Engine got a knocking cold start, silint when hot

Sorry but you have a bad piston rod bearing or main bearing ! You won't have any indicators lit on the dash as this is a engine mechanical fault ! EGR - Knock sensor has nothing to do with this ! Take it to a shop an they will tell you the same thing .

knocked the ECT connector wires loose?
so my guess you mean, hot engine races,because cold engines all do that , by design.
racing idle hot.

1. engine not hot. thermostat bad.
2. engine hot and Ect Sensor lies, (wires fell off)
3. ISC valve stuck open or wires, bad to it.
4. vacuum hose knocked loose or you cracked it, now sucks air and engine races, (speed density EFI systems
5. .

lots more, but am lazy , on beach

ionMr. Hugo. what to what you do have is the viscosity of your engine oil. Most probably is either long mileage used engine oil and due to that oil mud built up inside the engine, in the oil pan and most likely close to the oil pressure pump filter reducing the suction and that is why you do have cold lifter knocking,as the engine oil that time is thicker and when it gets hot become thinner and lifters stopped knocking. My persona advise do flush the old engine oil using ( RESTORE MOTOR CLEANER ) pour it into the engine old oil,start the engine in idle and few times reving it for 40 minutes. Then drain it and renew the engine oil with new and recommended engine oil for your engine,by renewing the oil filter as well. Also in the new engine oil put also (RESTORE FRICTION REDUCER ) additive and run the engine.For next oil change please do it every 5000 km ( 3000 miles)

check bolts on wheel at crank

Okay, it may be due to overheating, that may be the noise you heard, lets hope. first allow engine to cool, open radiator cap or the resivoir cap, which ever is the fill, remove the bleeder at top hose and fill radiator slowly until coolant comes out bleeder.

note if water pump was replaced due to leaking and engine was overheated at that time then it may be a good idea to replace the thermostat .
after filling is done start engine and allow it to run. watch temperature if temp start to climb past half way shut engine down and let sit for 5min. then restart and check level, in res do not open cap . feel air from fan and see if it is getting hot, this may take up to a half hour but do not drive,

A few questions, does this jeep have an electric fan?
when you heard the knocking was engine temp hot?
If you start jeep cold does engine knock?
Did this jeep get a new thermostat with waterpump job?
did it overheat when pump went bad and why did water pump get replaced?

sorry for all the questions ,just trying to get all the info to help you .

Hi, sounds like the cold start system has problems, like a choke on a petrol engine that hasn't shut off when the engine is hot. When you can see black smok coming out of a diesel exhaust it is unburnt fuel that you are seeing, there is a wire on the injector pump that controls the cold start on diesels, make sure it is connected to the solenoid on the pump.

knocking is a big thing, its a cry for help.
can be minor to horrific
knocking parked? or only driving.
in neutal or park?
knocking hot block, or cold block or both? at what RPM>/
only real oil pressure gauge works, not the idiot lamp
when the lamp comes on at 3-5psi, the war was lost.
my 96 makes 55psi cold just cranking, want a video of that?
find the knocking first.

if can ,be knocked , parked.?
id check oil pressure. real.
use a $5 stethoscope. find it.
drop all belts. to see if an accessory device knocks. (5min test max cold to start, yes, water pump dead)
PS/AC/ALT dead too.
still knock>
listen at valve cover. coming from there.
is the timing belt is old over 60k thy all shard and some knock load hitting that cover, it a for sure thing, skipping the 60k mile service point,
exhast header collerctor fange gasket , bad, allowing bang band bang as the 2 flanges pound themselves to death.
the top of the engine, see induction pips. (AIR) those mounts for sure can bang away, bolts missing.

knocking:
1 overheated the engine so bad its pinging? knocks up hills?
2: say exaclty when and not you get the knocks.

if its at the top end its pistion slap
if its at the bottem end(of your engine) its a crank shaft bearing.

with out going into extream detail,

a ting sound at the top is a pistion slap.... replace all your pistions posibly over hual the engine.

a dubble knock that gose with rpm but sounds 2 knocks very every fireing of the pistion is a crank bearing..... replace your crank shaft bearings.... all of them b/c metal gose threw an engine extreamly fast and will destroy other beraings. this knock on start up will turn into a knock all the time, then a very louad knock that will end your engines life.

unfortunetly the answer is engine rebuild and fast.

Fuel filter or sensor problems is likely

Is there any smoke when you first start it? what is happening is the valve seals are probably worn and letting the oil seep past them. when your engine is first started it has no oil or very little oil at the top of the engine, thus causing the knocking noise. could be more but this is a most likely answer. oh and is you haven't changed your oil every 3,000 miles you had beeter start doing it.... answer knocking sounds usually come from bottom of engine try a better quality and correct viscosity oil