Fuel Injectors

[viperBase1]

AFAIK, the Fuel Injectors on my '08 GenIV are 13 years old and have never been pulled, cleaned and/or replaced.

There is some concern that maybe one or more of 'em are not entirely closing properly. (might be running a tad rich on Bank1 ..according to my new O2 Sensors).
I always burn good gas (Shell Vpower 91) but am thinking that its time they get a little more TLC.

Sounds like the options are:

Fuel Injector Cleaner (Trechroline or RedLine or ?)
Pull 'em, clean 'em rebuild 'em
Replace 'em with new or refurbished Mopar injectors (no need for high performance units)



Wondering if there's a simple way to test 'em directly while they're still installed in the car.

Has anyone here rebuilt 'em yourself with a kit?
Is there a kit available?
Is it difficult?

Any other info. would be much appreciated.
Thanks!

[usmcfieldmp]

Bottles of injector cleaner can work to help clear up small issues, but they really don't do much... especially if you suspect that one is sticking open. I've tended to use the Lucas fuel injector cleaner, but also have never expected world changing results.

Honestly, they should be fine. If you run quality fuel and don't use one tank of fuel across 3 years, there shouldn't be an issue. I'm still running the OE injectors on the '95 Passat engine in my GTI. 150k miles and I beat the hell out of on track every chance I get. The car even sat unused for 5 years before I bought it.

If you care about precision, pull them and send them to a proper cleaner that will clean and flow test. I've used InjectorRX out of Houston before; without a doubt you should be able to find a semi-local injector cleaner with the same service. 1 day turn around. Shipped with my pre and post cleaning flow data, which actually assisted greatly when I started retuning the car.

If you want to flow check them on your own with limited resources, you can pull them out of the intake, stick the spray end of each injector in an empty beer bottle, crank the engine over for 20 seconds, and then compare your results. Proceed at your own risk. If you're pulling them out of the intake, replace the o-rings.

[Steve M]

Hard no on the fuel injector cleaner. I've used it on past vehicles, and was met with needing to replace the oxygen sensors shortly thereafter. It can't possibly do much when you think about how diluted it is when added to a tank of gas...you might be better off just pissing in your tank instead.

There's also a difference between running a tad rich on one bank vs. way rich (which would throw a code). Are you getting a code, or are you just watching fuel trims bank to bank? It stands to reason that the oxygen sensors you installed likely have enough production variance that you won't see exactly the same readings bank to bank even if your injectors were perfectly matched.

If you really think it needs done, pull the ones you have and send them to a reputable shop that can clean them and give you the before/after flow test and spray pattern results.

[FrgMstr]

AFAIK, the Fuel Injectors on my '08 GenIV are 13 years old and have never been pulled, cleaned and/or replaced.

There is some concern that maybe one or more of 'em are not entirely closing properly. (might be running a tad rich on Bank1 ..according to my new O2 Sensors).
I always burn good gas (Shell Vpower 91) but am thinking that its time they get a little more TLC.

Sounds like the options are:

Fuel Injector Cleaner (Trechroline or RedLine or ?)
Pull 'em, clean 'em rebuild 'em
Replace 'em with new or refurbished Mopar injectors (no need for high performance units)



Wondering if there's a simple way to test 'em directly while they're still installed in the car.

Has anyone here rebuilt 'em yourself with a kit?
Is there a kit available?
Is it difficult?

Any other info. would be much appreciated.
Thanks!

Good luck finding any new or rebuilt in stock nationally. I looked for the last two weeks. Mopar is out of stock on these currently and I could not get a solid answer on those coming back into stock. I spent a week and just found a full set from JonB here. (Should have asked him first.) I bought the last 12 he had as I just decided to replace as opposed to rebuild.

No way to test installed to my knowledge. It is my understanding you need a special machine to test, and I could only find one locally and I could not get access quick enough for my wants.

This was a recommended company I came across when it came to rebuilding/cleaning/testing. I have never used them, but I had more than one person point me in this direction. https://www.rcfuelinjection.com/Store/c/fuel-injector-cleaning

I am pulling mine out in the next week (already have the rails pulled, just need to get my lazy ass out there and finish up), if you want to buy those, so your car is not down during rebuild, PM me. While I am not having issues now, I had one injector that I had suspicion it was running lean and it made me a bit uncomfortable on the new Calvo build.

[Steve-Indy]

Another option would be to contact 1TONY1 via email through this site (also try a PM...but I don't know how often he comes here). Tony's shop is well known as a great place to send injectors for testing, service, etc.

[viperBase1]

Thank you gentlemen for the responses!
I was kinda surprised when my Forum search only returned a small amount info.. So hoping we can build out as much data as possible on this thread.


Bottles of injector cleaner can work to help clear up small issues, but they really don't do much... especially if you suspect that one is sticking open. I've tended to use the Lucas fuel injector cleaner, but also have never expected world changing results.
Honestly, they should be fine. If you run quality fuel and don't use one tank of fuel across 3 years, there shouldn't be an issue.
If you care about precision, pull them and send them to a proper cleaner that will clean and flow test. I've used InjectorRX out of Houston before; without a doubt you should be able to find a semi-local injector cleaner with the same service. 1 day turn around. Shipped with my pre and post cleaning flow data, which actually assisted greatly when I started retuning the car.
If you want to flow check them on your own with limited resources, you can pull them out of the intake, stick the spray end of each injector in an empty beer bottle, crank the engine over for 20 seconds, and then compare your results. Proceed at your own risk. If you're pulling them out of the intake, replace the o-rings.
That was my gut reaction too. Injector cleaners probably not that effective.
Especially when all the Top Tier fuel producers say how well their products clean these components.
Between the Shell VPower and Mobil Supremium+ I would expect my Injectors to be in fairly good condition.

The car is running and idling pretty damn smooth. Between the fuel injection system and the Coil Packs right on top of the spark plugs ..ignition is never a problem.
She starts every time without hesitation.

However after cold start, I have been hearing a little bit of a high pitched ticking sound that goes away after reaching operating temp.
N' by my rules => that means its not a problem ..yet. But I can imagine how that might be an Injector stuck open.



Hard no on the fuel injector cleaner. I've used it on past vehicles, and was met with needing to replace the oxygen sensors shortly thereafter. It can't possibly do much when you think about how diluted it is when added to a tank of gas...you might be better off just pissing in your tank instead.

There's also a difference between running a tad rich on one bank vs. way rich (which would throw a code). Are you getting a code, or are you just watching fuel trims bank to bank? It stands to reason that the oxygen sensors you installed likely have enough production variance that you won't see exactly the same readings bank to bank even if your injectors were perfectly matched.

If you really think it needs done, pull the ones you have and send them to a reputable shop that can clean them and give you the before/after flow test and spray pattern results.
Another no vote on the Injector Cleaners.

I'm watching O2 Sensor Traces (on brand new MOPAR O2 sensors) and trying to Complete the dreaded Drive Cycle.
They don't behave exactly alike ..n' Bank1 seems a little slower to go lean than Bank2.
Otherwise, so far I think they're functioning somewhat normally ..and so does Dan Cragin.
48372

I've also managed to make the O2 Sensor monitor go Complete on a single Drive Cycle attempt (out of MANY attempts).
48371
But so far haven't managed to reproduce that one good result.

So the good news is I'm moving the dial a little bit in the right direction, but I just don't think it should be this hard and I'm looking for reasons why.

No, no DTC's yet. Not even a one. Like I said, she's been running real smooth.


Good luck finding any new or rebuilt in stock nationally. I looked for the last two weeks. Mopar is out of stock on these currently and I could not get a solid answer on those coming back into stock. I spent a week and just found a full set from JonB here. (Should have asked him first.) I bought the last 12 he had as I just decided to replace as opposed to rebuild.

No way to test installed to my knowledge. It is my understanding you need a special machine to test, and I could only find one locally and I could not get access quick enough for my wants.

This was a recommended company I came across when it came to rebuilding/cleaning/testing. I have never used them, but I had more than one person point me in this direction. https://www.rcfuelinjection.com/Store/c/fuel-injector-cleaning

I am pulling mine out in the next week (already have the rails pulled, just need to get my lazy ass out there and finish up), if you want to buy those, so your car is not down during rebuild, PM me. While I am not having issues now, I had one injector that I had suspicion it was running lean and it made me a bit uncomfortable on the new Calvo build.

Wow, did not know they were so scarce. Looked to me like the SoCalMoparDirect.com webby indicated they had 'em in stock.
I came across the RCFuelInection webby last night ..but they're in New Yoawk Sit-ah!


Another option would be to contact 1TONY1 via email through this site (also try a PM...but I don't know how often he comes here). Tony's shop is well known as a great place to send injectors for testing, service, etc.
So I think its unanimous, pull 'em and have 'em serviced.

I found a shop close to home called "Injector Corrector". Gonna give 'em a call and check 'em out.

Pulling the Injectors
The general info. from the Interwebz is that you have to depressurize the system before pulling the Injectors.

I haven't RTFM'd the service manual yet, but does that hold true for the Viper too?
If so, exactly how do you do it? What to watch out for?

Thanks again!

[usmcfieldmp]

You could always do the ole Mechanic's Stethoscope test. Do a cold start, then stick the pointy end a long screwdriver/rod/etc on each injector while also up to your ear... if it's your injector that's ticking, that should tell you. You can actually buy a "real" mechanic's stethoscope from Harbor Freight for something like $5, as well.

Ticking like that could also be an exhaust leak that seals itself once thermal expansion takes hold. Something to consider.

[Steve M]

So I think its unanimous, pull 'em and have 'em serviced.

Definitely don't put me in that camp - I'm not convinced you need to do anything right now with the injectors.

I would also not put any weight on the O2 sensor traces you show above. They clearly aren't telling the whole story, because what you show isn't how narrow band O2 sensors work. They constantly switch back and forth between 0-1V...they don't just sit at 0.5V like those plots seem to indicate. The voltage readings averaged over a long enough period of time will be around that (0.5V), but that isn't what the PCM is looking for - it is looking for the switching behavior. Whatever you are using to generate those plots (I'm assuming an OBDII bluetooth diagnostic tool) doesn't appear to have enough resolution to show what's really going on, likely because it can't poll the data often enough through the OBDII port.

Also, based on what you show, bank 1 (O2 1x2) is showing leaner on average than bank 2 (O2 2x2). 1V = rich, 0V = lean.

You could look at the fuel trims, but you'd need to log both the long and short term ones to get an idea of the full picture. Again, I wouldn't put much weight on those either...as long as everything is within tolerances, it's good enough.

Trust the on board diagnostics system in this case - your car is fairly close to stock, so they should be quite effective at diagnosing issues. If it isn't throwing codes, things are working properly.

[viperBase1]

My bad on posting those O2 Sensor Traces, they don't show much. They were the only screenshots captured so far.
Was cruising at 40mph at that time. When I lift off, both Sensors to Lean (close to 0), but one side is slower than the other.

They are from the Torque app. on the phone w/BlueTooth Scanner.
Torque samples the OBDII port at a reasonable enough rate to show any and all switching being done by the O2 Sensors (both fronts and rears).

The Injector Corrector shop didn't pass muster.

I have trust issues.
More later.

[viperBase1]

Trust the on board diagnostics system in this case - your car is fairly close to stock, so they should be quite effective at diagnosing issues. If it isn't throwing codes, things are working properly.

Found a snap of the forward O2 Sensors in action ..switching like mad.
48390

BTW, am COMPLETELY STOCK now. Smog Test this year also calls for an INSPECTION. :eek:

Just installed a set of slightly used (~4K mile) GenIV CATs from Dan Cragin. Thanks Dan!
According to my local Dodge Dealer, no new GenIV CATs were available anywhere in the U.S..

Also, think I mighta found a trust-worthy injector service shop about 25 miles from home ..gonna give 'em a call today.
At this particular juncture, I understand there's scant evidence my injectors are suffering much.
But after 13 years I think a little injector TLC is worth while.

[Steve M]

That looks like what I'd expect to see.

While I still don't think injector servicing is necessary, I'm definitely curious to see how they check out before/after if you do.

[FrgMstr]

I am with Steve M on this one. I only pulled all mine due to the fact that I think I had one running very lean and caused a piston failure.

[viperBase1]

I am with Steve M on this one. I only pulled all mine due to the fact that I think I had one running very lean and caused a piston failure.
Hey FrgMst, over on the GREAT thread (https://driveviper.com/forums/threads/28604-2008-Gen-IV-Calvo-Motorsports-Build?p=441280&viewfull=1#post441280) about your Calvo build and your son ..you said


And yes you can change the injectors without pulling the fuel line or the intake, if you take your time and be a bit careful. Actually only took me about an hour.

Please share the details here.

[FrgMstr]

Hey FrgMst, over on the GREAT thread (https://driveviper.com/forums/threads/28604-2008-Gen-IV-Calvo-Motorsports-Build?p=441280&viewfull=1#post441280) about your Calvo build and your son ..you said


And yes you can change the injectors without pulling the fuel line or the intake, if you take your time and be a bit careful. Actually only took me about an hour.

Please share the details here.

If you remove the coil packs, you will have a lot more room to work, and it makes things overall simpler. Unplug all the wiring harness endpoints from the injectors. Then simply unbolt the fuel rails on each side. The fuel line between the rails is going to limit your movement. You can then wiggle loose the fuel rail loose. As I pulled the rail and injectors out of the block, I laid a towel down between the injectors and the block. This will soak up the extra fuel and protect the injectors. At that point you can push the injectors back and forth to work those out of the fuel rail. You may need to use a 90 degree pick to fish out the O-rings if they do not come out with the injectors. Once all the passenger side injectors are out, then you can do the drivers side. Having the passenger side injectors pulled with give you a little extra room to work on the drivers side injectors. Repeat the process on the drivers side. Lube up the injector O-rings with a dab of clean motor oil and get those installed on the driver side fuel raid, keeping a towel down to protect the injector faces.. Then install the passenger side. After that, pull your towel out and slide the injectors back into the black and bolt down the rails on each side. Reinstall you coil packs. Whole process took about an hour.

I would also suggest taking air compressor and blowing all the loose debris from around the injections before you start. You are going to have to deal with some fuel loss, so of course don't be smoking a stoagie in the process and keep a fire extinguisher close by. Just take your time as you have a small amount of room to work in. A pretty quick change if you just use some patience.

FWIW, I just sent all 10 injectors to this place in Oklahoma to be checked and rebuilt today. They were recommended by one of my P-Car buddies. https://deatschwerks.com/pages/injector-services

[viperBase1]

If you remove the coil packs, you will have a lot more room to work, and it makes things overall simpler. Unplug all the wiring harness endpoints from the injectors. Then simply unbolt the fuel rails on each side. The fuel line between the rails is going to limit your movement. You can then wiggle loose the fuel rail loose. As I pulled the rail and injectors out of the block, I laid a towel down between the injectors and the block. This will soak up the extra fuel and protect the injectors. At that point you can push the injectors back and forth to work those out of the fuel rail. You may need to use a 90 degree pick to fish out the O-rings if they do not come out with the injectors. Once all the passenger side injectors are out, then you can do the drivers side. Having the passenger side injectors pulled with give you a little extra room to work on the drivers side injectors. Repeat the process on the drivers side. Lube up the injector O-rings with a dab of clean motor oil and get those installed on the driver side fuel raid, keeping a towel down to protect the injector faces.. Then install the passenger side. After that, pull your towel out and slide the injectors back into the black and bolt down the rails on each side. Reinstall you coil packs. Whole process took about an hour.

I would also suggest taking air compressor and blowing all the loose debris from around the injections before you start. You are going to have to deal with some fuel loss, so of course don't be smoking a stoagie in the process and keep a fire extinguisher close by. Just take your time as you have a small amount of room to work in. A pretty quick change if you just use some patience.

FWIW, I just sent all 10 injectors to this place in Oklahoma to be checked and rebuilt today. They were recommended by one of my P-Car buddies. https://deatschwerks.com/pages/injector-services
Many thanks FrgMstr!
And thanks for the link to another injector service. So far, none of the injector shops close to home have passed muster.

So you didn't de-pressurize the system first?
The shop manual says to remove the fuse for the Fuel Pump and then run the engine until it stalls ..and then start removing things.

No stogies & a fire extinguisher ..gotchya/check. :cool:

[FrgMstr]

Many thanks FrgMstr!
And thanks for the link to another injector service. So far, none of the injector shops close to home have passed muster.

So you didn't de-pressurize the system first?
The shop manual says to remove the fuse for the Fuel Pump and then run the engine until it stalls ..and then start removing things.

No stogies & a fire extinguisher ..gotchya/check. :cool:

No, I did not take those precautions. Hence the reasons to have a towel down handy to soak up the gas you are going to drop out of the rail when you remove the injectors, and the small bit you are going to see when you pull the rail out with the injectors. That said, running it dry is likely a good idea. I was just being lazy.

[lisekplx]

Been a few weeks, did any of you guys actually notice a difference after getting the injectors professionally cleaned? Mpg or throttle response? Mine has 37k on the clock.

[FrgMstr]

Been a few weeks, did any of you guys actually notice a difference after getting the injectors professionally cleaned? Mpg or throttle response? Mine has 37k on the clock.

Mine came back as "clean" and within spec, and mine all flowed within 2% of each other. New filters, new O-rings. Car does seem to idle better now however.