I Need Help Again, Knocking At Under Acceleration.

88droptop5.0

88droptop5.0

Member
Mar 4, 2015
135
8
18
NEPA
#1
I am in need of your help again guys, I have some weird noises that kind of sounds like knocking or chatter on acceleration. I just installed a new upper and lower intake GT 40 and I have my EGR unhooked and vacume pluged because it constantly had vacume (even at iddle). I also installed new spark plugs, spark plug wires, and damn near every sensor on the engine is new. The noise goes with engine RPM'S but isn't prominent at iddle.
Could my EGR be the new issue?when I bought the car about a month ago it didn't run the best, but I could swear I didn't hear the noise.
Thanks.
 

  • Sponsors (?)


#3
I would pull your codes. You may simply have a vacuum leak that is contributing, but the computer may have picked up something as well.

What are the rest of your symptoms, and please add as much detailed info as you can regarding what was changed and how it was all done.
 
#4
And word to the wise, never modify an engine that isnt performing up to snuff. Always get a good base to start with. Then when issues arrise, as they always do, you can go through a process of elimination. In this case, sounds like you're not sure what the problem was to begin with and now you've likely uncovered more
 
  • Like
Reactions: 1 user
#5
Thanks for the replies guy's,
I installed the upper and lower because the original ( also a gt40) was damaged. My timing is set to 10* with the spout removed and a warm motor. I unhooked and plugged my EGR vacuum because it had (has) constant vacuum to the valve. I reinstalled my distributor with marks that I put for a reference with the rotor position when I pulled it out, then timed it to 10 with spout removed.
The car fires up great and idles good at 600/700 rpm's, and rev's good. when I am driving it is when the noise is noticeable more so on acceleration, and the noise goes with engine rpm's. I cant tell if its spark knock, valve train noise or whatever else it may or may not be.
Ill check for codes after I get off work, Also I am thinking of doing a compression check and possibly re timing from scratch with some help from this awesome forum..:)
The biggest difference is my EGR being unhooked from vacuum and plugged up. I have my PCV, fuel pressure regulator, brake booster,and the main vacuum line going to my manifold vacuum connections.. What else is there....I'm at a lost..
Thanks guys...I really appreciate the help.
 
#8
You won't get the engine running codes to dump while you have 67 code...


Code 67 –
Revised 2 Nov 2012 to add definition of the NSS functions for both 5 speed and auto transmissions

Cause of problem:
clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests.

External evidence from other sources claims that a code 67 can cause an idle surge condition. Do try to find and fix any issues with the switch and wiring if you get a code 67.

What the NSS (Neutral Safety Switch) does:
5 speed transmission: It has no connection with the starter, and the engine can be cranked without it being connected.
Auto transmission: It is the safety interlock that prevents the starter from cranking the engine with the transmission in gear.
What it does for both 5 speed and auto transmission cars:
The computer wants to make sure the A/C is off due to the added load on the engine for the engine running computer diagnostic tests. It also checks to see that the transmission is in Neutral (5 speed and auto transmission) and the clutch depressed (T5, T56, Tremec 3550 & TKO)). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.

The following is for 5 speed cars only.
The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear. Jumper the safety pin to the ground near the computer.
Be sure to remove the jumper BEFORE attempting to drive the car!!!

a9x-series-computer-connector-wire-side-view-gif.71316
 
  • Like
Reactions: 1 user
#9
Ok, thanks. I'll try grounding pin #30 to the chassis with the computer plugged in and see what I get for KOEO code's. I ran KOEO with out pressing my clutch to the floor, should I try again with the clutch pressed or dosent it matter at this point?
Thanks
 
#10
88droptop5.0 said:
Ok, thanks. I'll try grounding pin #30 to the chassis with the computer plugged in and see what I get for KOEO code's. I ran KOEO with out pressing my clutch to the floor, should I try again with the clutch pressed or dosent it matter at this point?
Thanks
Click to expand...

You've gotten the running codes before I thought. Did you have the trans in gear when you ran the codes this time?
 
#15
The noise is more noticeable under acceleration and quiets down when I let off the throttle. You can here it in the video above, good news or bad I'm just not good at determining engine noises unfortunately..
Thanks, I appreciate the help...As always.
 
#16
I just did a compression test, starting with the driver's side back cylinder and working to the front, 120, 110, 120, 120.
Passage side starting at the back and working tords #1 cylinder, 120, 120, 110, 100.
Between That and the noise in the video , what's going on?
Thanks.
 
#17
Make a trip down to the auto parts store or Harbor Freight and buy an automotive stethoscope.
image_22652.jpg
Cost ~ $4 at Harbor Freight.

OR
Take a tin can and open it up, leave the bottom in place. Take a long screwdriver and put the blade tip on the valve covers. Put the closed end of the tin can up against the end of the screwdriver. You now have a stethoscope to localize the noise. Try putting the screwdriver blade tip in various locations on the engine to find where the noise is loudest. Loudest noise = location of your problem.
 
  • Like
Reactions: 1 user
#18
jrichker said:
Make a trip down to the auto parts store or Harbor Freight and buy an automotive stethoscope.
image_22652.jpg
Cost ~ $4 at Harbor Freight.

OR
Take a tin can and open it up, leave the bottom in place. Take a long screwdriver and put the blade tip on the valve covers. Put the closed end of the tin can up against the end of the screwdriver. You now have a stethoscope to localize the noise. Try putting the screwdriver blade tip in various locations on the engine to find where the noise is loudest. Loudest noise = location of your problem.
Click to expand...
Ok, I'll do just that and see if I can't identify where the noise is coming form.
Did it sound fatale to you ,or am I over thinking it?
Thanks
 
#19
88droptop5.0 said:
Ok, I'll do just that and see if I can't identify where the noise is coming form.
Did it sound fatale to you ,or am I over thinking it?
Thanks
Click to expand...
It depends on where the noise is coming from. Rattles and clanks have different meanings according to their source of origin.
 
  • Like
Reactions: 1 user
You must log in or register to reply here.

Similar threads

S
Fuel Spits sputter pops and bangs under load. Help wanted
Replies
22
Views
1K
Fox 5.0 Mustang Tech
sickntired
S
AnthonyA1234
Drivetrain Knocking noise when I turn key engine off
Replies
1
Views
834
Fox 5.0 Mustang Tech
slow84lx
S
G
Fuel Need Guidance on no FP reg reading
Replies
28
Views
2K
Fox 5.0 Mustang Tech
Gnfanatic
G
Creomod
Car popping car starts up but wants to die if I don’t hold pedal down
Replies
26
Views
1K
Fox 5.0 Mustang Tech
Creomod
Creomod
maxine-70
Engine adjust roller rockers on new 393
Replies
16
Views
1K
Fox 5.0 Mustang Tech
AeroCoupe
AeroCoupe
Top Bottom
Back
New
Hot
Menu