it, and some people say it will affect the fuel system, some claim it doesn't´t matter. Opinions?

3. If my next quest for the air leak(s) doesn't give results, the only thing I haven´t exchanged or improved is the FFM and the line to the IP. I´d have to order the seals for the FFM from the US, so I´m considering ordering a kit for the FTB mod to do it while I have the FFM out anyway. It would make it even easier to T in a fuel pressure gauge AFTER the FFM which I am quite keen on having. However - my budget for this project is well spent, and I can´t really see myself buying new lift pumps again as well. Would the FTB mod work with the EP1000 lift pump, or is that asking for even more trouble?

Thanks for all answers and guidance. This newbie is learning every day on this forum!

Cheers,
Svein

 

[Will L.]

Get rid of the small lift pump. 9-14 psi is your target.

Sae30r9 fuel line. Replace the rest of the system you haven’t done yet and have it all reliable.

Yes on FTB

Yes on pressure gauge- as close to the ip inlet as possible, keep inind not to disturb flow. I am doing my next one as electric gauge, pressure sensor at ip inlet and another before the fuel filter so I can use 1 gauge & 1 switch to read filter restriction for filter changes.
With your system, multiple sensors and a rotory switch could be helpful. Someone here did theirs like that- drawing blank as to who...

Finding leaks under pressure is always easier than under vacuum. Pressurize the system- but very lightly to not damage tank. Possibly remove supply line from tank, plug at Injection pump & pressurize.

 

[FellowTraveler]

I like AN fittings w/teflon AN hose for all fuel lines when done properly they last a very, very, very long time. In your colder environment the AN teflon hose can be covered with a good quality pipe insulation too.
A heat exchanger tied into your heater lines and fuel supply work well It must be a good quality stainless or titanium unit.

 

[svein]

So, to day was a success! At least to some extent.

I´ve found the airleak. The airlock was ironically enough, in the temp. filter junction I used to measure the airlocks. I put it under water, and the air leaks stopped. Got rid of my temp. clear hose and sealed it up. Turns out my delivery system is all good! What a relief!

I also went trough all my sensor fittings, opened all the 1/8 not ports and resealed them with thread sealant instead of thread locker. Don´t know if it made a difference, but it feels good. At least my truck runs healthy.

Did another test run on wvo - that didn't go so well, the truck stopped after about 15mins of running.

I really think it is a delivery problem - Suddenly I have "no motor" on the pedal and it looses power. I´m considering to go for either a carter pump or a walbro frb-5. I think it would be worth it. And I should buy three, one for the diesel, one for the wvo and one spare. Always one more.

Any opinions on lift pumps are more than welcome!

Cheers,
Svein

 

[Will L.]

Leroydiesel.com on your pump(s).

@Hink wvo input ?

 

[Hink]

@Hink wvo input ?[/QUOTE]

On initial start up after conversion, it took me quite a few miles to really get the oil in the system to the injectors. I drove 70 mph on the freeway switching back and forth for several miles before it caught and stayed running on the oil. Of course, a smart person would have cycled the oil all the way to the point it enters the stock fuel system (likely the pollack valve) beforehand , but hey.

You absolutely need to know that your oil is up to ~195* at the IP input. Or else it will be too thick. You can get it too hot and will likely grenade your pump at the rotor. Don't ask me how I know.

I use a walbro FRB-5 from Leroy as my main pump and them have a secondary, stock style pump that kicks in tandem when I engage the WVO. Even though I have my oil heated from the tank forward, I wanted to make sure that I was not overly taxing my main LP with the thicker fluid. I would not use only one LP for the vehicle.

 

[svein]

Thanks to the both of you for chiming in! I really appreciate it!

@Hink wvo input ?

On initial start up after conversion, it took me quite a few miles to really get the oil in the system to the injectors. I drove 70 mph on the freeway switching back and forth for several miles before it caught and stayed running on the oil. Of course, a smart person would have cycled the oil all the way to the point it enters the stock fuel system (likely the pollack valve) beforehand , but hey.
[/QUOTE]

Hehe, I considering the "burping the baby" method, but so far I´ve been a good boy and primed the system before testing it by 1st running the truck up to operating temperature and then bleeding the air out trough the T-valve drain in the front.

@Hink wvo input ?

You absolutely need to know that your oil is up to ~195* at the IP input. Or else it will be too thick. You can get it too hot and will likely grenade your pump at the rotor. Don't ask me how I know.
[/QUOTE]

I am pretty confident that I am having the oil up to proper temperature. I´ve not switched until my truck is up to proper temperature. That gives me a reading of 80-84degrees C (about 176-185f) on the heated filters on the side of the truck. My coolant gauge in the dash shows roughly 194 at this point. From there, the vo runs trough a heat exchanger, then the selection valves and at last trough a plant drive vegtherm multipass before going trough the original filter.

This is a picture of the "filter bank" I have put on the drivers side of the truck still on the work bench: Red lines are diesel, green lines wvo.


And a shot of my valves and electric heater:

I am however struggling with getting proper readings on the fuel temperature. First, I tried T-ing in a temp sensor to the fuel line, but there was no circulation what so ever to the temp sensor, so it would gradually rise with engine temperature, but never really show any readings on the fuel temperature. Tried another way yesterday; ziptieing a probe to one of the injectors line, but with basically the same result. Any good tricks on how to get a proper reading of fuel temperature would be highly appreciated!

@Hink wvo input ?

I use a walbro FRB-5 from Leroy as my main pump and them have a secondary, stock style pump that kicks in tandem when I engage the WVO. Even though I have my oil heated from the tank forward, I wanted to make sure that I was not overly taxing my main LP with the thicker fluid. I would not use only one LP for the vehicle.[/QUOTE]

At the moment, I am running two ep1000 lift pumps - one for diesel and one for the wvo, in complete separate systems. It seems to me like the main problem with the veggie is not getting enough fuel - so I´m thinking a lift pump upgrade would be the next step to try to get it to work. I´m thinking I can go two ways here: either use the cheap carter pump, and replace it when it dies - OR, buy a bigger expensive pump like the raw fuel pump for the veggie side, but that would need some extra fundings, haha. The joker in my consideration is of course the FRB-5. Maybe that´s the pump I should go for both on diesel and the veggie side? I´m not SO concerned with strain on the wvo pump as the pump on the diesel side will never have to push any wvo, so if (when) it fails, I can always run on diesel till I get a replacement.

 

[FellowTraveler]

Have you considered a heat exchanger equipped for AN fittings then a temp probe can be inserted into the fuel line..or?

 

[Hink]

I´m not SO concerned with strain on the wvo pump as the pump on the diesel side will never have to push any wvo, so if (when) it fails, I can always run on diesel till I get a replacement.

That's why I set up the system the way I did. My entire stock fuel system is untouched except where it T's into the fuel line at the Pollack valve. All filters, heaters, extra pump, and Pollack valve is it's own system, then it T's in (the Pollack valve is essentially the T). This way I have the advantage of the secondary pump working in tandem which lowers the workload of both, and if there is ever a problem with the system, the stock side works completely as normal.

 

[svein]

Have you considered a heat exchanger equipped for AN fittings then a temp probe can be inserted into the fuel line..or?

I have a heat exchanger from plantdrive, that has some 90degree hose barbs on it. Would AN fittings help me - or would there be a trick with a temp probe I haven´t understood?

I originally ordered a T fitting with a nut 1/8 port, but the temp sensor was way to deep to get to the threads. That´s why I tried a hose T and put the temp sensor into the hose upwards and tighten in with a hose clamp. It didn't give much of a reading. I´m thinking I might need to fabricate my own little box with a 1/8npt port deep enough for the temp sensor to fit. Unless anyone have any other better ideas?

That's why I set up the system the way I did. My entire stock fuel system is untouched except where it T's into the fuel line at the Pollack valve. All filters, heaters, extra pump, and Pollack valve is it's own system, then it T's in (the Pollack valve is essentially the T). This way I have the advantage of the secondary pump working in tandem which lowers the workload of both, and if there is ever a problem with the system, the stock side works completely as normal.

So if I understand you correct, you T into the system before your diesel side lift pump?

 

[svein]

I should probably create a new more wvo related thread by now, but it feels like it makes sense to continue the discussion here. Please let me know if I should create a new thread instead!

Had a bit of a day today. Was supposed only to be thinking about which lift pump to install, but then my girlfriend called me cause the car was stopping. Turned out to be a blocked LP pre filter on the diesel side. Good thing I have that filter there, cause the new fuel tank I bought "only used 4 months" is full off all kinds of crap, and even though I did a good cleaning of it before putting it up it gives away fresh debris all the time. *sigh*

Anyway, as tonights plans was cancelled, I did another wvo test-run after having gotten some tips to try from plant drive who sold me the wvo parts. He did not think the lift pump was the problem since the truck was ideling well, but was mentioning the following possible problems:

1. Tank venting
2. Temperature.
3. WVO side still magically sucking air

My tank is in stainless steel under the car, and it has this tank vent mounted at the rear side of the tank, near the top, so when the 90degree bend is upwards, it has a couple of mm to the tank top. I tried rotating it 45 degrees on the test-drive today, without any luck. https://seatronic.no/vvs/toaletter/monteringsutstyr-toaletter/lufteventil-for-tank

Tank vent seen inside the tank:


The tank under the car:

It being -10C outside, this could obviousily be a bit of a problem. Before switching, I put my hand on the tank and the entire thing was nice and warm - at least warmer than my hand.

I had to drive for a good while to read 80C at the temp sensors on the two vm2 filter bases on the side of the car. The temperature drops quickly down to 60-70 when ideling, but when I kept it going at 1500rpm standing still I was reading about 70C.

I used 2 mins to do the switchover - 10s on/off vo in for the vegtherm to really get to work before I switched over. Then I idled for 10 minutes, last 2 mins keeping 1500 rpm. After that, I was able to drive pretty exactly 5mins before it died.

I have two pressure sensores tied in the system at the moment, one in the P port of the vm2 filter reading lift pump pressure, and one after the vegtherm just before the original filter. When I was ideling, they were both reading around 4,5psi, while I get 7psi running at diesel, so that seems like an acceptable difference due to the veg oil. When I was giving throttle in slight uphill, The pressure at the gauge just before the filter quickly dropped down to 1,2-1,5 while the pre filter was showing about 3. This tells me I need a stronger pump for the veg oil (and the diesel side) no matter where my veg oil problems might be.

When the truck finally died, I did as suggested by plantdrive, and jumped the lift pump for the veg oil while opening the drain valve on the fuel filter manager.. It seems like the filter house was empty - it took a while before anything came out, but when it did, it was a nice sizzling stream of veg oil. I double checked the drain valve from the bottom of the filter, and I was getting just as much veg oil as I usually do with diesel.

What do you think guys? am I still sucking in air somewhere, or is the LP just not delivering enough fuel fast enough?

 

[svein]

...I couldn't hold myself, so I now have two walbro frb-5s on the way. Exciting times!

 

[Hink]

So if I understand you correct, you T into the system before your diesel side lift pump?

Yes sir.

 

[tanman_2006]

Welcome to TTS!

 

[FellowTraveler]

I have a heat exchanger from plantdrive, that has some 90degree hose barbs on it. Would AN fittings help me - or would there be a trick with a temp probe I haven´t understood?

I originally ordered a T fitting with a nut 1/8 port, but the temp sensor was way to deep to get to the threads. That´s why I tried a hose T and put the temp sensor into the hose upwards and tighten in with a hose clamp. It didn't give much of a reading. I´m thinking I might need to fabricate my own little box with a 1/8npt port deep enough for the temp sensor to fit. Unless anyone have any other better ideas?

So if I understand you correct, you T into the system before your diesel side lift pump?

The good thing about AN fittings is that temperature probe adapters are placed at the fittings and accept standard probes both electric or mechanical. There are NPT compression adapters that will tee a probe into hard lines too.

IMO 90 degree fittings need to be a smooth radius type not a sharp right angle which inhibits proper flow of fuel.

Is there a heat exchanger inside aux your fuel tank too? I noticed it is similar to my tank.

 

[svein]

Welcome to TTS!

Thanks! I found good help here - thank you so much for inviting me over!

The good thing about AN fittings is that temperature probe adapters are placed at the fittings and accept standard probes both electric or mechanical. There are NPT compression adapters that will tee a probe into hard lines too.

IMO 90 degree fittings need to be a smooth radius type not a sharp right angle which inhibits proper flow of fuel.

Is there a heat exchanger inside aux your fuel tank too? I noticed it is similar to my tank.

I have a very simple heat exchanger in the tank, yes. It´s just a 10mm pipe running trough the bottom of the tank to preheat the veggie some.

Plantdrive also tipped me about looking for sharp bends and kinks in the hoses, so that´s definitely onto the list for next time I find some time in a shop!

I really need to look deeper into the AN-fitting world. I found a fitting yesterday that almost got me there, but I couldn't find the rest of what I need to connect onto a 3/8" line. Gotta keep looking. Although, the thought of fabricating a custom Tee with port for both temp and fuel sensor (thus eliminating a couple of hose clamps) tempts me more and more. Either I find a prefab solution soon, or I´m gonna start talking to my multi talent welder-friend about it. haha

http://www.getfast1.com/FRA-495030-...al-Probe-Oil-Coolant-Temp-Adapter_p_4854.html

 

[FellowTraveler]

Thanks! I found good help here - thank you so much for inviting me over!



I have a very simple heat exchanger in the tank, yes. It´s just a 10mm pipe running trough the bottom of the tank to preheat the veggie some.

Plantdrive also tipped me about looking for sharp bends and kinks in the hoses, so that´s definitely onto the list for next time I find some time in a shop!

I really need to look deeper into the AN-fitting world. I found a fitting yesterday that almost got me there, but I couldn't find the rest of what I need to connect onto a 3/8" line. Gotta keep looking. Although, the thought of fabricating a custom Tee with port for both temp and fuel sensor (thus eliminating a couple of hose clamps) tempts me more and more. Either I find a prefab solution soon, or I´m gonna start talking to my multi talent welder-friend about it. haha

http://www.getfast1.com/FRA-495030-...al-Probe-Oil-Coolant-Temp-Adapter_p_4854.html

I actually buy most of my AN items from getfast they have great service too. There are AN to steel tubing compression adapters that work well.

 

[svein]

Bumped into my welder multi mechanic artíst friend on work on Saturday....met him again at the warehouse yesterday, and three hours and a lot of talking later, this little wonder saw daylight:
Can´t wait to install it and get some proper temp readings!

 

[svein]

So after I got home from my holidays last week, I had gotten the new walbro frb-5 pumps and parts!

Got to it today, thinking it was gonna be a big step forward in the wvo-world. I was wrong.

The new walbros give me only 4psi at the pump head, sometimes even down 2.8 to just before the fuel filter manager, both on diesel and wvo. It ran for a while on wvo, but died out on me again (as the last time). Driving on diesel felt kind of better compared to the old ep1000 pumps, even though they were able to sustain 5-6psi on normal driving.

I was expecting to see a higher psi output, so I am a bit puzzled about what to do. I am wondering if maybe the hose barb fittings I used for the walbros may be sucking in air, or leaking air, or both? I´ve had some mixed results with these kind of hose barbs earlier in the progress. Would that make sense?

This is the fittings I used. I wonder if it would it be any use in double clamping them? :


I took a shot of the wvo lift pump after I mounted it. The diesel side lp went below it.


The only filter I haven't checked by now is the screen inside the fuel filter manager. I have done an attempt to remove it, but I just couldn't´t get it out and I´m afraid to remove it. I would have thought that if this screen was clogged, the pressure should rise just before it, but maybe I am wrong?

 

[NVW]

My FRB-5 produces 5 psi max on diesel