Popping and stumbling after exhaust and cai
02-03-2019, 04:18 PM
#1
On The Tree
Thread Starter
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.
02-03-2019, 09:31 PM
#2
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.
02-03-2019, 09:58 PM
#3
On The Tree
Thread Starter
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
02-04-2019, 07:30 AM
#4
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.)
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.)
02-05-2019, 04:09 AM
#5
On The Tree
Thread Starter
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.)
02-05-2019, 04:53 PM
#7
On The Tree
Thread Starter
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?
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02-05-2019, 08:35 PM
#9
On The Tree
Thread Starter
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.
02-06-2019, 02:02 AM
#11
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?
02-06-2019, 03:25 AM
#12
On The Tree
Thread Starter
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?
02-06-2019, 05:53 AM
#13
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.
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 06:07 AM.
02-06-2019, 02:40 PM
#15
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.
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 06:45 PM.
02-06-2019, 03:02 PM
#16
On The Tree
Thread Starter
Originally Posted by King Nothing
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 giving that exhaust leak.
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.
also, see about giving that exhaust leak.
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.
02-06-2019, 04:09 PM
#18
On The Tree
Thread Starter
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 thought what you were talking about so I g sounded very familiar lol
02-06-2019, 04:14 PM
#19
On The Tree
Thread Starter
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.
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.
02-07-2019, 02:21 PM
#20
On The Tree
Thread Starter
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.