Engine/Transmission (1998.5 - 2002) FASS hard start

[LSchulz]

I've been doing a lot of reading on past forum posts, but I haven't found the answers I've been looking for, so here we go.



I installed a FASS HPFP 95 on my truck yesterday. I bought it through Rover Hybrids, so that it comes with a 2 year warranty running WVO, although I have set it up to pull from the diesel and WVO tanks. The truck was running fine before I put the FASS in, just the other lift pump was pretty weak. The FASS is supposedly set at 18 psi, although it is running around 26 psi at idle, low 20's driving, and high teens at WOT.



So now, on the the problem. It starts hard if I let it sit a while. I wired the FASS off the original LP wiring harness, so it runs for a second once I turn the key, builds about 3-4psi, then shuts off until the engine is running (I noticed on past posts that it was recommended to have low IP inlet pressure while starting). It actually seems more like I'm getting air in the system. If I shut the truck off, then restart it again, it fires up no problem, even if I bump the starter so it builds full pressure. Once it's going, it runs fine, it just suddenly doesn't like to cold start.



Thoughts?

 

[LSchulz]

To continue on this - if 26 psi at idle is too much, where's the best place to get a regulator?

 

[DCreed]

The FASS has an explanation in the directions about hard start being linked to a cracked VP44 diaphram.

 

[LSchulz]

The FASS has an explanation in the directions about hard start being linked to a cracked VP44 diaphram.

Yeah - I've read about that as well. I just fired it up a little while ago, and it started really hard, but I did notice a few things. I have a transparent return line coming off the IP so I can check my purge cycle on WVO, and I noticed a lot of small air bubbles coming through. There is also a nice film of fuel down around the diesel filter/IP inlet, so once the shop warms up, it's time to go looking for leaks.

 

[DCreed]

ANY leaks will cause a start delay, so I guess you've pretty much found it. Happy Hauling!
P. S. what kind of WVO do you use, and how long have you been using it in a VP44 truck, and what problems if any have you encountered? Thanks in advance.

 

[icman95]

Had a hard/no start condition on mine first month I had it. Turned out the o-ring on the fuel filter cap was bad and letting air in. Simple fix-replace the o-ring and all was right as rain. Wouldn't have thought of it in your case except that you mentioned the film of fuel around the filter. That's how the dealer found my problem. The area around the cap and housing was slightly wet.

 

[LSchulz]

Problem solved - I went through and checked all the fittings (which is a lot with the modified fuel system), and found one that was a tiny bit loose. Cranked it down and now it fires right up.

As for the WVO - I pick up stuff from a few restaurants at home, and then get it from the dining halls here at school. For the most part, it's canola based Mel-Fry. I've only run the truck about 1500 miles on it so far, but everything seems to be going fine. I've talked a fair bit with a guy on the Frybrid forums, and he's run a VP44 on WVO for more than 100,000 miles now, with no trouble.

 

[DCreed]

Great news! Please keep us updated here as I'm sure more of us will be doing these conversions.

 

[LowFly]

Not always a cracked diaphram... ... here is our hard start diagram to rewire if needed... but seems like you got the issue resolved.