Well, I just finished my SVO conversion on my 87 F250 6.9 and have been running it on veggie for about 2 weeks. I believe that the oil get plenty hot because it runs through a hose in hose coolant sleeve, a coolant wrapped filter and a plate plate heat exchanger before the solenoid that goes to the IP.

I replaced the IP and all injectors with rebuilt units last year and have put very few miles on the vehicle since then. Basically I have just used the truck for short distance deliveries for work, but in the last month it has become my daily driver as my other vehicle is down.

So, in the past few days the truck has started idling rough, and now smokes heavily when i start it up. Seems to drive ok, and once its warm the idle settles down but still seems to miss a little. Im worried the veggie oil may have messed up the IP or injectors?

I have some clear fuel lines, going from the diesel filter to the IP and through out the veggie oil side, from what I can tell, there is no air in the lines here. However, it may be air is getting in at the injectors so plan to investigate that this afternoon.

Any suggestions or ideas would be appreciated, especially from fellow veggie oil drivers. I have heard these pumps are especially weak, but cant imagine driving a few hundred miles on SVO would wreck any seals or even coke injectors that quickly!

Hoping its a simple fix, cant put a whole lot of time or money into this thing at the moment, however need to have a vehicle for work...

Thanks!
- Ben

 

if you are starting on diesel and switching back to diesel be fore shut off. be sure to run it long enough to clear out the veg or it will start hard and smoke on start up.. the engine consumes only 8 oz per minute at 60 mph so much less at slow speeds or idle...

 

I hate to say it, but rebuilt injectors -- Unless they came from R&D -- are junk!
They are just worn out injectors that have had their pop pressures brought up to 'nominal'. A little ways down the road, they will be all over the place again, because they probably didn't all have the same amount of wear on them.
To properly rebuild an injector, you need a new nozzle and pintle, the wear parts. Only R&D has new ones currently(had them custom made), since the previous manufacturers stopped making them.

Back when I was nieve, I had a set of rebuilt injectors... never again. Within 20K, I had 1 total failure,
several leaking, and the pressures varied by 400 PSI or more. (Injectors should be within 100 PSI of another worst case).
The ones I've gotten from R&D are /much/ more reliable and consistant. Pulled them after like 20K and found the pressures all within 50 psi of what they were brand new. All working /right/.

 

^ good advice - shut down and startup on diesel .. and only using quality parts from a reputable re-builder

how are you de watering your svo .. to what micron level are you filtering out the particulates .. these pumps and injectors are not weak if built by someone who does a good job .. as you say it was running well .. then starting crapping out .. i would suspect the fuel

svo .. if not ABSOLUTELY and thoroughly cleaned of water will very quickly wear out an pump .. like can be destroyed internally within just days from rust damage

i have looked and continue to look into svo as it's a great fuel source .. but you must clean it well .. when and if i do this it will be processed by boiling water out with a 55 gallon drum immersion heater mill surplus from camp mess hauls ..

followed up with centrifugal separation and multi pass particulate filtration

i don't know your setup maybe you are already doing this and more

but if not ..

just hit the gas pump and work on your dewatering and filtration station

 

Yes I have been purging the fuel system for adequate time, I make certain of that. Thanks for the fuel usage info though!

I am also settling the oil for 10+ weeks then having a friend run it through his centrifuge, and then through a couple polishing filters down to 10 microns when I pump it into the tank, so Im hoping water and particulates are thoroughly removed. I've been running VO in my isuzu pup for over 10 years with great success, so this has me double guessing whether or not it was caused by the VO or coincidental timing?

Yeah you gotta be skeptical of $25 injectors! If that is the culprit then I learned my lesson and will order new ones tomorrow! Where do I find R & D injectors?

Some updates, yesterday I poured a bottle of diesel kleen in the 1/2 full front diesel tank and ran the truck for a while, went up and down the street, etc. Once it warmed up it still stumbled a little at an idle but the smoke went away. Performance above idle seemed fairly normal.

Today I drove the truck probably 40 miles to work and school only on diesel. Started this morning with a lot of smoke and rough idle, but again once it warmed up there was little smoke at idle, still a little stumble in it but sounded normal. I noticed at driving ~1800 rpms it sort of revs up on its own in short cycles like Im accelerating to a rhythm or something. About 1/2 mile from the job site it lost power and almost stalled but caught up with itself and I rolled into work.

Smokey start when I went to leave at 3:30, on the drive to school I noticed that the idle was sounding and feeling totally normal, still revving strangely at higher rpms but the rough stumble at idle was gone. Got less then a mile from school and it stalled out. Started it after a bunch of cranking, rolled a few hundred feet, repeat. Got it running and got to class. On the way home it died again and this time it took 20 minutes to start again, after which I had noticed air in the fuel line and fuel on the bottom of the diesel filter.

Got it home and put on a new fuel filter, ran engine for a while at different rpms... It now seems to smoke and stumbles at an idle, but above 1000 rpm runs real smoothly.

I do have a fuel pressure/vacuum gauge installed right before the IP so I can monitor changes in pressure on both VO and diesel systems. The needle was acting different today, showing that it was pulling harder as if the filter was clogging. It usually runs at between 5-7 psi of pressure (I assume because of the mechanical lift pump?) but today was swinging sporadically down to 2 or 0 occasionally under load.

Soo, I didnt test drive it, needed to eat and decompress but may do that tonite before another 40+ mile drive tomorrow. Its been losing steam in fairly convenient places (where I can pull off and not block traffic) but if this keeps up Im sure my luck will run out soon!

Any ideas or theories?

thanks!

 

Filter may be plugged, and/or you have an air leak somewhere?

Also, R&D - R&D IDI Performance - Home

 

well this is a long shot .. but just throwing ideas out there .. really i don't have a clue .. from what i read in one of r&d's posts .. fuel pressure effects pump timing .. maybe if you'r fuel pump is weak and surging that would effect how it is timed at different rpm ranges .. and cause timing issues at different ranges depending on what the pumps doing .. but from what i understand .. usually a mechanical pump works or it doesn't so that may not be it at all .. but maybe

maybe try a 5psi (i think that is the optimal idk for sure) regulated electric pump in parallel to your mechanical pump .. or if your desperate swap your mechanical pump .. i'm not much of a parts swapper to diagnose things .. i think i might try a regulated elec pump from a direct fuel tank straight to the ip .. to see if the problem is unchanged ..

remember if you add an elec fuel pump in series into your existing hose routing .. do so after the mechanical pump or do it in parallel .. not in series before the mechanical one .. and regulate it to 5psi (i think) for optimal timing and power

i think the red bottle of diesel kleen stuff binds to water and allows it to exit the injectors rather then allowing it to pool up on the bottom .. that should clear out any residual water after you've gone through a tank or two .. and eliminate that ..

as Macrobb said .. unfortunately alot of pump re builders suck and maybe you got a pump that is just going out .. that would really be crappy on a new pump but .. not unlikely .. i hope not though .. it's probably 'just out' of warranty ..

and everyone agrees r&d makes the best fuel components and he is a member of the forum so you can probably get a hold of him if you need help with a pump or injectors

just throwing out ideas probably none of the above .. i'm just here for emotional support .. i hope you don't get stranded on a one lane bridge

 

thanks, yeah the surging has me worried. seems like a pump issue, but cant tell for sure. thought about bypassing the mechanical lift pump with small electric fuel pump. really sucks that Ive got my daily driver down for the count, I hate dealing with this stuff on the side of the road...

 

today no break downs but still very smokey at start up and until its warmed up smokes and revs/surges... will keep trouble shooting air leak possibilities.