[JRmach1]

So i have this strange kind of rattle coming from the engine compartment. At first i thought it was my ragged trans, it was making all kinds of racket, but after i put the new one in, there is still some noise there. It happens at low rpm's under a very very light load, like 1800-2200ish rpm's or so, and as soon as i give it any gas it quits. Then i hear it again about 5k or so. It won't do it just reving, you have to be driving it. I've raised the hood and had someone rev it incase it might be an "accessory", but i can't hear anything. It does have the head tick, but the noise i hear is something different. Could the timing chain tensioners be wore out? The car runs fine, and has great power. Any ideas? I can try to take a vid so you can hear it if i need to.

[Trick Tuners]

Rule out detonation! Do you have a tune on it? Try adding higher octane and see if it stops.
Detonation Explained

[JRmach1]

Originally Posted by Trick Tuners Rule out detonation! Do you have a tune on it? Try adding higher octane and see if it stops. Detonation Explained

Yes it does have a custom dyno tune. I told the guy to see what he could get out of it, but still be a safe tune. I always run 93 octane in it, should i try some booster to see if it helps?

[Trick Tuners]

yeah. Pull some timing with the on device adjustments with the octane booster and see what happens. What engine mods are on the car?

[abhouse]

have you checked your exhaust pipes and shields my car had a bad rattle when i got on the throttle hard but only when i was going down the road just crawled under the car and started checking for loose bolts on all metal parts/shields and now its gone

[JRmach1]

It just has a c&l intake and 85mm mass air meter, o/r x pipe with flo's and turndowns. Made 293hp and 303tq, with the tune, on a mustang dyno back in the summer. And i honestly can't remember if i heard the noise before the tune or not. The trans made noises, and any new noises i heard i just assumed was it taking a dump.

[abhouse]

does your intake have a support brace that is bolted to the body of your car and to the intake tube?

[wraitherx]

where is the sound originating from? If it is your chain you can a broom handle or a long screwdriver and press it against the timing on each side to see if you hear anything. Also, as mentioned, check for any exhaust leaks.

[JRmach1]

It does have an exhaust leak from when i swapped the trans. The gasket on the header flange fell apart when i took the mid pipe off. But the sound i hear is completely different.

[JRmach1]

I took some videos but i doubt you can hear it. My exhaust kinda drowns everything out in the sound department.

xmas2009002.flv video by justinr1001 - Photobucket

xmas2009002.flv video by justinr1001 - Photobucket

xmas2009001.flv video by justinr1001 - Photobucket

xmas2009001.flv video by justinr1001 - Photobucket

[wraitherx]

I tried to listen to both videos but all i could hear was the exhaust try shooting a vid with the hood open and then push/pull the throttle lever so we can hear it. If your it were your tensioners you would hear a "chain slapping on metal" noise. If you dont hear anything close to that sound then it probably is something else.

[Safi]

Well there's your problem!























































Your gas gauge shows empty!

[Doc8224]

Does it sound like its kinda coming from the shifter area when you are driving?

[JRmach1]

Originally Posted by Doc8224 Does it sound like its kinda coming from the shifter area when you are driving?

Yes actually, it kinda does. Thats why i thought it was the trans at 1st. Then after i put the new one in, the "motor rattle/slap" was still there.

[98Cobra_sleeper]

is your motor stock? my engine does the same thing. it was rebuilt and there was a little too much clearance when the piston sizing was decided on, so there is a little piston rattle at light throttle, but it doesnt do it when i free rev it, only when i cruise.

[JRmach1]

Yes it is stock. Could it possibly be detonation? Maybe from timing being turned up to much or something?

[98Cobra_sleeper]

i think if it was detonation that it would do it all the time, could be wrong tho.

[Doc8224]

Did you put a new TOB and pilot bearing in when you did the tranny? If not that could be it, if you did, it's possible it went out or you got a bad replacement it happens more often than you'd think. I have the same rattle for over a year and it's the TOB. Forgot to put the new one in when the motor and trans went back in and got the same rattle.

[carnage]

im hearing the rattle but very little, but it almost sounds like what mine was doing and it turned out to be my mains where shot. but i would go through everything else first cause it will suck if it is your mains

[acidtonic]

Could be driveshaft too. If you get it while sitting still and revving then obviously no.

I had a u-join seize up which was completely unnoticeable until you hit speeds over 50mph when the shifter would vibrate like a cheerleaders purse.

Make sure the little weights on the driveshaft are there, and also lift the rear up with the car in neutral and spin one of the back tires by hand and watch the shaft spin to see if it has a wobble near the trans.

You should be able to swap between jacking the rear end, or jacking the body around the rear end to help diagnose. That will change the angle of the shaft and help you see a seized up u-joint which is harder to spot when the driveshaft is level with the trans.

If this happens without moving then scrap that as the issue. Next i'd pull the inspection plate on the trans and have a friend rev the car while you watch with the clutch in and again with it out in neutral. (be safe with eye protection since something could fly out)

I had a vibration from a failing TOB like suggested above. It was only obvious when the clutch was not pressed in. Car was squeaking in neutral while warming up in the mornings. It was loudest when the car was cold and got quieter as it warmed up.

Just a few things to think about. Good luck.