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popping sound and burning rich

(NW)Drake

who said that getting old sucks :-P
Ok, so my stang has a popping sound and its burning rich. I assumed the popping sound was an exhaust backfire but at a closer look I have carbon build up on my throttle body so now im thinking its an intake backfire. It also has power loss at any speed. All of this is intermittent (except the burning rich) and it seems to do it less when I let it warm up 100% all the way to 192 for the thermostat to open up. And it seems to it more when I don't let it warm up to 100%. Also I've replaced my cap and rotor, plugs, o2s, tps, evp sensor, iac, fuel filter. So tomorrow im going to double check my timing making sure its tdc then feasting the distributor. And if. Its still doing this im pretty sure I have a bad eec. I need input on this im so lost. I don't want to go get a new eec if I don't have to. And thanks Emilio you have been a great help. I just need some other input. I called a ford mechanic and he told me today that I could be down in the timing chain area where the problem is.
 

wickedstangs

Chula Vista, CA
Staff member
Administrator
1. Can you please post up all that has been done to the mustang like aftermarket parts. Is your timing chain gear adjustable? Meaning you are able to install it advanced or retard it a few degrees? Or was it installed straight up as in 0 degrees? Do you have adj rockers? And who set the valve lash on the adj rockers? Were the push rods checked for proper length? Push rod length is very important, if they are too long, the valves aren't closing properly. Remember to invest in a remote starter.

2. If it's not the rockers/push rod length, you need to check the timing gears and make double sure they are installed to 0 and not advanced or retarded. Backfiring through the intake usually means the intake valves are open and/or not all the way closed when the combustion chamber ignites, which could point to a degreed cam, wrong cam, incorrectly installed timing chain/gears, rockers out of adjustment, length of push rods, and so on....
 

(NW)Drake

who said that getting old sucks :-P
Everythis is stock except for cai, under drive pullys. As far as I know I will as the last owner today if anything else was installed.
 

Mustangcwo

Crew Chief
Staff member
Board Member
Drake, this sounds like a typical smog control issue. If you could pull down the codes and post them, it would allow us to evaluate it easier. If the car has an EGR, I would start there. I'm guessing that the EGR is hung open and therefore causing the car to run extra rich when it's cold and unable to adjust as you change speeds. This will cause also cause excess carbon to flow to the intake and create residue as well as backfiring from unburned fuel. If you do not have an EGR, then let me know; there are a couple of sensors to check.
 

(NW)Drake

who said that getting old sucks :-P
It does have an egr and im almost positive that I have a good one. The only codes is the o2 sensors say its rich. No codes for the koeo test just the koer test which is the o2s and idle is high. I replaced the tps
 

Mustangcwo

Crew Chief
Staff member
Board Member
If you replaced you TPS, you better verify the voltage. This could be the problem. If the throttle is not positioned correctly....OH MY!!! Sometimes Emilio amazes me...I know...it does happen.
 

Mustangcwo

Crew Chief
Staff member
Board Member
Did you set the timing? It should be set for 10 deg with the plug removed. Also, check your fuel pressure. With the vacuum line disconnected, it should be set for 36psi. To much fuel pressure can cause the car to pop. If you find no problems with timing or fuel, I would say a valve job is needed if it's popping through the intake.

One more shot in the dark would be a PCV.
 

(NW)Drake

who said that getting old sucks :-P
no i havent but all the symptoms stop after i let it idle for a few, they dont show back up till after its been off awhile. so if it was the timing chain it would be constant.
 

Mustangcwo

Crew Chief
Staff member
Board Member
The last two pieces to the ignition would be the module or pickup in the distributor. Can you swap distributors with someone? Maybe swap modules and see if the problem goes away.
 
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