This is bugging me....seems to happed when the motor is cold, but every one in a while I'll get a quick pop from the right side of the motor when accelerating. I have installed new o2 sensors and a new mass air. I have a MAC cold air intake but I don't think that is causing it. I know I haven't given too much to work with but anyone know what would cause a pop (or backfire) from the right side of the motor? Thanks in advance.
Weird pop
- Thread starter Ostang351
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What year is your stang? Or what kind of car is it? I've heard alot about the 88's having bad injectors. Mine had them, every now and then, especially when the motor was cold, I would get a pop through the intake. After I replaced my injectors with ford racing ones, it never has happened again. You need to pull the codes and do the cylinder balance test. After you read the last engine running code, rev the engine once, just make sure it goes up to 2500 or so. The puter will pull the injectors one at a time and record the rpm drop that each one causes. If there are any weak injectors, it will flash the # of those cylinders. If it detects weak ones, this is most likely the cause of your "lean pop". Here is how you can pull the codes, all you need is a test light if you dont have a check engine light in the car. Use the test light in place of the analoge volt meter.
Thanks for the reply...it is a 1990 5.0 5spd, cobra upper and lower, edlebrock aluminum heads, stock ignition, exhaust, cold air intake, pro m mass air, tb b303 with 1.72's. It only really does it when the engine is cold and will pop once or twice. I can tell it is going to happen because if I shift easy into second and give it a bit of gas, it will hesitate then pop, then pick up and it won't do it again. After it warms it is fine. The coolant gague isn't working...it is hooked up on he intake but the gauge doesn't work in the instrument cluster. Could the computer be seeing that? Maybe a vacuum leak? It idles fine with the B303 right around 800....no surging. I am stumped. I have a check engine light so how would I jump the test breaker? (where you put the test light in)????
giddyup306
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- Oct 22, 2002
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Ostang351 said:
It could be. If you have too much air entering the engine it will act like it's overcarbed (although it's SEFI). What size tb do you have? Could also be a valve not seating properly or a lose timing chain as well. It could aslo be a vac leak. The only time I've seen the injectors be the cause of a popping sound is when people replace them and the o rings aren't sealed properly. This will cause a vac leak and the sounds your describing.
The diagnostic connectors pictured are located behind the drivers side strut tower. Since you have a CE light, you will only need the jumper wire pictured, then read the flashes on you CE light. If one injector is not putting out enough fuel, the puter will read that as lean and put more fuel to all of them. Thats the purpose of the cylinder balance test, to make sure they are all equal. That was my fix anyway, may not be yours. Try pulling all the plugs and look for one or two that are different than the rest. Remember what cylinders they came from if you see something suspicious.
mine does that too, its a 88 with a 93 motor in it, when its idlein its popin out or mostly the drivers side tail pipe, i thought it was the mufflers doing it but its not you see barly any moisture out ot the drivers side and when i rev it up lets say 2500 you can hear a loud pop out from the back on deaccel, just wonderin if that is the same thing, i mean this baby pops like crazy, could equal lenght headers do that popin sound or no cats????
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