Good way to clean fuel injectors? Also, DSM pro advice needed --->

[mhuffman]

Is there a better way to clean fuel injectors than to just run fuel system cleaner thru the system? I've already run a good cleaner thru and the problem hasn't gone away.

I am getting a bad misfire above 4k rpm's at full boost, perfect driveability when i'm not WOT. I recently put in NGK plugs and Accel wires so those shouldn't be the problem. I've also done a pressure test and i dont have major leaks. I'm not throwing a CEL, and i get good (25+) gas mileage. 91 FWD turbo... The car spins tires in second gear so its not like its low on power. But it drives terrible at WOT high rpm ever since i did my 2.5" cat and 3" DP.

I'm thinking it's either my ignition coil or one or more of my fuel injectors. Any ideas?

 

[JayRolla]

Does it go in and out, does a cel ever pop on? I had injectors go out before and it would usually through a cel. What gap do you run on your plugs. How much boost? More info is needed. Fill out your cars profile, I dont even know what you have.

 

[xioca]

If you want to clean your injectors you can pull them out of your car and send them out to get ultrasonic cleaned and the likes, but it will lighten your wallet. You could just hook them up to a double A battery and feed carb cleaner through them with compressed air and a piece of fuel hose. I think there is a nice article on it at plymouthlaser.com

 

[kenamond]

If you still have your old set of plug wires and they're in running condition, you might try swapping out the Accels and see if that helps. I've heard of some of these plug wires arcing and causing EMI problems brand new.

Make sure the wires aren't running right next to each other and touching (route them through the plug wire guides if possible).

Also, do you have any water or oil in your spark plug wells (see it on the tips of the plug wire tips when you pull them out). That can cause the plug wires to arc through the insulation under high engine load where the arc has to jump across a denser air/fuel charge.

And what plugs you have (BPR6ES?) and what did you gap them to (0.28"?)? If you gap them too large, they can miss under full boost but not at less boost.

 

[dcg9381]

To clean them properly and flow test, you need special equipment.

Best deal i've found is witchunter.com - good guy and $15/each - clean, flow test, new rubber.

 

[mhuffman]

-91 GST
-3" DP/ 2.5" cat / 2.5" muffler
-K&N filter, modded aircan, stock MAS
-Stock boost... with the BCS restrictor removed
-Python injection ECU (i donno what it does it came on the car )
-Accel wires and NGK plugs gapped about 0.030"

I never get a CEL.

If you still have your old set of plug wires and they're in running condition, you might try swapping out the Accels and see if that helps. I've heard of some of these plug wires arcing and causing EMI problems brand new.

Make sure the wires aren't running right next to each other and touching (route them through the plug wire guides if possible).

I am using multiple guides to keep them seperated. Most people have run the accels to good advantage. I inspected the wires and didn't see any signs of arcing.

If you want to clean your injectors you can pull them out of your car and send them out to get ultrasonic cleaned and the likes, but it will lighten your wallet. You could just hook them up to a double A battery and feed carb cleaner through them with compressed air and a piece of fuel hose. I think there is a nice article on it at plymouthlaser.com

I am going to try this when i have some free time.

 

[BISHILVR]

It would take more than a AA battery to turn the injector on. The current draw alone would require more of a motorcycle or lawnmower battery.

 

[Defiant]

Is there a better way to clean fuel injectors than to just run fuel system cleaner thru the system?

Run filtered gasoline through them any time you run the engine.

I don't know how they sell the public the idea that injectors might ever get "dirty".

 

[1gcrazy]

It would take more than a AA battery to turn the injector on. The current draw alone would require more of a motorcycle or lawnmower battery.

Not entirely true. They only need 1.5 volts which just happens to be how much a AA battery is. Now for a long amount of time...yes. Check out http://www.plymouthlaser.com/injectest.htm

Run filtered gasoline through them any time you run the engine.

I don't know how they sell the public the idea that injectors might ever get "dirty".

Even then. Injectors actually have individual filters per injector. I think the cleaning does help though.

 

[luv2rallye]

Not entirely true. They only need 1.5 volts which just happens to be how much a AA battery is. Now for a long amount of time...yes.

Clarification and warning so people don't get the wrong idea and burn out their injectors: Inductors such as injectors run on current not voltage. Stock injectors are spec'd to have 2-3 ohms dc resistance so a 1.5V AA battery will drive 0.5 - 0.75 amps thru it if it has the capacity to do so. This is usually enough to turn on the injector safely. A stock engine has 5.5-6.5 ohm series resistors (for current limiting) on each injector which at 12V, will drive 1.2-1.6 amps thru it. More current than that will burn out the injector. So if you use a 12V battery (eg. from car or motorcycle - say to run them longer than your AA battery is capable of, or you just don't have fresh AA batteries), you MUST use a series resistor of at least 5.5 ohms, 14 watt to limit the current. Of course a 14W resistor is expensive and hard to come by which is why the lower voltage AA battery without a series resistor works safely and is much more practical. (If you insist on using 12V you could actually use a series resistor anywhere from 5.5 ohms, 14 watt up to maybe 15 ohms, 7.5 watt safely and have it still operate.)

 

[1gcrazy]

Clarification and warning so people don't get the wrong idea and burn out their injectors: Inductors such as injectors run on current not voltage. Stock injectors are spec'd to have 2-3 ohms dc resistance so a 1.5V AA battery will drive 0.5 - 0.75 amps thru it if it has the capacity to do so. This is usually enough to turn on the injector safely. A stock engine has 5.5-6.5 ohm series resistors (for current limiting) on each injector which at 12V, will drive 1.2-1.6 amps thru it. More current than that will burn out the injector. So if you use a 12V battery (eg. from car or motorcycle - say to run them longer than your AA battery is capable of, or you just don't have fresh AA batteries), you MUST use a series resistor of at least 5.5 ohms, 14 watt to limit the current. Of course a 14W resistor is expensive and hard to come by which is why the lower voltage AA battery without a series resistor works safely and is much more practical. (If you insist on using 12V you could actually use a series resistor anywhere from 5.5 ohms, 14 watt up to maybe 15 ohms, 7.5 watt safely and have it still operate.)

 

[merqury]

In my opinion it might be your electronic coils. I had the same problem you are having and like you did, I also changed the wires and plugs and the misfire was still there. Now I have 2g so I just scanned it and it showed my third cylinder was where the misfire was occuring. So I changed the coil that was connected to the third cylinder and the car run perfect after that. I only changed one coil because I'm not sure about 1g's but 2g's have two coils; each of them firing two cylinders. To make long story short, I think you should change your coils.

 

[BISHILVR]

Your not going to get .5 amps from a AA battery though. And according to my fsm the injector resistance is 13-16 ohms at 68*f and the resistor is 5.5-6.5 ohms at 68*f. those together averaged out come out to around 20 ohms at 68*f. Ohms law says that 12v / 20 ohms = .6 amps. That would be the normal current draw to operate the injector. So at 1.5 volts you get 1.5v / say 14 ohms (no resistor) = .10714 amps. to power the injector with. Not likely to work very well. It just might, but it does'nt look like it would very well.

 

[xioca]

Well I'll admit I don't fully understand the principle behind what you guys are talking about. But for clarification I did it with a double A battery on a spare set and it was enough to open them. And the injectors seem to work just like they had before.

 

[BISHILVR]

Well I'll admit I don't fully understand the principle behind what you guys are talking about. But for clarification I did it with a double A battery on a spare set and it was enough to open them. And the injectors seem to work just like they had before.

Would it hold them open? or just crack them for a second? I could maybe see it cracking them for a second from the fast ramp up of current.

 

[xioca]

No, you could hear it click and it would remain open for as long as it took me to flush them out, a good minute or two.

 

[Splitpi]

What NGK's are you running?

 

[1gcrazy]

Yup they stay open...I had to blow on my fuel rail to try and get the fluid through the injector.......that was an experiance....

 

[PieEyedPiper]

Run filtered gasoline through them any time you run the engine.

I don't know how they sell the public the idea that injectors might ever get "dirty".

I suffered from a clogged injector just 2 days ago. I blame california gas. But you are absolutely correct there are no solid particles floating through the lines because its filtered a bazillion times between the tanker, the pump, my tank and the injectors.

 

[BISHILVR]

Ok, so I like to know that I'm right. So I just built a rig to test the theory about a AA opening an injector. An AA battery will not open an injector, a D cell will not open an injector (much bigger battery), two D cells together wont open an injector! When I checked amperage draw on the AA on the injector guess what it came up with? 102 ma or .102 amps, pretty close to my calculation above huh? I then used a 9volt battery (heavy duty alkaline) it WILL open the injector and draws about 320ma or .320amps (maximum that my 9v battery was able to deliver). All of the batterys were brand new heavy duty batteries name brand (energizer). Also when the injector was open you can barely, and I mean barely with all of your might blow through it as I expected, this is why fuel systems operate at 40-50 psi for fuel injection as opposed to 3-4 psi for carbureted. Therefore, a can of carb spray would in no way ever be able to pass through an open injector (if you managed to get it open) as the can does not have more than the pressure than we have in our mouths 1-2 lbs. Anyone that tried cleaning thier injectors with a 1.5 volt AA battery and a can of carb cleaner just wasted some time and money and accomplished nothing.

 

[mhuffman]

Ok everyone i regapped my NGK's to 0.028" and the misfire is less but it still feels like i'm weak on spark on the top end.

It's possibly that tightening the plug gap has made the possibly weak coil be able to bridge the gap better.

I'm gonna try to swap out a coil with a friend and see if that helps me get stronger spark in higher full boost rpm's.

I also would like to add, that I just read the article and the guys theory is wrong. The reason for my saying so is that he said he measured the voltage at the injectors while cranking the car and it was 2-3 volts. What he actually measured was the voltage drop across the injectors! He then based the 1.5 volt battery theory on that which is flawed from the begining. Also if you look in the picture where he is putting shop air to the rail with the injector "spraying" the spray looks photoshopped and he writes "I know that the picture of the spray is'nt to good but its the best I could get" then why are all of the other pictures so clear? Also notice that in the picture of the injector "spraying" into the cup that the wires coming from the injector are not connected to anything in the backround and look to be just lying there funny.

 

[jumpfroggy]

I also would like to add, that I just read the article and the guys theory is wrong. The reason for my saying so is that he said he measured the voltage at the injectors while cranking the car and it was 2-3 volts. What he actually measured was the voltage drop across the injectors! He then based the 1.5 volt battery theory on that which is flawed from the begining. Also if you look in the picture where he is putting shop air to the rail with the injector "spraying" the spray looks photoshopped and he writes "I know that the picture of the spray is'nt to good but its the best I could get" then why are all of the other pictures so clear? Also notice that in the picture of the injector "spraying" into the cup that the wires coming from the injector are not connected to anything in the backround and look to be just lying there funny.

Seems like a controversy is developing here. The battery method seems interesting, because it'd be nice to be able to clean injectors a bit without sending them out.

Just some comments on your post: You mentioned that the guy only measured the "voltage drop" across the injectors. What other kind of voltage would you measure in this case? I think the real question is like others have stated, amperage.

As to the wires being not connected to anything, and the photoshopped spray... the only photos showing actual spray are closeups, can't see where the wires go. I don't really care if that guy was faking it at all, but if someone else can try out and post results that'd be great. Nice to know if this works.

 

[xioca]

Hey dude I'll throw up a video this weekend if you don't believe me that it opens up the injector . I also filled a up a chunk of fuel line with carb cleaner and sprayed 80psi of air behind it.

 

[jumpfroggy]

Hey dude I'll throw up a video this weekend if you don't believe me that it opens up the injector . I also filled a up a chunk of fuel line with carb cleaner and sprayed 80psi of air behind it.

Do it!! I really want to see the DIY cleaner method.

 

[BISHILVR]

In that case its the 80 psi from an air compressor that is opening the injector. Why would i lie? I will take pics if I have to.