Richest fuel mixture I've ever seen.

[ARChapman23]

Here's the deal; my car is running extremely rich right now, and I have no idea why. I did a 2.7i build in march and it ran well for a while, until it recently started misfiring when i would get on the throttle. I took the car out of commission and checked the spark plugs; they were fowled and the previous owner had put platinums in... I decided that I needed tuning.

-Replaced the spark plugs with OEM copper ones

-New OEM o2 sensor

-switched to a Miller MAF and WAR chip to accommodate for 19# injectors

-New ignition wires, cap and rotor (just because it was needed)

-I checked fuel pressure and I was at about 40-42ish psi when the car is running

I have the injectors out right now and it looks like the filters might be dirty, but why? they are practically brand new (rebuilt, flowtested, the works...) I was thinking that my fuel hoses might be disintegrating? I have 8 more rebuilt injectors that haven't been used that I could throw in, but I'm not sure if it will help.

Possible ideas:
- coolant readings have always been a little bit off since the rebuild, could my sensor be bad? and how does a faulty sensor make the car run rich (or lean?)?

-Miller tunes aren't right? Seems highly unlikely, but I am confused when I look at their P/T fuel tables... why are all of the values 128 for the entire RPM band? And why are the tables measured in rpm on one axis and load (ms) on the other as opposed to RPM and air pressure/flow, ect...like a MS or other standalone system? And what are the values in the table actually measuring? They tell you that higher value = more fuel, lower value = less fuel. Okay, but what am I actually changing? (I can't get in contact with miller anyways... )

-Injectors are clogged so that they are always open? Possible and seems the most likely at this stage...


I apologize for a long post, but I figure I would try to give as much info as possible in order to diagnose the problem. Thank you in advance for any help :)

TL;DR Car runs very rich. Using 19# injectors. new maf, tune, ignition system; yet still rich

[jlevie]

Are you claiming that it is running rich just from the plugs, or from wide band O2 sensor data on a dyno? The later is only valid data. You need full throttle and part throttle pulls to determine what is going on.

[ARChapman23]

I haven't even driven the car. This is just idle in my garage. plugs are practically drenched in gasoline.

EDIT: sorry, didn't understand your question at first. I know it is running rich because of the smell from the tailpipe, I don't have a wideband to tell exactly. its very obvious that it is running rich though.

[justrack]

It might be worth it to check the fpr to make sure its not dumping fuel through the vacuum reference line

[ARChapman23]

I swapped the FPR with one from an eta just to see if it would make a difference; no luck.

I know that the eta FPR has lower pressure, but it is still a useful test. I think my FPR is fine.

[SmokeE30]

if the car is having an ignition related misfire and is not burning the fuel it will make it smell like its running rich because of all the unburnt fuel. are you sure you have no ignition related issues

[ARChapman23]

I pulled ignition wires one by one and they all seemed to be working. all of them are getting spark as well. However, the exhaust note makes it sound like it is misfiring (not very smooth), it also sounds like it is running a 288 cam, but it has a stock cam.

It could be possible that when I installed the new cap/rotor and ignition wires I messed something up. I was triple checking which wire to what cylinder before i put them on, but I suppose I could have put wire cyl 4 on cap number 3... I'll go check.

[SmokeE30]

yea double check everything is in the right spot, ive mixed up wires before the enclosed loom makes it easy to not realize what is what

[ARChapman23]

MAF install


Difference between injector filters that I was using and new ones...
OLD


NEW (notice clean filters, haven't used these yet)


Looks like everything is hooked up properly!

[kamotors]

does the WAR chip have the correct tune on it?

[ARChapman23]

does the WAR chip have the correct tune on it?

War Chip is using the 19# 325i Gen3 MAF tune. I also tried a base 325i tune and the alpina 2.7 tune. I don't think that the tuning is the problem because the car was doing this before I got the WAR chip. I purchased the WAR chip to see if it would fix the richness, but it didn't. Seems like the problem is not tuning related.

[Click]

Possible ideas:
- coolant readings have always been a little bit off since the rebuild, could my sensor be bad? and how does a faulty sensor make the car run rich (or lean?)?

Could be the issue. Test it with an ohmmeter as per bentley.

[ARChapman23]

Tested the coolant temp sensor, its working. Replaced all the injectors and soft fuel lines. Spark plugs are all new. Ignition wires are new. everything I can think of has been replaced. Sounds like there are misfires when I start the car. Not sure if it's because of the rich mixture or if its timing related. Leaning more towards fault in the tuning. No reason that the miller tune should be running this poorly though...

I'm puzzled.