Titles says it all. Which is better, replacing one or all of the fuel injectors at a time?

 

Depends on what's wrong with the ones you have now and whether they are stock or not...

 

All stock, but one or two might be out for one reason or another. Nothing electrically involved, just a bad injector or two.

 

Take a volt meter and check the Ohms on EVERY injector. You should get a pretty consistant reading across the board if all are good. If one or two are out like you suspect, than those one or two should have a reading way above or way under the reading from the other 6.

 

That's all good and well, but that still leave the question standing, replace all or just the ones that are bad????? My last post above this one explained the conditions.

 

It doesn't sound like you are sure you have bad injectors. If someone local has an injector flow bench, might be worth it to have them cleaned and flowed so you know what going on. Have you taken a good look at them? Sometimes the screens get clogged and they are easy to replace. Unfortunately, it's a little pricey to have them cleaned and flowed - locally a buddy of mine charges $25/injector, but he does replace the screens and O-rings. Anyway, IF I knew I had one or two bad injectors I would just replace the bad ones.

Rich

 

Alright, sounds good. Thanks! Yeah, I am still unsure as to what is really causing the dead cylinder(s), but I just was curious anyway.

 

You didn't post whether you found dead cylinders yet.

In your last thread you replied that 2 of the plugs you changed looked "grungy". Does that mean kinda black? If so that proves you have fuel to the plugs but are not burning it off properly. If it were from too much fuel, you would have a starting issue which you did NOT indicate. Therefore if you have black plugs (did not say yet) we would have to concluded you have an ignition issue.

We assume you are concluding the injectors are defective since you don't believe after changing components in the ignition system, that could be the culprit. However, you have to go where the trouble leads you.

You must find the dead cylinders first. Have you done that yet? It only takes 5 minutes.

As far as the injectors are concerned. You merely have to raise the fuel rails and have someone crank it to see if there is a problem.

With regard to the injector and possibly saving them if they are spraying poorly. My shop uses this for several cleaning jobs.
http://www.harborfreight.com/25-lite...ner-95563.html
I use denatured alcohol from Lowes in it and have had 0% problems from it. Doesn't even harm the foam rubber seals on some of the carburetors we put in it.

My friends shop uses the same ultrasonic cleaner with water and this. http://www.harborfreight.com/6-oz-ul...der-91593.html
Keeping the cost way down.

To me it makes more sense to buy this for $70 and try cleaning them yourself. Then to pay $25 per injector.

You have to identify which cylinders are dead before you go doing anything else.
Just my $.02

 

Thanks man. Yes I understand this, I am just trying to soak information in hypothetically. This way I won't waste time once I know what the problem is. The answer is yes, I did have two grungy looking plugs. One was fairly bad, the other was just a little bad. I know, very ambiguous. Do I remember which cylinders they were? No................ :-/ I have been so busy with med school stuff I didn't have time to check the injectors yet, but JUST TO CLARIFY:

I simply pull each clip off the injector one at a time (placing them back on after checking, of course) while starting the vehicle to see which one makes it run different?

What's the difference between that and lifting up the fuel rail to inspect the squirt pattern??

 

Yes. You can also just swap injectors with a "good" cylinder, if the problem follows the injector you know it's bad.

 

First you have the engine running the entire time you lift and replace the clips. Not stopping and restarting the engine.

The difference between that and lifting the rails is in your case lifting the rails won't tell you anything.

You are looking for dead cylinders. The one that is dead will not change the way the engine runs when you remove the plug wire on the bad cylinder. Or the way the engine runs will not change when you remove the injector clip on the bad cylinder.

Since you finally indicated that you had 2 black plugs. That indicates you are not burning the fuel properly. But that it is getting fuel. So lifting the fuel rail is likely to show nothing.

Find the dead cylinders

 

Agree with Speedy but suggest you describe the plugs again. Black and wet..oil, or black and dry with 'fluffy' stuff on it...way too rich. The difference is important to figuring out the problem.

 

Definitely black and dry. ;-(

Speedy, great info. That's exactly what I needed. I've never checked for dead cylinders before, so this helps a lot.

 

Re: Misfire Continues...Culprit at Large....HELP!

From 11/13 and another discussion.

So what's the problem? Why is this not done?

 

Lol, I'm a premed student! I don't have tons of time lying around here folks. :P But I did do it in between classes today... Here's what I found:

Pulled clips on the passenger side and every one made a difference in the running as far as I could tell.

On the drivers' side, 3,5,7 seemed to make no difference except for 5, which is a bit ambiguous.

Two odd things:
1. In order to make the engine run normal again after pulling clips 1 and 4, I had to step on the gas a bit.... :-/
2. I climbed in the car, and there was no shake so I took it out on the street, and oh my gosh was there power. It seems that pulling the clips and replacing them made the misfire go away. WTF?! Now what the heck am I supposed to do?? So it appears to be a fuel issue, then? I mean, seriously, what the heck? Should I remove all my injectors and clean them??

One more thing: WOT and at idle the car runs amazing now (is it possible to have a misfire but smooth running car????). However, there is a light stall in power at 1200 rpm every once in a while when giving it *light* gas.