I have a 85 Bronco II 2.8L v6 that has developed a backfire issue. I've gone through a number of rounds of getting the codes and replacing parts but so far with little improvement.

The first set of codes were: 23, Throttle Position (TP) sensor signal out of range, 32 Canister or EGR valve control system signal out of spec or EVP voltage low & 83 so I replaced the Throttle Position sensor, the EGR valve, the EGR Control and the EGR Solenoid (solenoid from the junk yard)

With all that done I' don't get the the 23 and 32 code anymore but I still get code 83 & 84

Some other perhaps related things going on is the backfireing blew out the muffler so I replaced it (now the new one is blown too, gotta fix the problem before I replace this one too) but I'm unsure how well it's sealed to the tail pipe and I wonder if the catalytic converter might have been damaged also (how would I check?)

I also noticed my cruse control stopped working around the same time my rough idle/backfire issues started to appear.

My speedometer will sometimes jump way out of range registering 60+ mph while I'm going slowly down the street at 15 mph then bump erratically then suddenly stabilize at what seems to be the correct speed.

I'm not sure at this point how to proceed. I need to eliminate the backfireing and I need to get the timing right and I need to trace down the code 83 & 84.

I've been messing with the timing a bit and my biggest problem is how to get the idle in range (800 rpm) I don't have a tachometer so I have no way of checking that idle is in range before I set the timing :/ Is there a way make sure my idle is reasonable before I set my timing without some sort of tachometer?

Any and all advice on how to troubleshoot any of these problems would be much appreciated.

Frustrated :/

Mark

 

*update*

OK, so I *think* I set the timing correctly. I had a bunch of trouble because I've got one of those timing lights that have a spring connector to expose the primary ignition wire to the timing light lead. First my timing light primary ignition wire lead aligator clip broke off and I had to do a quick repair, then the Engine would not start and run with the timing light connected. I left the spring connector in place and disconnected the aligator clip and I got it started. So I went to time it and found that whenever I touched the timing light aligator clip to the spring (connecting the primary ignition wire to the distributer cap) the engine would die (I assume becuase there wasn't enough power to push the spark through both the spring connector and the aligator clip). While the engine would bog down and die, I would get a flash or two from the timing light - just enough so I was able to set it at 10 degree's TDC.

I ran another set of codes and here is what I got:

E - 83, 83 then 1, 1, 4, 1, 8, 1, 4, 1, 8

What should I do next?