Port Injection causing engine failure

Does PI cause engine failures due to lean conditions on factory DI cut?


  • Total voters
    34

dyezak

Major
May 4, 2017
1,768
1,515
0
Plano TX
Ride
335is
Did I just ruffle your feathers? Hahaha. Take a deep breath, relax....now, I'm just curious what your opinions are.
 

dyezak

Major
May 4, 2017
1,768
1,515
0
Plano TX
Ride
335is
Are we rediscovering fire here ?

Don't know...you tell me. Just in the last 10d I can quote people on both sides of the fence on just this forum...but there hasn't been a real discussion around it (that I can find). Generally it's a tangential discussion spawning inside a thread where someone blew their engine. I'm just looking to pluck this topic out of those sidebar conversations and put the discussion in a single consolidated thread.
 

Bmwfixerguy1

Lieutenant
Jun 5, 2017
873
288
0
Ride
07 335i MT
Let's put it this way I've grown to o see the short comings in it. Now if we had a sequential controller than we might be better off. Until then I think tony might have been so ahead of us all with his overdriving options that we looked at his as a mad manna instead of a genius. Once again not dick riding they tony just seeing more method in his madness
 

BMWE92_Harry

Specialist
Apr 28, 2017
62
15
0
Ride
N54 E92
It caused engine failure because not enough safety is built in to the system yet. Make misfire a lot more devastating.
 
  • Agree
Reactions: BKBMW335I

AD-ENG

Corporal
Oct 22, 2016
122
138
0
36
It caused engine failure because not enough safety is built in to the system yet. Make misfire a lot more devastating.

This is the biggest rumor and untrue.

This rumor started from a lack of understanding what is happening and linked an engine failure to their PI.

The reason is lack of tuning itself. The most dangerous thing associated with PI is open loop. An ethanol car has a large percentage of fuel added to the fuel scalar + PI for additional fuel. A lack of tuning can cause the need for extreme stft's and a maxed out stft will kick the car into open loop. Why is this so bad on e85 cars? Well, an open loop car not only has no lambda feedback, but you also lose all your additional fuel in the scalar. The result is a full load pull without lambda control and 25-35% fuel pulled out. Stay in it long enough and boom.
 

Subaru335i

New Member
Apr 20, 2017
3
1
0
Ride
Subaru
It definitely can cause problems just like any time you have multiple non integrated systems trying to work together like this.
It is a bit more reliable that meth injection which is also dangerous and can blow engines but it is far from perfectly safe.
A standalone like the syvecs that can control both at the same time with the same CPU would be about as good as you can get. DI upgrades would be just about the same without the valve cleaning benefit of PI.
 
  • Like
Reactions: langsbr

Bmwfixerguy1

Lieutenant
Jun 5, 2017
873
288
0
Ride
07 335i MT
This is the biggest rumor and untrue.

This rumor started from a lack of understanding what is happening and linked an engine failure to their PI.

The reason is lack of tuning itself. The most dangerous thing associated with PI is open loop. An ethanol car has a large percentage of fuel added to the fuel scalar + PI for additional fuel. A lack of tuning can cause the need for extreme stft's and a maxed out stft will kick the car into open loop. Why is this so bad on e85 cars? Well, an open loop car not only has no lambda feedback, but you also lose all your additional fuel in the scalar. The result is a full load pull without lambda control and 25-35% fuel pulled out. Stay in it long enough and boom.

So I definitely agree with this that the lack of tuning is a huge result of failures..
More so than anything that I didn't add be cause I was at a red light
Id have to say without a doubt that the number 1 failure culprit is too much power! Let's see so we have a big ole turbo and were maxed out on the stock fuel system so we add PI to create more cylinder pressure.. Has anyone considered that the urban legend of being a super strong stock rotating assembly is just that. A little bit of a stretch of the truth??
Let's put it this way If you have PI than your trying to crack 600whp.
If your doing that on stock internals its gonna break. Your gonna bend rods over time. Score piston walls and crack skirts and lose compression in that hole.
The real poll would be built motor failures with PI ;)

In closing I'm liking the idea of increased high pressure system more and more
 

R.G.

Lieutenant
Nov 17, 2016
669
325
0
Henderson, NV
Ride
E92 335, F10 M5
Unless your watching your data points constantly, (some do some don't), then you can be thrown into open loop at any minute for X reason. So isn't that point being used as reassurance moot?
 
  • Informative
Reactions: rooringhusky

DennisKing

Specialist
Nov 5, 2016
94
54
0
Portland, OR
For years and years, DI tuners have used overdriven pumps and secondary (tandem) pumps with stock injectors or even reworked DI injectors. This was in the diesel world though but I'm sure many principles carry over to the gasoline world. This is why the Shotgun and Double Barrel Shotgun make more sense. At some point, we will see a new DI pump that flows way more fuel and we will look back on the days of PI and wonder why it took so long.
It seems like batch firing PI injectors with poor controllers is a band-aid. At some point, someone will make a high flowing DI pump and it will be all controlled off the stock DME with a flash tune.
 

V8bait

Sergeant
Nov 2, 2016
481
739
0
Texas
Back on topic- here is a screenshot of a log from someone I'm tuning. He's OEM turbo's with PI on full E85. Factory coils with 0.022" gap and we just got him to around 21psi (pretty much maxed factory TMAP). His HPFP is 1500psi or higher, LPFP is 70psi+, no timing corrections, fuel trims generally good without significant deviation, AFR is flat on all previous logs around 12.2:1 or so. Stock turbo car in great shape with ~30k miles it logs great.

With the higher boost on this map, he encountered a misfire. Half way through the pull, he got a code for Cylinder 2 misfire. It was during a datalog so this is a picture of what happens with a misfire with PI, with everything else running perfectly:

PI cylinder shutoff.png


You can see the initial misfires in bank 1 (housing cyl 2), circled. In a misfire, the air doesn't combust and shows as a lean spike. After a few of these, the car throws the code and goes into open loop, seen when fuel trims both go to zero. This causes an E85 car to run lean generally, as seen by both banks being much leaner than target in the 12's. But, since cyl 2 is shut off fully, you can see bank 1 is much leaner than bank 2. 14:1 vs 18:1, and cylinder 2 is likely MUCH leaner than that, since PI is still flowing.

Now is this dangerous? Doubtful for this car. Full E85 at that lean of a mix is probably not going to ignite to begin with, especially with lowly stock turbo's. But make this 28psi with hybrids, an E50 mix, or any other set of conditions and I would be a little worried about this. The PI makes the other 5 cylinders a little safer during the open loop event, but not the offending cylinder.

Any other ideas? I've seen this a few times. I do believe it has claimed at least 2 or 3 motors of those really pushing things, maybe more. I do not say this to scare people from PI... just the way I interpret the nuances of many logs I've seen. 98% of the time PI works great, it's a cheap and effective solution etc. Stay away from misfires and you're good.
 

TEC

Specialist
Jun 15, 2017
81
47
0
Ride
335i
Any other ideas? I've seen this a few times. I do believe it has claimed at least 2 or 3 motors of those really pushing things, maybe more. I do not say this to scare people from PI... just the way I interpret the nuances of many logs I've seen. 98% of the time PI works great, it's a cheap and effective solution etc. Stay away from misfires and you're good.

Do you think the source of the misfires is something that can be cleared up with a PR or BL coil upgrade or is it something inherent with the PI?
 
  • Like
Reactions: Speedman3

V8bait

Sergeant
Nov 2, 2016
481
739
0
Texas
Do you think the source of the misfires is something that can be cleared up with a PR or BL coil upgrade or is it something inherent with the PI?

In this case yeah, that or lowering the gap some. His PI is definitely not the issue, he's running a haltec in semi-sequential which is better than nearly everybody else with PI using the split second, with new injectors iirc, not the China refurb "Bosch" injectors ALL the companies pass off in their kits.

While PI is a little more misfire prone than DI in general, the DI in our cars is a common cause of misfires itself, so I'd say it's kinda a wash between them. DI only cars run even leaner in open loop like Andy said, but it's easier to tell that way and the highest danger cylinder is off. With PI, especially some brands that just flood you (JB4 PI), you might not be able to tell. I have mixed feelings on the topic I guess.
 

dyezak

Major
May 4, 2017
1,768
1,515
0
Plano TX
Ride
335is
I know Syvecs technically is selling a product that is in competition against an add-on PI kit so they have a financial benefit of pointing out the flaws, but @V8bait does not. The video above is Syvecs themselves talking about add on PI kits for Labo's and Porsche's who are also limited by their DI systems.
 

[email protected]

Lieutenant
Nov 5, 2016
596
606
55
Bay Area
But broskis! PI blew up my sweet N54 I just bought for $4500 with 125K on it. My friend (IG screename CraziBoiN54Tooner) tuned the car for me. He said I have plenty of Torques, and many much horsepowers, but because I ran PI my engine is blown. Now I have to go back to my civic to get back, and forth to community college.... Sad Face
 

DennisKing

Specialist
Nov 5, 2016
94
54
0
Portland, OR
Not sure how to take that Tony. It's like you're making excuses for PI instead of showing the merits of the Double Barrel.
I'm bought in to the Double Barrel idea.