Chasing hard cold start issue

[daSNAK3]

So I have been chasing a hard starting issue when the car is cold only. I was thinking it was one or more of the direct injectors and found one post online that had the same issues and codes as me.. but never had a resolution but I was able to successfully contact the guy and confirmed he also had a couple bad Direct Injectors.

So I just pulled the spark plugs today, #8 was really dark and wet when I pulled it, reeked of fuel. #3 was also a little darker than all the others and slightly wet and smelled like gas, so I am thinking I have an issue with both of those Direct Injectors.

Also before I pulled the #1 plug, I could see there was a tiny amount of oil in there (picture 3 & 4). Do you think this is the valve cover gasket or the O-ring for the spark plug tubes? I am guessing the O-ring for the spark plug tube since none of the other ones had any oil that I could see.

I am trying to figure out my plan here... I will swap the 2 Direct Injectors out for new ones, new plugs, new O-ring and valve cover gasket for passenger side.

Pictures are below. Any advice would be appreciated, especially for pulling the intake manifold and valve cover off, I have not had to do either before, thanks.

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[Andy13186]

E85 doesnt like to start in cold weather. You could try an e50 tune if your tuner would make one for you. Should make the same or nearly the same power. Im on e50 and it solved a few issues like hard cold starts, and o2 sensor failures. Makes the same power as e85. E50 tune in winter e85 summer would also work.

 

[daSNAK3]

E85 doesnt like to start in cold weather. You could try an e50 tune if your tuner would make one for you. Should make the same or nearly the same power. Im on e50 and it solved a few issues like hard cold starts, and o2 sensor failures. Makes the same power as e85. E50 tune in winter e85 summer would also work.

I’m on 93 tune now cuz it was in storage, changing fuel made zero difference. Been dealing with this issue since last year. And no issues the prior 2 years. Always fired right up. So it’s not the fuel type.

 

[Andy13186]

possibly gunked up e85 clogging injectors or filter? have you tried using a fuel system cleaner like techron?

 

[daSNAK3]

I’m pretty sure 2 of my direct injectors are no good. I ordered two new ones.

 

[daSNAK3]

When removing the intake manifold on the Gen 3 mustang, is it only the gasket part #: MS97215 that I will need to worry about replacing? You can reuse the bolts or will I need new ones?

 

[robvas]

When removing the intake manifold on the Gen 3 mustang, is it only the gasket part #: MS97215 that I will need to worry about replacing? You can reuse the bolts or will I need new ones?

They can't possibly be TTY since you only put like 8-10lb/ft on them

 

[sk47]

Hello; Some WAG here. I figure you pulled the plugs after the engine was not hot. My notion works better if the engine was cold. Injectors could be leaking a bit. Not enough to hydro lock a cylinder. but maybe enough to drop the pressure in the fuel rail.
If the pressure drops in the fuel rail it can take a bit for the pump to build up proper pressure in the port injectors. Often around 50-60 psi in port injectors.
Not clear to me the higher-pressure direct injectors would affect cold starts. Think I read on a post it is the port injectors which work at lower engine power demands which might include starting.

The other part which can affect fuel rail pressure is a pressure relief valve plumbed into the fuel rail. Since a fuel pump can make more pressure than required in the fuel rail a relief valve opens to bleed off some fuel and keep the pressure at the target pressure sending fuel back into the gas tank. A leaky regulator can cause cold start problems by releasing pressure over time when the engine sits while turned off.

 

[daSNAK3]

Hello; Some WAG here. I figure you pulled the plugs after the engine was not hot. My notion works better if the engine was cold. Injectors could be leaking a bit. Not enough to hydro lock a cylinder. but maybe enough to drop the pressure in the fuel rail.
If the pressure drops in the fuel rail it can take a bit for the pump to build up proper pressure in the port injectors. Often around 50-60 psi in port injectors.
Not clear to me the higher-pressure direct injectors would affect cold starts. Think I read on a post it is the port injectors which work at lower engine power demands which might include starting.

The other part which can affect fuel rail pressure is a pressure relief valve plumbed into the fuel rail. Since a fuel pump can make more pressure than required in the fuel rail a relief valve opens to bleed off some fuel and keep the pressure at the target pressure sending fuel back into the gas tank. A leaky regulator can cause cold start problems by releasing pressure over time when the engine sits while turned off.

I tested and cleaned my ID1050 injectors, had no leaks and all sprayed the same, so those are good.

Not sure about the Direct Injectors and can't get answers anywhere to my questions, but another guy had same issues as me and he had two bad Direct Injectors, so this is what I am going to try, especially since two plugs were wet and smelly after sitting all night and just opening my driver door and pumps priming once.

I just want to make sure I have everything I need for pulling the passenger side valve cover (to replace spark plug gasket) and pulling the intake manifold to replace the Direct Injectors (which I am going to number them and test them all before just swapping out the two I think are bad.

If this don't work which I think it will, then I continue on to the regulator.

 

[sk47]

two bad Direct Injectors, so this is what I am going to try, especially since two plugs were wet and smelly after sitting all night and just opening my driver door and pumps priming once.

Hello; This makes sense. I discovered that I need to let my fuel injected car to warm up a bit even if I just need to move it a few feet. Say i want to pull the car inside the garage. I start it and drive it a few feet then shut it off quickly. Next time i start it, say the next day, it will stumble and run rough for a short while. Clears up after a short while.
What happens seems to be at th first cold start and quick shutoff the fuel management is still in the rich cold start mode. I think one or more cylinders have extra fuel in them. When I do the next start the plugs are fouled rich and so the rough start.
I find if I let it run for a little while, say till after the RPM's drop and then shut it off I do not get the same rough start next time.
good luck.

 

[daSNAK3]

An update for anyone in the future. Fixed the cold hard starting issue, finally.

I pulled my Direct injectors, tested them all and as I suspected #3 and #8 were leaking. So I replaced those two and cleaned the others.

Put new plugs in as well.

Now the car fires right up. So leaky direct injectors were the culprit for me.

and some critters decided to make under my intake manifold their home at some point… I knew they got under my backseat at one point and on top of the intake manifold but can’t believe they got under it.

 

[LCK22GT]

An update for anyone in the future. Fixed the cold hard starting issue, finally.

I pulled my Direct injectors, tested them all and as I suspected #3 and #8 were leaking. So I replaced those two and cleaned the others.

Put new plugs in as well.

Now the car fires right up. So leaky direct injectors were the culprit for me.

and some critters decided to make under my intake manifold their home at some point… I knew they got under my backseat at one point and on top of the intake manifold but can’t believe they got under it.


Glad to hear you nixed it! I once had mice make a nest in that valley in one of my trucks. They tore off pieces of hood lining for extra comfort.

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