Temporary Misfire and Pending Low Fuel Rail Pressure Code

[kryptto]

Here we go again, on the way to work cylinder 4 injector decided to exit the chat. Not even 2 months later and I'm going back under the intake, this time I'm doing the 5 remaining injectors. Budget and time still being an issue going with the standards again. Posting for 2 reasons, #1 @SHOdded you were right (not that I doubted that) i shouldve done all 6 and wouldve if not for the budget at the time. #2 anyone who goes down the injector rabit hole dont do what i did, just replace all of 6 injectors. My car is at 118k and they're failing one by one.

it truly is like every manufactured part - average time before mean failure - all from the same batch when the car was manuf, then they will always fail soon and close to each other based on time and use.

I used to deal with that with servers, we would plan the replacement parts needed based on MTBF. So doin one half shaft, as an example, for joint failure, just do all, unfortunately.

 

[Bronco2fan]

That falls under the category of while it's apart I may as well do............ Seen it so many times, I always prepare for it lol.

 

[Junkyard_Mad-Scientist]

Believe me I was kicking myself when it happened. Saw the code knew exactly what it was and it went faster this time lol. She's over 100k and like every car ive ever had once it gets that far its just piece by piece, so I get to rebuild it one SET of parts at a time lol

 

[Shadow351]

Welp, mine returned with a vengeance this time. Was on the interstate and heard a pop and the car started misfiring. Pulled off and these are the codes (if anyone can decipher them)


Shut it off and it wouldn't restart at first, but did after a couple attempts. Has a full on misfire now and I did see some smoke. These are the codes it has now.

Currently waiting on AAA (they estimated 2 HOURS).

 

[Junkyard_Mad-Scientist]

Mine did the EXACT same thing and threw the same codes for both fuel injector failures, first time was cylinder 2, second time was cylinder 4. the first time I dug into the injectors I could only afford 1 so I took a chance and replaced cylinder 2 since it popped up as a misfire and the problem went away for a solid 3000 miles until cylinder 4 started acting up. after that I just replaced the remaining 5 and havent had an issue since (2 weeks). For a set of Standards from Oriellys they were about $85 each, I figured thats a good place to start rather than the extremely pricey HPFP.

As recommended on here several times, if the funds are available, go with motorcrafts and send your old set out for flow testing and maybe have them refurbished, the learning curve on these direct injected engines is a long one but something tells me oem spares are a good thing to have around especially considering this platform went extinct 5 years ago.

The one thing I noticed when mine threw the codes was the misfire seemed less severe with my foot in the throttle 3/4 or better, still noticeable just not as violent as if the injector was stuck open dumping fuel in the hole causing a misfire and a low pressure in the rail (since its dumping and cant build pressure), so by jamming air down its throat it almost would keep up.

 

[kryptto]

Mine did the EXACT same thing and threw the same codes for both fuel injector failures, first time was cylinder 2, second time was cylinder 4. the first time I dug into the injectors I could only afford 1 so I took a chance and replaced cylinder 2 since it popped up as a misfire and the problem went away for a solid 3000 miles until cylinder 4 started acting up. after that I just replaced the remaining 5 and havent had an issue since (2 weeks). For a set of Standards from Oriellys they were about $85 each, I figured thats a good place to start rather than the extremely pricey HPFP.

As recommended on here several times, if the funds are available, go with motorcrafts and send your old set out for flow testing and maybe have them refurbished, the learning curve on these direct injected engines is a long one but something tells me oem spares are a good thing to have around especially considering this platform went extinct 5 years ago.

The one thing I noticed when mine threw the codes was the misfire seemed less severe with my foot in the throttle 3/4 or better, still noticeable just not as violent as if the injector was stuck open dumping fuel in the hole causing a misfire and a low pressure in the rail (since its dumping and cant build pressure), so by jamming air down its throat it almost would keep up.

Great write up...sounds like solid advice.

 

[Shadow351]

Anybody use Bosch injectors and HPFP? They are $78 on rock auto and the HPFP is $110. Do we know who the OE is? My O'Reilly wants $170/each for standard motor injectors, so I'm thinking the Bosch injectors from RA are my best bet

 

[Jordan_R]

Food for thought. Problem is the LPFP has a built in fuel filter that naturally overtime becomes clogged. Essentially what happens is as the fuel pressure from the LPFP lowers the injectors compensate for in how long they stay open to keeps things in check. Now the way it's been told to me is they can stay open to the point where the combustion cycle happens essentially back feeding them and that's how they get crammed open.

Long story boring we've got a lpfp causing failure in the injectors then we are only replacing the injectors. I think at the point of failure we need to make sure that we aren't just focusing the failure point. We need to make sure to track the failure to the final point.

 

[kryptto]

Food for thought. Problem is the LPFP has a built in fuel filter that naturally overtime becomes clogged. Essentially what happens is as the fuel pressure from the LPFP lowers the injectors compensate for in how long they stay open to keeps things in check. Now the way it's been told to me is they can stay open to the point where the combustion cycle happens essentially back feeding them and that's how they get crammed open.

Long story boring we've got a lpfp causing failure in the injectors then we are only replacing the injectors. I think at the point of failure we need to make sure that we aren't just focusing the failure point. We need to make sure to track the failure to the final point.

So I told AJP Turbo I am installing my GH IC and getting my LPFP upgraded to the Deatschwerks pump. I asked him about the XDI pumps and suggestions of when to send logs.

He told me that I can run the LPFP without a tune, however strongly advised getting him logs to compensate for the extra pressure up to the HPFP. I also told him I dont see myself hunting down ethanol and mixing fuels, that said he told me I can run the stock HPFP - and that the extra pressure from the LPFP will help with controlling the high pressure rail fuel pressure much better, if I can interpret - making it more stable for the fuel injectors.

My two cents

 

[Junkyard_Mad-Scientist]

Anybody use Bosch injectors and HPFP? They are $78 on rock auto and the HPFP is $110. Do we know who the OE is? My O'Reilly wants $170/each for standard motor injectors, so I'm thinking the Bosch injectors from RA are my best bet

@SHOdded recommended the Bosch to me but I didn't have the time to wait for any shipping. He also said he wasn't sure if they were the OE mfg or not, that said all of the ones I pulled out of my car said FoMoCo. At the end of the day I just went with what had a warranty for a decent price and Bosch is by no means a bad brand in my experience.

 

[Junkyard_Mad-Scientist]

Food for thought. Problem is the LPFP has a built in fuel filter that naturally overtime becomes clogged. Essentially what happens is as the fuel pressure from the LPFP lowers the injectors compensate for in how long they stay open to keeps things in check. Now the way it's been told to me is they can stay open to the point where the combustion cycle happens essentially back feeding them and that's how they get crammed open.

Long story boring we've got a lpfp causing failure in the injectors then we are only replacing the injectors. I think at the point of failure we need to make sure that we aren't just focusing the failure point. We need to make sure to track the failure to the final point.

with the miles I can see in your signature @Shadow351 it might be good policy to replace the pump in the tank as well.

 

[Zpak]

Food for thought. Problem is the LPFP has a built in fuel filter that naturally overtime becomes clogged. Essentially what happens is as the fuel pressure from the LPFP lowers the injectors compensate for in how long they stay open to keeps things in check. Now the way it's been told to me is they can stay open to the point where the combustion cycle happens essentially back feeding them and that's how they get crammed open.

Long story boring we've got a lpfp causing failure in the injectors then we are only replacing the injectors. I think at the point of failure we need to make sure that we aren't just focusing the failure point. We need to make sure to track the failure to the final point.

Now that is something I had never thought about. Makes perfect sense.

 

[Shadow351]

Rock Auto has 2 in tank pumps. An "Autobest" for $22 with a lifetime warranty, and a "GMB" for $69 (Nice) with a 1 year warranty. $22 seems suspiciously cheap. Anybody used the GMB pump?

Another option would be replacing the entire pump/housing assy. "Ultra Power" is $85, "Carter" $158, Delphi $215, or Motorcraft for $300. The MC is the preferred, but that'd put me at another $1000 into the car (just put $150 battery in it last week, and $600 turbo in it the previous week, hopefully this doesn't become a trend.)

 

[Jordan_R]

Rock Auto has 2 in tank pumps. An "Autobest" for $22 with a lifetime warranty, and a "GMB" for $69 (Nice) with a 1 year warranty. $22 seems suspiciously cheap. Anybody used the GMB pump?

Another option would be replacing the entire pump/housing assy. "Ultra Power" is $85, "Carter" $158, Delphi $215, or Motorcraft for $300. The MC is the preferred, but that'd put me at another $1000 into the car (just put $150 battery in it last week, and $600 turbo in it the previous week, hopefully this doesn't become a trend.)

You need to buy the entire pump assembly because the fuel filter is part of the pump assembly not the fuel pump itself

 

[Shadow351]

Oh FFS, The pump is replaceable but the filter isn't? Genius. Next are they're gonna remove oil filters and change to replacing engines instead? I might start with pressure testing the LP fuel system to see what pressure it's making, pretty sure i saw a port on the line at the firewall.

 

[Junkyard_Mad-Scientist]

Oh FFS, The pump is replaceable but the filter isn't? Genius. Next are they're gonna remove oil filters and change to replacing engines instead? I might start with pressure testing the LP fuel system to see what pressure it's making, pretty sure i saw a port on the line at the firewall.

Dodge already started by removing the dipstick from the new Ram lol. Testing your line pressure is a very good idea, if youre making the right pressure to the HPFP then no sense in throwing money at a problem that doesnt exist. but I still believe it would be a wise investment in the near future given the miles on your car from a preventative perspective. Also, some fuel system cleaner like seafoam or I just experimented with royal purple with no bad results, but something to maybe help dissolve some deposits and move some of the crap out of the filter. $10 is better than $300 and it couldn't hurt, i did the fuel treatment after my injectors just for peace of mind incase I got a spec of something in them during the install.

 

[Jordan_R]

Dodge already started by removing the dipstick from the new Ram lol. Testing your line pressure is a very good idea, if youre making the right pressure to the HPFP then no sense in throwing money at a problem that doesnt exist. but I still believe it would be a wise investment in the near future given the miles on your car from a preventative perspective. Also, some fuel system cleaner like seafoam or I just experimented with royal purple with no bad results, but something to maybe help dissolve some deposits and move some of the crap out of the filter. $10 is better than $300 and it couldn't hurt, i did the fuel treatment after my injectors just for peace of mind incase I got a spec of something in them during the install.

Pressure off lpfp doesn't mean anything because it needs to be a measurement of flow. A restricted pump will still build pressure.

 

[SM105K]

Now that is something I had never thought about. Makes perfect sense.

It does make a lot of sense. I never touched the LPFP in M to be clear.

 

[Zpak]

It does make a lot of sense. I never touched the LPFP in M to be clear.

I figured. It’s on my list of things to replace. Irritating these cars don’t just have an external fuel filter.

 

[SM105K]

This got quite long winded, but I believe it is worth a good read.

I have been watching a lot of the this guy.......

The Motor Oil Geek

As a Certified Lubrication Specialist with over 20 years experience, The Motor Oil Geek channel delivers real data about motor oils from an expert perspective instead of speculation. Twice each month I will upload a new video that either analyzes a new oil, dyno tests an oil, reveals the details...

www.youtube.com

His dad is Nascar Driver Lake Speed. He is Lake Speed Jr. He worked in the engine department and developed oils for Joe Gibbs Racing. He works for Total Seal Piston Rings....so he knows his shit and backs all of his shit with science.

He has a lot of cool information about oil ect. What really got me was his explanation about fuel saturation in the oil in Boosted/DI motors. If the fuel injectors aren't pulsing correctly or efficiently they essentials adding fuel to the oil. The unburnt or dribbled fuel goes past the rings and straight into the oil. Getting a oil diagnostic can be a huge benefit in detecting exactly something like this. If you are seeing high amounts of saturation, you could be seeing the start of something bigger. Either pump failure, injector failure, inefficient injector spray ect.

I bought one of his kits and had the oil tested in the AMG. It came back okay for 5000 miles. He said things look okay but to start changing my oil every 4000 miles. I don't agree, I am staunch 3000 mile changer regardless of what it is. It seems that the Mobil 1 0W-40 Euro Car Formula isn't the best oil for my application because the viscosity break down and high calcium. Viscosity break down is normal, but not at the rate this oil should have across the board. The high calcium is a detergent that lends a big hand in LSPI. He actually has a video just about this particular oil. I had changed the oil in the AMG 200 miles ago with M1 0W-40 Euro Car Formula and after looking on the MB forums and seeing what MB says. After that video and seeing the break down on the analysis, I switched over to Liquid Moly 5W-40. Yes I dropped the 200 mile freshly changed oil. I might throw it in the VW Jetta however. When I get to 3000 miles I will change the Liquid Moly. However I am super interested in the Castrol Edge 5W-40 Euro Formula as well. I had great results with the Castrol Edge in the SHO.

What Lake suggests in a nutshell:

DO NOT FOLLOW MANUFACTURERS RECOMMENDED OIL CHANGES INTERVALS. They have incentives and CAFE requirements by the EPA and FED GOVT to prolong oil changes. Less oil used ect. It is long and winded, but they get kick backs.

Max mileage for a oil change should be 5000 miles or less depending on driving conditions and habits.

ALWAYS PREFILL THE NEW OIL FILTER with fresh oil before install. He has a whole video about this. If you don't, it does cause wear during the first start up after the oil change, because there is no oil pressure. It is not a myth, so fill the new damn oil filter. If you have a filter that cannot be filled (I do) then use the no start/ignition cut start to turn over the motor for at least 10 seconds. I did this with the SHO every oil change while filling the new filter.

Every oil change throw an bottle of complete fuel system cleaner in your vehicle esp if it is direct injection. Doesn't matter what brand just as long as it has polyether amine in it. He has seen a correlation in reduced fuel saturation in the oils tested when this is used each oil change. It helps clean the injectors and helps with spray pattern ect. I use the Chevron Complete Fuel System Cleaner.

If you buy a new car, change the oil after 500 miles. You need to get all of the crap out of that engine before "the first recommended oil change". Manufacturers do not use break in oil anymore. You would be shocked at how much crap they pulled out of his daughters brand new Toyota that had factory 0W-8 in it. He has a whole video on that as well.

A oil analysis (to track trends), oil, a filter, and bottle of injector cleaner is cheap compared to a potential motor failure.