Like tick/tap when idling, after PI swap

Mar 25, 2020
72
5
8
19
Springfield,MO
The car runs great, has good power but I noticed when it’s idling there’s a light tick/tap noise that I can’t hear from the engine bay, but rather under the car,I think it’s exhaust but I’m not too sure, has anyone else experienced this?
 
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XOTrumpet

Member
Dec 12, 2018
8
1
13
42
Huntsville, AL
I had an NPI block from a Crown Vic that was in mine when I got it. Just did a PI swap with heads from an '04. I noticed last week that I had a slight tick (not a knock) coming from underneath the car, noticeable exiting / entering the driver's side. I assumed it might be exhaust since I can't hear it in the engine bay. I also have a theory that, because it still had regular gas that had been sitting for 10 months before I did the swap, and I only put enough premium in it to get the bugs from the swap worked out that it is a slight ping. I'm filling it up this Thursday with premium, so I'll repost then.
 
Last edited:
Mar 25, 2020
72
5
8
19
Springfield,MO
I had an NPI block from a Crown Vic that was in mine when I got it. Just did a PI swap with heads from an '04. I noticed last week that I had a slight tick (not a knock) coming from underneath the car, noticeable exiting / entering the driver's side. I assumed it might be exhaust since I can't hear it in the engine bay. I also have a theory that, because it still had regular gas that had been sitting for 10 months before I did the swap, and I only put enough premium in it to get the bugs from the swap worked out that it is a slight ping. I'm filling it up this Thursday with premium, so I'll repost then.
That’s also what crossed my mind was that
It was just a slight ping, I can’t hear it at all when I’m driving which I thought was kind of weird.
 

McFly2

Member
Nov 21, 2020
68
10
18
63
Cincinnati
You can check your fuel STFT with live data scanner. If it is over + or - 5% at idle ( 12% or more) on bank 2 [that would indicate an exhaust leak] on the drivers side exhaust manifold to exhaust pipe connection. That would give you an out of normal range on O2 1 sensor also. ( Normal .1volt - .9 volt). A leak there ( drivers side exhaust manifold to exhaust pipe connection) will eventually give you a P0174 (bank 2 lean code) if it is a bad leak.

If exhaust leak is downstream of O2 1 sensor and (before O2 2 sensor ) you will get - out of range voltage reading there
(O2 2 sensor) when you live data scan on PCM scanner.
Midas usually has a ramp drive on lift. Easy to check for leak then.
 

XOTrumpet

Member
Dec 12, 2018
8
1
13
42
Huntsville, AL
That’s also what crossed my mind was that
It was just a slight ping, I can’t hear it at all when I’m driving which I thought was kind of weird.
Got a tank of premium in 'er and that seems to have quietened mine down. McFly2's suggestion seems good for a diagnosis if premium doesn't fix it. It'll keep you from rolling around on your back wrestling with the midpipe connection to the manifold. Those can be hard to seal, especially if you don't rotate through the bolts gradually when tightening them up. Good luck, and let us know!
-Josh-
 
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Mar 25, 2020
72
5
8
19
Springfield,MO
Got a tank of premium in 'er and that seems to have quietened mine down. McFly2's suggestion seems good for a diagnosis if premium doesn't fix it. It'll keep you from rolling around on your back wrestling with the midpipe connection to the manifold. Those can be hard to seal, especially if you don't rotate through the bolts gradually when tightening them up. Good luck, and let us know!
-Josh-
Well I tried premium didn’t change anything. Got a mechanics stethoscope and put it on the valve cover and I can hear a very very light tap that I can’t hear unless I use the stethoscope, but I placed it on the passenger side exhaust manifold and I can hear it pretty loud and clear, so I’m probably going to pull the valve cover and check the cam rollers because I’m thinking one of them is worn down? Not sure but I’m kicking myself for not inspecting everything better because i was thinking “ oh the heads only have 90k on them”:shrug::doh:it doesn’t affect anything it just sounds real crappy to me. But I will also be checking it out for an exhaust leak which id definitely prefer if that was the issue. Do you guys think a cam roller could cause this?