Intake pop
 

I've been having an intake backfire here lately. But it only does it when it is cold and not all the time. What would be the cause of it? Any help is appriciated. timing is set at 10* I think.

Hello,

I had this happen to me on a 90 GT I had a couple years ago.

I replaced the motor with the GT-40 345 Hp crate motor. After that I had the pop in the intake when cold. When looking around I discovered a vacuum leak between the upper and lower intakes, beacuse the bolts weren't tightened all the way. The sound went pretty much away. It totally went away after I put a cobra intake on. So I do believe it was the vacuum leak.
I have also read that intake pop can be a emissions device problem. Like a stuck open EGR valve.

I have no emissions on the car at all. checked all the vacume lines had a small leak at the vacume tree. But after I fixed that it did it again just about a block away.

I had a similar problem with popping when I first got my Stang. It wasn't really isolated to th intake, but it wasn't a full on backfire either. Turned out to be a weak fuel injector. Once that was replaced, I never had the problem again.

I pop all the time when cold, blub, blub, pop, bang, ssss, etc.

It's a cold condition for me, no leaks etc.

Once Im warm, its warp speed, or speed limit. No more pop.

pop in the intake when cold is a lean condition, the Air temp sensor in the intake could be faulty and its a 10 dollar item. Also a vaccum leak would do this, or just as simple as a tune up is needed, possibly from moisture entering the igntion system components ( cap, rotor, wires, ). If an injector is bad or weak it will cause that too. Disconnect your mass air sensor and see if it pops from that.. it will hesiate but run the motor rich, if it pops still then its something else, like egr or worst case scenerio, burnt valve, however that would do it almost all the time.

i have the same conditon, slthough not sure if it is intake or exhaust. anyway, where is the air intke sensor located exactly and what does it lok like so i can check.change mine? thanks

jim

its on the lower intake manifold, under the plenum...

Looked at it today the bracket that holds the 10 pin conerters had poped off and disconected my vacume to the fuel pressure reg.

Rich condition, and vacuum leak... That will do it.. easy fix!

Where is the temp sensor on the driver side or on the pass side.

the Air Intake Temp sensor is on the drivers side of the intake..

right next to the thermostat housing??

no, its under the plenum ( upper intake ) it mounts at an angle.. Thats sensor is the coolant temp sensor..

i take it the upper intake needs to come off?

yea, there is way to much $hit in the way to get to it.

UHHHH I don't see a sensor under the plentum. Just Vacume lines.

There is one under there.. Its mounted on the lower intake manifold near the runners...

AHHH after the fifth cyl injector. You said under the plentum it doesnt look that hard to change with a deep well socket. I took it as under the plentum way the F@#% back there. OK