5.0MX5

Quick recap, back in June of 2011 my car was initiated with a 1,000 mile shakedown trip to Eastern Tenn. It was HOT, but we traveled a lot of small two lane roads and had a good trip (we won't talk about the clutch issue), my point is the car ran great, no engine drive-ability issues.

Fast forward to yesterday when on a little 150 mile Sunday afternoon back road drive, I didn't know if I'd make it back home without a trailer being involved. The first 40'ish miles all was good, then after several miles at 45mph or so on a particularly curvy stretch of road while slowing at an intersection, the car died and was very hard to start, lots of cranking required. Check underhood and see nothing wrong, this went on for the next hour, anytime we'd slow or stop had very rough running and hard starting.

The first real clue on what was going on (although I'd already started suspecting I had fuel boil going on) was near home later in the evening the temps cooled some and it stared running more normal. As an experiment I hit my favorite station and filled up with 92 octane "no ethanol" gas and all is back to normal.

The previous week at the tailend of a 500 mile Ozark Mt. jaunt (I highly recommend the New Orleans Hotel in Eureka Springs, AR), I bought gas (10% ethanol laced gasoline), it may have been formulated for cool spring weather and yesterdays early 90 deg. heat made it dang near unusable in my carbed car.

The following link has a great summary on the issue http://www.militarytrader.com/milita...other-gas-woes

So, realizing ethanol is a fact of life now, I'm adding a non metal spacer under the carb and rerouting the fuel line from the tank to the carb to try and mitigate the heat induced fuel boiling issues.

We'll see, I'm running a Edelbrock carb which has a history of hard hot starts due to fuel boiling, which raises the internal fuel pressure and forces gas past the needle and seat with gas then pooling in the intake. This causes long crank times, and with today's fuel it may be the perfect hard start recipe.

tbone heller

Did your gas tank seem like it was pressurized? The vent on my tank was plugged and caused the same issues.

5.0MX5

Now that you mention it, there was pressure when I took the cap off. Along with the other planed steps, I'll check the vent. Old school fix was to drill a very small hole in the cap.

Thanks

tbone heller

I disassembled the cap & cleaned some stuff off of the screen in it. I also applied some compressed air to the vent hose at the charcoal canister (MAKE SURE YOU HAVE THE GAS CAP REMOVED) to free up a stuck valve in the tank.