It was I and I stand by that assessment. I have semi- permanently installed a circuit that runs the fuel pump long enough to purge the rail of any vapor and still have some of the symptoms.
It now starts every time, as long as I hold the throttle slightly open after a very hot soak. Still idles low and misfires for 15-30 seconds, although not as bad as before.
Only solution that I see would be a custom fuel rail to eliminate the hoses, but would probably require different injectors; and if I go to different injectors I would probably go to a different fuel management system, such as MegaSquirt. For now I am happy with what I have.
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That theory would also explain why Jaguars solution was to increase rail pressure, which could re-liquify the fuel in the hoses, vs any sort of rail “flushing” scheme.
Most MPI systems operate at 3.0bar or higher and none have hose connections to the injectors…hmmmm.
Another experiment, if anyone has the extra cash! Fill up near empty with 0% Ethanol gasoline. Pure gasoline definitely doesn’t vaporize as easily.
My first tankful in the spring is always ethanol-free. I store the car with a full “free” tank. Now I’m running “normal” fuel, and it hasn’t changed anything. After a twenty minute hot soak, the car starts first time without foot on gas pedal, never stalls, and just has slightly lower idle speed, which lasts maybe 10-15 secs. Then off we go!
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Sounds like mine. Starts fine, won’t stall, and just idles a bit lower than normal for 15 secs or so. If i rev it i bit, that helps get idle rpm back to normal a little quicker.
I have to believe we ALL have hot fuel issues, but IMO those of us with more perfectly maintained cars don’t suffer as much? We know who we are!
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Both rubber and plastic (on the injector bodies) are effective heat insulators. They keep some heat away from the fuel, especially during heat soak. In addition, the injectors are further insulated by the manifold to injector seals, and the large rubber cushion under the injector clamps.
Most early electronic fuel injected cars had rubber lines to the injectors. All were problematic with the fuel line hardening, cracking and leaking over time. Newer cars eliminated them by using o-rings between the fuel rail and injectors which are less problematic, but still sometimes leak. I believe the leakage issues with the rubber lines was the main reason for the change.
Fuel, at least in the US, varies significantly in formulation, depending on time of year, altitude, etc. Much of the variation is driven by the EPA. Formulations sold in cold winter climates cannot be sold in summer. Because of the high price of fuel, the EPA granted some waivers this year allowing different formulations to be sold out of season. I suspect a large portion of the issues some people, but not others, are seeing in hot start is the particular fuel blend involved.
Before I go jeeping in the mountains for a bit of a break, thought I’d shoot a quick update.
In trying to keep the original mount for the fuel pump, I’ve gotta wait for a few parts for the 90 degree bends. I tried to farmer method of boiling the hose in the shape needed and then setting it in cold water, but the hose still collapsed - really has to be molded or modified, in my case I’m gonna use some small 90 degree fittings with a tiny bit of hose to connect - should work great.
Since I got rid of the trumpet intake boxes, I had no place to mount the A/C lines with the fuel cooling element. I found that there was a perfectly aligned mount on the throttle body that I could use with a small piece of aluminum that I fabricated. Works perfectly…
Last time I went jeeping, we had a fun time with a Jeep Gladiator on a tight turn and cliff drop-off - it was balancing on 2 wheels. I’d post the video, but it was a Jeep…
Ummmm, pics…
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Hi Robert,
Can you please elaborate?
Did you do it through the fuel pump relay or directly at the pump?
What signal did you use? Drivers door opening, ignition On or else?
Where did you tap into the wiring? Inside the cabin or engine compartment?
Reason I ask is that ever since I installed a Bosch Turbine Fuel Pump I noticed that the pump takes a bit more time to prime the rail than the Roller Pump, so the engine needs to crank more to start.
If I turn the ignition On and Off a couple of times before it starts immediately.
Otherwise the Turbine Pump is super quiet and works flawlessly.
Thanks.
Make or buy a coil from wire the fits snugly to the hose and you will be able to do a much tighter bend without the hose collapsing.
That’s interesting. Is that just a normal condition of a
Turbine pump. I was going to install a Bosch and a gear
Reduction starter in an attempt reduce cranking time not
Increase it. Not that I have any issues with the pump or
The starter just looking to upgrade.
All the components are located by the fuse block under the right dash, except the thermostat, which is under the hood mounted to the washer fluid reservoir.
I installed a thermostatic switch (the adjustable type used with electric radiator fans) with the bulb strapped the the fuel rail; one terminal fed through a 10A fuse, the other to pin 30 of an ISO relay. I connected pins 85 and 86 across the courtesy lamp that is mounted in the lower right of the dash. Pin 87 connects to the white wire of the 45 second timer (which connects to the fuel pump at the fuel pump relay).
Function is that the relay coil is activated whenever the courtesy lights are on; when the door opens and approximately 15 seconds after. Current flows through the fuse, then the
thermostatic switch (if the rail temperature is 125F), through the relay to the fuel pump.
That’s a crucial piece of information. Thank you.
I consider the Turbine pump to be an upgrade.
No noise and, in theory, there are no rollers so no wear and lasts longer.
And also a much lesser possibility of jamming.