The Project Pad

I have been trying to run a Walbro 450 inside of a home brew surge tank and it's been nothing but headaches. I have been getting a random hot start issue that is easy to blame on ECU hardware, but it must be vapor lock upon further consideration. It only happens after I shut the car off and restart it. My theory is the fuel is boiling when I shut the car off and it is preventing it from running right on restart. I was able to log a complete loss of fuel pressure yesterday. Had the car towed home, let it cool off and it restarted like nothing ever happened.

So, it could be the regulator, fuel pump, or my surge tank. I don;t suspect the regulator because I had it on the old setup and it always worked great. The pump setup is all new.

What are some good external options now days? I have seen the magnafuel pumps, but they are super loud. I'd like a 1000 hp pump that is reliable and can run ethanol.

Has anyone seen these Fuel lab pumps in person yet? They are variable speed, so I suspect they are much quieter than most large pumps running full blast at idle.

http://fuelab.com/products/performance/ ... i_in_line/

waaaaah my 800hp audi is loud. waaaaaaah.

STFU and buy a magnafuel

either that or do something fancy like parallel pumps with the magnafuel kicking on above x psi.

Marc, that's what I am trying to avoid:)

Wonder if using fire sleeve (like for turbo lines) under the hood would insulate enough to make a difference? At least to verify vapour lock...

Otherwise, you could possibly try to ramp up your fuel pressure regulator and compensate for your injectors in VEMS. Thinking that higher pressure fuel will take more heat to vapourize.

My 04 jetta uses a fuel cooler on the return to the tank. It's just fastened to the underside of the car, underneath the front passenger. You could perhaps implement something like that?

Not sure on your system if you only have one line going to fuel rail or pass through but you do have a checkvalve right after the pump right?

Thanks for the feedback everyone. I think I have eliminated the pump setup, pressure is logging good now. I managed to get most of the fuel line insulated, it's right next to the I intake manifold and may be getting too hot. We will see, this is really a bazaar problem. I was able to reproduce it today just letting me the car idle and get hot so that was nice. Now I can track it down if this doesn't work.

Fuel pump aside, the regulator is the same as my old setup as well as fuel line routing. The one big difference is the black fuel rail vs the bare silver fuel rail. I could not get the car into a poor running situation today so the fuel line insulation seems to be helping. It does sputter and miss still once in a while if hot at idle or after sitting and heat soaking. However, it recovers quickly now.

Maybe the black fuel rail is absorbing just enough more heat?

No idea if the fuel rail would make that much difference, but it sure does sound like vapor lock. Engine bay is looking great, Jim. Track events this year?

I would say it could not hurt to add a fuel cooler in your return line right before the tank. I have that on my wimpy AEB and I can tell you it is quite warm after regular driving. Imagine your fuel temps after spanking it around the track with a big pump. You could just put it in the trunk with a PC fan or two on it. E85 is highly oxygenated, remember.

There was a link posted a while ago in the thread I opened on fuel temps. Seems like anything above 70c is "undesirable".
If your fuel is "boiling"... well, need I say more?
EDIT:
http://injectordynamics.com/articles/in ... -feb-2013/

Scroll down to the temperature part.

Thinking the large pump is overheating it. I either need to slow it down or put in a smaller pump and overdrive it. I'd rather not put a cooler in there, but that's what may be the easiest.

I would try slowing down the pump via PWM controller. That's what the manufacturers of the huge pumps like Weldon recommend for longevity of the pump and for fuel heating reasons.

Other things to note: Your fuel rail appears to be anodized aluminum. The emissivity of anodized Al is fairly high (0.77- 0.9) which means it both absorbs and emits radiation readily. A polished Al fuel rail, and even a rough, diffuse one, would have an emissivity roughly an order of magnitude lower. Let me break it down here... your current fuel rail both emits and absorbs thermal radiation better than a normal, rough aluminum one.

Therefore, you may have one of two situations. If your fuel temperature is hotter than your engine bay temperature, your current black rail is helping you (compared to a non-anodized rail) because it will emit energy to its surroundings better. However, if the engine bay is hot relative to the fuel temperature, the black rail will absorb this heat more readily than will a non-annodized aluminum fuel rail.

The more you know...



Also, adding ethanol to fuel lowers the fuel's boiling point typically, so you have several things working against you here. Just one more reason I don't like ethanol. Also, be sure you have a 10 micron or smaller filter in your line. People seem to be ignoring this lately and it is most important on EV14 injectors, especially when running ethanol.