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Popping and stumbling after exhaust and cai

 
Old 02-03-2019, 05:18 PM
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Default Popping and stumbling after exhaust and cai

I have an 01 firebird (v6) it has mid tube headers, built trans, deleted 02 and egr, and a tune. Recently (last weekend) I punt on a new exhaust and a dual cone "ram air" style cold air intake. Immediately after it felt.... different. Slower. So I just ignored it for a while then later that night in my way home it would start popping at idle not like a backfire but more like a quiet "putt...putt putt" sound. And under heavy throttle (50% or more) it would stubble, hesitate, bog down and not have ANY power at all. Operated fine if driving like a grandma. Well a whole day went by and it finally threw a p0171 code (mass air flow too lean, not enough fuel. So, I bought a new maf. Never fixed the problem. Tried reinstalling the oem air box and that didn't solve it either. Then it threw 2 codes p0171 and p0174 (mass air flow too lean. Not enough fuel. Hopping to get some help cause I just can't figure this out. So far I have: replaced maf, replaced iat, fuel filter is a few months old, fuel pump is a year old, clean map, maf, throttle body. Changed plugs and wires. Also sprayed around with brake parts cleaner for vacuum leak and couldn't find anything. Turning ac off doesn't make a difference. Only when I sprayed on a small leak I have on my header to y pipe flange does it actually backfire and idle up a little but I highly doubt that is causing such a major issue.
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Old 02-03-2019, 10:31 PM
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Originally Posted by BamaBird22 View Post
I have an 01 firebird (v6) it has mid tube headers, built trans, deleted 02 and egr, and a tune. Recently (last weekend) I punt on a new exhaust and a dual cone "ram air" style cold air intake. Immediately after it felt.... different. Slower. So I just ignored it for a while then later that night in my way home it would start popping at idle not like a backfire but more like a quiet "putt...putt putt" sound. And under heavy throttle (50% or more) it would stubble, hesitate, bog down and not have ANY power at all. Operated fine if driving like a grandma. Well a whole day went by and it finally threw a p0171 code (mass air flow too lean, not enough fuel. So, I bought a new maf. Never fixed the problem. Tried reinstalling the oem air box and that didn't solve it either. Then it threw 2 codes p0171 and p0174 (mass air flow too lean. Not enough fuel. Hopping to get some help cause I just can't figure this out. So far I have: replaced maf, replaced iat, fuel filter is a few months old, fuel pump is a year old, clean map, maf, throttle body. Changed plugs and wires. Also sprayed around with brake parts cleaner for vacuum leak and couldn't find anything. Turning ac off doesn't make a difference. Only when I sprayed on a small leak I have on my header to y pipe flange does it actually backfire and idle up a little but I highly doubt that is causing such a major issue.
Sounds like your car is too lean and itís doing everything it can to try to tell you. A free flowing intake and exhaust will make your engine more efficient, but it only works if extra fuel is added to the mix. Sounds to me like you need to have it retuned.
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Old 02-03-2019, 10:58 PM
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All I did was go from magnaflow to flowmaster and go from stock air intake to cai I've had that tune for months with zero issues until I did those two things
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Old 02-04-2019, 08:30 AM
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Originally Posted by BamaBird22 View Post
and a tune
Generally, when you have emissions/control issues and have a tune, you need to go back to your tuner or ditch the tune and go back to a known baseline. Who knows what you are dealing with? But...

Originally Posted by BamaBird22 View Post
a dual cone "ram air" style cold air intake
I have to ask... Does this thing have an oil type air filter? If so, did you apply oil to it when you installed it? (The oil on these things don't play nicely with our MAF's. They foul the MAF elements, causing the sensor to sense LESS air going into the engine, which can cause the fuel to be cut. How it really acts would depend on the tune/programming.)
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Old 02-05-2019, 05:09 AM
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Originally Posted by wssix99
Generally, when you have emissions/control issues and have a tune, you need to go back to your tuner or ditch the tune and go back to a known baseline. Who knows what you are dealing with? But...I have to ask... Does this thing have an oil type air filter? If so, did you apply oil to it when you installed it? (The oil on these things don't play nicely with our MAF's. They foul the MAF elements, causing the sensor to sense LESS air going into the engine, which can cause the fuel to be cut. How it really acts would depend on the tune/programming.)
If I were to take it back to the tuner is this something that would be at his expense or mine? Basically what I'm asking is did he do something wrong to mess this up or is it just something that happens sometimes.
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Old 02-05-2019, 04:50 PM
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Originally Posted by BamaBird22 View Post
If I were to take it back to the tuner is this something that would be at his expense or mine? Basically what I'm asking is did he do something wrong to mess this up or is it just something that happens sometimes.
The minute you start installing parts that weren't there when it was tuned, it's a different car. I would expect a tuner would not entertain you on this for free. Maybe they would talk to you about it on the phone?

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Old 02-05-2019, 05:53 PM
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Originally Posted by wssix99
The minute you start installing parts that weren't there when it was tuned, it's a different car. I would expect a tuner would not entertain you on this for free. Maybe they would talk to you about it on the phone?
Okay. I put a vacuum gauge to it and while it IS around 22 inches of mercury it also bounces around. Not all over the place but the needle kind of "vibrates" I guess. It does drop a little every time it pops. As far as the cai I didn't put any oil on it and I don't believe it came oiled. Here is the cai and air dam when I installed it
Attached Thumbnails Popping and stumbling after exhaust and cai-photo493.jpg  
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Old 02-05-2019, 07:42 PM
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An easy thing to try might be to unplug your MAF. Uncertain what this will due because you have a tune - but it's an easy thing to try. If the MAF is bad or fouled, the situation might self-correct if you take it out of the loop.
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Old 02-05-2019, 09:35 PM
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Originally Posted by wssix99
An easy thing to try might be to unplug your MAF. Uncertain what this will due because you have a tune - but it's an easy thing to try. If the MAF is bad or fouled, the situation might self-correct if you take it out of the loop.
I have tried that. I cleaned the maf that was on it and that didn't work so I pulled a maf from a junk yard, cleaned it before install and that didn't work so I bought a new one and installed, that didn't work either so I cleaned that one also and still nothing. Put a vacuum gauge on it lastnight and it holds vacuum pretty well but when it makes the putt...putt putt sound at idle it drops maybe one inch of mercury but then returns immediately before popping again and drops again. I am going to check out my fuel pressure and radiator pressure this weekend. Will keep updated. But please feel free to throw more possibilities I've been at this for 2 weeks now.
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Old 02-05-2019, 09:44 PM
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Here is a video of me driving it and slowly taking of then trying to hop on it you can hear the shutter or stumble
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Old 02-06-2019, 03:02 AM
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A vacuum leak will have your RPM’s bouncing when idling, if it’s not doing that you can stop looking for a vacuum leak. Also these cars had CAI from the factory, if you didn’t have a seal around those cones (doesn’t look like there is one) you were pulling in hot engine bay air into your intake. Why did you choose that intake? Which o2’s did you delete and why?
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Old 02-06-2019, 04:25 AM
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Originally Posted by King Nothing
A vacuum leak will have your RPM’s bouncing when idling, if it’s not doing that you can stop looking for a vacuum leak. Also these cars had CAI from the factory, if you didn’t have a seal around those cones (doesn’t look like there is one) you were pulling in hot engine bay air into your intake. Why did you choose that intake? Which o2’s did you delete and why?
It is typically a cai for a vette and I chose it because I wanted to get rid of the big bulky intake that was there for looks and to free up some room. I deleted the rear o2s because I got rid of my cat. And was tired of the engine light being on all the time and to clear it up so if something goes wrong I'll know immediately. I've had the tune for MONTHS probably close to 5 months with zero issues until I changed exhaust and air intake. And it wasn't bad at first but progressively got worse.
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Old 02-06-2019, 06:53 AM
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I'd pull the valve covers and check the valve springs and valve lift action etc. I'd do a exhaust pressure test too. Doesn't sound blocked BUT I'd still test it to see what you have. Should be less than 2lbs @2k rpms. Test it at one of the o2 bungs. Another way to check for a blocked exhaust or flow problem is connect a vacuum gauge and drive it. Watch what the gauge does when it starts to stumble.


Before you even drive it just connect a vacuum gauge start it up and slowly raise the rpms to 2500. Vacuum should stay steady and INCREASE as the rpms go up. If it drops you may have anything from a blocked exhaust to a cracked valve spring to a worn cam-lifter.

Last edited by RockinWs6; 02-06-2019 at 07:07 AM.
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Old 02-06-2019, 07:50 AM
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^ Yes, I'd check the exhaust for leaks. Scanning the O2 sensors to make sure they are performing is probably a good idea since they would have been disturbed in this whole thing. (Sometimes people cut or burn the wires when doing headers.)
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Old 02-06-2019, 03:40 PM
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Originally Posted by BamaBird22 View Post
It is typically a cai for a vette and I chose it because I wanted to get rid of the big bulky intake that was there for looks and to free up some room. I deleted the rear o2s because I got rid of my cat. And was tired of the engine light being on all the time and to clear it up so if something goes wrong I'll know immediately. I've had the tune for MONTHS probably close to 5 months with zero issues until I changed exhaust and air intake. And it wasn't bad at first but progressively got worse.
By placing it where it is, you do not have cold air intake at all. So really you aren’t helping the engine run any better with that. Put the stock intake back on and leave the battery unhooked for a day. Hook it back up and drive it around to get some drive cycles through and see how it is running.

Also, see about getting that exhaust leak fixed.

side question, we’re you on FB last week or the week before talking about doing something to your car that nobody ever did? It had to do with people asking others why they don’t search google before asking FB questions.

Last edited by King Nothing; 02-06-2019 at 07:45 PM.
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Old 02-06-2019, 04:02 PM
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Originally Posted by King Nothing
By placing it where it is, you do not have cold air intake at all. So really you arenít helping the engine run any better with that. Put the stock intake back on and leave the battery unhooked for a day. Hook it back up and drive it around to get some drive cycles through and see how it is running.

also, see about giving that exhaust leak.

side question, weíre you on FB last week or the week before talking about doing something to your car that nobody ever did? It had to do with people asking others why they donít search google before asking FB questions.
In my original post I stated that I already installed the stock air box. And yes that was me.
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Old 02-06-2019, 04:13 PM
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Originally Posted by BamaBird22 View Post
In my original post I stated that I already installed the stock air box. And yes that was me.
Did you unhook the battery for a day and reconnect both cables?

I thought about what you were talking about and it sounded very familiar lol

Last edited by King Nothing; 02-06-2019 at 07:46 PM.
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Old 02-06-2019, 05:09 PM
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Originally Posted by King Nothing
Did you unhook the battery for a day and reconnect both cables?

I thought what you were talking about so I g sounded very familiar lol
I have disconnected the battery to reset codes but only 30 minutes not for a day. I'm on nights working 12s so until the weekend I don't have much time to mess with it.
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Old 02-06-2019, 05:14 PM
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Originally Posted by RockinWs6
I'd pull the valve covers and check the valve springs and valve lift action etc. I'd do a exhaust pressure test too. Doesn't sound blocked BUT I'd still test it to see what you have. Should be less than 2lbs @2k rpms. Test it at one of the o2 bungs. Another way to check for a blocked exhaust or flow problem is connect a vacuum gauge and drive it. Watch what the gauge does when it starts to stumble.


Before you even drive it just connect a vacuum gauge start it up and slowly raise the rpms to 2500. Vacuum should stay steady and INCREASE as the rpms go up. If it drops you may have anything from a blocked exhaust to a cracked valve spring to a worn cam-lifter.
Didn't get to do a drive test but before I went to work I tried the revving to 2500. Let the car warm up and tried it it's a very smooth steady increase with rpm. Also if I snap/blip the throttle real quick vacuum drops down real fast then up to about 25 then slowly returns to 20. It seems heathy but like I said when it's idling, everytime it pops the vacuum drops just the smallest amount. So whatever it is is making the ignition either weak or cutting it out. That's all I can assume.
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Old 02-07-2019, 03:21 PM
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Okay small update. Today I go outside to check injectors and when I crank up the car everything is running fine. No popping, no rough idle. Idling like a champ. Code is gone. So I hop in and take it for a spin. First hard pull is nice and strong. Second pull I get a little hesitation then it picks back up. Nothing terrible like before. In my video I posted it was what I would consider severe hesitation, now it is mild. Pulled back into the garage and no popping noise at idle. Let it idle a little longer and then the popping starts again. Starts off popping every 30 seconds or so and slowly starts popping more and more. Had to go to work so I didn't get to mess with it much.
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