running rich, fuel in oil.

[e30Rooster]

I have a 1986 325es with a 89 m20b25 with a myster-e head and a miller maf ( =*[ ) I was running the 274 cam and 19# ford injectors rebuilt and flow tested. the tune from miller was for a more aggressive cam #19 injectors, their maf, and a free flowing exhaust, so I assumed once I swapped out cams I wouldn't run as rich as I was ( not to rich, but enough to shoot a flame that you could see at night out of the exhaust every now and then.) I swapped in a more aggressive cam put it back together and now I'm running super rich, like white/blue ish pure fuel out of the exhaust rich. loss of power, fuel in my oil rich.


Things I've done.

Replaced 02
replaced plugs
replaced plug wires
replaced distributor and cap
replaced cps
replaced tps
checked to make sure my fuel return line is not clogged
check to make sure all wires are connected, clean, and undamaged
checked timing marks
check compression 155,160,160,160,160,155
replaced FPR (car now has a perfect idle)
replaced DME (car has now leaned out a little and runs better over all but is still way rich 5.6 mpg)

So I think I've narrowed it down to:
coolant temp sensor - ( stuck in pen/closed loop) will check resistance when I get home tomorrow 5/3
leaky injectors 19#- this is what I think it is because the oil is so saturated. Going to replace them with m50 green tops tomorrow 5/3
millers tune actually for 17# injectors or less even though it says 19#.


Does this sound about right? anything I'm missing?

[LJ851]

White/blue out the exhaust is oil.

Rich puts out dark grey/black smoke.

I highly recommend you invest in a wideband 02 meter so won't have to guess what your AFRs are.

[e30Rooster]

Its so rich its shooting out unburnt fuel that is white.

[LJ851]

Bad injector(s), and yes i saw you said they were just rebuilt.

[e30Rooster]

Bump, anyone else? What's supposed to happen when you remove the vaccume line from the fpr?

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[ttrousdell]

Bump, anyone else? What's supposed to happen when you remove the vaccume line from the fpr?

I would leave that. As the engine speed increases there is a greater vacuum being pulled in the intake system, so there is a greater vacuum being pulled on the diaphragm in the FPR. The port to the return line is more closed so fuel pressure goes up. At idle there is less vacuum and the spring pulls on the diaphragm more allowing more fuel to go to the return port and decrease rail pressure.

A bad FPR can cause you to run rich

#19s sound like much even with those mods. I had #17s in my stock m30 and she ran rich

[e30Rooster]

I would leave that. As the engine speed increases there is a greater vacuum being pulled in the intake system, so there is a greater vacuum being pulled on the diaphragm in the FPR. The port to the return line is more closed so fuel pressure goes up. At idle there is less vacuum and the spring pulls on the diaphragm more allowing more fuel to go to the return port and decrease rail pressure.

A bad FPR can cause you to run rich

#19s sound like much even with those mods. I had #17s in my stock m30 and she ran rich

Thanks, for the advice/solutions so far. I just got my rebuilt and flow tested m50 injectors today and I'm going to swap them out tomorrow, while also keeping the fuel rail hooked up and toggling the fuel pump to see if the injectors I have now are leaking.

I switched out my DME with another, The pure white unburnt fuel is now gone, and it's shooting out visibly less fuel with only about half the cloud of richness. I changed my oil( it came out like water and smelled like fuel and I also noticed it seem to have cleaned my engine like an engine flush =/... ), and decided on replacing the FPR because it's easy, it was one of the only things I haven't replaced, and I wanted the peace of mind. Turns out it fixed my idle issues and my car finally idles like it's supposed to with a cam. Also my oil is saturated again and I got 5.6mpg on that short drive. I'm hoping somehow with the m50 green injectors I won't run rich. Maybe millers tune for the #19 injectors, was with what they thought were 19's and it's actually not. Maybe they had unknown fuel pressure where they thought they were at 3.5 bar and were actually at 3 bar or less. There are so many possibilitys and I don't know enough, It's hard to diagnose car problems over the internet and millers customer support sucks dick.

[Kozworth]

well technically a bad fpr can make you run lean. If you remove the vacuum line to the fpr your rail fuel pressure should increase 5-10psi. The fpr works off of vacuum which is a slight assist in opening the diaphragm. If the diaphragm was leaky, you wouldn't notice a change whether it be vacuum controlled or not since its just leaking past the fpr. I guess in a sense if a fpr doesn't open it would raise fuel pressure and lower the afr. If the fpr was bad and it leaked past the fpr, then what would cause it to build rail pressure to the oem spec? nothing, since it isn't sealing, causing less fuel pressure and a possibility to be leaner.

And at idle there is more vacuum usually 18-20 ish hg. When you are under load, there is less vacuum. Think about it, if you remove a small vacuum line, you create a vacuum leak. The computer thinks that more air is entering so it increases fuel, thus raising the RPM. The way the fpr works is that with higher rpm, there is less vacuum. Since the vacuum nipple to the fpr assists the fpr to open, less vacuum with increasing rpm allows a richer mixture. This is necessary to feed more fuel in the higher rpms, until when your WOT there is nearly no vacuum and this increases the fuel pressure <5-10 psi

[e30Rooster]

Ohmed out my harness and injectors. Then I checked the voltage on the miller maf and it's off spec. So I packed it up and shipped it to them to be repaired.

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[Sirotto]

This is all wrong,

No unburnt fuel will ever come out white. If you have white, you have coolant.

[e30Rooster]

This is all wrong,

No unburnt fuel will ever come out white. If you have white, you have coolant.

Already solved my UN burnt fuel issue, it was white because I was running on 3 cylinders I had a bad ecu (injector driver failure), now I'm waiting on miller to inspect my maf and chip to eliminate that part of the issue and I should be good to go.

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[Slicktop_serg]

Try that coolant temp sensor once i changed mines my MPG sky rocketed

[e30Rooster]

Got my shit back from miller with a good tune. Threw it together and it runs better but is still 7mpg rich, so tomorrow I'm going to pull out the fuel rail with injectors attached and toggle the fuel pump to see if they are leaking or not. Switch them out with some other 19# that my neighbor has and if that doesn't work I'm stumped and ill have to pay the pros to diagnose my car.

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[Vtec?lol]

Regardless of cam, your chamber is the same size and 19's are too much. I would run stock injectors unless you're strokin or boosting.

You're more than likely going to end up with cylinder wall damage with all that fuel washing past your rings. That being said, one of those injectors may be leaking.

[dnguyen1963]

What's with the fascination of using 19# injectors in stock E30? It does not improve anything and you just have fuel related problems. Put back your stock injectors and be happy. If you want to go 19# then mod your car so that it can handle the extra fuel capacity.