My Suburban has a two tank system and runs WVO. Last fall after about 2K miles running WVO I started having starting problems which I called cold starting problems. It was confusing as I wasn't sure if it was my running the WVO that was doing damage to the vehicle or what. I had owned the truck for 1 year at this point and it always started great even in the cold of the winter here in Vermont. Well I stopped running WVO last winter so that I could make it through hopefully and I did. It was weird as I found that if I started the truck mid day or right before going to bed at say 11pm then it would start OK about 7 hours later. I replaced what I believe to be original injectors and IP with 182K on them, and swapped my lift pump to a holley blue pump. It seemed at times like a made changes but none that really lasted. It was actually getting worse to the point where the intial crank would have no firing, so I'd crank and crank. The fix? Simple. Air in the lines due to about 4 different leaks. Most due to the Swagelok comression fittings which I didn't use the barbed inserts in as I didn't want any reduction in the ID or the line. I may replumb at some point and try the inserts. For now the fittings are cranked down tight, basically overtightened, but they don't leak air. When these were leaking air I saw no signs of fuel leaks. I also was using an isolator for my fuel pressure sensing. It's the kind that has a rubber bladder so that the line going to the cab has antifreeze in it. Well the isolator had an air leak so I removed it and now have diesel in the line coming into the cab. At any rate I can part the truck now and after sitting all night I have no air and starts perfectly! Before I would start to see air right away after shutting the engine off, that's how bad it was. Oh, to clarify things a little many of my fuel lines both WVO and diesel are teflon tubing which you can see through.
Moral of the story is that Dave has learned how important air leaks are in a diesel and how much the IP hates air.

So the veggy is back on! Did a 1,100 mile round trip excusion to Maryland last week all on veggy.

So if I understand your theory, the IP had failed from too much air correct?

I am asking only because I have a slight amount of air when my system kicks over to WVO but I haven't had the time to tighten the engine compartment fittings. I suspect my leak's are post lift pump since it runs fine once the system is running for 5 minutes. My theory is that if the leaks were pre-lift pump I would have air problems the whole time I was running on WVO. Maybe I should bump up the priority on fixing the air leaks if it will cause early IP failure or just turn off the WVO for now until I get it fixed.

You thoughts?

No actually I believe the old IP is still good now. While troubleshooting I took the supply line and return line from the IP and capped them off to see if air developed and it did. It was wet under my IP so I suspected a leak but never actually saw one. I spent about 45 minutes with a small mirror looking for one but its really tight and hard to see. Now I'm thinking that my two compression fittings that I had capped off were just leaking air. So now I have a used 183K mile "spare" IP, and experience which builds character ;) .

And yes even though I'm running good now I've still got my sights on in inline 6 cylinder diesel like a Cummins or International DT 360 or 466. No rush, but I will have one at some point. A 466 in a Suburban?? :ro)

asnowsquall glade to hear you fixed your problem, I went through alot of air leaks on my Benz. conversion and finally added a lift pump at the veg. tank and I have had no problems since. I am also converting a Suburban any chance you could explain how you tied into the ip and which lines are the return? I installed a coolant loop in the stock tank and ran my hih to the engine comp. today but am held up waiting for switching valve and heated filter.

Mike

I've got two 3-way Frybrids valves, one for supply and one for return. No delay between the two so I get a smidge of WVO in my diesel over time. Hasn't been an issue so far. I think there are some good pictures at www.Frybrid.com (http://www.Frybrid.com) if you poke around in the conversions section. I'll see if I can't take some pictures at some point. If I forget send me a private message and I'll see what I can do.