View Full Version : Hot starting problems
The engine can be ticking over on the drive or just been thrashed and the water temp is around or over 170*F and is still ticking over nicely..... Switch off and try to restart.... no joy, even though the laptop shows the inputs to the Emerald are all happy.... Fuel pressure is good and spark @ the plugs is good. Once the engine cools a little then we're off again... Any ideas? Fuel temp due to recirculation?
strat24v
31-05-2013, 23:29
Maybe fuel temp getting high enough to have a bit of vapourisation if you are circulating through your swirl pot. Stock Bosch unit on a 164 has a built in immersed cooler.
Should be a hot starting setting in the mapping Al?
Add more fuel at that temp and cranking revs. Try 20% more fuel for hot cranking ( only )
may need less once you know that is what it needs, worked for me.
Bobbler
My 1st thoughts John, could be proved by filling the tanks full? When replacing the engine, I also revised the fuel config. I now have the Bosch 044 T'd in direct to the tanks (No swirl pot) and the return T'd into the top of both tanks (Poss vapourisation!!)........................Rob, I'll send an email to Emerald and see what they come back re settings. Interestingly, I picked this up from another forum and may have a play today..................He's from Hungary and translates via Google...Hi, guys! http://www.rhocar.org/public/style_emoticons/default/smile.gif
Finally I found the problem my Zetec engine. http://www.rhocar.org/public/style_emoticons/default/spiteful.gif
As always, everything was very simple. After reading a bunch of information about Emerald ECU, having tried various settings ECU, I measured the level of the oscilloscope and the phase of the signal from the crankshaft sensor. Proved that the sensor has been connected with reverse polarity. Just on the sensor did not specify - and signal ground. And in reverse polarity sensor is unstable when the engine is hot. Now engine starts well and is stable at any temperature. So if someone has run into this problem, see the polarity of the crankshaft sensor.
Good luck!
Interestingly, I picked this up from another forum and may have a play today..................Proved that the sensor has been connected with reverse polarity etc....
Good luck!
I didn't agree with the above but fitted a temp cross, which resulted in the expected red LED on the ECU :-) Back to plan A...
strat24v
01-06-2013, 13:09
My 1st thoughts John, could be proved by filling the tanks full? When replacing the engine, I also revised the fuel config. I now have the Bosch 044 T'd in direct to the tanks (No swirl pot) and the return T'd into the top of both tanks (Poss vapourisation!!)........................Rob, I'll send an email to Emerald and see what they come back re settings. Interestingly, I picked this up from another forum and may have a play today..................He's from Hungary and translates via Google...Hi, guys! http://www.rhocar.org/public/style_emoticons/default/smile.gif
Finally I found the problem my Zetec engine. http://www.rhocar.org/public/style_emoticons/default/spiteful.gif
As always, everything was very simple. After reading a bunch of information about Emerald ECU, having tried various settings ECU, I measured the level of the oscilloscope and the phase of the signal from the crankshaft sensor. Proved that the sensor has been connected with reverse polarity. Just on the sensor did not specify - and signal ground. And in reverse polarity sensor is unstable when the engine is hot. Now engine starts well and is stable at any temperature. So if someone has run into this problem, see the polarity of the crankshaft sensor.
Good luck!
on your return line to your tanks, how is the fuel discharged back into the tank? Do you just have a welded on fitting or do you have a welded in tube which discharges below the level of fuel in the bottom of the tank. You may have fuel aeration?? Just grasping at straws really, reverting to how it was setup on the 164 should solve your problem, just difficult to re configure it like that. Guys method of the complete pump assembly fitted in the tank is as good a solution as any.
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...
Guy Mayers
01-06-2013, 14:02
Guys method of the complete pump assembly fitted in the tank is as good a solution as any.
Thanks for the vote of confidence John, my dead donor Alfa is going to be dragged away tomorrow (no wheels or subframes so dragged is the appropriate word!) and the last part that I'd meant to remove weeks and weeks ago was........ the fuel pump and swirl pot! So, now I've got two spares sat on the shelf if anyone needs one drop me a line!
Guy
Are the front hubs available Guy?
Guy Mayers
01-06-2013, 16:27
Gone to a good home already Allen. Rear hubs are still there but I doubt they're interchangeable!
Guy
ChrisCar6
01-06-2013, 22:21
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!
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.
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??
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.
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.
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