Spark Knock/Dieseling Problem

Reply Subscribe

Thread Tools

Search this Thread

Apr 13, 2004 | 01:15 PM

cwgoff

Thread Starter

Junior User

Joined: Mar 2004

Posts: 85

Likes: 0

Spark Knock/Dieseling Problem

I have a '97 4.6L, manual transmission with 116K miles. Ever since I bought it last summer (@ 104K miles), I have noticed a little spark knock/dieseling when changing gears, especially if I am accelerating uphill. Recently, I changed the plugs/wires and cleaned the MAF. Since that work, the dieseling is definitely better, but it is still there some. If I am very careful as I come off the clutch, I get no noise, but if I shift normally, I get a little knocking.

In general, I get pretty good power (also better since the plug/wire change), but the dieseling is very annoying.

Can anyone offer advice on something else to try?

Apr 13, 2004 | 02:11 PM

PaulC

Posting Guru

Joined: Sep 2002

Posts: 2,297

Likes: 0

Carbon build-up in the combustion chambers?

Apr 13, 2004 | 07:38 PM

DRP

Senior User

Joined: Oct 2003

Posts: 239

Likes: 0

From: Heart of Dixie

I'm a little slow, so if somebody doesn't mind, please tell me what dieseling is.

Apr 13, 2004 | 10:24 PM

LxMan1

Moderator

Joined: Dec 2001

Posts: 22,436

Likes: 17

From: Louisville,Ky.

Actually dieseling is when it keeps trying to run after you turn it off. He is refering to pinging or detonation. It is when there is carbon built up in the combustion chamber that will get hot spots in it that will start to fire the air/fuel mixture before the spark plug does. Then when the plug fires, the two flame fronts crash together and this makes the knocking/pinging sound that you here. It will destroy pistons and such if it gets too bad.

Apr 13, 2004 | 10:33 PM

DRP

Senior User

Joined: Oct 2003

Posts: 239

Likes: 0

From: Heart of Dixie

Ahh, I had a feeling that is what it meant, but I was just making sure. Thanks

Apr 13, 2004 | 10:52 PM

PaulC

Posting Guru

Joined: Sep 2002

Posts: 2,297

Likes: 0

Do a site search on a product called "Seafoam".

Apr 14, 2004 | 07:00 AM

cwgoff

Thread Starter

Junior User

Joined: Mar 2004

Posts: 85

Likes: 0

Lxman1, you are right, I should have said pinging. Learn something new every day.

PaulC, the Seafoam sounds like something that I should try. I search the forums here as well as some info on other sites. It seems to be pretty hard to find. Any ideas on stores or online merchants that sell it. Does anyone know if any of the FTE sponsors would have it.

Speaking of FTE sponsor, where on the site are they all listed. If I do a parts search, I go to Motorhaven, but I have noticed if someone puts a link to a non-sponsor merchant, the site flashed a list of all sponsors before re-directing you to the linked merchant. I would like to go to FTE sponsors first, but where is the list? Thanks.

+++++++++
UPDATE: I found the Seafoam website (seafoamsales.com). On their site, they list several other retailers for their additive product. I called my local NAPA and they have it. I will give it a try soon.

By the way, the instructions say to add the product in several different locations (crankcase, throttle body and fuel). Any guidance on the procedure that you have used?

Thanks.

Last edited by cwgoff; Apr 14, 2004 at 07:44 AM.