Tuning out hot start issues

[SnakeBoostE85]

Well guys I tried everything under the sun yesterday. Spent several hours in the car with PRP and didn't get anywhere... all sort of combinations were tried. Less/More fuel, less/more air, less/more timing...timing while exiting crank etc... Everything I did only seemed to exacerbate the problem or just didn't make any difference.

I'm convinced at this point the only way to solve this is to try and keep the fuel cooler. Perhaps a return line heat sink?

If your running E85 with a roots blower and return fuel system and you are NOT having these issues, I want to know how you are setup. Please share your tune strategy, fuel system configuration, anything in the system to cool the fuel etc...

I have also proven that cooling the fuel pretty much solves the issue, because I will go to the gas station heat soaked with a near empty tank and fill up with fresh E85 that is nice and cool give it a couple primes to clear out the hot stuff and boom - it fires right up.

Also something to consider just from a heat/pressure, thermodynamics perspective.... I live at close to 7500 feet. I often wonder if that is playing a role, because the boiling point will be even lower for E85 at this altitude.

 

[MG0h3]

If its happening in the summer and after a heat soak I think you have your diagnosis.

Lots of guys running dead head without issue so that might be your best best.

 

[SnakeBoostE85]

If its happening in the summer and after a heat soak I think you have your diagnosis.

Lots of guys running dead head without issue so that might be your best best.

Happy to try the dead head configuration, I'd like everyone's consensus on the crank fuel settings first though.

Look with all do respect - I find it amazing how everyone is so quick to throw out simple solutions here but not a single person can post a single screen shot of their PRP tables for crank fuel.

 

[SnakeBoostE85]

So in talking with another very intelligent individual with a similar setup, he said he has ran both dead and circulating setup and it doesn't make a damn bit of difference on hot starts. While the fuel in the tank stays cooler, the problem is, the fuel sits in the rails boiling while the car is off, which can even exacerbate the issue because at least with circulating rails you can prime it and get "cooler" fuel from the tank.

So once again. IF you are running E85 on a return system and have solved the hot start issue without introducing other problems, PLEASE share your tune and configuration!!

 

[xtreme_exploder]

Does your car hold fuel pressure after you turn the key on, before you crank it? If it is, you can try raising your base pressure, since higher pressure will raise the fuel's boiling point. Just an idea.

 

[SnakeBoostE85]

Does your car hold fuel pressure after you turn the key on, before you crank it? If it is, you can try raising your base pressure, since higher pressure will raise the fuel's boiling point. Just an idea.

So, I have a FORE regulator and it doesn't hold pressure unless the fuel pump is running. I spoke to FORE about this, and he said that is how his regulator works. I know some of the other regulators hold pressure and bleed it off slowly after the car shuts off. So perhaps swapping regulators will help.

 

[cj428mach]

So, I have a FORE regulator and it doesn't hold pressure unless the fuel pump is running. I spoke to FORE about this, and he said that is how his regulator works. I know some of the other regulators hold pressure and bleed it off slowly after the car shuts off. So perhaps swapping regulators will help.

Don't go chasing your tail thinking its pressure not being held by the regulator.

When I first went return I swore this was the problem as my car would go from 40 psi to 0 in probably 10-15 seconds after shutting it off. I called Justin at Fore and he explained that lots of OEM systems have no check valves and they fire up first crank of the key. I ended up sending him my regulator to test and he said it was fine, I then inquired about buying a check valve as apparently my pumps weren't holding pressure. Justin said he could sell me one but he was 99.99% sure it was a tuning issue and that I would be better off not buying the valve. I ended up buying the valve just to satisfy myself and that wasn't the issue, it ended up taking more tweaking of my tune in order to get the car to start better.

My setup has changed to dead head and I'm now on e85 and I have an issue on restart sometimes that I haven't gotten tweaked out. It usually occurs once the car has been up to operating temperature and is shut off and allowed to cool part way. Upon cranking it the car will start, sputter and then die, like its barely getting any fuel. It'll take a second or two of cranking and then the car will fire up and run fine. If I try to restart the car immediately after shutting the car off it'll start just fine, it just has to sit for a 15-30 mins and the problem arises, cold starts are like factory.

Me and Malcolmv8 have discussed this and he thinks it has something to do with deadhead allowing warm fuel to sit in the rails and thats where the issue arises. He even went back to a conventional return system and the problem went away. I just can't say I buy that because with the stock PPRV system the fuel sits in the rails just like a dead head, but since I don't have a better answer I can't argue with him.

 

[xtreme_exploder]

Does anyone run returnless with E85 though?

 

[c6zhombre]

Does anyone run returnless with E85 though?

Of course. 04sleepers car has run returnless and E85 since 2009. Still runs like an animal to this day, no hot start issues, fuel temp stays remarkably low even in Texas summer.

The only time I thought I might have a hot start issue....it ended up being the battery going south.

 

[SnakeBoostE85]

Don't go chasing your tail thinking its pressure not being held by the regulator.

When I first went return I swore this was the problem as my car would go from 40 psi to 0 in probably 10-15 seconds after shutting it off. I called Justin at Fore and he explained that lots of OEM systems have no check valves and they fire up first crank of the key. I ended up sending him my regulator to test and he said it was fine, I then inquired about buying a check valve as apparently my pumps weren't holding pressure. Justin said he could sell me one but he was 99.99% sure it was a tuning issue and that I would be better off not buying the valve. I ended up buying the valve just to satisfy myself and that wasn't the issue, it ended up taking more tweaking of my tune in order to get the car to start better.

My setup has changed to dead head and I'm now on e85 and I have an issue on restart sometimes that I haven't gotten tweaked out. It usually occurs once the car has been up to operating temperature and is shut off and allowed to cool part way. Upon cranking it the car will start, sputter and then die, like its barely getting any fuel. It'll take a second or two of cranking and then the car will fire up and run fine. If I try to restart the car immediately after shutting the car off it'll start just fine, it just has to sit for a 15-30 mins and the problem arises, cold starts are like factory.

Me and Malcolmv8 have discussed this and he thinks it has something to do with dead allowing warm fuel to sit in the rails and thats where the issue arises. He even went back to a conventional return system and the problem went away. I just can't say I by that because with the stock PPRV system the fuel sits in the rails just like a dead head, but since I don't have a better answer I can't argue with him.

This is my exact symptoms to the "T" man!!

If its hot and I shut it off, and restart it right away... starts right up. If it sits for a few minutes it takes a few tries to get it started. Exact same problem and I have also been chatting with MalcolmV8. Sharp dude.

 

[SnakeBoostE85]

Of course. 04sleepers car has run returnless and E85 since 2009. Still runs like an animal to this day, no hot start issues, fuel temp stays remarkably low even in Texas summer.

The only time I thought I might have a hot start issue....it ended up being the battery going south.

Can we get his "crank fuel" tables?

 

[c6zhombre]

Can we get his "crank fuel" tables?

I can't speak for 04sleeper....but I'm pretty sure he will consider that proprietary information and I doubt he'd be real thrilled seeing customers just "giving" away his intellectual property.

You could always pm him and request some info about a tune, tho. His tuning is second to none IMO, especially supercharged modular fords running ethanol. He'll probably correct your hot start issue and fine tune the rest of it gaining you additional hp/tq and drivability.

 

[SnakeBoostE85]

I can't speak for 04sleeper....but I'm pretty sure he will consider that proprietary information and I doubt he'd be real thrilled seeing customers just "giving" away his intellectual property.

You could always pm him and request some info about a tune, tho. His tuning is second to none IMO, especially supercharged modular fords running ethanol. He'll probably correct your hot start issue and fine tune the rest of it gaining you additional hp/tq and drivability.

I'll give it a try. Your better off sharing the information as it helps everyone and those that tune for income and hobby learn also. No one is going to loose money over sharing a crank table for an E85 03/04 Cobra.

 

[SnakeBoostE85]

so I have a exchanged a few PM's with 04sleeper. He said that you shouldn't have any issues with hot starts on E85. If you do, its not a tuning issue. Only cold start problems can be solved in your tune, by adding fuel. He felt any hot start issues on E85 is purely mechanical. I have another PM into him asking him about his recommended fuel system configuration on E85.

So as one guy suggested above, the fact that most regulators don't hold pressure after the prime could perhaps add to the problem with the fuel boiling without pressure being held.

Another thing - I know myself and several others wired our return fuel pumps into the FPDM so that the pump primes like stock and is hooked into the enertia switch. If you don't wire it through the FPDM, it will run full time with key on which would almost certainly solve the problem on a fully circulating fuel system going through the rails because your going to push tons of fresh fuel through the rails, while it may be hot it won't be boiling like the fuel is sitting in the rails.

I asked 04sleeper what his configuration is, I have not heard back yet. This prime configuration could be the difference. Is anyone bypassing the FPDM and priming full time with key on and still having issues?

One thing I noticed on my Powerstroke is that it I believe it has a very similar setup with a return fuel system, when I turn the key on, I hear the fuel pump running full time, it does not prime.

The only reason I wanted it wired into the FPDM is so that the enertia switch is in the loop just in case of an accident, the fuel pump is shut off. Other than that, I could care less if the pump runs all the time with the key on.

 

[MG0h3]

Maybe try cycling the key a few times when the problem normally occurs. This should tell you if changing your wiring would solve the issue. Seems like one key cycle should bring the pressure up anyways?

 

[need4snake]

sub'n

 

[fbody83]

I have the same problem. Running a deadhead return setup with E85, custom cams and I need to blip the throttle a few times to get the car to start when the motor is warmed up. My pumps are wired to continuously run when the key is in the on position. If I turn the key on for 10 seconds prior to firing it does not help. I'm going to mess around with the tune some more and will follow up if I get this resolved.

 

[SnakeBoostE85]

Re-kindling this thread because its summer time and the problem is back with no resolution.

This is not a tuning issue... I've tried everything. The problem is that you have these fuel rails sitting next to a blower that is probably around 250-300 degrees when you turn the car off and all that heat transfers into the fuel rails while the car sits for the 1st 30 minutes until the blower starts to cool off.

Has anyone tried insulating or heat shielding their fuel rails?

 

[decipha]

Have you tried kicking up the fuel pump prime time?

 

[SnakeBoostE85]

Would love to... no parameter for that in the AMZ1 computer using SCT that I know of. If I could, I would just set the pump to run for about 10 seconds. If you know of a way to do it, please do share.