Knock Knock Knock Knock Knock Knock .......help!

Hey,
I'm new to dsm's and considering getting one. The engine has recently been replaced with a remanned one. The car is a 1990 Eagle Talon TSi AWD & of course turbo.
The problem is the engine is knocking once warmed up. My question is what is the likely culprit for the knocking? I noticed when driving the car the radiator light was on right away and shortly after the check engine light was on. The car then started to die if the rpm's fell below 1000. I was thinking that the temp sensor is telling the cpu the engine is overheating & then retards the timing in return makes it knock. It sounded like it was coming from the top of the engine but am not sure. I havn't done a compression test yet, but I don't suspect low compression.
So how can I test this theory? Does this car have one or 2 temp sensors & where are they located? What should the readings be on it with a ohm meter? What else should I check?
Well that's it. Let me know what you guys think!
Thanks in advance...

[A//// Guy]

Temp sensors will not be the problem at all...

I would be that the timing belt skipped a couple teeth and you are close to destroying the engine if you start it a couple more times.

If you are going to buy that car beware that you will need to do a tbelt job and if the valves are slightly bent then a new head or rebuilt head will be needed.

As for the radiator light its prolly low on coolant.

ALSO ummm.. who are you, not many people are going to respond to someone that joins and just blurts out a problem. Read the rules about posting.

[LightningGSX]

Overheating itself can cause knock, timing retard will reduce/eliminate (not cause) knock.Fix the overheating issues and as long as everything else is in order, the knock should disappear.

So is it likely the car is overheating & that's it? If the temp sensor is reading normal how can I tell if the car is overheating? I am going back to the guy's house on Wednesday to check it out better, so what do you suggest I look at? What I was planning on is checking the compression, checking the timing marks & try to get the codes off the ecu.

Sorry "EclipseTurbo" about not posting anything about myself, but if I get the car I am sure you will see a lot of me!

Thanks for your help!

PS I hope this post makes sense. I wrote in a rush.

[TheBlizzard]

I think he is talking about the engine making a knocking noise guys, not that is actually knocking because of coolant temps, running lean, ect.

If you are hearing a knocking SOUND from the top of your motor and its not just a clicking noise from a lifter than you have some serious problems most likely. I would guess a rod bearing has went out on it. If it is knocking really loud you shouldn't be driving it or starting it at all.

Coolant temp sensors can cause the car to idle bad and to not start very good when its cold out due to the fact that it tells the ECU what fuel map to use for your weather temperature, hence the colder the more fuel you need. If one of them is bad, when its colder than 20 degrees, you will barely be able to start the car if at all. Since they ECU will think that air temp is way warmer than it really is and not give enough fuel. If you can get it to start it will run like shit until it bypasses that fuel map and goes to a alternate fuel map. Then it wil throw a CEL and start to run pretty decent until the next time it cools down.

DMM4ME, explain the problem a litte more. So is it noise or do you have a logger or something on it telling you its knocking other than noise?

CRAIG

[A//// Guy]

If the noise is audable at idle and while driving and its a deeper knocking not just a ticking lifter then I would guess that the valves are tapping on the pistons a little. This happened to me but not bad enough to bend anything.

If the engine sounds lumpy then I would assume the timing like I said before.


If I were you I would contact QPR and have "Raptor" -Mike- look inside the engine and see if everything is ok in the cyclinders. Also I would take a compression test because that is the BEST thing to do before buying a car especially one like this.
I have never experienced any problems with cooling causing knock.... Unless your really overheating but that would only produce real knock under boost.

[LightningGSX]

According to his first post, its only knocking when warmed up.And he stated the coolant light comes on, so overheating is the first thing that comes to mind(mine at least).I agree you should give more details, and definately check codes, cam timing, etc.

BTW Overheating can cause audible knock at any RPM or Boost level, not just WOT and under boost.

[JET]

I am with Craig, it really sounds like a rod bearing. The other possibility is if they decked the block or head too much, then the piston would hit the head at the very top of the stroke (the same thing can happen with a bad rod bearing). If you are describing it right, it sounds serious.

Now if it is just severe lifter tick or an exhaust leak or something (not sure how much experience you have with cars) then it isn't a big deal. Where is the car located at? Maybe an experienced member will take a look at it with you.

Thanks for all the posts!
Sorry for not responding faster but I switched the option to receive e-mail notifications for this post but got none!

I am in Salt Lake City, Utah. So if there is anyone here, please e-mail me. I don't know how much better to describe it. I took it for a short test drive & it started up fine. Once I got back to the guy's house I got out with it running & heard a loud constant which I assumed was a knock but I am not sure. I don't have a datalogger or anything like that. I have another car that 2 years ago broke a hose & overheated and that car sounded like a knock but once it cooled down it was ok. The talon sounded like this car except much louder & my other car is a Infiniti Q45 V8 (never ran right after that). I assume this car could be louder just because but I don't know! If it was a rod or the height of the head, how come it only knocks when warmed up? Does the timing belt or tensinor expand once warmed up? Probably a stupid question but this car does not have variable valve timing, does it?

So as it stands right now I will check the timing, compression(nervous about that) & the codes. I guess there is no way to know for sure if it's rod knock or a bad bearing huh?

So based on the info given, what do you guys think???

[JET]

If it is rod knock, it will be because of a bad bearing. There is no variable timing and the reason it will be louder when it warms up is that the metal will expand.

I would steer away from it, unless you are fine with putting a new engine in it.

[npaulseth]

Sounds like my car. It has a spun rod bearing.

So there is no simple way to check the rod bearings with out taking the oil pan off is there? What are the chances of something simple?

[JET]

With a deep sounding knock (not a high pitched lifter tick) the chances are pretty slim that it isn't serious.

[Raptor]

There isn't a lot (going by your description) that would make that type of knock and be easily or cheaply repairable. I would also say to steer clear of this thing unless it is some amazing deal and you don't mind sinking money into it. I think everyone has pretty well covered it.

Ok i'm back!

I partially checked out the car since there was no one home when there should have been. The cam timing was right on. The cooling system including the overflow was bone dry! The oil was burnt but not as severely as I've seen before. So now that the car has water, it should smoke pretty bad once started. I'm still going to do a compression test to determine if the head gasket is bad. Is there any way to check the turbo for water leaks? Correct me if I'm wrong, but the car is an iron block which isn't going to warp as fast an an aluminum block so do you think the car will be ok? The plugs weren't white so I assume the car wasn't driven since it started overheated.

What do you guys think?