Hard to start when Cold

[boost4me]

Just did a recent E85 conversion, whipple install yada yada...

Whenever the car sits overnight, the first start is always very difficult... Once I get it started, every start after that is perfect even before its warmed up. Hot starts are fine also. We've tried throwing more fuel at it, doesn't seem to make any difference. We got the plugs gapped at .028 to prevent blowout, I know wider gaps help with cold starts.

Its a return fuel system, with a FORE pressure regulator and rails.... when running, all my AFR's are good etc

Any ideas would be mucho appreciated!

 

[SN8KBYT_1]

Mine does the same thing. First start always a little harder. Not sure why...

 

[boost4me]

Mine does the same thing. First start always a little harder. Not sure why...

Return or returnless fuel system?

 

[gaspasr]

Mine too. Return

 

[SN8KBYT_1]

Return or returnless fuel system?

Mine is a return system also.

Here's a couple plumbing pics... I was in the garage and the hood is off so I figured I'd snap a few....

 

[itSSlow98]

How cold has it been outside when it does that? I know ive read plenty of these issues in colder climates and i do recall florida having som epretty frigid temps recently.

 

[SN8KBYT_1]

I think it makes a huge difference. Colder it is, the harder it starts. I was told the tuners can tune for warmer weather, but if it is warm outside they can't compensate for colder weather. I am no expert on tuning, just what I was told....

 

[Tractionless1]

Same for me, sputters to a start 200rpm and I have to feather the throttle. No problem on warm starts. I have 3 codes that won't clear, overboost, fuel pump driver module offline, and egr. LP Return system with a tune for said system. Working with the tuner now to resolve. It's been happening with 57* coolant, and 70's* coolant.

Strange part is that it's the exact opposite that used to happen with the return (93 oct) system that displayed the same issue but on heat soaked starts. Leads me to believe there's some compensation going on that's incorrect. In the latest issue I reset the PCM to no avail.

 

[boost4me]

Same for me, sputters to a start 200rpm and I have to feather the throttle. No problem on warm starts. I have 3 codes that won't clear, overboost, fuel pump driver module offline, and egr. LP Return system with a tune for said system. Working with the tuner now to resolve. It's been happening with 57* coolant, and 70's* coolant.

Strange part is that it's the exact opposite that used to happen with the return (93 oct) system that displayed the same issue but on heat soaked starts. Leads me to believe there's some compensation going on that's incorrect. In the latest issue I reset the PCM to no avail.

dude! Me too, exactley! When I was still returnless, it wouldn't start when it was heat soaked... I had to de-pressurize the fuel rail and then it would start. It started perfectly when it was cold though. So this is one of the reasons we went return. Now its the opposite problem. Temperature doesn't seem to matter although in FL I have not tested sub-freezing temps. 40-50's is the lowest its gotten, and even when it was 70-80 degrees it didn't matter, same results. When I say won't start when cold I just mean first start in the morning when it hasn't run for a day or two.... and also... the longer it sits the harder it is to start.

So... I want to try and establish a pattern. I'm wondering if everyone having cold start problems is using a FORE pressure regulator. Please post what regulator your using and your current situation if any.

MalcomV8 is using Aeromotive regulator and has zero issues.

Also I have another problem, once its heat soaked I get delayed throttle response from idle. When its cold and running, throttle response is perfect. So riddle me that one too.

 

[Chosyn1]

Same here.minus the e85/ whipple..I just turn the key so I hear the fuel pump cut on,give it a few seconds, then it starts right up...did the same in my dad's diesel truck

 

[boost4me]

so you let the pump run for a bit?

Even though we are return, we hot wired my FPDM back in so it just primes the system, rather than key on pump running full time.

MalcolmV8 has no issues and his this wired the same way...

 

[SN8KBYT_1]

I have a toggle by the shifter for the fuel pump. It helps when I prime mine for 3 seconds or so before starting...

 

[02SILVERBULLET]

With my lightning, programing works a little different but my tuner added timing under cold start cranking, way more cranking fuel and richened the cold start table. my truck will start pretty quick unless its down in the 40* or less temps then it lights off shakes a little bit and misses but once it runs for about 30 seconds it runs fine. Before the changes it would take 3-5 attempts to get it to start.

 

[Chosyn1]

@ boost4me

yes..2nd winter doing this and it seems to do the trick...in the summer i only wait for my fuel press to hit 40psi(usually 1-2 secs) and it starts up fine. this VA cold is no bueno.:nonono:

 

[boost4me]

Yeah its not THAT bad... I mean it starts on the first crank, it just takes several extra cranks, stumbles misses, and then its fine within 10 seconds or less.

This morning, I keyed on and off several times and it started a bit easier.

 

[TXEnginerd]

Maybe this is a dumb question but is this not just a result of ethanol fuels being more sensitive to cold weather? The whole reason they switch to E70 during winter months up north is because you need more gasoline in the mix to get reliable starts when temperatures are lower. Ethanol produces less fuel vapor when cold so before the fuel gets warmed up it will always be harder to ignite.

This makes sense for those of you who are return style and say it doesn't happen if you cycle the pumps on for a few seconds before cranking. You're basically just agitating the fuel in the lines.

 

[stangfreak03GT]

Same with mine. E85 return, Magnafuel pump. Not that cold here in Cali but, very hard cold start, then warm or hot starts fires right up.

 

[Tractionless1]

This makes sense for those of you who are return style and say it doesn't happen if you cycle the pumps on for a few seconds before cranking. You're basically just agitating the fuel in the lines.

Mine cycles much longer than a few seconds as I have to wait for a wideband 02 to heat, call it more like 20 seconds. My issue is happening in the 50-75* range.

Regulator is DX by Magnafuel, 40psi base.

 

[Tractionless1]

With my lightning, programing works a little different but my tuner added timing under cold start cranking, way more cranking fuel and richened the cold start table. my truck will start pretty quick unless its down in the 40* or less temps then it lights off shakes a little bit and misses but once it runs for about 30 seconds it runs fine. Before the changes it would take 3-5 attempts to get it to start.

Are you running E85?

 

[boost4me]

OK I'm nearly convinced this problem is being caused by the fuel pressure regulator...

I have it wired to prime rather than run full time, per MalcolmV8's write up... so it doesn't run full time when key on... but when it primes it immediately drops pressure to zero after the pump shuts off.

All pressure regulators are supposed to hold pressure and bleed down slowly from what I understand. So I called Justin at Fore Innovations... he said we have never had a regulator failure or at least a bad one ship out... He said its gotta be something further down the line and suggested I pull my fuel hat...

That doesn't even make sense... The return line just connects to the hat and dumps the fuel back in the tank, there is nothing mechanical there that would help the system hold pressure when the pumps are off right?

Just making sure that's the case before I call Justin back and tell him to send me a new regulator to try.