Okay so it all started with a very light almost unnoticeable backfire. Just like a putter that's it then kept getting a little more little more and I know I lost my muffler I know we're just going right out the pipe so redid the entire exhaust system and got rid of the cat I put the EGR return into the exhaust pipe itself figuring that's where it came from that's where it needs to go. Now it's go back firing so I do a full tune up plugs wires filter I replace the idle air sensor I replace the throttle position sensor I completely clean out the TBI like brand new I replace the EGR valve and even a few old vacuum lines that could have been cracked or broken. Now when I unplug the electronic timing and start it up it runs great no problems at least it seems like no problems so I undo the battery reset the computer put everything back up and she falls on her face backfiring the whole time. Also the check engine light is on but when I try to get a code all I get is a blink pause then 2 quick blinks. When i have the electronic timing wire plugged in check engine light flashes and it runs very rough the entire time but when I unplug that wire the check engine light does not come on and it runs pretty good. The last 3 months messing around with this thing has really giving me a severe headache and I feel like I put in a lot of time and did nothing. Someone tell me what this is before I run this thing off of a f****** Bridge into the river. Thanks for any help I can get. Camron
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Since it runs fine with the electronic timing bypassed , as long as the base timing is actually correct my first guess would be the ignition control module in the distributor .

 

You should put a timing light on it and see where it's at when you have the ECU timing control unplugged. IIRC, the TBI setups want the base timing set to 0 degrees BTDC. It may be that the distributor has moved or it needs moved into correct alignment. Always check and adjust base timing if you have some situation like this.

GD

 

I added some more to whats going on as I was just down messing around with it and remembered more info that may tip somebody off and thank you for your comments so far...

 

"Timing" WILL NOT cause a misfire. LEAVE IT ALONE and troubleshoot the car.

First thing I might do is a crude compression test... unhook the power wires to the dist, and the injectors; spin the motor with a good hot battery; listen to see if all cylinders sound even, with none that either slow the starter down nor let it speed up, compared to others.

 

Timing too retarded will cause a backfire. Your symptoms sound strange though. Not like just a timing issue. Definitely do a cranking compression test as sofa recommended. Possibly a damaged intake valve or two. Or one or more exhaust valves not opening. That the engine ran okay at one point, with no other change than the EST disconnected, then went to severe backfiring. This makes me wonder if the timing chains and gears are okay. A timing light will tell you if the chain is sloppy.

 

I would wonder about the timing chain. How is the idle?
A good way to check the timing chain is to observe the base timing. No matter where it is set, it should not wander or hop around . If it wanders, your timing chain could be worn out.