signs of a bad injector?
05-24-2005, 07:57 AM
#1
3.0 BAR
Thread Starter
Join Date: Apr 2003
Posts: 11,058
signs of a bad injector?
well, as many of you know, i broke 2 sets of ringlands in less than a month, it gets pretty old pretty quick tearing your motor apart that often. the only thing is, i can't figure why they broke again the second time when i had a very conservative tune (no too much timing at all, and a/f never going above 11.8 in higher boost). i dropped some pretty serious coin in to the motor for this next build, and if i broke something again (within a couple months anyways), i'll seriously end up hurting someone or something. i've narrowed it down to a few possible options as to why the motor went the second time.
1) staying in full boost pulls while hitting boost cut (boost cut is a fuel cut, so possibly staying in the pull was causing lean conditions under full boost)?
2) stock plugs at stock gap (i was experiencing no spark blow out and plugs never showed any signs of detonation what so ever, so i didn't see a need to gap them down or run colder plugs)
3) the used cast pistons that i put back in after the first rebuild could have possible been weakened from exposure to detonation the first time the motor went?
4) faulty injector(s)
well, i'll definitely be running colder plugs this time, just for some insurance and peace of mind to know that if that was the cause, it will be fixed. obviously forged internals, so weak cast ringlands won't be an issue, i'll be tuning for 3 bar, so i won't be limited to the 11.2 psi boost cut anymore. so the only thing that leaves is the injectors (rest of the fuel system is new from the pump up). but i'm thinking if it was an injector, i would have noticed either in my afr, or the way the car ran. my afr always reacted normally to changes made in teh map, and the car ran fine with no misses or stumbles. maybe i'm just really paranoid because i'll be fucked after spending all this money if something goes wrong, but give me some input/experience on as many as the possible causes that i have listed. (dave and jeff chime in now
)
1) staying in full boost pulls while hitting boost cut (boost cut is a fuel cut, so possibly staying in the pull was causing lean conditions under full boost)?
2) stock plugs at stock gap (i was experiencing no spark blow out and plugs never showed any signs of detonation what so ever, so i didn't see a need to gap them down or run colder plugs)
3) the used cast pistons that i put back in after the first rebuild could have possible been weakened from exposure to detonation the first time the motor went?
4) faulty injector(s)
well, i'll definitely be running colder plugs this time, just for some insurance and peace of mind to know that if that was the cause, it will be fixed. obviously forged internals, so weak cast ringlands won't be an issue, i'll be tuning for 3 bar, so i won't be limited to the 11.2 psi boost cut anymore. so the only thing that leaves is the injectors (rest of the fuel system is new from the pump up). but i'm thinking if it was an injector, i would have noticed either in my afr, or the way the car ran. my afr always reacted normally to changes made in teh map, and the car ran fine with no misses or stumbles. maybe i'm just really paranoid because i'll be fucked after spending all this money if something goes wrong, but give me some input/experience on as many as the possible causes that i have listed. (dave and jeff chime in now
)
05-24-2005, 09:40 AM
#4
3.0 BAR
Thread Starter
Join Date: Apr 2003
Posts: 11,058
Re: signs of a bad injector?
Originally Posted by junkyard racer
how many miles were on the injectors? they were brand new! I say, 15psi, stock internals...it was bound to happen sooner or later. 
at least now you are stepping up to what the turbo needs
at least now you are stepping up to what the turbo needs
and if it was making too much power, i think something would have broke besides ring lands like a rod or something
05-24-2005, 10:47 AM
#5
3.0 BAR
Join Date: Jan 2004
Posts: 5,708
Re: signs of a bad injector?
id point fingers at those used pistons. remember what jeff said when you rebuilt it. they only last so long . new injectors can still be faulty also. heh just because their new doesnt mean they cant ---- up
. new injectors can still be faulty also. heh just because their new doesnt mean they cant ---- up
05-24-2005, 12:23 PM
#6
3.0 BAR
Join Date: Nov 2003
Posts: 2,200
Re: signs of a bad injector?
Did you ever setup a PVC setup? It may not be the primary problem but could have added to the problem.
Used pistons on a turbo setup... UHm no no? <SHRUG>
Fuel cut is definately not a good thing on a boosted car esp when its WOT. Its like hitting redline!
Used pistons on a turbo setup... UHm no no? <SHRUG>
Fuel cut is definately not a good thing on a boosted car esp when its WOT. Its like hitting redline!
05-24-2005, 12:29 PM
#7
3.0 BAR
Thread Starter
Join Date: Apr 2003
Posts: 11,058
Re: signs of a bad injector?
yeah, i'm pretty sure it was from staying in it while hitting boost cut, b/c when i had it off, the car was fine for a week or so and ran great, then i grenaded it in less than 24hrs. when i enabled the boost cut/extra features. as long as it's not my injectors, i'm good. i've got lower comp. forged internals now, and everything else taken care of, i'm just trying to get a peace of mind that the injectors are fine basically, because i'm about tapped out and that's all i need is to have to buy some new injectors.
05-24-2005, 01:03 PM
#8
3.0 BAR
Join Date: Nov 2003
Posts: 2,200
Re: signs of a bad injector?
Im sure your injectors are fine. If not you can always try the ghetto way of testing out the injectors. Someone posted up a while a go a thread on how to clean o test out injectors using a battery and a turkey baster or something... worth a try if u want a piece of mind...
