So like the title says, ...I have a light "popping noise" from the exhaust only when the engine is under load. (going up a hill or accelerating hard) Power seems unaffected, so I am assuming it might be something on the trailing ignition. I will confirm trailing spark at idle to rule out a coil, but if it is the ignitor, I am in need of advice as how to comfirm a bad ignitor...other than swapping in a known good component and driving. BTW...this is on the GLC...12a stock ignition.

 

I know that you said that it did not affect power but I still would be suspicious that it was pre-ignition. Have you done anything lately that would timing?

 

I wonder....it really seems to happen after the car is been on a long run. It might be time for a bit of maintenance anyway. The car has been a turn key driver for the past two seasons and I haven't even had the plugs out. I better confirm my timing too before I break this thing.

 

Just pulled my plugs...lol...everyone of them was so loose I could turn them by hand to remove them. I cleaned them well with a wire brush and a bit of brake parts cleaner. Despite all my flooding issues, theystill looked great, but they were really loose. Not sure if this was the issue or not, but I'm sure it doesn't help your ignition system to have loose plugs. Gonna get hold of a timing light now and see if my timing is ok.

 

Most people dramatically over-tighten plugs, so it's interesting to hear of some being too loose for a change.

 

Timing will have to wait until I get home this eve...we dont have one in the shop, and auto zone wants like 100 buck deposit to rent one. I have two at home...just have to remember to bring one to the shop and leave it here for instances like this. I'll just take it easy going home

 

its true...I have done more than a few cylinder head jobs that started out as tune ups due to overtightened, galled, and neglectedspark plugs. Ford's Triton V10 holds a special place in my heart for this...The worst thing the manufacturers could tell people is that they dont need to change their plugs for 100k!!!! By then they have practically welded themselves to the cylinder heads.

 

theres a thread somewhere here to test bad ignitor its not hard u just need sum jumper wires a 12volt battery and a test light but when one of mine failed the car just putterd to a stop n didnt start, but just maybe could be the igniter as mine did back fire and putter but i know on other cars with clogged cats ive heard this popping along with wat sound like a soft whistle( no noise just like blowing but with out sound) under load. make sure all exhaust flanges are tightned down. good luck tho!

 

haha and if youve ever had this happen on the ford engines that have sleeves on the heads for the plugs its a pain in the *** lol

 

Well I may have gotten to the bottom of it. My carb has been running very rich due to a bad float. The one barrel literally drips fuel in at idle. I think when I"get on it" after extended idling like at a red light for instance, the excess fuel is not getting burned and is leading to the pop pop pop noise in first sec and a tad of third. Power is def not affected...in fact the car feels better than ever aside from this and since the noise is in the exhaust and not the engine I will focus on sourcing some floats and a rebuild kit as well as maybe a wide band to do a proper tune on the nikki. I took several people for a ride to confirm my suspicions and all agree it may very well from being too too rich at idle for extended periods and then dumping that fuel in the engine to get burned all at once. It was fun to scare the **** out of my passengers all day today as well as drive the hell out of the GLC...always a good time.