Knock Sensor? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

chich · 05-16-2004, 16:56

Hi guys. Been having a few dramas with my 96 Fairmont recently.. it seems to be activating the knock sensor or something and i cant pin point whats causing it. As the cars accelerating is makes a sound similar to that when hitting a limiter, stops accelerating, drops revs then picks up again and does this about three times. I've noticed it only does it on one particular stretch of road and i'm stumped as to what it might be. I initially thought the box was slipping but i've since had that checked out and everything is fine. Any ideas as to what it might be??
Just for the record i ran the car on optimax last week and didn't have a problem. Any help will be much appreciated

FE LTD · 05-17-2004, 19:27

Quote:

Originally Posted by chich

Hi guys. Been having a few dramas with my 96 Fairmont recently.. it seems to be activating the knock sensor or something and i cant pin point whats causing it. As the cars accelerating is makes a sound similar to that when hitting a limiter, stops accelerating, drops revs then picks up again and does this about three times. I've noticed it only does it on one particular stretch of road and i'm stumped as to what it might be. I initially thought the box was slipping but i've since had that checked out and everything is fine. Any ideas as to what it might be??
Just for the record i ran the car on optimax last week and didn't have a problem. Any help will be much appreciated

A mate of mine has a similar problem with his on LPG. When flicked over to petrol it comes good and then plays up a little while on LPG then comes good. Its always hard to know where the problem lies.

chich · 05-17-2004, 20:44

Do yoou know what caused the problem and how he fixed it? The thing thats got me stumped is why the problem only exists while going up slight inclines. Its really starting to shit me..

Mike Gayner · 05-17-2004, 21:37

Obviously spark knock. Check your timing (cam and ignition), fuel pressure, injectors and cooling system.

mongrelEB · 05-18-2004, 09:18

Sounds kind of like knock. Is there a high-pitched metallic rattle that accompanies it?

chich · 05-18-2004, 16:07

There's no metallic sound when the car does it. I spoke to another ford service guy and he recons its an electronic problem with the spark as well. He suggested changing the coil pack first and if that doesn't solve the problem start looking at the fuel system. What sort of life expectancy do the packs have? For the record its a 96 model with 135,000 kays.

mongrelEB · 05-19-2004, 10:12

No noise = not knock then. Weak spark could well be the go. Get Ford/any car sparky to test the coil pack, or, borrow a spare good one from a mate and give it a go.