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Backfire after cleaning injectors

  • Thread starter Thread starter Choneymaster545
  • Start date Start date Aug 4, 2020
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    backfire help
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Choneymaster545

New Member
Aug 3, 2020
1
0
1
Illinois
Aug 4, 2020
#1
  • Aug 4, 2020
  • #1
Hi, recently bought a 2004 v6 stang and have been having some trouble.

When I first bought the car it was running great, no problems as far as I could tell and I was happy. Then I ran out of gas.

After I refilled it the car was running terribly. Rough idle and felt like the car was really struggling. Replaced the fuel filter, fuel pump, egr valve, dpve sensor. Still runs rough.

Cleaned the injectors recently and after putting back everything the car started backfiring through the exhaust.

Anyone know what might be causing the backfire? I want to be able to drive it to clean out all the gunk that might have gotten sucked up when the gas ran out.
 

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,387
2,745
194
Kearney, NE
Aug 4, 2020
#2
  • Aug 4, 2020
  • #2
One cause of backfire in the exhaust is late timing. Running very rich (a like a stuck injector or bad O2 sensor) and ignition problems are others. The backfire out the exhaust is from unburned fuel in the exhaust. Before adding more parts, I suggest asking the computer what it sees is wrong (do a code check).
I am not as familiar with that engine, so I will ask if you could have changed the ignition timing and if you can check it anyway.
When a young Ford Tech adjusted my timing to after TDC, the headers glowed from the gas burning in them in addition to your car’s symptoms.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Aug 11, 2020
#3
  • Aug 11, 2020
  • #3
+1 on above.

In addition. Double check that the spark plug wires have been routed correctly to the correct cylinders. If run to the wrong cylinders this could cause "timing" problems.
 
S

ShagsSN95

New Member
Jul 22, 2020
10
0
1
California
Aug 26, 2020
#4
  • Aug 26, 2020
  • #4
Choneymaster545 said:
Hi, recently bought a 2004 v6 stang and have been having some trouble.

When I first bought the car it was running great, no problems as far as I could tell and I was happy. Then I ran out of gas.

After I refilled it the car was running terribly. Rough idle and felt like the car was really struggling. Replaced the fuel filter, fuel pump, egr valve, dpve sensor. Still runs rough.

Cleaned the injectors recently and after putting back everything the car started backfiring through the exhaust.

Anyone know what might be causing the backfire? I want to be able to drive it to clean out all the gunk that might have gotten sucked up when the gas ran out.
Click to expand...

Were you able to figure out what the solution was?
 
S

Shuttleman83

Active Member
Jun 30, 2019
239
13
28
USA
Aug 26, 2020
#5
  • Aug 26, 2020
  • #5
Double and triple check the injector o rings, also, did you multi prime a few seconds each after first getting ready to start it the first time? Also, make sure the rail is fully and completely seated down tight.

Things to try:

Whack and reset the inertia switch once or twice.

Check Gas Cap (simple but happens)

Fully reset battery KAM (disconnect neg battery terminal for a few hours and tap the brake pedal once or twice to discharge while disconnected

Fuel Pump Ground

Vac line that goes to FP Regulator (make sure it's on and getting vacuum)
 
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