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Resolved Slow throttle response and misfire

  • Thread starter Thread starter Tas_Jak
  • Start date Start date Sep 1, 2024
T

Tas_Jak

Member
Jun 1, 2024
42
10
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Virginia
Sep 1, 2024
#1
  • Sep 1, 2024
  • #1
Hey guys, I’m back rebuilding the engine and it seems to throttle up and seems to sputter and backfire. I’ll post a video of it in a bit but any ideas?
 
T

Tas_Jak

Member
Jun 1, 2024
42
10
18
Virginia
Sep 1, 2024
#2
  • Sep 1, 2024
  • #2
 

limp

wrap a little cheese around it and its a done
5 Year Member
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Sep 1, 2024
#3
  • Sep 1, 2024
  • #3
Timing?
Recheck your spark plug wires
Is your firing order correct for your cam? HO or non HO????
 
T

Tas_Jak

Member
Jun 1, 2024
42
10
18
Virginia
Sep 1, 2024
#4
  • Sep 1, 2024
  • #4
limp said:
Timing?
Recheck your spark plug wires
Is your firing order correct for your cam? HO or non HO????
Click to expand...
Ho, all spark plug wires are correct for the HO, my timings at idle is around like 8, which I know is low but shouldn’t affect it that much right? 88 Mustang btw with a maf conversion done.
 
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Tas_Jak

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Jun 1, 2024
42
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Sep 1, 2024
#5
  • Sep 1, 2024
  • #5
Also most of the sensors I’ve replaced
 

89ripper

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#6
  • Sep 1, 2024
  • #6
Tas_Jak said:
Ho, all spark plug wires are correct for the HO, my timings at idle is around like 8, which I know is low but shouldn’t affect it that much right? 88 Mustang btw with a maf conversion done.
Click to expand...
8? Stock base timing is 10. Was the conversion done right? This is efi so these things are important
 
T

Tas_Jak

Member
Jun 1, 2024
42
10
18
Virginia
Sep 1, 2024
#7
  • Sep 1, 2024
  • #7
89ripper said:
8? Stock base timing is 10. Was the conversion done right? This is efi so these things are important
Click to expand...
Set timing back to 12 since I’m running 93 in it, yeah pretty sure it wasn’t running like this a bit ago
 

89ripper

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Rockford, Illinois
Sep 1, 2024
#8
  • Sep 1, 2024
  • #8
Well you said replaced every sensor, did you reset battery? Because if you did it could cause driveability issues until it relearns everything. You have lots of variables here.
 
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Tas_Jak

Member
Jun 1, 2024
42
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18
Virginia
Sep 1, 2024
#9
  • Sep 1, 2024
  • #9
89ripper said:
Well you said replaced every sensor, did you reset battery? Because if you did it could cause driveability issues until it relearns everything. You have lots of variables here.
Click to expand...
It has a main electrical disconnect as it used to be a drag car, so the battery has been off and on repeatedly
 

89ripper

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#10
  • Sep 1, 2024
  • #10
Are you on a stock ecu?
 
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Tas_Jak

Member
Jun 1, 2024
42
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Virginia
Sep 1, 2024
#11
  • Sep 1, 2024
  • #11
89ripper said:
Are you on a stock ecu?
Click to expand...
That I’m not sure about, I know it has a msd ignition box but I’m pretty sure it’s a stock ecu but upgraded for the maf
 
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Tas_Jak

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Jun 1, 2024
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Virginia
Sep 1, 2024
#12
  • Sep 1, 2024
  • #12
But also this engine was running before and revving just pouring smoke out cause the heads were warped, I just don’t know why it would be doing this now.
 
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Tas_Jak

Member
Jun 1, 2024
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Virginia
Sep 1, 2024
#13
  • Sep 1, 2024
  • #13
Tas_Jak said:
Click to expand...
Update on this video, after holding down the pedal for a bit longer it will rev up but misfire, I can post a video if that will help again
 

General karthief

wonder how much it would cost to ship you a pair
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#14
  • Sep 1, 2024
  • #14
No video, thanks.
Unless it's longer..
Also do you have another thread with this car here?
I don't want to ask all the obvious questions about the build.
 
T

Tas_Jak

Member
Jun 1, 2024
42
10
18
Virginia
Sep 1, 2024
#15
  • Sep 1, 2024
  • #15
General karthief said:
No video, thanks.
Unless it's longer..
Also do you have another thread with this car here?
I don't want to ask all the obvious questions about the build.
Click to expand...
No the other thread I had was a few months ago for a smoke out the exhaust that led to me rebuilding the motor.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,892
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polk county florida
Sep 1, 2024
#16
  • Sep 1, 2024
  • #16
Then refresh the setup please.
 
T

Tas_Jak

Member
Jun 1, 2024
42
10
18
Virginia
Sep 1, 2024
#17
  • Sep 1, 2024
  • #17
General karthief said:
Then refresh the setup please.
Click to expand...
Simple 302, gt40 intake, b cam, cobra valavetrain.
 

89ripper

Founding Member
Jun 3, 2002
926
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Sep 2, 2024
#18
  • Sep 2, 2024
  • #18
So lets rewind, was running before, just fine now you got issues...what things did you change? You changed sensors, but why?
 
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