Hot starting problems

[ChrisCar6]

Again, I'm thinking on the same lines John. The return discharges back into the tank via a weld on but the tanks are foam filled, which should help. I was considering fitting a length of suitably sized 1/4" clutch / brake pipe with a flared end inside the weld on, routing the return fuel to the bottom of the tank. Not sure if the foam will cause me problems with pipe routing though...

I like that idea.....might just try that!

[Sando]

Glad Emerald agreed about the extra shot of fuel Al. It can take at least a couple of revolutions of cranking before the ECU even gets in sync, so although that initial shot is important it also needs it over the first few seconds of cranking.
As soon as it fires the revs rise and take it out of these cranking sites on the map and gets the correct fuelling anyway.
if it persists I'd take it back to your Dyno man. he should have done this for you when he did the mapping if he was worth his salt.

Agree about aeration of the fuelling and vaporisation being a possible cause too. Your Bosch 044 pump will flow a lot of fuel on tickover when at pressure but the injectors taking very little (that pump is meant for big turbo cars) and if you haven't got return feeds down to the bottom of the tanks. Also the amount of fuel in the tanks may affect this if you are running quite low when it is sitting and getting hot. Would have thought the fuel circulating and in the tank would need to be quite hot to do this though. With the open slats of our engine bay though not sure our cars would ever get as hot as a car with a tight fitting insulated bonnet and hot rad. Stick a fuel pressure gauge on and see what happening at your standing temperatures.

[Cadami]

To eliminate possible aeration and vaporisation I've inserted 1/4" tubes into the -6 weld-ons at the top of the tank so the fuel returns to the bottom of the tanks. Neat and simple job BUT it's still the same!!!!!!!
All warmed up and ticking over fine. Switched off and unable to start again. If I leave it for a decent minute then she'll start again.......... Fuel pressure is fine and the tanks don't feel that hot.
Any ideas??

[Sando]

Have you tried adding more fuel to hot cranking sites in the map Al as per my earlier post?
There is an explanation to this in Dave Walkers book where this is his remedy to the common problem.
It worked for me. Just whilst cranking at high engine water temps.

[Cadami]

Thanks for reminding me to persist with the ECU Rob. I used both your's and Karl's advise today and wound the numbers up as neither worked in isolation. Result... There's definitely an improvement so need to fine tune. Thanks for the help :-)

Chris R, the fuel return tubes are a simple solution but unsure if they actually help.