1994 Pontiac Firebird 94 Firebird has a miss/backfire

Tiny
LUTHERNICHOLS2769
  • MEMBER
  • 1994 PONTIAC FIREBIRD
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 196,000 MILES
Hey my 1994 Pontiac Firebird is an automatic, and has a 3.4 V6. The woodruff key broke, and the car died and would not start. So we took it apart and fixed the woodruff key and put a new timing set on it. Now she starts and runs, but has a miss/and will backfire. I am wondering if the timing could be off, cuz we eyeballed the timeing. Or if its abent valve. Or what. Any help would be appreciated. THANKS!
Monday, October 27th, 2008 AT 6:38 PM

14 Replies

Tiny
RASMATAZ
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Hi luthernichols2769 and welcome to 2carpros

When you changed the timing set did you put the no.1 piston on its compression stroke? If not the valve timing is off-
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Monday, October 27th, 2008 AT 6:47 PM
Tiny
LUTHERNICHOLS2769
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We changed the woodruff key, the cam gear, and the crank shaft gear. What do you mean about the valve timing?
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Monday, October 27th, 2008 AT 6:59 PM
Tiny
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If the cam and crank gear are not line up as indicated in the repair manual the valve timing will be off-meaning the valves are opening and closing at the wrong time-
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Monday, October 27th, 2008 AT 7:05 PM
Tiny
LUTHERNICHOLS2769
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Me and my friend alligned the cam shaft dot with the crank shaft dot, then with the harmonic balancer. I bought a repair manual and it shows me that the cam shaft is supose to line up with sometingn on the oil dampener, then the crank shaft is also supose to alligne with something on the oild dampener. However we alligned the cam and the crank to eachother. We did not use a repair manual or timing light we just eyeballed it like I said. However I bought the repair manual today and it shows that the cam and crank allaigh on different spots on the oil dampener. I want to make sure im not just missreading the diagram and instructoins. So if you could double check I would appreciate it. Ill attach a picutre of what it looks like in the diagram.
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Tuesday, October 28th, 2008 AT 12:23 AM
Tiny
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Heres the diagram as shown in the GM Chilton repair manual


https://www.2carpros.com/forum/automotive_pictures/262534_Timing_Set_Diagram_1.jpg

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+1
Tuesday, October 28th, 2008 AT 12:26 AM
Tiny
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The pic below does it look anything like yours for cam/crank alignment?
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Tuesday, October 28th, 2008 AT 12:59 PM
Tiny
LUTHERNICHOLS2769
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Well no. Me and my friend alligned the cam gear dot inline with the crank gear dot. Unlike in the picture in the repair manual, where it looks like they line up with something on the oil dampener seperatly. And NOT with eachother. The picture below is how we did it.


https://www.2carpros.com/forum/automotive_pictures/262534_Timing_Set_Diagram_g_2.jpg

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Wednesday, October 29th, 2008 AT 2:18 PM
Tiny
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Did you put the engine no.1 piston on its compression/TDC before you line the cam and crank-also did you stabbed the distributor properly and align rotor to no.1 cap tower
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Wednesday, October 29th, 2008 AT 2:23 PM
Tiny
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I am not sure lol. My buddy is workin on it, Im just there watching. I do know tho that it does not have a distributor. Its a 3.4 l V6. So idk what that would be called that takes place of the distributor.
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Wednesday, October 29th, 2008 AT 2:30 PM
Tiny
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Oh! Boy-okay disregard the distributor its a DIS-if its not on no.1 piston compression stroke and not align properly it will cause the valve timing to be off-
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Wednesday, October 29th, 2008 AT 2:39 PM
Tiny
LUTHERNICHOLS2769
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Ok. How do I check to make sure its on the no.1 piston compression stroke? And if its not How do I go about doing that. Would it tell me in the manual?
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Wednesday, October 29th, 2008 AT 2:48 PM
Tiny
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Its in the repair manual
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Wednesday, October 29th, 2008 AT 5:02 PM
Tiny
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Ok well we believe the timing is correct. So now Im completly out of ideas. She backfires lol. And were pretty sure its in the no1 piston compression stroke or w.E
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Wednesday, October 29th, 2008 AT 10:42 PM
Tiny
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Check the fuel pressure make sure its within specs-
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Thursday, October 30th, 2008 AT 12:29 PM

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