[R&T]

Quick recap. I’ve been battling a misfire condition in all 4 cylinders for a thousand miles or so. There are no indications of a misfire except the CEL is on. I’ve replaced plugs, ran fuel system cleaner, changed fuel suppliers, and even the battery for something else not related. After the fuel cleaner and plugs it was off for 500-750 miles maybe. Before this issue came about I bounced the motor off the rev limiter and it immediately went into limp mode. The code was low fuel pressure or something like that and the HPFP was sounding very loud and erratic. I drive it home in limp mode(12-15 miles). About 2 miles from home it cleared itself up and went out of limp mode and the HPFP sounded normal. No issues for a few hundred miles then this issue came up. It has gone into limp mode one more time when I hit a slick spot taking off in first gear and the pump did the same thing again. This time it cleared up after 6-7 miles of driving.
I’m suspecting the HPFP could be the culprit for the reasons above by thinking I may have damaged it somehow. The other issue I’m having once in awhile is a stumble taking off from a stop. I’ll give it gas and it will stumble for a second or two or it will feel like I’m not giving it gas. The rpm’s will also drop to 450-500 while idling every now and then. The other issue I have once in awhile is after it sits for a couple days it will take 2-3 seconds of cranking before it fires but not every time it sits this long. Perhaps the O ring inside is cracked or something in the pump itself isn’t working correctly. I never had any issues until after the limp mode incident. The guy at the auto parts who ran the code says check wiring harness for injectors I believe. I’m not sure what I would be looking for and have only looked for a few minutes and couldn’t see anything from the norm. Any other suggestions? Thanks

 

[HHGadget]

I had this exact same problem. Unfortunately my problem was probably one in a million as I discovered a loose washer had lodged itself in the intake side of cylinder 3 after living an unknown amount of time bouncing around my air intake.

Of course not knowing this I replaced the plugs, coils, fuel pump, fuel pump lobe thingy (technical term), VVT solenoids, pulled checked and reseated all fuses, checked all grounding points, pulled the charge tubes, intercooler, replaced all worm drive clamps with t-bolt style, both the MAF and MAP, replaced the evap canister filter on top of the gas tank, blew out all the fuel lines, and that’s just off the top of my head.

after discovering the washer after all the above (I had the same diagnostic you had of “check fuel injector wiring harness” I still had some misfire issues however this time it was just one cylinder and that turned out to be a bad aftermarket coil.

all that being said, if you pull the fuel pump, make sure to pop out the fuel pump roller (depending on the position of the cam you can either just grab it and slide it out or use a small magnet to pull it out) as it is possible that it is starting to wear out and no extra effort to check if you pull the HPFP.

that particular part (if it is that) was a lot cheaper than a new HPFP…

good luck!

 

[HHGadget]

Also you may want to check the fuel flow from the pump in the tank to make sure the issue isn’t before the HPFP.

I got a graduated cylinder, disconnected the low pressure line (after depressurizing with the Schrader valve that’s right there in the HPFP area) and then had a friend turn the key but not start the car.
I was able to measure the amount of each key turn and was looking for consistency with each key turn.
Can’t remember the numbers but it was close enough that I felt comfortable the low pressure fuel pump was fine.

 

[kgschlosser]

Do you have all of the codes stored in the computer on the car?

If you could post all of them it would be really helpful.

 

[R&T]

Also you may want to check the fuel flow from the pump in the tank to make sure the issue isn’t before the HPFP.

I got a graduated cylinder, disconnected the low pressure line (after depressurizing with the Schrader valve that’s right there in the HPFP area) and then had a friend turn the key but not start the car.
I was able to measure the amount of each key turn and was looking for consistency with each key turn.
Can’t remember the numbers but it was close enough that I felt comfortable the low pressure fuel pump was fine.

Thank you for the replies and that information is very helpful. I sure hope I don’t have to go through all that to find it is something like a washer or garbage in a cylinder. I might be asking for help on checking the low pressure fuel delivery.

Do you have all of the codes stored in the computer on the car?

If you could post all of them it would be really helpful.

Yes, I’ll have to dig out my paperwork when I get home. Thank you.

 

[HHGadget]

Thank you for the replies and that information is very helpful. I sure hope I don’t have to go through all that to find it is something like a washer or garbage in a cylinder. I might be asking for help on checking the low pressure fuel delivery.

Yes, I’ll have to dig out my paperwork when I get home. Thank you.

I hope nobody goes through all that
One in a million odd ball issue.

checking the low pressure fuel feed is basically a free thing as long as you have some basic tools and some time.

as others have mentioned if there are stored codes that may help in steering you in a better direction.

also if you get to the point of pulling the HPFP it is recommended to replace the “single use” bolts.
Also the gasket between the pump and motor.

Others have reused theirs with no issue but it is recommended. When I replaced my pump it did not come with the bolts so just a heads up if you go down that path, they are pretty cheap if I remember correctly.

I personally highly recommend removing the plastic cowl in front of the windshield as it makes access to the pump 100% easier. If you do that be very mindful that there are plastic clips that slide over the bottom edge of the windshield glass and you absolutely do not want to break them. Also not a big deal but something to be cautious of if you perform the work. Once you see where they are the first time it makes sense and you just proceed with care.

good luck.

 

[R&T]

I only have access to the p0300-p0304. Random misfire detected in all cylinders. When this was pulled he said there were no other codes stored in the system. I don’t remember the code(s) that popped up when I went into limp mode. I do remember it was low fuel pressure and something else. I thought I posted it on here previously in another thread but I can’t find it.

 

[kgschlosser]

Check your oil for gasoline. Pull the dipstick and give it a sniff. There might be a slight odor of gasoline and this would be normal. It shouldn't be a strong smell. Put some of the oil on a piece of white paper and check how light or dark it is. If it is older oil it should be dark. also look at how fast the oil spreads out after putting it on the paper. Basically check if the oil has thinned. A HPFP usually goes bad in one of 2 ways. It stops working all together, no warning or anything. The other way is they will leak gasoline into the crank case but the pump stays working. Depending on the leak it could cause a low pressure condition in the fuel rail.

Check your oil level. If it is overfull you probably have gasoline mixed in with it and the pump will need to be replaced.

 

[R&T]

Check your oil for gasoline. Pull the dipstick and give it a sniff. There might be a slight odor of gasoline and this would be normal. It shouldn't be a strong smell. Put some of the oil on a piece of white paper and check how light or dark it is. If it is older oil it should be dark. also look at how fast the oil spreads out after putting it on the paper. Basically check if the oil has thinned. A HPFP usually goes bad in one of 2 ways. It stops working all together, no warning or anything. The other way is they will leak gasoline into the crank case but the pump stays working. Depending on the leak it could cause a low pressure condition in the fuel rail.

Check your oil level. If it is overfull you probably have gasoline mixed in with it and the pump will need to be replaced.

Ok. Thank you. I will check that. Do you think it is ok to drive? There’s no difference in performance when the CEL is on or off. Could damage occur?

 

[R&T]

This is two wipes off the dipstick. I have 40%left on the oil monitor. I normally change it when it hits 25-30% and my oil is as dark as night when I change it. This looks very light unless oil changes to dark in the last 10-15%. I also have a strong smell of gas and it’s more pronounced than it was just a few years ago. I could have sworn I checked for gas smell not long ago but I guess not. I don’t always smell my oil. I also saw that my oil level is right at the top of the black tip where it meets the metal rod. I’m thinking that’s about an 1/8” above the full mark.

 

[JohnWR]

View attachment 118349
This is two wipes off the dipstick. I have 40%left on the oil monitor. I normally change it when it hits 25-30% and my oil is as dark as night when I change it. This looks very light unless oil changes to dark in the last 10-15%. I also have a strong smell of gas and it’s more pronounced than it was just a few years ago. I could have sworn I checked for gas smell not long ago but I guess not. I don’t always smell my oil. I also saw that my oil level is right at the top of the black tip where it meets the metal rod. I’m thinking that’s about an 1/8” above the full mark.

Those are definite signs that you are getting fuel in your oil.

 

[syjos]

Check low pressure with a gauge and the high pressure with an OBDII scanner and the Torque App on your phone.

There are UTube videos showing the steps.

That's how I was able to diagnose a failed HPFP.

 

[HHGadget]

Strong smell of gas is a pretty good indicator.
I have seen mechanics that will taste the oil though I would personally strongly discourage that behavior

 

[kgschlosser]

Check the level, you will probably find that it is a little high. If it has an odor that would make you stop someone from lighting a cigarette near the oil then it's time for a new HPFP.

It does look on the light side for having 3000+ miles on it.
I am thinking you found the problem.

 

[agent008]

You see? The NA is not worse than the GXP at everything... No HPFP, no HP injectors, no Intercooler, no turbo and all associated piping/valving to be worried about. And it can run on regular gas (very important to me as premium is expensive and low availability here). Glass half full point of view 😁

 

[R&T]

Check low pressure with a gauge and the high pressure with an OBDII scanner and the Torque App on your phone.

There are UTube videos showing the steps.

That's how I was able to diagnose a failed HPFP.

Ok. I want aware we could download an app to diagnose our car🤦‍♂️🤦‍♂️🤦‍♂️ I’m not on here daily but I try to check biweekly or so and must have missed those threads. Thank you.

Strong smell of gas is a pretty good indicator.
I have seen mechanics that will taste the oil though I would personally strongly discourage that behavior

WTH!!! Yes, I will pass on that test. 😂😂

Check the level, you will probably find that it is a little high. If it has an odor that would make you stop someone from lighting a cigarette near the oil then it's time for a new HPFP.

It does look on the light side for having 3000+ miles on it.
I am thinking you found the problem.

.
Yes, I definitely wouldn’t put a cigarette next to it. I can smell it with the oil cap off and my face about 8-10” away.
Btw, my wife drives the car occasionally since she can work from home. Is there any chance of damage for short trips if need be?

 

[agent008]

Ok. I want aware we could download an app to diagnose our car🤦‍♂️🤦‍♂️🤦‍♂️ I’m not on here daily but I try to check biweekly or so and must have missed those threads. Thank you.

WTH!!! Yes, I will pass on that test. 😂😂
.
Yes, I definitely wouldn’t put a cigarette next to it. I can smell it with the oil cap off and my face about 8-10” away.
Btw, my wife drives the car occasionally since she can work from home. Is there any chance of damage for short trips if need be?

I would change the oil and tell her to avoid full throttle. The first is to prevent your tainted oil not lubricating the engine satisfactorily. The second to avoid a potential fuel lean condition which is never good for the engine (especially a turbo).

 

[kgschlosser]

OK. Look at it this way. Would you pour gasoline down the oil fill in your engine? And why would you not do that? After pouring gasoline down into the engine like that would you start the car? Now think about the exact reason why you would not do this.

That HPFP leaking gasoline into the crank case is the exact same thing as pouring gasoline down into the oil fill. You know of the problem and if you still operate the vehicle that is basically what you are doing.

If enough gasoline vapor builds up inside the crank case when it ignites (not if) you are going to grenade the engine. That's not a figurative statement, it's a literal one. Now here come the reality of how possible that is. The gasoline breaks down the lubricating properties of the oil. The bearings inside of the engine are going to get cherry hot, and that is what is going to ignite the gasoline.

Here is a video showing a 5 gallon can of gas blowing up.

This is important because a plastic can that is melting is not much in the way of containment. If you take that same amount of gasoline and put it inside of a steel container the explosion is exponentially stronger. 1 cup full inside of a engine block when it ignites will blow the emblems off the car. Trust me I know this, and no I am not the person that did it I was a bystander.

 

[agent008]

Again glass half full... the added gasoline might have been helpful on cleaning any coking/oil deposits around the intake valves? 😬

 

[kgschlosser]

I don't think you will have to worry about the carbon on the valves anymore.