rough idle and black smoke only when warmed up

[onthefly]

K guys and gals i have me a chipped 85 325e all the upgrading is in suspension nothing done to the motor except a chip and cold air any ways car ran great for the past year then one day it just dropped all power under 2000rpm's and it onley does it about 10 minuts into driving it and it starts blowing black smoke so any help would be greatly appreciated ive already replaced all the hoses and vac lines so im pretty sure thats not the problem and my maf is fine and ive also replaced all sensors any ideas out there? Im stumped

[timninja]

You might have a bad piston ring,and it starts to seal better after you warm up because under heat piston rings are meant to expand and seal.
But thats what ussaly comes to my mind when I see black smoke from any motor.

[dnguyen1963]

Check your fuel pressure regulator. It might be responsible for dumping too much fuel into the cylinders. Does your exhaust smell like gasoline?

[onthefly]

Thanx guys but as far as the piston ring the problome onley happens after the car has been running for about 10 minuts then it just boggs down and has no power in the lower rpms as soon as i get it up around 2500 to 3000 rpms it runs nice and strong its just getting it to that range thats the issue lol

[JCarp90]

Sounds like it's running rich. Check your fuel pressure.

[onthefly]

Ya running way rich im gonna dive into it today check fuel pressure regulator and all that good jazz i also found a way suspect fuel pump relay lol it was nasty but the car runs great for the first 10 minutes or so the when it warms up it just boggs down hella could that be pressure related? Im stumped guys

[dnguyen1963]

Tee a pressure gauge to the fuel rail to monitor the fuel pressure. Check to see if the pressure drops when the car bogs down.

[onthefly]

Good advice man im gonna try the pressure i messed around with icv it is running a little better but not much step 1 find a pressure gauge and a tee splice im gonna get on the search

[onthefly]

Ok just throwin this out there but if it was a fuel pressure issue wouldn't that effect it from the second it start? Or wouldn't it not start at all? Im confused because it starts and runs awsome for like 10 minuts and then it just drops all power unless i can get it above 2000rpm's. I know im running rich as well it just seems like i might have 2 separate problems going on.......i dont know i'm just trouble shooting at this point

[onthefly]

Well now its back firing through the intake maifold and the other problems are still there. I haven't got around to checking the fuel pressure but i did change the fuel filter it was shot but still no change

[dnguyen1963]

Remove the vacuum hose from the FPR to check for fuel. If present, the FPR is dead. Take out you plugs to see if it is wet with fuel. The injectors would be next on the list. But, please check the fuel pressure before you go any further. While you're at it, check all of your fuel lines...small cracks might be ok until the engine warms up then sudddenly you lose the fuel pressure.

[onthefly]

Good call thats rite where i was going with it so hears a question any body know anything about the after market fpr's with the gauges on em are they worth the extra loot or should i just keep it bosh? .....any ways thanx for everything guys i do appreciate all the advice i have replaced all the fuel lines and vacuum lines the one on the fpr reeked of gas so i guess as soon as i get one I'll replace it

[onthefly]

Thanx for everything guys i really appreciate all the tips i changed all fuel and vacuum lines the one on the fpr reeked like fuel so im hoping that along with everything else i have done will fix my problem now hears one more question after market fpr with a gauge or og bosh? Is it worth the little extra to get the adjustable one with a gauge?

[TurboJake]

Is it worth the little extra to get the adjustable one with a gauge?

No.

[onthefly]

Aaahhhhhhhhhhh!!!!! Grrrrrrrrr!!!!! So apparently this is a very common problem with no set solution a hole lot of the same discussions all over the net with no one saying "o that worked thanx" lol guess its just time for a full on rebuild