What Are Signs of a Bad Injector?
04-03-2003, 08:39 PM
#1
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What Are Signs of a Bad Injector?
What are the symptoms of a bad fuel injector?
What does it cause the engine to do?
Do the injectors when they go bad; stick open, closed, partially open/closed, not open all the way, not close all the way, or what?
Can they starve the engine for fuel at high rpms?
Thanks in advance.
What does it cause the engine to do?
Do the injectors when they go bad; stick open, closed, partially open/closed, not open all the way, not close all the way, or what?
Can they starve the engine for fuel at high rpms?
Thanks in advance.
04-03-2003, 09:59 PM
#2
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rough idle can be a sign of a bad injector.
unplug each injector one at a time, if it makes a diff when you unplug it, it was still good, if it doesnt change the idle its prob. bad.
sorry to be so simplistic, but its a shade tree mechanic way of checking them.
Chris
unplug each injector one at a time, if it makes a diff when you unplug it, it was still good, if it doesnt change the idle its prob. bad.
sorry to be so simplistic, but its a shade tree mechanic way of checking them.
Chris
04-03-2003, 10:01 PM
#3
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Can't running an engine with no fuel in a cylinder potentially scratch the walls from lack of lubrication? Maybe I am just thinking of 2 stroke engines...
Originally posted by 95BLKTA
rough idle can be a sign of a bad injector.
unplug each injector one at a time, if it makes a diff when you unplug it, it was still good, if it doesnt change the idle its prob. bad.
sorry to be so simplistic, but its a shade tree mechanic way of checking them.
Chris
rough idle can be a sign of a bad injector.
unplug each injector one at a time, if it makes a diff when you unplug it, it was still good, if it doesnt change the idle its prob. bad.
sorry to be so simplistic, but its a shade tree mechanic way of checking them.
Chris
04-04-2003, 11:18 AM
#6
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So, besides a bad idle, what else?
What do they cause the engine to act like when they aren't operating properly?
Do injectors just fail completely when they fail? Or can they partially fail?
What do they cause the engine to act like when they aren't operating properly?
Do injectors just fail completely when they fail? Or can they partially fail?
04-04-2003, 11:53 AM
#8
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OK, I have an engine vibration from off idle that vibrates noticeably more at 1800 rpm, and then slows a bit until you hit 4000+ where it will jingle the change in the cupholder. Also at 4000 + rpm it feels as though power tapers off instead of pulling strong to redline.
BTW, I have eliminated the ignition system with replacing parts.
BTW, I have eliminated the ignition system with replacing parts.
04-04-2003, 12:45 PM
#9
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It certainly does sound like an ignition miss, does it happen only under load, or all the time?
If it is under load, you might have a cracked spark plug, and or grounded wires. Check those first.
It could be injectors also, usually means that the car would be running overly rich or complety not firing at all.
Check for leaky/frozen injectors. Best way to this is to pull up the fuel rail with injectors still on them turn your ignition key to the on position (do not crank),, by doing this, your fuel pump will pre-pressurize your fuel system and if you have a leaky injectors they will leak. Do this by removing the 4 bolts, and prying up the rail, watch out for those fuel lines and be patient.
You can also eliminate the possiblity of one injector not firing at all by doing the following.
Turn on engine, let it idle, and disconnect each injector one at a time. Upon disconnecting one, if there is a change on the way it idles (usually dramatic change), then that injector is ok and firing, put it back and proceed with the next one. If you disconnect and there is no change in engine idle then you have found your source of the problem.
Other possibilities include an vaccum leak, you can diagnose by hearing it, if you think you found your source. Spray some soapy water around the area, (only a little, do not spill it if you know what I mean), if there is a leak around the area, then the engine would suck the water in. You could also diagnose this by using a vaccum gauge (around $25 at local auto parts store).
Another possibility is that your fuel pressure may be fluctuating (defective pump, leaky regulator, or clogged fuel filter). Best way to check this is with a fuel pressure gauge (around $35 at local auto parts store). See if it fluctuates under normal conditions and under load. Should be around 43psi +/- 4. And would probably go down a little at WOT.
Are you getting any codes? I would imagine you would not have power over 4,000rpm because the pcm may pull timing on you (knock retard) if it senses abnormal vibration), not necessaraly fuel starvation).
You are probably getting a code. Are you?
If it is under load, you might have a cracked spark plug, and or grounded wires. Check those first.
It could be injectors also, usually means that the car would be running overly rich or complety not firing at all.
Check for leaky/frozen injectors. Best way to this is to pull up the fuel rail with injectors still on them turn your ignition key to the on position (do not crank),, by doing this, your fuel pump will pre-pressurize your fuel system and if you have a leaky injectors they will leak. Do this by removing the 4 bolts, and prying up the rail, watch out for those fuel lines and be patient.
You can also eliminate the possiblity of one injector not firing at all by doing the following.
Turn on engine, let it idle, and disconnect each injector one at a time. Upon disconnecting one, if there is a change on the way it idles (usually dramatic change), then that injector is ok and firing, put it back and proceed with the next one. If you disconnect and there is no change in engine idle then you have found your source of the problem.
Other possibilities include an vaccum leak, you can diagnose by hearing it, if you think you found your source. Spray some soapy water around the area, (only a little, do not spill it if you know what I mean), if there is a leak around the area, then the engine would suck the water in. You could also diagnose this by using a vaccum gauge (around $25 at local auto parts store).
Another possibility is that your fuel pressure may be fluctuating (defective pump, leaky regulator, or clogged fuel filter). Best way to check this is with a fuel pressure gauge (around $35 at local auto parts store). See if it fluctuates under normal conditions and under load. Should be around 43psi +/- 4. And would probably go down a little at WOT.
Are you getting any codes? I would imagine you would not have power over 4,000rpm because the pcm may pull timing on you (knock retard) if it senses abnormal vibration), not necessaraly fuel starvation).
You are probably getting a code. Are you?
04-04-2003, 02:54 PM
#11
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Originally posted by Dr.Mudge
Listen to each injector, and pay attention to any abnormal sounds from one or more of them, compared to the others. You can use a screwdriver for this.
Listen to each injector, and pay attention to any abnormal sounds from one or more of them, compared to the others. You can use a screwdriver for this.
It is hard as hell to hear anything and doesn't really work. Either that or I am getting hard of hearing. Maybe a mechanics stethoscope would help, but that isn't a very good way of determining conclusively if they are faulty or not .
About it missing under load, it doesn't matter. It is NOT ignition related, trust me. I replaced the opti, coil, ignition module, plugs and wires. I have also checked for vaccum leaks thouroughly and there are none.
Will unhooking an injector while the car is running harm anything in the computer?
It seems that if one injector was not working at all then it would be more obvious that how it is acting now.
Fuel filter has been replaced very recently.
I do have a booster pump that is in line from the tank to the filter that I do not use, could that be restricting flow? It has worked fine that way for a year now with no problems, so I kind of doubt it. (It was like that when I bought it.)
04-04-2003, 03:17 PM
#12
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Originally posted by Dr.Mudge
Listen to each injector, and pay attention to any abnormal sounds from one or more of them, compared to the others. You can use a screwdriver for this.
Listen to each injector, and pay attention to any abnormal sounds from one or more of them, compared to the others. You can use a screwdriver for this.
And it does work you just gotta know what you're listening for..Tails
04-04-2003, 03:31 PM
#13
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I guess it's time for me to go get my hearing checked then.
I tried that trick, but there is so much other racket under the hood, and the exhaust, I couldn't hear enough to decide if there was ABSOLUTELY a problem or not.
I tried that trick, but there is so much other racket under the hood, and the exhaust, I couldn't hear enough to decide if there was ABSOLUTELY a problem or not.
04-15-2003, 06:30 PM
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Is there any way to check them by using an ohm-meter or volt meter while the engine is running?
I just got another distributor, new cap/rotor, the MSD coil is less than 5 months old and the wires arent very old Accel Extreme 9000's.
#1 Won't hardly ever fire. It worked for a bit after changing that plug out but went bad again. I pulled the plug out and it strongly smelled like gas, making me think #1 injector is stuck open and fouling the plug.
Any other ideas?? Is there anything that can be done other than replacing the injector?
I just got another distributor, new cap/rotor, the MSD coil is less than 5 months old and the wires arent very old Accel Extreme 9000's.
#1 Won't hardly ever fire. It worked for a bit after changing that plug out but went bad again. I pulled the plug out and it strongly smelled like gas, making me think #1 injector is stuck open and fouling the plug.
Any other ideas?? Is there anything that can be done other than replacing the injector?
04-16-2003, 05:52 AM
#15
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I was having problems with my injectors a while ago. I was chasing down my 1000-2000rpm stumble, and replaced everything I thought would solve the problem, but nothing. 
Then, I've got my cable and I made a Datamaster log, and it made everything clear! At 1000-2000rpm, the engine was actually flooded with fuel! At idle, the right side was pulling fuel like crazy, and we were like WTF. Changed plugs and found at least 3 or 5 gas fouled ones. They were dripping wet with fuel. Then, changed the stock injectors to Accel's, and everything is gone now! (Now, I'm waiting for SVO's)
Good luck!
Then, I've got my cable and I made a Datamaster log, and it made everything clear! At 1000-2000rpm, the engine was actually flooded with fuel! At idle, the right side was pulling fuel like crazy, and we were like WTF. Changed plugs and found at least 3 or 5 gas fouled ones. They were dripping wet with fuel. Then, changed the stock injectors to Accel's, and everything is gone now! (Now, I'm waiting for SVO's)
Good luck!