#1 plug sooty

[lwasson]

Merry Christmas!

Been driving the Esprit so I decided to check the plugs to see how she was working internally. All the plugs were great but for #1. It was black. Not wet just sooty.

The carbs were balanced with a 4-pot manometer about 3 weeks ago. All barrels should be in sync. Also cleaned and switched #4 and #1 plug. Same result so I know its not the plug. Could be the dizzy? Still smells and acts like she's running a little rich.

Any ideas before I tear into the carb.

Thanks!

louis

'83 Turbo

[WayneB]

Could be a bad #1 HT lead or your distributor cap #1 post is tracking.

[molemot]

The only real way to tell if you have a mixture problem is to do a proper "Plug cut". This involves driving the car at full throttle (not necessarily in top gear!) and then simultaneously switching off the ignition (but watch the steering lock!) and declutching, allowing the car to coast to a stop. Then you take the plugs out and examine them - this gives you a "snapshot" of what the inside of the engine is like when under stress. There are a number of illustrations which show what your plugs should look like, you'll find them somewhere on the interweb, but the main thing is they should all be the same! Sort of clean, not oily, light brownish - difficult to describe. If you have one sooty plug it could be that you have oil getting past the piston rings or valve guides; if it's OK on the plug cut then it's probably your idle mixture setup thats wrong.

[lwasson]

Thanks guys

Wayne I'm not familiar with distributor tracking? Can you give me a brief explanation. I will double check the distributor again.

I don't believe the soot is coming from oil in the combustion chamber. The soot is 'fluffy' so we're thinking on the lines of it being carb related. Never heard of 'Plug Cut' either. Will give it a shot. The 3 remaining plugs are the correct color. Lightly toasted. Not burnt or white.

Thanks!

louis

[WayneB]

If no.1 cyl was burning oil, the plug would be oil fouled (kinda wetish black deposit)

Carbon tracking is when the current to the plug electrode decides to follow another path which has a lower resistance.

The path coul be a hairline crack in the distributor cap, plug inslator or a split in the HT lead.

High resistance in the lead(broken continuity inside) can make this condition apparent as well.

It might not even manifest itself until higher engine loads or RPMs, when increased cylinder pressures increase the chances of this happening.

Edited December 23, 2005 by WayneB

[Kimbers]

If no.1 cyl was burning oil, the plug would be oil fouled (kinda wetish black deposit)

Carbon tracking is when the current to the plug electrode decides to follow another path which has a lower resistance.

The path coul be a hairline crack in the distributor cap, plug inslator or a split in the HT lead.

High resistance in the lead(broken continuity inside) can make this condition apparent as well.

It might not even manifest itself until higher engine loads or RPMs, when increased cylinder pressures increase the chances of this happening.

Seriously Wayne? is there no limit to your knowledge? Want a job?....

[WayneB]

You need Tiegans expertise, he works for NASA

[Kimbers]

   

You need Tiegans expertise, he works for NASA

Happy Christmas Mate, hope it's a good one......by the way, I', looking for some good Technicians for our Mercedes product!

[WayneB]

Thanks for the offer Tony, but my grandad would turn over in his grave if he found out I was working for the Geermonz

You and your dad should leave blighty and move out here its great

Edited December 23, 2005 by WayneB

[lwasson]

If no.1 cyl was burning oil, the plug would be oil fouled (kinda wetish black deposit)

Carbon tracking is when the current to the plug electrode decides to follow another path which has a lower resistance.

The path coul be a hairline crack in the distributor cap, plug inslator or a split in the HT lead.

High resistance in the lead(broken continuity inside) can make this condition apparent as well.

It might not even manifest itself until higher engine loads or RPMs, when increased cylinder pressures increase the chances of this happening.

<{POST_SNAPBACK}>

Thanks Wayne

Merry Christmas!

louis

'83 Turbo

[f1karting]

Hi Louis.. best of the season to you

I would also check 1) that the jets are seated fully; 2) that no crap has gotten into the idle or main jet air correctors; 3) to make sure the accel pump check-ball is seating. If it isnt, small amounts of fuel may leak thru the accel circuit/jet under normal running making the cylinder rich; 4) make sure the starter circuit is not bypassing fuel under normal running. cheers J

[lwasson]

Hi Louis.. best of the season to you 

I would also check 1) that the jets are seated fully; 2) that no crap has gotten into the idle or main jet air correctors; 3) to make sure the accel pump check-ball is seating. If it isnt, small amounts of fuel may leak thru the accel circuit/jet under normal running making the cylinder rich; 4) make sure the starter circuit is not bypassing fuel under normal running.  cheers J

<{POST_SNAPBACK}>

Merry Christmas to you Jan.

I will go thru your list.

Ho! Ho! Ho!

louis

[AJay]

The only real way to tell if you have a mixture problem is to do a proper "Plug cut". This involves driving the car at full throttle (not necessarily in top gear!) and then simultaneously switching off the ignition (but watch the steering lock!) and declutching, allowing the car to coast to a stop. Then you take the plugs out and examine them - this gives you a "snapshot" of what the inside of the engine is like when under stress. There are a number of illustrations which show what your plugs should look like, you'll find them somewhere on the interweb, but the main thing is they should all be the same! Sort of clean, not oily, light brownish - difficult to describe. If you have one sooty plug it could be that you have oil getting past the piston rings or valve guides; if it's OK on the plug cut then it's probably your idle mixture setup thats wrong.

<{POST_SNAPBACK}>

Careful doing a plug Chop on a turbo engine, 100000 rpm turbo suddenly starved of oil pressure when the engine is turning off is asking for premature bearing failure.

You pays your money you takes your choice!!

[USAndretti42]

What about the Gunson Colourtune? Lets you see the colour of the flame in the chamber. Sounds it might be safer than a plug cut.

Has anyone had any experience of the Colourtune?