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Your 6.5 wont run for more than a month on WVO!
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It is cooler here than it has been but still 70's at night and high 80's during the day. I drained about 15 gallons of blend and added about 10 gallons of diesel to see if I can get it running with thinner fuel. Right now I am getting air in the lines so have to figure that out.
Rusty
 
Registered: September 26, 2007Reply With QuoteReport This Post
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I have installed 3 wvo systems in my life none have given me as many problems as my 6.2. I can’t seem to figure out the problem. This is what is going on. I have a 32 gallon tank in back with HOTFOX. Then it hits the Vegmax(Raamco heated filter) then pollak valve then Vegtherm then lift pump then injection pump.

Problem : It seems like I am clogging filters I drive for like 150 miles then it starts to go voom voom voom (Hunting).
Especially when I step on the gas and all of a sudden jump off the gas then it really does it, Some times this produces a stall.
Starts fine Idles fine, but under load it chokes and humms driving me freakin nuts. Also I could drive around town at like 25 to 30 miles an hour without having a problem especially if I am steady with the gas pedal.

Tried to fix it by : Installing a 5-9 PSI electric pump in the back right after tank.
Replaced the hose after the vegtherm with metal fuel line because it was collapsing because of heat(I think).

Your help would be greatly appreciated.
 
Registered: December 12, 2008Reply With QuoteReport This Post
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Is it running fine on diesel, just giving you the problems you describe on wvo? It sounds like a fuel pressure problem to me, that's where I'd start. You need to put a fuel pressure gauge on the T-valve in the front of the engine bay, this fuel line comes from the under-hood fuel filter housing. I have a gauge from Heath Diesel that can be connected, then taped to the windshield so you can see the results as you drive.

Are you running the same lift pump for diesel and wvo? Does wvo go through the under-hood stock fuel filter? If not, you'll have to hook up the gauge elsewhere.

With your electric booster pump you would think there would be plenty of pressure, but I'm wondering if having your vegtherm in the back, before the lift pump, might be causing problems. I have the vegtherm under the hood, in the line between the fuel filter and the IP, so the lift pump is seeing warm fuel, not very hot as comes out of the vegtherm.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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I have run my 1998 6.5 on a blend of gas/WVO/cetane boost. I mix it in 20L jerry cans: 3L gasoline, 100ml cetane boost, top it up with filtered/centrifuged WVO. Runs like a charm as long as it does not get colder than -25 deg C. The engine sounds normal, doesn't smoke, glow plugs come out cleaner than with normal diesel.

I have run this mixture for the past 8 months, during a cold Canadian winter. No unexplainable issues.
When it gets really cold (i.e. -25) the mix becomes too thick for the stock transfer pump to deliver fuel to the IP. Something produces a blockage, I think it's inside the transfer pump. Anyway the IP starts to draw vacuum and eventually starves and unprimes itself. This never tripped a code - contrary to my expectations. It has happened to me a number of times and it's a bit of a hassle to fix this on the road. For emergencies I ran a hose through the firewall and attached it to the fuel test port on the water neck. Inside the cab I had a 20L jerry can with fuel, that the IP could then draw from when necessary. At least that got me to the next gas station to fill up with regular diesel and dilute the mix in the tank. I understand that crap like this shouldn't happen too often Wink

So far my IP seems to have lived through the ordeal. Recently I got a hesitation/miss problem, which slowly got worse. It's only when the engine is warm and under load. No codes on the computer. I suspect it is the PMD, not so much the IP itself. The symptons sure look like a PMD problem. My PMD is on a heat sink on the intake plenum - I will relocate it behind the grille for better cooling.

In summary, I cannot agree that the DS4 pump fails within one month. On this one I think it is perfectly worthwhile to install a two-tank system. Looking forward to starting the project this summer.
 
Registered: April 20, 2009Reply With QuoteReport This Post
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mnahas, when you post with an ending statement "Your help would be greatly appreciated", you'd think when someone replied you might continue the thread. Not sure if you are still around, just thought I'd mention it.

5point9, I wanted to update the thread and agree with you. I replaced my IP (DS4 like yours) back in October, have run clean dry wvo in a 2 tank system since, and I'm running fine with no problems. I'm always tweaking things a bit, making small changes, but I've run maybe 12,000 plus miles on wvo now and am still running strong.

So, if I were you I'd go ahead with your 2-tank project, just make sure you burn very good fuel!

David


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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I think I have diagnosed my problem with the engine missing. I don't think it's the PMD or the IP - it's air getting into the system. I disconnected the fuel return line at the back of the engine and attached some clear tubing draining into a jerry can. I am not getting much return flow. There also gas bubbles coming out of the return port and as the engine warms up it starts to miss. After a miss it will take 15 seconds +/- and about 20 air bubbles come up through the tubing. The engine seems to be missing because of air getting into the fuel supply. I think I have an issue with fuel supply pressure. Go figure.
Question: I'd like to know what you guys are using for aftermarket fuel transfer pumps? Is there anything you would really recommend, maybe something that fits into the stock location without much tooling required? I was thinking some Walbro high pressure EFI unit...

I will post this elsewhere in a more general thread.

Thanks.
 
Registered: April 20, 2009Reply With QuoteReport This Post



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I'm using a Walbro FRB-5 lift pump, and highly recommend it. You don't want or need much pressure on a 6.5, no more than 10-12 psi and 6-8 is fine at idle, and OK to drop to 3-4 psi under load.

You probably found the problem with the air leak. A few months ago I could run on diesel but not on veg, it would run for 5 minutes then start to sputter, I could keep it going for another minute or so then it would die. Turned out my vacuum gauge on my racor filter, which has a tiny plastic line to read vacuum, had abraded on a steel edge and had a hole in it, would slowly let air in when I switched to veg.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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It's funny though that I still have positive fuel pressure at the fuel test port. The fuel test port goes down to the bottom of the fuel filter and can be used to drain water from the filter housing. I would think that since the fuel system is somewhat pressurized fuel should leak out rather than air being drawn in. I will run clear lines in between the filter and IP and the supply line up to the filter. Then I can see where the air gets in. I hope it's not in the IP....bad seal or something. Can these be fixed on the work bench at home without screwing up calibration?
 
Registered: April 20, 2009Reply With QuoteReport This Post
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You're right about it being pressurized, so you would think the leak would be before the lift pump, I'd check your hose from the tank forward, especially the lift pump inlet.

If you see air bubbles on your return to tank line, do you see any from the filter drain line that you mentioned?

I don't think you'll be able to fix your IP yourself, at least I haven't heard of anyone being able to do that. Lets hope your IP is OK and the problem is elsewhere!

Earlier you mentioned that it seemed like a PMD problem. Do you have a spare PMD you could plug in to eliminate that, after of course you tackle the possible air leak? Once a PMD starts going bad you won't help it by re-locating it, you'll need another one. Either way you ought to re-locate it now, get it away from the engine heat.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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Yep, I did all that.
I have a spare PMD and changing it does not make a difference. Clear lines between the fuel filter and IP intake show no air coming in upstream of the IP. Clear lines between the IP return port and the fuel return rail show air coming out of the IP. Mostly it's just fizz, which is normal according to our local diesel injection specialist. Just every once in a while there is a larger bubble coming out, coinciding with a miss just prior to that. Recently missing has been much less of a problem, given we had warm temperatures. Generally it seems to get worse with increasing fuel viscosity and load on the engine (climbing a hill). My diesel injection guy suggested it is a bad seal around the input shaft, which is a common problem these pumps have and not particularly related to veg oil or mixtures. High viscosity fuels just precipitate the symptoms more, since the vane pump inside the IP labours more against partial vacuum. The rest of the IP is most likely ok, but what does it help when you have to tear the whole thing down to reach that damn seal and then reassemble and calibrate the IP. It's cheaper to buy a rebuilt pump from the US than have work done locally. For now it works ok, just driving around the city with it, picking parts for my two-tank system Wink. Chances are once the viscosity problem is solved the miss will clear right up.

Oh by the way, last week I got a P0251 code (fuel metering issue) on the computer (check engine light on), which I have had a number of times since GM put this particular IP on the truck on warranty. Whenever they looked a that they can't find an issue with the pump and the code would clear fine and not come back for 6-8 months. Same thing this time, I erased it and it's not coming back. I have had this issue for years.
 
Registered: April 20, 2009Reply With QuoteReport This Post
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I had the same problem with air bubbles in the return line after the IP. In my previous post I mentioned problems I was having with poor idle, lurching on deceleration etc. I tried everything, pump, filters, thought it was vapor lock due to running rug in my blend everything I could think of. Finally the surging got so bad I could not even drive it, it would barely run, puffed out lots of smoke and lurched terribly. I realized the only thing it could be was the IP, I replaced it and everything was great, better than ever, more power, better mileage, everything! I had been plagued with problems since day one with this engine so I am sure the IP was on it's way out the entire time.
I have since sold the car but put another 4-5,000 miles of blending on it before selling it without any problems.
Rusty
 
Registered: September 26, 2007Reply With QuoteReport This Post
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Actually, throughout much of this past summer and fall I omitted mixing gasoline into my fuel blend, just to see what difference that makes. It is quite the difference - no more hick-ups and no more bubbles coming out of the IP, except for the normal fizz. Problem solved I guess. Just thought I should update people on that. If you get hick-ups when you blend with gas, omit the gas!
It's logical in some respect. I experienced hick-ups when the engine was warm; heat typically volatilizes gas, as we all know. If the resulting bubbles make it into the injector lines, why wouldn't that cause a miss??
 
Registered: April 20, 2009Reply With QuoteReport This Post



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I have had an example of a failure now. Here is the link of a thread I posted:
http://biodiesel.infopop.cc/ev...=464103724#464103724

Hope this will work.
Keep in mind that the IP in this truck worked without any kind of conversion system. I had sold it a few months prior to failure and the pump was subject to some other abuse after that. Hats off to this pump, it did great. Oh, and it lasted a lot longer than a month.
 
Registered: April 20, 2009Reply With QuoteReport This Post
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quote:
Originally posted by Donniej:
1993 and older 6.5's are mechanically injected.
1994 and newer are electronic.


Not true. All 6.2 - 6.5 Diesels are mechanical. The later models had digital controls, but are mechanically injected.

Surprised no one caught this.


________________________________________________________
Has anyone converted a W210 Mercedes to use SVO?
http://biodiesel.infopop.cc/ev...=857104535#857104535
 
Location: Arlington, Va.  | Registered: October 14, 2009Reply With QuoteReport This Post
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Wow, talk about bringing back a thread from the past!

I think he was just referring to the difference between db2 and ds4 IP's, and in that sense he is correct about mechanical vs. electronic. '94 up with the ds4 uses the optic sensor and electronic input for control, older db2 has the simpler old fashioned mechanical control. I'm not sure I'm stating that correctly, but you get what I mean hopefully.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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Ummmm... kinda true. The 2008 Optimizer 6500 that I put in my Suburban came with a mechanical lift pump and mechanical injection pump. Smile


Blessings. Joe 1999 Chevy Suburban w/new optimizer 6500 TD and 1995 Chevy Cube van 6.5L. WWW.RillaBioFuels.com
WWW.RillaBioFuels.com
 
Location: Sterling Hts. Michigan USA | Registered: October 18, 2001Reply With QuoteReport This Post
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Joe, the Optimizer came with a db2 injection pump? Was that a special request on your part? I thought they came with ds4's.

The electronics on the ds4's were flawed right from day 1. GM of course never figured it out, it was the aftermarket that learned that remote mounting the PMD in cool air flow, with a heat sink, solved much of the problem.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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The optimizer comes turbo, NA, or supercharged. Mechanical or electronic injection. Mine was mechanical. I don't know if it is a DB2 or not, I didn't use it. It has a cable operated throttle. It also has a 24 volt shut-off solenoid. I still have it in my garage.Here is a link to General Engine Products. Smile


Blessings. Joe 1999 Chevy Suburban w/new optimizer 6500 TD and 1995 Chevy Cube van 6.5L. WWW.RillaBioFuels.com
WWW.RillaBioFuels.com
 
Location: Sterling Hts. Michigan USA | Registered: October 18, 2001Reply With QuoteReport This Post



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