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-   -   grinding noise on engine start (http://www.wranglerforum.com/f274/grinding-noise-on-engine-start-85298.html)

redz1 03-18-2011 02:18 PM

grinding noise on engine start
 
So even though my Jeep is under warranty, I can't take it to the dealer because this only happens once every couple days so i wouldnt know how to prove it.

Basically, if I leave my jeep in the driveway for over 2days without running it, the morning I do start the engine, the second the engine starts there's a quick grinding that goes away in a split second. Only happens once and then its fine until the next morning...the rest of the day it sounds fine.

Is this normal? The noise kinda sounds like a zip tie being tightened (that's the only thing I can think to describe it as).

My jeep is only 3 months old with 3k miles, and its a 2010.

It happens so quickly... Just a split second when the engine starts... But its a sound I haven't heard in any other car I drove, so I got worried...

BLEGAN 03-18-2011 02:20 PM

is it a loud sound? the only thing i can think of is.. (and it sounds dumb) youre holding the key turned too long :P

Wallygator 03-18-2011 02:25 PM

Could be a sticky bendix in the starter when its cold. Loosens up during the day. Or the starter might need shimming

GroundHawg 03-18-2011 02:27 PM

Quote:

Originally Posted by BLEGAN
is it a loud sound? the only thing i can think of is.. (and it sounds dumb) youre holding the key turned too long :P

JK's have the starting sequence computer controlled. For example when you turn the key for just a split second, the Jeep continues to crank till it engages.

That sound you hear is being discussed in another thread. A buzz type sound. Mine does more of a whine type deal on start-ups under about 15 degrees or so with a cold engine. I've only seen 2 JK's buzz at start-up and one had a starter slow to engage, the other had the fan make noise

BLEGAN 03-18-2011 02:28 PM

Quote:

Originally Posted by GroundHawg (Post 1124520)
JK's have the starting sequence computer controlled. For example when you turn the key for just a split second, the Jeep continues to crank till it engages.

That sound you hear is being discussed in another thread. A buzz type sound. Mine does more of a whine type deal on start-ups under about 15 degrees or so with a cold engine. I've only seen 2 JK's buzz at start-up and one had a starter slow to engage, the other had the fan make noise

too automated for me -.- haha. thats upsetting

Nu2Jeep 03-18-2011 02:31 PM

I know the noise you speak of. You are not alone. It was happening to my 2011 on very cold mornings this winter after not being run for a day or so. A split sound grind then normal operation. Wouldn't do it the rest of the day. Have not heard it since the warmer weather arrived. I don't think I was holding the key in the start position any longer than usual either. Meh, plenty of warranty left on her so I'm not losing sleep over it. Yet another "Jeep thing" I suppose.

bc3_Jeep 03-18-2011 05:31 PM

It really sounds like the starter is NOT disengaging at the appropriate time. I would definitely talk to the dealer about it. If you ignore it and it turns into something a bit more MAJOR...like flywheel teeth broken or starter going out......AFTER warranty period is up you will have no documentation that there WAS an issue.

Could be an issue with a relay being held on too long by the microprocessor ( internal timer value too large or output device faulty) OR a sticking relay after he microprocessor.

redz1 03-18-2011 05:49 PM

As much as you guys have explained so far... there's one thing wrong with some of your answers... I live in Florida. Our mornings are in the mid 70's, it isn't cold.
Could it be the fan starting up, or the AC? My roommate knows nothing about cars, but he told me his dad always says to turn the AC off when you turn the engine off... My AC is usually on.

Like I said earlier, it's less of a buzzing noise and more of a grinding noise, like the sound a zip-tie makes

Dgreen5630 03-18-2011 10:48 PM

My jeep does the same thing every once in awhile, I noticed only when I leave my ac on and the jeep has sat for awhile.

greenenvy 03-19-2011 10:02 AM

Quote:

Originally Posted by redz1 (Post 1124505)
So even though my Jeep is under warranty, I can't take it to the dealer because this only happens once every couple days so i wouldnt know how to prove it.

Basically, if I leave my jeep in the driveway for over 2days without running it, the morning I do start the engine, the second the engine starts there's a quick grinding that goes away in a split second. Only happens once and then its fine until the next morning...the rest of the day it sounds fine.

Is this normal? The noise kinda sounds like a zip tie being tightened (that's the only thing I can think to describe it as).

My jeep is only 3 months old with 3k miles, and its a 2010.

It happens so quickly... Just a split second when the engine starts... But its a sound I haven't heard in any other car I drove, so I got worried...

mine does exact same thing when its really cold out!! i know you said its not cold were you are.

chucky cheese 03-19-2011 09:28 PM

Not the cold. I'm in louisiana and mine does the same. Only on the first start of the day. Did not do it today though. I posted about it hoping someone else had the same issue and what it is.

mlebwill 03-19-2011 11:07 PM

I got that this morning for the first time. This morning was the first night outside of the garage and it was in the low 40's when I started the car. I'm going to leave it outside again tonight to see what it is. It sure doesn't sound like a starter motor grinding, in fact I'm not sure it was metal on metal grinding, more like plastic on metal. But I wasn't expecting to hear anything like that so I wasn't paying attention.

It sure got the "What the Hell!!!" juices flowing this morning.

Mike

HobieJeep 03-20-2011 12:14 AM

My 11 JKU Sahara used to do the same thing. It's the A/C. It doesn't do it anymore. Are you using Remote Start, and have Auto-Temp-Control?

chucky cheese 03-20-2011 07:34 AM

It could be the a/c. Will experiment and post results.

redz1 03-20-2011 02:49 PM

Quote:

Originally Posted by HobieJeep (Post 1127099)
My 11 JKU Sahara used to do the same thing. It's the A/C. It doesn't do it anymore. Are you using Remote Start, and have Auto-Temp-Control?

No and no :(

chucky cheese 03-20-2011 07:56 PM

OK, started it today without a/c on and no grind. Tomorrow I will start it with the a/c on.

im-ocd 03-20-2011 09:14 PM

Could it be related to the oil filter?
Maybe the drain back valve is allowing the oil to escape, so it takes a second or two for oil to get up there?

chucky cheese 03-21-2011 06:35 AM

Quote:

Originally Posted by im-ocd (Post 1128492)
Could it be related to the oil filter?
Maybe the drain back valve is allowing the oil to escape, so it takes a second or two for oil to get up there?

I changed my oil about 900 miles ago. I have a Bosch filter. Unless everybody else has Bosch I would rule that out.

gritsgresham 03-21-2011 06:38 AM

Quote:

Originally Posted by chucky cheese
I changed my oil about 900 miles ago. I have a Bosch filter. Unless everybody else has Bosch I would rule that out.

I have the same prob. I have a 2010 rubi and does it on mainly cold days

chucky cheese 03-21-2011 06:59 AM

Quote:

Originally Posted by gritsgresham (Post 1128956)
I have the same prob. I have a 2010 rubi and does it on mainly cold days

Mine stared the noise when it was approx. 55f out. My son was using it and he had the a/c on because it got up to 80f or so the day before. So it sat out all night at 55f with the a/c in the on position. Got in it at 4pm temp approx 80f started it and the grind/buzz happened. My son was about 8 feet in front and I asked did you hear that? and he said yes. So the next day same thing happened. I haven't had the a/c on the past few days, had the sunrider open so I have not shut it off and left overnight w/a/c in on position. Gonna start it today and see but I forgot to turn a/c on before stopping last night.

Mr-Ford-drives-a-Jeep 03-21-2011 08:35 AM

Mine does it too. I haven't localized to the ac yet but one thing to keep in mind for all of you is that the ac pump does get engaged when you have it to the defrost or floor positions. It does this to pull moisture out of and not cool the air to aid the defrost process. So even though your ac button says off the pump is still engaged. I'm gonna put it on dash only vents to make sure the pump is off.

Mr-Ford-drives-a-Jeep 03-21-2011 08:36 AM

Any combination of defrost only, floor only or a mix of the 2 does this. Floor and dash combo shouldn't.

redz1 03-21-2011 08:38 AM

Keep us updated. I feel like if I address the issue to the dealer they'll just blame it on my offroad adventures, since first impression of my engine bay is quite filthy. But the issue has been going on since before I took the jeep offroad

gritsgresham 03-21-2011 01:18 PM

Quote:

Originally Posted by Mr-Ford-drives-a-Jeep
Any combination of defrost only, floor only or a mix of the 2 does this. Floor and dash combo shouldn't.

Mine does it on combo also

Peepers 03-21-2011 01:24 PM

The a/c comes on with any combination with defroster, so if it is an a/c problem it would happen in the cold or warm.

ghendrix6 03-21-2011 01:33 PM

Mine did the same thing for a couple months in cold and hot temps. Now it seems to have stopped.

chucky cheese 03-23-2011 06:40 PM

OK I have narrowed it down to the a/c. When I last drove the jeep the a/c was on. Did not turn the a/c off when I turned the ignition off. Two days later started the jeep and grind noise. My theory is that there is head pressure on the compressor and when the jeep starts the belt cannot turn the compressor and the belt drags across the pulley causing the noise. I will experiment further and post. Oh yeah I am sure somebody will post that the compressor should not kick n when starting but I believe there is a fault with the system not Eliminating the compressor load at start causing the belt to vibrate.

Steel02001 03-23-2011 07:07 PM

So I have had it too

But only in the winter.

I think it has something to do with the blower. I say this because I have had the Jeep do this, turn off the heater and the noise stopped. Mine has only done it twice though so Im not to worried about it.

Just my $.02

Oh, and I have yet to use the A/C in my Jeep, if that adds anything.

chucky cheese 03-23-2011 07:14 PM

Quote:

Originally Posted by Steel02001 (Post 1134503)
So I have had it too

But only in the winter.

I think it has something to do with the blower. I say this because I have had the Jeep do this, turn off the heater and the noise stopped. Mine has only done it twice though so Im not to worried about it.

Just my $.02

Oh, and I have yet to use the A/C in my Jeep, if that adds anything.

See post # 21. Other settings the compressor is on.

Steel02001 03-23-2011 09:18 PM

Quote:

Originally Posted by chucky cheese (Post 1134520)
See post # 21. Other settings the compressor is on.

Sorry, thought I had read through it well.


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