Help with flooding issue

[Scott R]

It looks like this is pretty obvious in terms of the condition of the plugs. I have a flooding problem on startup and I pulled the plugs this morning to see if I had a leaky injector. Much to my surprise I don't. However the #5 plug looks as if it's not been getting spark, what do you all think?

1-2-3


4-5-6

[911pcars]

Are the plugs sooty or wet with fuel?

Sooty = rich
Wet = more than rich
Oily = excess oil from valve guides or oil ring

Sherwood

[Scott R]

Originally posted by 911pcars
Are the plugs sooty or wet with fuel?

Sooty = rich
Wet = more than rich
Oily = excess oil from valve guides or oil ring

Sherwood

Soot, you can chip it of like varnish. This engine had better not be blowing oil by, it has only a 100 miles on it. I just replaced all of the plugs, but I need an injector o-ring before I can fire it up. I think I fouled them during the initial tuning.

[911pcars]

Let me add:

Wet = more than rich or not firing

Sherwood

[Scott R]

They were fouled. I was able to get a set of NGK's on short notice, replaced a viola! CO is back down to 0.8% idle is nice, and starts are no longer a problem. Now I need to get on the road and dial the rest of the VE table in.

[RoninLB]

i need 10mi to clean off start-up carbon?

[Scott R]

Originally posted by RoninLB
i need 10mi to clean off start-up carbon?

No I think this happened when I first was tuning in the EFI after the rebuild. I think I had the pulse width to high, or the VE was too rich, and the plugs were burned up. It's running fine now.

[Grady Clay]

Scott,

I see five plugs that should have been replaced long ago and one that looks correct. It is remotely possible that #5 hasn't been firing.

My recommendation is to put in a set of new plugs and drive normally for a week or so. Then remove them and post pictures. Reinstall and take the 911 out for some “sporting” driving and repeat the inspection. I’m not talking about track time, just driving down to Pueblo via the “mountain route” (US-285, CO-9 and US-50).

This will give you a much better indication of the engine running condition and your heat range choice.

If the plugs all appear perfect, install a set of “colder” plugs and repeat until they no longer stay clean. This is a good way to diagnose your engine condition and determine your correct spark plug heat range.

With your SC, you might start with NGK BP7ES and go to BP8ES and then nine and ten (too cold for normal use in your engine). These are relatively inexpensive sparkplugs but great in many 911s. Eventually you may compare to your Bosch plugs. With some careful comparison, you can find the best for your application.

One “size” doesn’t fit all. (That means that there isn’t a single sparkplug for every application.) Today’s sparkplugs have a wider “range” than 3-5 decades ago. In the good (bad?) ‘ol days, much of the “art” of engine tuning was selecting the correct sparkplug. Not too far off today.

I recommend everyone keep multiple sets of good (not fowled or overheated) sparkplugs as test indicators for your 911 engines. They are inexpensive indicators of your engine performance.

Best,
Grady

[Scott R]

Originally posted by Grady Clay
Scott,

I see five plugs that should have been replaced long ago and one that looks correct. It is remotely possible that #5 hasn't been firing.

My recommendation is to put in a set of new plugs and drive normally for a week or so. Then remove them and post pictures. Reinstall and take the 911 out for some “sporting” driving and repeat the inspection. I’m not talking about track time, just driving down to Pueblo via the “mountain route” (US-285, CO-9 and US-50).

This will give you a much better indication of the engine running condition and your heat range choice.

If the plugs all appear perfect, install a set of “colder” plugs and repeat until they no longer stay clean. This is a good way to diagnose your engine condition and determine your correct spark plug heat range.

With your SC, you might start with NGK BP7ES and go to BP8ES and then nine and ten (too cold for normal use in your engine). These are relatively inexpensive sparkplugs but great in many 911s. Eventually you may compare to your Bosch plugs. With some careful comparison, you can find the best for your application.

One “size” doesn’t fit all. (That means that there isn’t a single sparkplug for every application.) Today’s sparkplugs have a wider “range” than 3-5 decades ago. In the good (bad?) ‘ol days, much of the “art” of engine tuning was selecting the correct sparkplug. Not too far off today.

I recommend everyone keep multiple sets of good (not fowled or overheated) sparkplugs as test indicators for your 911 engines. They are inexpensive indicators of your engine performance.

Best,
Grady

Grady, #5 was not firing, the plug on the injector was not making contact with the pins. The other five were flooded a few times, and probably useless.

After having replaced the plugs, and fixing the connector I then found a plug wire that, when shaken went open, what a day. So now that all of that is replaced it's running fine. I'll pull the plugs again in a few days as I owe Eurosport another leak down test.

[Grady Clay]

Scott,

Good for you. Finding an actual problem is great. That is the way to a solution and you found it.

Now is the finesse. The guys at Eurosport can help you there.

This is a “Yahoo” day. Every mechanic lives for that kind of solution. Congratulations.

Best,
Grady

[Steve@Rennsport]

Great thread and applicable for many situations.

I'll add my 2 cents worth by recommending the installation of a set of Magnecor 8.5mm plug wires. These use connectors without those confounded and always troublesome resistors found in Beru & Bosch connectors. These are the foundation for a myraid of little misfires when they go "open", (its not IF; its WHEN).

Its a nice upgrade that eliminates a major source of running issues when trying to troubleshoot these cars.

[Scott R]

Originally posted by Steve@Rennsport
Great thread and applicable for many situations.

I'll add my 2 cents worth by recommending the installation of a set of Magnecor 8.5mm plug wires. These use connectors without those confounded and always troublesome resistors found in Beru & Bosch connectors. These are the foundation for a myraid of little misfires when they go "open", (its not IF; its WHEN).

Its a nice upgrade that eliminates a major source of running issues when trying to troubleshoot these cars.

I'm going to take your suggestion, I had them on my 951 and they were an excellent product. I may also go with an MSD at this point, or maybe Crane depending on which is a better fit for my EFI system.