help. sputtering popping and backfireing under boost.
07-05-2012, 08:41 AM
#11
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07-07-2012, 07:23 AM
#12
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Join Date: Jan 2012
Posts: 68
Yes could be. Im scared to death to run any higher the 12.5:1 Afr's under boost. Lean is mean but rich is just safe im my mind. Id rather be safe(under12:1 Afr's). Last thing I want is to have a hicup with boost and melt rings, psitons, plugs..exc
07-09-2012, 03:46 PM
#13
1.5 BAR
Join Date: Oct 2009
Location: CHICAGO
Posts: 935
your first and only problem is your not adding fuel to compensate for the additional air the turbo is putting into the motor. your stock fuel injection will not compensate for boost without a tune or without the addition of some kind of additional fuel controller. you can adjust the timing all you want but without more fuel it is not going to make a difference. stop driving the vehicle before you blow it up. right now your damaging the pistons by running lean. the popping and sputtering is a sign of running lean.
if you cant afford to tune it then remove the turbo as your just going to have to buy an engine. your next cheapest option is to install a fmu (fuel management unit) or better known as a rising rate fuel pressure regulator. this will increase the fuel pressure as boost is applied causing more fuel to exit the fuel injectors.
if you cant afford to tune it then remove the turbo as your just going to have to buy an engine. your next cheapest option is to install a fmu (fuel management unit) or better known as a rising rate fuel pressure regulator. this will increase the fuel pressure as boost is applied causing more fuel to exit the fuel injectors.
07-09-2012, 06:35 PM
#15
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Join Date: Feb 2012
Posts: 35
ive unplugged the vacume to the fuel pressure regulator and it will bring the fuel pressure up to 40 psi from 32psi. and driveing it the 8 pounds dosent seem to make any differance. any idea of how much pressure i need to get the injectors to add more fuel? i may need a better fuel pump maily due to the fact hat this pump is only makeing 40psi when i plug the line with a pressure gauge installed.
back to what i was saying earlier about the motor running without a 02 sensor pluged in. it seems that if its not useing the 02 to control the fuel that theres another issue other than the fuel delivery.
with a good 02 sensor installed how much can the factory efi change the amount of fuel that goes into the engine? i ordered a new 02 sensor but i will not see it till the end of the week.
back to what i was saying earlier about the motor running without a 02 sensor pluged in. it seems that if its not useing the 02 to control the fuel that theres another issue other than the fuel delivery.
with a good 02 sensor installed how much can the factory efi change the amount of fuel that goes into the engine? i ordered a new 02 sensor but i will not see it till the end of the week.
07-09-2012, 07:01 PM
#16
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Join Date: Jan 2012
Posts: 68
What injector size do you have in the car? If you get a FMU the pressure matters but its way better in my opinion to just get larger injectors and do a quick tune. I know this is a homemade site so Im not sure what you can afford and what not.
If 8psi doen't feel like much you have some issues. As it should! I started with a 140Hp car and when I got to 8psi it was a monster compared to before.
YOU NEED TO HOOK THE VAC LINE BACK UP!! As when you are boosting the pressure in the vac line is what will make sure the fuel pressure stays like it should. Imagine 40psi of fuel and 8psi in the cylinders (boost) pushing back? Now you are worse then you started. That vac line allows the boost pressure to push down on the fuel pressure regulators, diaphram. Im most cases 1:1 ratio. Which means for every PSI of boost=raise the fuel pressure 1 PSI. So it will equal out.
Take for example, I raised my fuel pressure awhile back from 43psi to 55psi both with the vac line unhooked. BUT I hooked it back up. I used a 1:1 AFPR. Now I had 28lbs injectors on a V6. And the results. I added 12 psi and it only made those injectors "act" like 32lbs. That is nothing. Im my opinion. You need you need to at the very least get a FMU. Im not sure about your emc and if its speed sensity or MAF so I can't say much about that ATM. But you really need to have the capibilities to tune the car. Mainly the spark and fuel managment part.
I now have 48lbs injectors with the stock 43 base Psi and they can handle way over 400hp on a 6 cylinder. My prior 28lbs injectors could only make 275Hp and I had them maxed out all the way. So if you do tune get large injectors. As what you have will only flow so much without jacking the fuel pressure sky high. I bet your so lean that you have no substantial HP gain whatsoever for those amounts of boost. IIRC about 13.2:1 is prime afr for Hp although thats on the edge of frying a engine.
I have a walbro 255LPH fuel pump. Im not sure what your stocker will flow if you plan to make some real big Hp numbers. I tosted mine after 10psi of boost, poor thing couldn't keep up with the injectors.
Have you changed up the timing at all? Retarding it at a minimum of 1 degree per lbs of boost? A BTM.
Just some ideas here, I don't want to see anyone trash a motor.
If 8psi doen't feel like much you have some issues. As it should! I started with a 140Hp car and when I got to 8psi it was a monster compared to before.
YOU NEED TO HOOK THE VAC LINE BACK UP!! As when you are boosting the pressure in the vac line is what will make sure the fuel pressure stays like it should. Imagine 40psi of fuel and 8psi in the cylinders (boost) pushing back? Now you are worse then you started. That vac line allows the boost pressure to push down on the fuel pressure regulators, diaphram. Im most cases 1:1 ratio. Which means for every PSI of boost=raise the fuel pressure 1 PSI. So it will equal out.
Take for example, I raised my fuel pressure awhile back from 43psi to 55psi both with the vac line unhooked. BUT I hooked it back up. I used a 1:1 AFPR. Now I had 28lbs injectors on a V6. And the results. I added 12 psi and it only made those injectors "act" like 32lbs. That is nothing. Im my opinion. You need you need to at the very least get a FMU. Im not sure about your emc and if its speed sensity or MAF so I can't say much about that ATM. But you really need to have the capibilities to tune the car. Mainly the spark and fuel managment part.
I now have 48lbs injectors with the stock 43 base Psi and they can handle way over 400hp on a 6 cylinder. My prior 28lbs injectors could only make 275Hp and I had them maxed out all the way. So if you do tune get large injectors. As what you have will only flow so much without jacking the fuel pressure sky high. I bet your so lean that you have no substantial HP gain whatsoever for those amounts of boost. IIRC about 13.2:1 is prime afr for Hp although thats on the edge of frying a engine.
I have a walbro 255LPH fuel pump. Im not sure what your stocker will flow if you plan to make some real big Hp numbers. I tosted mine after 10psi of boost, poor thing couldn't keep up with the injectors.
Have you changed up the timing at all? Retarding it at a minimum of 1 degree per lbs of boost? A BTM.
Just some ideas here, I don't want to see anyone trash a motor.
Last edited by fasteddi; 07-09-2012 at 07:09 PM.
07-09-2012, 08:49 PM
#17
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Thread Starter
Join Date: Feb 2012
Posts: 35
everthing you say makes perfect sence to me this is my first turbo setup so ive got alot to learn.
still im looking for answers about this 02 sensor issue i seem to be haveing.
to me, if my buddy is running the exact same setup for 2 years with zero issues ever, why the hell is my engine not running at all?
hes running up to 4 more psi of boost thats up to 12 psi on a bone stock engine with bone stock efi. my engine just idleing will lean out and 17-1 or even worse it will not even register at all on my wide band aem guage even with no turbo on the engine. im still trying to find the underlying issue. i relize that my motor is very lean and isnt working at all.
im now looking for the problem. if my engine would run at 14-1 afr at 8psi of boost i would then look into a way to get the afr down but with the engine just leaning the hell out when ever and running just the same with or without the 02 id like to get that squared away first.
if i were smart id probly just put in a bigger engine but now that ive heared the turbo whistle and seen how it looks under the hood id really like to finish this the right way. i was told i would get the turbo fever once i had a turbo and now i kinda see what he meant.
i appreciate all the help and im takeing in all that ive been told i just still think ive got other issues even when there is no turbo installed ive got nearly the exact same issues. i welded a bung in the stock exhaust so that i could use the wideband to see how the engine acted without the turbo and its nearly the exact same. only dosent pop and krackle when the rpm get up above 3500 or 4500.
my thoughts
engine is stuck in ''limphome'' due to bad 02 sensor
bad injectors
bad ecu
bad mass air sensor. for some reason when i hold my hand over the intake, i can get the afr to change just by how much i restrickt the airflow into the engine?
still im looking for answers about this 02 sensor issue i seem to be haveing.
to me, if my buddy is running the exact same setup for 2 years with zero issues ever, why the hell is my engine not running at all?
hes running up to 4 more psi of boost thats up to 12 psi on a bone stock engine with bone stock efi. my engine just idleing will lean out and 17-1 or even worse it will not even register at all on my wide band aem guage even with no turbo on the engine. im still trying to find the underlying issue. i relize that my motor is very lean and isnt working at all.
im now looking for the problem. if my engine would run at 14-1 afr at 8psi of boost i would then look into a way to get the afr down but with the engine just leaning the hell out when ever and running just the same with or without the 02 id like to get that squared away first.
if i were smart id probly just put in a bigger engine but now that ive heared the turbo whistle and seen how it looks under the hood id really like to finish this the right way. i was told i would get the turbo fever once i had a turbo and now i kinda see what he meant.
i appreciate all the help and im takeing in all that ive been told i just still think ive got other issues even when there is no turbo installed ive got nearly the exact same issues. i welded a bung in the stock exhaust so that i could use the wideband to see how the engine acted without the turbo and its nearly the exact same. only dosent pop and krackle when the rpm get up above 3500 or 4500.
my thoughts
engine is stuck in ''limphome'' due to bad 02 sensor
bad injectors
bad ecu
bad mass air sensor. for some reason when i hold my hand over the intake, i can get the afr to change just by how much i restrickt the airflow into the engine?
Last edited by nickrocks; 07-09-2012 at 08:55 PM.
07-10-2012, 11:19 AM
#20
1.5 BAR
Join Date: Oct 2009
Location: CHICAGO
Posts: 935
the maf will see the extra airflow coming into the engine up to a point. this isnt the concern. the stock fuel injectors can only supply so much extra fuel while in boost.
if your o2 sensor has failed then the ecm is going to run in open loop. in open loop the engine is being run from a programmed map in the ecm. when in open loop the ecm doesnt look at o2 sensor data so it doesnt know if your rich or lean and it will not compensate for it.
your friend is not telling you something because there is no engine in this world that can run 12 psi without some sort of fuelling modification. a naturally aspirated ecm can not see boost so it cant compensate for the extra airflow with extra fuel. theres only so much adjustment outside the programmed map an ecm can do. this doesnt include larger injectors and timing adjustments that are also required when boosting.
talk to your friend and find out what he did to the engine. there has to be something he forgot to tell you.
does he have a rising rate fuel pressure regulator?
does he have larger than stock injectors?
does he have an extra injector controller setup?
does he have a different ecm from a boosted engine?
if your o2 sensor has failed then the ecm is going to run in open loop. in open loop the engine is being run from a programmed map in the ecm. when in open loop the ecm doesnt look at o2 sensor data so it doesnt know if your rich or lean and it will not compensate for it.
your friend is not telling you something because there is no engine in this world that can run 12 psi without some sort of fuelling modification. a naturally aspirated ecm can not see boost so it cant compensate for the extra airflow with extra fuel. theres only so much adjustment outside the programmed map an ecm can do. this doesnt include larger injectors and timing adjustments that are also required when boosting.
talk to your friend and find out what he did to the engine. there has to be something he forgot to tell you.
does he have a rising rate fuel pressure regulator?
does he have larger than stock injectors?
does he have an extra injector controller setup?
does he have a different ecm from a boosted engine?
