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2012 C63 with P30, LSD, and EES Supercharger, 1959 Plymouth with Viper V10 and Tremec 6sp
Originally Posted by FactoryFast
agreed, this is extremely poor advice.
Yes, if you have dirty injectors the additives are essentially useless. I ran several bottles of Techron through my injectors before finally getting them cleaned at 30,000 miles and it did nothing. Look at the results. Maybe if you have new or clean injectors and put it in every month it would help but I doubt it. I have had several sets of injectors cleaned and flow tested over the years by RC Fuel Injection and for racing engines they recommend flow testing all new injectors as they find differences in the new ones as mentioned above. It is worth while looking at their web site as they have lots of information on fuel injectors and I found it very educational. I didn't know you could get new injectors so cheap for our cars but even if it isn't cheaper to clean them at RC Fuel Injection at least you know exactly what you have and they should last as long as the new
. And now about 2000 miles later I installed an ESS supercharger and that came with new higher flow injectors! I sure didn't plan that well, haha.
Out of curiosity, if you have a stuck injector and get it cleaned, will it no longer be stuck? Also, wouldn’t the potential for Q1-4 injectors to get stuck still ve there even after cleaning? The price and piece of mind of getting rid of old injectors that are prone to failure are what made me swap mine for the bosch. Night and day difference. I don’t think I have seem my amber triangle blink as much as it has with the new injectors.
2012 C63 with P30, LSD, and EES Supercharger, 1959 Plymouth with Viper V10 and Tremec 6sp
Originally Posted by chrisridebike8
Out of curiosity, if you have a stuck injector and get it cleaned, will it no longer be stuck? Also, wouldn’t the potential for Q1-4 injectors to get stuck still ve there even after cleaning? The price and piece of mind of getting rid of old injectors that are prone to failure are what made me swap mine for the bosch. Night and day difference. I don’t think I have seem my amber triangle blink as much as it has with the new injectors.
The guys at RC injectors would be the true professionals to answer all of your questions but from my experience of 3 other cars and over 100k miles after cleaning, the injectors don't wear out, they just stick and inject poorly because they get full of gunk. When they flow test perfectly they are no longer stuck. I have a viper engine that sat with fuel in the fuel rails for 3 years and it turned to varnish and all 10 injectors were completely stuck. RC was able to clean and flow them to factory specs and the engine still runs perfectly 6 years later. I also had a Lexus LX450 cleaned at 90K and still ran perfectly when I sold it with 140k. So there is certainly nothing wrong with buying new injectors, but having a company with the quality and reputation of RC clean and flow them is certainly a legitimate option. I am sure there are a bunch of fly by night places that would not clean them properly, but if you use the sources trusted by serious racers it is hard to go wrong.
I think that there are differences between injectors being stuck shut and injectors that have a severe leak, bad enough to hydro lock an engine.
The causes are different.
2012 C63 with P30, LSD, and EES Supercharger, 1959 Plymouth with Viper V10 and Tremec 6sp
The injector is just a valve that has an electromagnetic switch that opens and shuts the valve. The fuel is under constant pressure so the longer it is open the more fuel and power for each combustion. The computer controls the length of time the FI is open. So if the injector freezes while in the shut position like my viper engine did, not a drop of fuel ever gets to the intake valve. If it freezes open then when you shut off your car all that pressurized fuel will run through the injector until the pressure is all gone. That is how you get the hydrolock. In my report some of the valves were leaking and dripping when off but not enough to cause hydrolock, thank goodness.
Or maybe he just never noticed minute ripples in his glass of water before because he never looked and is now paranoid after the trip to the shop and looking for problems...
It’s a 6.2L V8. These cars vibrate. Just drive it.
That is another possibility.
I assume if one of the injectors had a real bad spray pattern or was starving the motor I would have known already anyways. For some reason the low cost that originally had me interested in these injectors has now got me a bit worried, although that's my nature. I'm just on a quest to have the car as refreshed as possible before doing the headers and EC tune.
The guys at RC injectors would be the true professionals to answer all of your questions but from my experience of 3 other cars and over 100k miles after cleaning, the injectors don't wear out, they just stick and inject poorly because they get full of gunk. When they flow test perfectly they are no longer stuck. I have a viper engine that sat with fuel in the fuel rails for 3 years and it turned to varnish and all 10 injectors were completely stuck. RC was able to clean and flow them to factory specs and the engine still runs perfectly 6 years later. I also had a Lexus LX450 cleaned at 90K and still ran perfectly when I sold it with 140k. So there is certainly nothing wrong with buying new injectors, but having a company with the quality and reputation of RC clean and flow them is certainly a legitimate option. I am sure there are a bunch of fly by night places that would not clean them properly, but if you use the sources trusted by serious racers it is hard to go wrong.
What was the cost to do this? They are local to me.
I don't understand why these injectors are under scrutiny when there's no proof that they actually cause any issues or don't flow as well as the factory ones. Does this now mean that for all the years where owners have been buying Bosch lambda replacements for a third of the MB/AMG price at the dealer, that's why their cars might have....had a fuelling issue or been down on power? The theory kinda makes sense to me, but in reality I don't buy it.
If your M156 is vibrating, it's most probably because of worn motor mounts. For the injector flow pattern to actually have anything to do with the vibration would mean that they have a serious deviation from the expected amount of fuel/spray patten to the chambers, which would point more to a defect of that particular batch more than anything else.
In a nutshell - Shane, keep the injectors, get tuned with the headers and hell while the headers are out and you've got easier access to the mounts, give them a change too. The Jurassic Park water test will testify to this.
2012 C63 with P30, LSD, and EES Supercharger, 1959 Plymouth with Viper V10 and Tremec 6sp
I would assume the new Bosch injector are all good quality and sure better than the dirty ones being replaced! I was surprised the flow testing of mine showed they were all virtually identical with only 0.5% variation. Maybe like someone mentioned above, that is why they charge more for the AMG injectors, they are flow matched just like they do for racing applications. But all of this cleaning and testing isn't cheaper than new ones, and at RC it is $25 per injector for the cleaning and the computerized report you see above. You can also send them your new ones and just get them flow testing for $12.50, just like the racers do! On their web site they also have a calculator that figures out exactly what your flow/minute needs to be for any specific horsepower application and if you plug in 500 crank hp and 8 cylinders it comes out to 410cc which is exactly what my injectors flowed!
The fuel pressure is not constant.
The ECU controls the injector duty cycle.
This is port injection. So the injector has to leak into open intake valves, then when cranking after the valves shut, then it hydrolocks. But this is only the theory.
I had something that should have hydrolocked a W126 E420 SEL. I was messing with the fuel distributor in that car and it decided to dump a crazy amount of fuel as I was cranking. I didn't hydrolock and when I drained the oil, a mix of oil and gas came out in a crazy quantity, instead of the 9 quarts, I drained 15+ quarts smelling like raw gasoline. The gas station where I was trying to recycle the used oil in quarts refused to accept it for recycling, that's how bad it smelled.
I spent the money on a factory refurbished fuel distributor, it started right up and ran without problem for the next 2 years.
As to what causes an injector to be stuck open, maybe a weak spring would cause a hydrolock, or debris inside would jam the plunger. A bad solenoid or varnish would cause a no start.
Around here, we have South Bay Fuel injectors, they did my Subaru injectors and increased the flow to my specs. I'm going to drop off my injectors to them when I'm ready.
I had one of these fail after 3000 miles. After replacing all of them, my oil temps were stable again. 3000 miles later, the oil temps were bouncing all around again. I pulled the fuel rail and could see the driver’s side front injector leaking (number 1 cylinder, not sure how the cylinders are numbered). I replaced the injector with another Bosch, and oil temps are stable again. If it happens again, I will rip all of them out and replace with OEM. I plan to send the bad one out to get flow and leak tasted.
edit: i looked up which cylinder. Number 5.
Last edited by chrisridebike8; 08-04-2018 at 02:11 PM.
I had one of these fail after 3000 miles. After replacing all of them, my oil temps were stable again. 3000 miles later, the oil temps were bouncing all around again. I pulled the fuel rail and could see the driver’s side front injector leaking (number 1 cylinder, not sure how the cylinders are numbered). I replaced the injector with another Bosch, and oil temps are stable again. If it happens again, I will rip all of them out and replace with OEM. I plan to send the bad one out to get flow and leak tasted.
where was it leaking? Where it snaps into the rail?
Damn.how did you know its leaking? Did you get miss fires on that cylinder?
I have a brand new set of these and debating on installing them now.
before installing, oil temp was bouncing all over the place. After install, oil temp was steady. The oil injectors were leaky. Then 3000 miles after install, the oil temp was bouncing around again. I pulled the rail and you could see a little bit of fuel on the end of the injector, kind of like an eye dropper about to drop a drop. I swapped the injector and the oil temps are normal again.
before installing, oil temp was bouncing all over the place. After install, oil temp was steady. The oil injectors were leaky. Then 3000 miles after install, the oil temp was bouncing around again. I pulled the rail and you could see a little bit of fuel on the end of the injector, kind of like an eye dropper about to drop a drop. I swapped the injector and the oil temps are normal again.
not sure but your fuel injectors should have nothing to do with oil temps.my temps are all over the place but its 90 degrees out with 70% humidity.
the oil temps will fluctuate alot in summer depending on driving conditions and ambient temps.
I can baby my car right now and hit 240 oil temps with ease.
not sure but your fuel injectors should have nothing to do with oil temps.my temps are all over the place but its 90 degrees out with 70% humidity.
the oil temps will fluctuate alot in summer depending on driving conditions and ambient temps.
I can baby my car right now and hit 240 oil temps with ease.
I’ve had the car for 6 years and know the difference between normal temperature rising and falling. When you lift off the throttle, the temp should not immediately fall from 212F to 165F. That’s not normal. Look through this thread. That’s how mine was and directly correlates to when my injectors are bad.
I’ve had the car for 6 years and know the difference between normal temperature rising and falling. When you lift off the throttle, the temp should not immediately fall from 212F to 165F. That’s not normal. Look through this thread. That’s how mine was and directly correlates to when my injectors are bad.
if your temp drops from 212 to 165 you have a bad oil temp sensor.
Your oil stabilizing is just a coincidence with changing the fuel injector.
the sensor is brand new and is reading the correct voltage according to HG Motorsports. Every time I have replaced bad injectors, the temp has stabilized. 2 other C63s have had the same thing happen. Fluctuating oil temps, then new injectors and oil temps stabilize.
The injector shop will certainly indicate why kind of leak this injector has on the report.
How long had the car been sitting when you pulled the injectors ?
The injector shop will certainly indicate why kind of leak this injector has on the report.
How long had the car been sitting when you pulled the injectors ?
Overnight. The car was cool. It wasn’t very much fuel on the end of it, but it was the only one.
Please, nobody listen to this retardedness. In fact, you should do almost the exact opposite of all of this.
Im curious your thoughts on replacing injectors after 100,000+ miles.. I currently have misfire and flooded cylinder on 7, coil on 7 was also bad. Car has 177,000 miles, injectors are Q2 and intake manifold plus everything around the outside was pretty nasty since PCV valve failed, was giving the whistle after shutting off.. Debating if I should have the injectors ultrasonic cleaned or replaced? What are your guys thoughts anyone?
07-28-2018, 01:34 PM
The theory kinda makes sense to me, but in reality I don't buy it.
