Backfiring and popping; what now???

[GTSnake]

It has not been a fun summer for me. The car was running great until last night. It started backfiring and popping more and more. Anytime i decel under load it backfires. If I put it in neutral the engine goes to idle and no backfiring. Under acceleration it runs a little rough. Seems like there's a loss of power and sometimes would hesitate.

So far no codes have shown up. I've checked the MAP sensor and it seems ok. Couldn't be spark plug wire since it would throw a code right away.

Anyone have any ideas?

 

[plumcrazy]

you sure it would throw a code if it was wires or plugs ?

do you have a VEC unit ? try changing the tune if so

 

[GTSnake]

I had a loose wire when I changed headers once. Within 1 mile a misfire code popped up. I haven't changed the program since last year. Ill try reentering a leaner program but how can it change on its own?

 

[99 R/T 10]

I would start by changing the wires if they are over a year old, could be crossfiring.

 

[mjorgensen Woodhouse]

Could be an 02 sensor going bad and giving incorrect data to the PCM.

 

[mike & juli]

Another guy had this problem, where his Viper just started out of the blue popping on decel in VERY HOT AND MUGGY weather....since it's a *new* problem, do you think that's the case for you, also, being in Detroit----is it extremely hot/muggy right now? Just a thought as it happened to another NYC guy when it was dripping hot/muggy...not much air to flow thru. ~juli~

 

[dave6666]

Another guy had this problem, where his Viper just started out of the blue popping on decel in VERY HOT AND MUGGY weather....since it's a *new* problem, do you think that's the case for you, also, being in Detroit----is it extremely hot/muggy right now? Just a thought as it happened to another NYC guy when it was dripping hot/muggy...not much air to flow thru. ~juli~

From Texas... What ya'll call a hot & muggy day?!?

 

[IEATVETS]

I had the exact same thing happen when I had my Gen1. What it ended up being was a spark plug. Part of the insulator had broken off and slid down to where the plug actually sparks and that was preventing that plug from sparking. I replaced that plug, test drove the car and problem was solved! That is where I would start, good luck.

 

[mike & juli]

From Texas... What ya'll call a hot & muggy day?!?

LOL--DEFINITELY not what you guys have!!! Us here in Michigan, NY State--same type of weather, hot and muggy; air is so humid that there's not much air going THRU the car/filters..much less COOL air.... you guys have that there 'dry heat' thing???? ~juli~

 

[dave6666]

LOL--DEFINITELY not what you guys have!!! Us here in Michigan, NY State--same type of weather, hot and muggy; air is so humid that there's not much air going THRU the car/filters..much less COOL air.... you guys have that there 'dry heat' thing???? ~juli~

Reeeeeeeeeeeealy dry...

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Hey... Screw that dry heat thing. 100 degrees is 100 degrees!

 

[mike & juli]

LOL--yeah, that's why I brought up 'dry heat', being sarcastic actually there!!! 100 IS 100 no matter WHAT the humidity, I agree!!!! Your 40% humidity is low though, as we're usually higher, tho I didn't 'officially' check our humidity...don't know what it was in Detroit yesterday either, where GTSnake wrote he's from and had the popping problem....sure, it could be a spark plug/wires, whatever...but I know another guy who had the same problem and it was that the air was so heavy with humidity, no air, much less COOL air was getting thru...should say LITTLE air was getting thru the car/filters/exhaust....soooooo could be a mixture of things. (Hope you have a/c!!!!!) 'feels like 103' bleahhhhh......ugghhhhhhhh......ickkkkkk......argggghhhhh.....!!!
~juli~

 

[GTSnake]

My wires are very new. They are Magnecores and have about 5,000 on them.

The weather here has been very mild. It's low 80's and low humidity. I'll check the plugs when I get home.

 

[dave6666]

LOL--yeah, that's why I brought up 'dry heat', being sarcastic actually there!!! 100 IS 100 no matter WHAT the humidity, I agree!!!! Your 40% humidity is low though, as we're usually higher, tho I didn't 'officially' check our humidity...don't know what it was in Detroit yesterday either, where GTSnake wrote he's from and had the popping problem....sure, it could be a spark plug/wires, whatever...but I know another guy who had the same problem and it was that the air was so heavy with humidity, no air, much less COOL air was getting thru...should say LITTLE air was getting thru the car/filters/exhaust....soooooo could be a mixture of things. (Hope you have a/c!!!!!) 'feels like 103' bleahhhhh......ugghhhhhhhh......ickkkkkk......argggghhhhh.....!!!
~juli~

Texans have air conditioning, margaritas, chips and salsa made by people that must press 1 when calling my bank...

 

[mike & juli]

Texans have air conditioning, margaritas, chips and salsa made by people that must press 1 when calling my bank...

Sooooo, you are saying food made by English-speaking people??? What, you have chips and salsa DELIVERED to you at work at a bank....is that what I am getting out of this post?
WOWWWW~~THAT is service!~! And, duh, yeah, a/c would be a MUST in Texas--Mike lived there, he knows what it's like....again, BLEAHHHHHH!!!!! Where would be the BEST climate in the US of A??? San Diego? 70's most of the time? Would miss our seasons here though, especially Fall and Spring...NOT winter....that's another bleahhhhhh!~!
~juli
(((((Effectively hijacked ANOTHER thread!!!! Dave--you and I have to stop this!!!)))))

 

[dave6666]

El banco de América pide que usted apriete uno para español.

But since I am of English speaking talent, I do not press 1. I just have to listen to my bank say the above, which really ****** me off.

 

[mike & juli]

El banco de América pide que usted apriete uno para español.
But since I am of English speaking talent, I do not press 1. I just have to listen to my bank say the above, which really ****** me off.

I don't speak spanish, so I'm guessing you meant that pressing ONE means for Spanish??! That is outrageous~~~~WHAT are things coming to, when now we 'presume' that SPANISH is the #1 language, probably especially in Texas where you have more immigrants than I imagine we have. Now I get what you meant....sorry--I misunderstood...here still pressing 1 is for English, 2 is for spanish....and I really feel for the teachers who are now being pressed to TEACH in both languages...if you're here in America, speak English, write English...(when in Rome, do as the Romans do???).....that bugs the heck outta me, and we already had a HUGE thread about this starting with Chad going into a Home Depot and the self-serve was TOTALLY IN SPANISH....I don't normally rant or get upset over things, but this one bothers me.......probably because I took French in school, not Spanish~~ . Sorry to be on a rant here.... ~~juli (((((I'm also a thread-stealer!!! WHAT is this world coming to?! LOL))))))

 

[dave6666]

Juli... The scary version...

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[mike & juli]

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Where do you FIND these things, Dave!?? LOL--back to topic on hand (or I'll be BANNED for LIFE!!!).....GTSnake, please let us know the results of checking your wires/popping continues...on decel only? (whew--had to get back to topic, or I'd hate to be banned foreverrrrrrrrrrrr)....don't want to start up a new *spanish* thread...we have enough of those!!!~!!! ~juli~

 

[dave6666]

You must be registered for see images

Where do you FIND these things, Dave!?? LOL--back to topic on hand (or I'll be BANNED for LIFE!!!).....GTSnake, please let us know the results of checking your wires/popping continues...on decel only? (whew--had to get back to topic, or I'd hate to be banned foreverrrrrrrrrrrr)....don't want to start up a new *spanish* thread...we have enough of those!!!~!!! ~juli~

Graphics wizard of sorts...

 

[mike & juli]

Graphics wizard of sorts...

For SURE!!!! Love your sense of style and humor, Dave....keep 'em coming!! ~juli~

 

[YouWish]

An exhaust leak in your headers would cause this also. If no to the plugs check out your headers.

 

[GTSnake]

I pulled all the plugs and they're fine. Very normal looking right down to the slightly rich no. 8 & 10 cylinders. Reattached the wires very securely and it still back fired.

So just for the hell of it I thought to reflash the VEC2. The first two times it wouldn't take the program and had a red light. The third time it took and went green. During the test drive it was improved 80%. No backfiring on decel. However, initial start from a dead stop it still had issues. It felt heavy and still back fired. It seems like it's still very rich on the low end with a low load. Once up in the higher revs and speed it smoothed out.

I'm thinking it's the tune now. But how can the program change by itself. I haven't played with the tune for months. The battery did drain very low for a period of about 1 week before I put the tender on it. I think the battery tender couldn't charge the low battery fully.

 

[plumcrazy]

did you wash the engine recently ?

how old is the battery ? replace if 3 or more years old

 

[GTSnake]

Nope, didn't wash the engine. I did wash the car though. Maybe something splashed onto somewhere. Battery is fairly new. It's only about 1.5 yrs old.

 

[plumcrazy]

i had a problem where the car wouldnt start one time when i washed the engine....thats why i asked.

id charge that battery properly, swap tunes again and then try it

 

[Simms]

This is probably a very dumb question, but are you still running the same size pulley as you were before?

 

[GTSnake]

Yeah, no pulley change.
I'm going to pull more fuel out from low rpm's and see how it runs.

Can it be a faulty injector that's not closing fully?

 

[dansauto]

is this a lean backfire or rich backfire? There is a differance. How do the plugs look? Typically if you "hang up" and injector it will skip not back fire and also cause you to foul out that cylinder. DO NOT disconnect the injectors with the car running to find the skip. This may cause you to fry the injector driver in the VEC2, instead pull the plug wires. But if you are having a back fire rather than skip, I would assume tune not ignition. I would disconnect the battery, ground out the postive side reconnect the battery and reflash your tune. Then drive the car moderately for 30 miles to relearn the PCM and watch your wideband.

 

[GTSnake]

It really sounds like a rich backfire. The exhaust even smells rich. On acceleration it does sometimes feel like a skip from ingesting too much fuel and choking on it.

 

[GTSnake]

Well I put in a leaner program and it's about the same. Under 2000 rpms it feels like its missing and it's stuttering. Above 2k it smooths out. I think there's something else going on besides the tune.