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penguinz
10-27-2006, 12:34 PM
My car won't start. I hooked up a computer diagnostic tool and it said that the Knock Sensor is faulty. Could this prevent a car from starting?

Brock
10-27-2006, 12:38 PM
Maybe put some gas in it?

dtebbe
10-27-2006, 12:39 PM
Year, Make, Model?

I would say no to the knock sensor, if anything that would just cause the ECU to pull some timing out.

DT

penguinz
10-27-2006, 12:40 PM
Maybe put some gas in it?
Has a full tank smartass. :)

Brock
10-27-2006, 12:42 PM
Maybe the battery is dead.

penguinz
10-27-2006, 12:43 PM
Year, Make, Model?

I would say no to the knock sensor, if anything that would just cause the ECU to pull some timing out.

DT'96 Nissan Altima.

Already checked the fuel pump and filter and they are fine.

When trying to start it acts as though it is not firing except for the occasional backfire.

Has new( couple months old) plugs and wires.

Bowser
10-27-2006, 12:43 PM
Maybe the battery is dead.

Do you have a key?

Radar Chief
10-27-2006, 01:05 PM
Year, Make, Model?

I would say no to the knock sensor, if anything that would just cause the ECU to pull some timing out.

DT

Agreed, at least I wouldn’t think that’d be the case.
A “knock sensor” is basically a microphone attached to the engine block that’s look’n for a certain frequency range of noise to determine “knocking”. If it encounters knocking, it’ll retard ignition timing ‘till the knock goes away.
I ‘spose it’s possible, but wouldn’t think it’d keep your engine from fire’n all together.

StcChief
10-27-2006, 01:26 PM
'96 Nissan Altima.

Already checked the fuel pump and filter and they are fine.

When trying to start it acts as though it is not firing except for the occasional backfire.

Has new( couple months old) plugs and wires.Checked recalls
I didn't see one call Dealer may have been a recall for faulty sensor.

Here is the part.
http://www.autopartswarehouse.com/shop_parts/knock_sensor/nissan.html

penguinz
10-27-2006, 02:14 PM
:(

Halfcan
10-27-2006, 02:22 PM
Take it to carmax and trade it in.

penguinz
10-27-2006, 02:37 PM
Take it to carmax and trade it in.
If I could afford a monthly car payment I would have traded it in a year ago.

C-Mac
10-27-2006, 02:57 PM
A knock sensor will not keep the car from starting, but a flow sensor will. You need to first determine if your getting spark and/or fuel to start any kind of analysis.

penguinz
10-27-2006, 03:10 PM
I found this on another site where someone was having a similar problem with an Altima that was a year older..

Knock Sensor: A sensor mounted on the engine that is designed to detect the high-frequency vibrations caused by detonation. By employing a knock sensor, a computerized engine-control system allows an engine to operate very near its detonation limit: thereby improving power and efficiency.

If the knock sensor is shorted it will advance timing too far and stall the engine. If it is out of the loop then timing will be retarded and stall the car.

penguinz
10-27-2006, 03:11 PM
A knock sensor will not keep the car from starting, but a flow sensor will. You need to first determine if your getting spark and/or fuel to start any kind of analysis.Fuel flow is fine. The distributer is sparking. Plugs and plug wires are only a couple of months old.

PastorMikH
10-27-2006, 03:14 PM
I found this on another site where someone was having a similar problem with an Altima that was a year older..

Knock Sensor: A sensor mounted on the engine that is designed to detect the high-frequency vibrations caused by detonation. By employing a knock sensor, a computerized engine-control system allows an engine to operate very near its detonation limit: thereby improving power and efficiency.

If the knock sensor is shorted it will advance timing too far and stall the engine. If it is out of the loop then timing will be retarded and stall the car.




This makes a lot of sense to me. If the sensor has shorted and the timing is way off as a result, that would explain the backfires.

I'm planning on calling dad later. I'll try to remember to ask him about it. (he's worked on nissan/datsun since '72)

penguinz
10-27-2006, 03:16 PM
This makes a lot of sense to me. If the sensor has shorted and the timing is way off as a result, that would explain the backfires.

I'm planning on calling dad later. I'll try to remember to ask him about it. (he's worked on nissan/datsun since '72)
Thanks!

C-Mac
10-27-2006, 03:29 PM
I havent experienced a knock sensor that would prevent a car from starting. I wonder if your timing belt has shot the craps.

Hog Farmer
10-27-2006, 03:45 PM
There's only one thing that will cause the Knock sensor to malfunction.

penguinz
10-27-2006, 03:52 PM
I havent experienced a knock sensor that would prevent a car from starting. I wonder if your timing belt has shot the craps.My car has a timing chain.

penguinz
10-27-2006, 03:53 PM
There's only one thing that will cause the Knock sensor to malfunction.
Thanks for the descriptive help.

C-Mac
10-27-2006, 06:32 PM
My car has a timing chain.

The ones I seen had a belt, but chain is good. You can reset the computer by taking the positive terminal off and touching the negative. If you have fuel and spark you should have ignition. One of the two isn't sufficient enough. If you have some starter fluid sqirt some in the intake and see if it fires.

PastorMikH
10-28-2006, 08:37 PM
Talked to dad today. He said that the Knock Sensor would NOT cause the problem you are having. I told him about it not starting and the only sign of the ignition system working was occasional backfiring. He said to check on the bottom side of the distributor cap and see if it was oily - you can also pull the cap and check for oil inside the distributor. If this is the case, the problem is an oil seal is out causing engine oil to get into the distributor. He said you could temporarily fix it by pulling the cap and rotor and spraying everying down really well with brake cleaner but it won't last and will eventually need a new distributor.

That was the only think he could think of given what I was able to tell him. Hope this helps.

penguinz
11-04-2006, 06:15 PM
Thanks

PastorMikH
11-04-2006, 06:25 PM
Thanks


Hey! Your back!

Did dad's info help?

penguinz
11-06-2006, 02:28 PM
Hey! Your back!Endelt banned me for a week. :p

Did dad's info help?There is oil on it. I had to replace a valve gasket not too long ago. The oil leak fried an alternator so it is very feasible it crapped out the distributor also.

Thanks again.