popping noise @ WOT

[6-Banger]

I have been getting a popping noise @ WOT and its not detonation. It will pop a lot when boost is over 21psi. I have a scanmaster and recording no knock. The car still pulls good. I did a compression test and had 145psi on 1,3,5 cylinders and 150 on 2,4,6. Any ideas? The car has the original coil pack and plug wires as it only has 16,000 miles.

 

[87NAT]

Either coil pack, ignition module or both. Ohm your plug wires. Check for a cracked spark plug.

I have had all of these issues along with a well rounded cam that caused some headaches one time.

 

[mikestertwo]

Is it popping in the intake or exhaust? Could be anything from running lean, ignition breakdown, to a blown/leaking head gasket.

 

[Top Speed]

Check your plug gap. You might need to tighten up the gap to 0.030" or less.

 

[6-Banger]

my plugs are gapped @ .032. It seems to be more of an exhaust sound than in the intake. If it were the headgaskets I would think that my compression test would have identified that problem. Could it be coil pack, module, or plug wires?

 

[kenny]

Yes, plugs, coil pack, wires, or ignition module can and will do that. A bad ground can cause it too. Check the grounds on the back of the head.

If you recently installed a MAF translator make sure you correctly set the dip switches...

 

[QUIP'6']

i second plug gap go a tight 30 and report back if it where a coil pack and or module it would do it at a lower boost. has this done it before at this boost level if not then i would look into coil pack or module. wires too

 

[mikestertwo]

If it were the headgaskets I would think that my compression test would have identified that problem.

Not necessarily. It could be caused by a high pressure leak during combustion. I would check the ignition system first though.

 

[gossamer]

i second plug gap go a tight 30 and report back if it where a coil pack and or module it would do it at a lower boost. has this done it before at this boost level if not then i would look into coil pack or module. wires too

If a coil was only getting weak, it might not show up at lower boost levels because there wouldn't be enough pressure to "blow out the spark". My car did the exact same thing and only at higher boost levels (15 psi or higher) Checked the coils and had 1 weak one. I agree though, check the entire ignition system. Coils, module, wires. :smile:

 

[GNVYUS 1]

Is the popping noise causing the boost gauge to spike due to an intake backfire?

Or is the popping causing the car to buck like a pissed off horse due to missfires which can be plugs, plug gap, wires, coil, module, damn too many things.

 

[GNRick]

Is the popping noise causing the boost gauge to spike due to an intake backfire?

Or is the popping causing the car to buck like a pissed off horse due to missfires which can be plugs, plug gap, wires, coil, module, damn too many things.

Add a bad TPS sensor to the list. Mine tested fine but under load it caused a nasty back fire or pop.

 

[6-Banger]

The popping noise is fast and a lot at times(not real loud, but loud enough to bo heard by driver and pass) only at high boost/ full throttle and it does not surge or jerk, it just keeps pulling hard. I'm going to check everything out this weekend.

 

[TurboBuRick]

Sounding more and more like a worn cam lobe. Prolly #3 exhaust.

 

[SloGN]

check the feul pressure to see if it's falling off in the upper rpm range. also close the plug gap up to a tight 28

 

[87NAT]

Sounding more and more like a worn cam lobe. Prolly #3 exhaust.

Thats what happened to me with my stock cam.

 

[QUIP'6']

headgasket!!!!. exhaust is escaping between the head and block. check out the other easy ways to eliminate first but it sure sounds like a headgasket especially if this just started

 

[mikestertwo]

headgasket!!!!. exhaust is escaping between the head and block. check out the other easy ways to eliminate first but it sure sounds like a headgasket especially if this just started

+1

 

[QUIP'6']

+1

i didnt see your post of the headgasket. that what it sounds like to me

 

[buickrob]

I had the same exact thing a few years back. It was bad plug wires. You could actually see them arc blue if you had the car running and popped the hood at night. I'd definitely spend the few bucks and do wires before anything else.

 

[6-Banger]

The coil pack ohmed good. Now it seems that when I'm in WOT not only do I here the noise(which gets louder with more boost, I've played with different settings, it starts around 18psi) but the boost will surge at times under WOT(feels like its cutting out). Fuel pressure is good(under WOT). I changed the plugs to the NGK UR5's gapped @ .028. The old Delco's and the new NGK's are way rich(I think my 02 sensor is bad), what would be a good replacement? Is there a way to visually check a ignition module? I opened it up and it looked/ felt like a semi-soft glue ( shortly after driving the car).