wierd engine noise

[Mxpx182lit]

whenever my jeep's engine is running (4.0) it makes a very strange clicking sound. It sounds as if there is a leaf in the fan or the eqivilent of a baseball card in spokes. I checked, and there is nothing in the fan. Has anyone else had this happen or know what it could be? Also around when this started to happen my check engine light came on, but the only code it will give my is the Throttle Position Sensor, the same code its been giving me since i bought it. Any ideas or suggestions are greatly appreciated. Thanks in Advance
Justin

	Throttle position sensor A throttle position sensor (TPS) is a sensor used to monitor the position of the throttle in an internal combustion engine. The sensor is usually located on the butterfly spindle so that it can directly monitor the position of the butterfly throttle valve. The sensor is usually a potentiometer and therefore provides a variable resistance dependent upon the position of the butterfly valve (and hence throttle position). The sensor signal is used by the Engine Control Unit (ECU) as an input to its control system. The ignition timing and fuel injection timing (and potentially other parameters) are altered depending upon the position of the throttle, and also depending on the rate of change of that position. For example, in fuel injected engines, in order to avoid stalling, extra fuel may be injected if the throttle is opened rapidly (mimicking the accelerator pump of carburetor systems).

[Snitty]

can you at least pinpoint the sound to a particular area of the engine bay

[Mxpx182lit]

Well i have tried, but it is pretty loud. It seems that it is coming from the front of the block near the radiator fan and all the pulleys and stuff, but i wouldn't bet the farm on it.

[hi_c]

Perhaps you water pump is about to go. It should turn at the same speed as your fan. That'd be my guess. A remanufactured pump is pretty cheap and easy to install. I'd just swap it out.

[Snitty]

is it a constant pulasting click, or does it happen randomly

[Tug-n-pull]

Is it a valve tapping! tug

[Mxpx182lit]

could you explain to me what a valve tap is? Also, to answer snitty's ? it is a constantly pulsating click at what seems to be equal intervals of less the 1 second.

[Craig]

Check under your radiator. I think there's a rubber cover under the rad and fan. It could be pushed up, hitting the fan. Could happen if you've been through a mud hole recently. Try spinning the fan by hand to see if it hits anything. If it doesn't, you can rule that out.

[Mxpx182lit]

no, i checked and there was no rubber thingy, and when i spun the fan with the engine off it cleared everything and made no noise.

[Snitty]

does it increase with rpm? are there any cuts/nicks/holes in your belt? it could be valvetrain noise, it would be coming from your valve cover, or throttle body, or exhaust... unless there is a leak somewhere, you would also hear it from there

[Mxpx182lit]

it does not increase with RPM and there are no visible holes or cits in my belt? Any chance it could be the auto tranny? i did drive it home with no oil in it once and this was just before teh jeep started making noises?

[Snitty]

it could very well be the tranny... i didn't think about that... might be your TC being dry... or... could it be a rattle of some sort... maybe a broken weld somewhere, or a mount?

[jay89]

I had a similar problems and like Hi C said it was the water pump. grab the water pump pulley and move it up and down side to side to see if there is any movement. If there is then your pump is about to go.

[Bounty__Hunter]

Probably a cracked exhaust manifold. Get a 3ft. section of garden hose and hold it to your ear like a stethascope(sp). Listen to suspect areas and try to pinpoint the noise. Careful of the fan

[Mxpx182lit]

cracked exaust manifold? Would this be repalced if i got some headers?

[Snitty]

yeah, a header would take care of that... IF that is the problem

[Mxpx182lit]

would a proper way to check this be to spray some soapy water on the manifold and see if it bubbles? Also, could someone explain to me a valve tap and a way to tell the diffrence?

[Snitty]

well... you COULD remove your valve cover and see if the noise gets louder... and feel all the rocker arms, see if any is loose... if they are... torque them to the proper specs.... it is a good idea to take the cover off to clean it now and then anyway... the pcv system isn't the greatest, and is known be faulty when gummed up.... it is an easy process, and there really is nothing you can mess up if you stick to simply removing the cover, listening, and feeling...

as for the soap trick... i'm not sure if it would work or not.. i don't think it would because of the flow that would be coming out of it... it might work for household plumbing, and tire leaks... but the flow is much less there... i think a cracked manifold would simply blow the soapy water off in an instant... usually, you can see a crack if there is one... if it is in the back of it... use the stethascope trick with a hose... move around the engine bay and see where it seems to come from

[Mxpx182lit]

Thank you Snitty, you are a great help! I'll let you know what i find out but i cant check it now because my Jeep is in the shop getting the front Axle alligned.

[Snitty]

no problem my man.. keep us posted