Questions to be answered after changing Fuel injectors - N54Tech.com

mixhali

Hi all, I recently changed all injectors with index 12 units this week. Everything went well and the rough idle I was hoping to solve has been eliminated, thankfully. I have a couple of questions resulting from it.

1. Since changing the injectors I still don't get a nice strong startup. When the car starts it sounds as if it does a little cough stumble then away she goes. After that it is completely fine

2. It seems to crank longer when starting, from overnight maybe 2-3 seconds. I never had that with the old injectors. I pulled the engine cove off again as I thought I might have a slow fuel leak which is discharging the fuel circuit but couldn't find any evidence. HPFP was replace few months back as a stupid suggestion by my deadbeat mechanic to fix the rough idle issue.

3. A lot of oil around first three injectors. My mechanic who I'm starting to have serious doubts about changed the rocker cover seal a few months back so should not be leaking from there, any chance oil is getting past the injector seals? I wouldn't have thought there would be that much oil in the combustion chamber anyhow to get to enable this possibility.

4. Is my mechanic an idiot? When I last spoke to him about the rough idle he called me to tell me he had found the cause of the issue. Due to the rocker cover gasket leaking, oil was getting into the coil tubes, over night the oil is seeping past the seal of the spark plug into the cylinder. I'm not a mechanic but logic suggests to me that if the spark plugs are sealed to handle a compression ratio of 10:2 that there is no way oil is getting passed them. I may have believed that the oil was getting in past the injectors after changing them my self and seeing how it's set up. The injector seals definitely needed replacing.

Thanks for your replies in advance

Fmonteiro444 · 01-16-2016, 07:11 AM

Quote:

Originally Posted by mixhali

Hi all, I recently changed all injectors with index 12 units this week. Everything went well and the rough idle I was hoping to solve has been eliminated, thankfully. I have a couple of questions resulting from it.

1. Since changing the injectors I still don't get a nice strong startup. When the car starts it sounds as if it does a little cough stumble then away she goes. After that it is completely fine

2. It seems to crank longer when starting, from overnight maybe 2-3 seconds. I never had that with the old injectors. I pulled the engine cove off again as I thought I might have a slow fuel leak which is discharging the fuel circuit but couldn't find any evidence. HPFP was replace few months back as a stupid suggestion by my deadbeat mechanic to fix the rough idle issue.

3. A lot of oil around first three injectors. My mechanic who I'm starting to have serious doubts about changed the rocker cover seal a few months back so should not be leaking from there, any chance oil is getting past the injector seals? I wouldn't have thought there would be that much oil in the combustion chamber anyhow to get to enable this possibility.

4. Is my mechanic an idiot? When I last spoke to him about the rough idle he called me to tell me he had found the cause of the issue. Due to the rocker cover gasket leaking, oil was getting into the coil tubes, over night the oil is seeping past the seal of the spark plug into the cylinder. I'm not a mechanic but logic suggests to me that if the spark plugs are sealed to handle a compression ratio of 10:2 that there is no way oil is getting passed them. I may have believed that the oil was getting in past the injectors after changing them my self and seeing how it's set up. The injector seals definitely needed replacing.

Thanks for your replies in advance

If your valve cover gasket is leaking, it will allow oil to sneak into the spark plug well and eventually into the cylinder. I currently have this issue with spark plug #3, but my car starts, idles, and runs perfectly fine.

mojo20032004 · 01-16-2016, 07:20 AM

Quote:

Originally Posted by Fmonteiro444

If your valve cover gasket is leaking, it will allow oil to sneak into the spark plug well and eventually into the cylinder. I currently have this issue with spark plug #3, but my car starts, idles, and runs perfectly fine.

X2 on this. Remove spark plugs and check the tip. If there is any oil on them it's a sign you have a valve cover leaks that's somewhat clogging the spark plugs and preventing them from firing smoothly

OldBooster · 01-16-2016, 01:27 PM

"4. Is my mechanic an idiot? When I last spoke to him about the rough idle he called me to tell me he had found the cause of the issue. Due to the rocker cover gasket leaking, oil was getting into the coil tubes, over night the oil is seeping past the seal of the spark plug into the cylinder. I'm not a mechanic but logic suggests to me that if the spark plugs are sealed to handle a compression ratio of 10:2 that there is no way oil is getting passed them. "

When I read this I was laughing so hard my eyes watered and I could hardly breath! Especially after you said "Is my mechanic an idiot?"

Now it turns out the "deadbeat mechanic" is right! Humble pie! Thanks for lifting my spirits, Mixhali :-)

mixhali · 11:02 PM

Thanks Guys

He may be right on this one however I'm still not happy that in order to get my rough idle fixed on his advice I have shelled out money for:

Coils
Plugs
HPFP
Valve cover gasket

All contributed 0 improvement to the rough idle that I went in for.....and the valve cover is still leaking so Yes he is still a deadbeat!

Injectors solved it and it was the advice of another mechanic who suggested I pull a plug from over night and see if it is covered in fuel to which it was.

I really didn't think that oil can get passed a spark plug, After doing the injectors myself I would think it was plausible to be getting in past the injectors.I must go out and buy a pie!