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-   -   Something is definitely Wrong... '91 GT (http://mustangforums.com/forum/5-0l-1979-1995-mustang/694582-something-is-definitely-wrong-91-gt.html)

TripleG 05-03-2013 05:35 PM

Something is definitely Wrong... '91 GT
 
I have a 91 GT that recently developed this loud annoying sound on startup. I have searched the net and some people have mentioned a Camshaft Position Sensor...but none specifically for a foxbody 5.0. The sound is similar to videos posted on the CPS, however I have uploaded 3 videos in an effort to solve this quick since it is related to the engine and it is my daily driver.

The noise is definitely not pulley or belt related as it is coming from the driver side of the engine near the firewall. Descriptions of videos will pertain to the stage.

Here's to hoping its not something major...

Video 1

Video 2

Video 3

TripleG 05-03-2013 05:38 PM

In video 1, when the car gets close to dying, that was me pushing on the throttle housing in the opposite direction...

mattdel 05-03-2013 06:25 PM

Its mechanical in nature, and goes away with throttle, so its a moving part, possibly oiled. Broken valve spring/seat ?

Maxwelhse 05-03-2013 06:48 PM

Under the hood it sounds like a heinous exhaust leak to me....

You still have your EGR cross over tube?

89StangGTConvertible 05-03-2013 06:54 PM

sounds like a valvetrain related issue to me... possibly lifters...?? sounds awful... hope you get it figured out quickly... I wouldn't run it too much...

holyshift 05-03-2013 07:24 PM

Definitely a valve train issue. Pop that intake off and valve covers....time to get dirty.

pedalhappy 05-03-2013 11:07 PM

yep under the valve covers

tinman 05-03-2013 11:56 PM

I'd go with valve-train here too.
Look real careful at pushrod/rocker arm...........

TripleG 05-04-2013 04:59 PM

Got the valve cover off and the rocker arms and push rods look ok. Any specific way to inspect these besides visual and checking the security of the components?

TripleG 05-04-2013 05:41 PM

Quote:

Originally Posted by 89StangGTConvertible (Post 8206738)
sounds like a valvetrain related issue to me... possibly lifters...?? sounds awful... hope you get it figured out quickly... I wouldn't run it too much...

found a great video on the youtube about lifter noise. Going to try the engine flush technique and see if that alleviates the problem. Thanks for the direction.

TripleG 05-04-2013 08:16 PM

Well, the noise is gone for now. I opened up the valve cover, everything appeared to be in good condition. Taking the lifter direction, I found a video with a similar sound and lifters in the conversation. With that, I took motor flush to the engine, some B-12 ChemTool into the hole of the rods near the suspected sound. Bolted everything back up, ran the motor flush for 5 mins as directed. The noise had not quite subsided yet, changed the oil again (noise originally started about a week after an oil change). Let engine circulate oil, noise subsided for now. Test drove it around the block, all was good. Letting it sit the rest of the night and see how it does on a cold start tomorrow. Thanks for the help so far!

89StangGTConvertible 05-04-2013 08:37 PM

Quote:

Originally Posted by TripleG (Post 8207324)
Well, the noise is gone for now. I opened up the valve cover, everything appeared to be in good condition. Taking the lifter direction, I found a video with a similar sound and lifters in the conversation. With that, I took motor flush to the engine, some B-12 ChemTool into the hole of the rods near the suspected sound. Bolted everything back up, ran the motor flush for 5 mins as directed. The noise had not quite subsided yet, changed the oil again (noise originally started about a week after an oil change). Let engine circulate oil, noise subsided for now. Test drove it around the block, all was good. Letting it sit the rest of the night and see how it does on a cold start tomorrow. Thanks for the help so far!

sounds like your lifters, etc., were gummed up... hoping the flush does the trick... cautiously optimistic.


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