

| Subject: | Re: Bucking/Loss of power on HOT days |
| From: | Scott - IMAP |
| Date: | Wed, 3 Aug 2016 14:20:28 -0700 |
there actually was a an engine compartment fan .. fitted to some Datsun 280Z sports cars ... aimed at the fuel rail area. a factory fix just for this issue. a Bit dorky, but works. On 8/3/2016 1:43 PM, Neil N wrote: > On my '81 with Jetta 2.0, a similar thing happened. The fuel pump has > always been prone to being noisy ( new at time of swap as was tank etc.) > but would always get louder on hot days especially if climbing a > steep grade for any amount of time. > > On a trip through a desolate area, with my fuel pump screaming away, I > pulled over, let engine idle. It sputtered and died. It felt like vapour > lock. It wouldn't start so I pulled the gas cap and heard a "whoosh" of > air. With cap off, engine started. On a spare gas cap, I removed a little > material to help allow tank to pull in ambient air. Not sure if this helped > but no more stalls. I swapped in a used charcoal canister after that and of > course reinstalled the other gas cap. > AKAIK, my fuel pump hasn't been that noisy since. > > My swap uses the Jetta charcoal canister purge valve which is > quickly cycled open closed by the ECU. Does the obd1 Suby swap use a > similar valve? > > At one point I wondered if my different purge valve system pulled more air, > over a given period of time, than the OEM design. i doubt it though. Even > if it did, the charcoal filter should vent to atmosphere right? > > On my swap the fuel hoses likely pick up heat in engine bay but then I have > to imagine that the WBX fuel hoses being so close to the engine case, would > also allow fuel to pick up heat. > OTOH, I can't recall if the WBX return hose is above the WBX engine. > > I'd be curious to see how your Suby swap would work with a fuel tank having > the 12 mm outlet. > > Neil. > > > On Wednesday, August 3, 2016, Richard Koerner <rjkinpb@sbcglobal.net> wrote: > > Am having bucking and loss of power on very hot days. >> My van is an 85 2WD (233,000 miles), manual tranny, with a 2.2 Subie >> engine (recent conversion by California Westys in San Diego), ..... > > >> The symptoms are classic "vapor lock"; yes, unusual with pressurized fuel >> delivery on fuel injected engines, but I've been going through the List >> Archives and there have been cases resembling vapor lock. >> Typically, everything runs fine at freeway speeds in hot conditions; the >> bucking problems start when I pull off freeway and have to contend with >> stoplights and idling and low speed. >> >> This has happened at low elevations but hot (Florida and Laughlin, Nevada) >> and also at high elevations (Gunnison, Colorado) on a warm summer day. >> Problem disappears when van is allowed to cool overnight; starts fine and >> runs fine the next day.....until it gets hot outside and van is moving slow. >> >> Mild whining (not screaming) from fuel pump when this happens. I suspect >> some cavitation and pump damage occurred. Anyway, I've replaced fuel >> pump.... > > >> Other things I've read about include: gas cap, charcoal cannister, bad >> coil, fuel pressure regulator, bad ignition coil. >> >> > -- > Neil n > > Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca> > > 1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy> > > 1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/> > > Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>
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