honda-mini

Hi guys- I'm a newb on this forum, but I'm sure someone here can help me.

I have a 99 B18B Integra LS motor installed in my 1974 Austin Mini with a Blox intake and custom 4-2-1 Header. Stock everything else.

The issue I'm having is specific to the road course that I take the car to for track days. The car will do about 1.5 laps, then acts fuel starved- usually at the end of a straight where its been spun up to high RPM for a good time. If I upshift early to drop the RPMs, it comes back to full power. I learned to use a higher gear to prevent the problem, but this is not the fast way around the track.

I'm running a brand new Walbro 255 fuel pump, standard pressure reg, and standard filter. Both days when this happened, it was extremely hot 90-97 degrees, and the car was running around~ 220 degree water temp. I don't have a fuel pressure guage to see whats going on, but I have one thought:

I used the small standard Mini 1/4 fuel line for a return, but used 5/16" for the feed.-- could the return cause a bottleneck of some sort?

Any ideas what to look for? I'm a bit stumped.

90_EX_Civic

standard pressure regulator for the car or for the engine?

are you running a stock ecu? at what rpm is it acting up at? type of tranny? gear set?

honda-mini

It's a GSR fuel pressure regulator. Stock Integra LS ECU. It only acts up after a whole lap at speed, and then only intermittently, but it gets worse as it gets hotter. I can upshift a gear, and it'll be fine for another half a lap. If I keep it below about 5000 under heavy load, it doesn't miss a beat. Running LS gears, but the tires are 4.5 inches smaller, so its geared very low.

slowturbocx

I think if anything, it sounds like ignition problems.

honda-mini

One thing I should add-- the condition seemingly can't be repeated anywhere but the race track. It never does it on the road, no matter how hard I drive it.

It does seem heat related -- could it be vapor lock? Maybe the coil gets hot and causes ignition issues? Strange that it goes completely away until the next lap though...

1998GsRIntegra

Does it in any way sound like a misfire? Or does it just get sluggish? It really sounds ignition related.

honda-mini

not a missfire, or sluggish running-- simply turns OFF completely until you drop RPM, and ease off the throttle. Like I said, I can upshift a gear and it runs fine, will accelerate smoothly with no issues.

I'm thinking it may be a vapor lock issue/ fuel pressure problem. It really seems like it runs out of fuel. Seems heat related because usually I can do at least 1 full lap before it happens. It is a tiny engine compartment crammed full of engine, radiator, fans, etc. My standard integra fuel filter sits directly behind the radiator/ fan, so I guess hot air is being blasted right at it.

As far as ignition goes-- could the coil be going bad in the high temps? When it gets hot, can't supply spark at high RPM?

Fastguy

What are you running for a pickup? I have had this happen on two older cars and both times it was the fuel sock in the tank. Over time, they become non porous.