troubleshooting, looking for input
Thread Starter
Registered User
Joined: May 2007
Posts: 279
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From: Central Florida
troubleshooting, looking for input
alright so i had this problem about 3 months ago and it went away, then came back last night. i went to full throttle in third gear last night and the car makes a sound like i blew a charge pipe, but i checked and it didnt. nothing changes after that, its just when i hit full boost i believe.
Here is my setup;
-Inlinepro kit
-3mm hg
-gt3255 turbo
-rc engineering 650cc injectors
-aem ems
-turbosmart mbc
-turbosmart 38mm wastegate dumped
-600 h.p. in tank fuel pump
- 3" exhaust open at the axle
I thought this problem might be overboosting, but i have an MBC and i turned it all the way down and it still did it. after thinking about it all night i went to rc engineerings website and looked up the h.p. rating formula for the injectors;
using that formula, i got 99.2 h.p. per injector which is 396 h.p. total. could i be maxing out the injectors?
here is a list of what I think could be going wrong;
-Detonation?
-Overboosting?
-Tune needs to be cleaned up? (its over a year old)
-Air/fuel screwed up?
I am still learning how to troubleshoot these types of problems so i am just looking for help and advice on what to look for. Also i hooked up to AEMPRO last night and my o2#1 reading was wround 3.5 and o2#2 was round 4.5, is this normal? i really dont know how to use the program as a diagnostic yet so it kind of scared me seeing numbers that low related to a/f.
I had plans to get retuned this week but i am trying to determine whether to get bigger injectors before the tune so i dont waste my money.
Here is my setup;
-Inlinepro kit
-3mm hg
-gt3255 turbo
-rc engineering 650cc injectors
-aem ems
-turbosmart mbc
-turbosmart 38mm wastegate dumped
-600 h.p. in tank fuel pump
- 3" exhaust open at the axle
I thought this problem might be overboosting, but i have an MBC and i turned it all the way down and it still did it. after thinking about it all night i went to rc engineerings website and looked up the h.p. rating formula for the injectors;
using that formula, i got 99.2 h.p. per injector which is 396 h.p. total. could i be maxing out the injectors?
here is a list of what I think could be going wrong;
-Detonation?
-Overboosting?
-Tune needs to be cleaned up? (its over a year old)
-Air/fuel screwed up?
I am still learning how to troubleshoot these types of problems so i am just looking for help and advice on what to look for. Also i hooked up to AEMPRO last night and my o2#1 reading was wround 3.5 and o2#2 was round 4.5, is this normal? i really dont know how to use the program as a diagnostic yet so it kind of scared me seeing numbers that low related to a/f.
I had plans to get retuned this week but i am trying to determine whether to get bigger injectors before the tune so i dont waste my money.
Joined: Feb 2008
Posts: 3,964
Likes: 7
From: USA
As for the noise that is very hard to say, I would recomend taking to your tuner to check everything out. Though for a quick check you could pull your plugs and take a look at them and run a few data logs, as for crazy AFR's you will have to change your load units.
For the injectors you need to make a few changes
(1) BSFC on our cars is closer to 0.6
(2) Duty cycle can be 90% w/o issues
(3) All the numbers are based on Flywheel power not the wheels
That being said I would guess you would run out of injector at 12-14 PSI depending on how well everything is setup.
For the injectors you need to make a few changes
(1) BSFC on our cars is closer to 0.6
(2) Duty cycle can be 90% w/o issues
(3) All the numbers are based on Flywheel power not the wheels
That being said I would guess you would run out of injector at 12-14 PSI depending on how well everything is setup.
Joined: Jan 2008
Posts: 9,570
Likes: 3
From: New Jersey
Originally Posted by dsddcd,Aug 2 2009, 10:49 AM
As for the noise that is very hard to say, I would recomend taking to your tuner to check everything out. Though for a quick check you could pull your plugs and take a look at them and run a few data logs, as for crazy AFR's you will have to change your load units.
For the injectors you need to make a few changes
(1) BSFC on our cars is closer to 0.6
(2) Duty cycle can be 90% w/o issues
(3) All the numbers are based on Flywheel power not the wheels
That being said I would guess you would run out of injector at 12-14 PSI depending on how well everything is setup.
For the injectors you need to make a few changes
(1) BSFC on our cars is closer to 0.6
(2) Duty cycle can be 90% w/o issues
(3) All the numbers are based on Flywheel power not the wheels
That being said I would guess you would run out of injector at 12-14 PSI depending on how well everything is setup.
Thread Starter
Registered User
Joined: May 2007
Posts: 279
Likes: 0
From: Central Florida
ok so ive found out that the car hiccoughs randomly, which could be the same thing thats happening during boost/WOT, it just seems more drastic during boost.
does anyone know what the cause of these random hiccoughs could be? corrupt files in the tune? tune needs to be refreshed? injector problem? i guess the best thing to do would be to get a wideband and see what the air/fuel does during
does anyone know what the cause of these random hiccoughs could be? corrupt files in the tune? tune needs to be refreshed? injector problem? i guess the best thing to do would be to get a wideband and see what the air/fuel does during
Registered User
Joined: Jul 2009
Posts: 64
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if the injectors were fine before, and you did not turn up the boost or add any parts to make more power....thats not your problem (unless they got dirty/failed etc but thats pretty unlikely)
the tune does not change its self. if it was good from the beginning its still good now unless you changed parts, or something broke. (assuming all the air temp comp stuff is correct etc)
wideband is always a good idea. keep in mind when it missfires, you can throw the AFR value out the window. whats important at that time is what the AFR was BEFORE the missfire.
something that i see over looked on a regular basis is something as simple as spark plugs. changing plugs can cure little issues like that more often than not.
as far as the noise, its hard to day. almost sounds like your just hearing a missfire occur.
good luck getting it figured out. sometimes with problems like that its easier to throw it on the dyno so you can monitor everything rather than driving down the road having to pull over every 3 min. can view a lot more data on the dyno....and finding what kind of noises you are hearing are a thousand times easier as well.
good luck
the tune does not change its self. if it was good from the beginning its still good now unless you changed parts, or something broke. (assuming all the air temp comp stuff is correct etc)
wideband is always a good idea. keep in mind when it missfires, you can throw the AFR value out the window. whats important at that time is what the AFR was BEFORE the missfire.
something that i see over looked on a regular basis is something as simple as spark plugs. changing plugs can cure little issues like that more often than not.
as far as the noise, its hard to day. almost sounds like your just hearing a missfire occur.
good luck getting it figured out. sometimes with problems like that its easier to throw it on the dyno so you can monitor everything rather than driving down the road having to pull over every 3 min. can view a lot more data on the dyno....and finding what kind of noises you are hearing are a thousand times easier as well.
good luck